Patent ID: 12237822

DETAILED DESCRIPTION

FIG.1Ais a simplified block diagram of duplex signal transceiver architecture10according to various embodiments. As shown inFIG.1A, architecture10includes a power amplifier module (PA)12, signal duplexer module20, radio frequency (RF) switch module40, low noise amplifier (LNA) module14, mixer module60A, and RF signal antenna50. In operation a signal8to be transmitted on the antenna50may be amplified via the PA module12, filtered by the duplexer module20, and coupled to the antenna50via the RF switch module40. In a duplex signal architecture a received signal on the antenna50may be simultaneously processed the duplexer module20. The resultant receive signal24may be amplified by the LNA module14and down-mixed to a baseband signal60C via the mixer module60A and a reference frequency signal60B.

FIG.1Bis a simplified diagram of an RF channel configuration70A according to various embodiments. As shown inFIG.1B, a transmit (TX) band73A and a receive (RX) band73B may be located in close frequency proximity. The TX band may have a width defined by72A,72B (start and end of the TX band), the RX band may have a width defined by72C.72D (start and end of the RX band), and the frequency separation between the bands may be the difference between72C and72B (start of the RX band and end of the TX band). The TX band73A and the RX band73B may include a plurality of sub-bands or units74A,74B,74C and75A,75B, and75C as shown inFIGS.1C to1G.

At the antenna50the TX band signal energy73A may be greater than the RX band signal energy as shown inFIGS.1B to1G. Such a differential in signal energy may saturate the LNA module14and occlude the RX signal24in duplexed signal architecture10. The duplexer module20may include one or more filters (shown inFIG.2F) to limit interference of TX and RX signals in the TX and RX bands73A,73B. The combined TX and RX signal42may be communicated according to one or more communication protocol or standards including Code Division Multiple Access (“CDMA”), Wide Band Code Division Multiple Access (“W-CDMA”), Worldwide Interoperability for Microwave Access (“WIMAX”), Global System for Mobile Communications (“GSM”), Enhanced Data Rates for GSM Evolution (EDGE), and other radio communication standards or protocols. Such standards or protocols may provide minimum signal separation or interference mitigation requirements for communication of signals on the respective networks via an antenna50.

The PA module12may also introduce noise or interface due to its fall off in power about the TX band to be amplified. The excess PA power may interfere with the LNA module14operation. A blocker signal near the TX, RX bands73A,73B or between same present on the antenna50(may be due to other signals in the communication network) may also interfere with the LNA module14operation and cause loss in the RX signal24.

Duplex systems or architecture10may employ filter modules including duplexer modules. The duplexer modules may include known filter elements such as resistors, capacitors, inductors, digital signal processors (DSPs), and resonators. Configurations of these components may form filter modules to attempt to meet or exceed adjacent channel or band interface requirements according to one or more communication protocols or standards. In an embodiment, the channel configuration70A may be used for a CDMA band five (V) signals where the TX band73A extends from 824 to 849 MHz (72A,72B) and the RX band73B extends from 869 to 894 MHZ (72C,72D). In this configuration, The TX band73A and RX band73B are 25 MHz in width and separated by 20 MHz (72C minus72B). As shown inFIGS.1C to1G, the TX band73A may include a plurality of sub-bands74A,74B.74C and the RX band73B may including a plurality of sub-bands75A.75B,75C. In an embodiment, the sub-bands may be about 1.5 MHZ wide (CDMA) and 5 MHz wide (W-CDMA).

In order to limit interface between adjacent bands, a filter module having a frequency characteristic76A as shown inFIG.1Dmay be applied to the TX band73A. Similarly, a filter module having a frequency characteristic76B as shown inFIG.1Emay be applied to the RX band73B. As shown inFIGS.1D and1Ethe filter characteristics76A,76B ideally have a large dB rollout on either side of the communicated band (pass-band). The capacitors, inductors, and resistors required for such filter characteristics may be large and consume significant real estate when constructed on a dielectric wafer as known to those of skill in the art. One or more resonators may be employed to attempt to achieve a TX or RX signal42filter characteristic76A.76B.

Resonators may include surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices. Such devices may be used in filters, oscillators and transformers and commonly cause the transduction of acoustic waves. In SAW and BAW, electrical energy is transduced to mechanical energy and back to electrical energy via piezoelectric materials. The piezoelectric materials may include quartz, lithium niobate, lithium tantalate, and lanthanum gallium silicate. One or more transverse fingers of conductive elements may be placed in the piezoelectric materials to convert electrical energy to mechanical energy and back to electrical energy. The SAW or resonator may include one or more one or more interdigital transducers (IDTs) (transverse fingers of electrical conductive elements) for such energy conversions or transductions. A resonator construction and material requirements may be more complex and expensive for electrical signals having high frequency content such as signals transmitted according to one or more RF communication protocols or standards.

It may be desirable for a filter or duplexer module20to generate frequency characteristics76C.76D specific to one or more sub-unit or bands of a TX or RX band73A,73B such as shown inFIGS.1F,1G. Such duplexer modules20or filter modules may significantly suppress interface between TX and RX bands73A,73B and may be required for some communication protocols. In order to filter one or more sub-units74A,74B,74C,75A,75B,75C of a band73A,73B or different bands selectively (such as band I to V in a CDMA system), separate filters modules or duplexers may be required.

FIG.2Ais a block diagram of an electrical signal filter module90A including resonators according to various embodiments. The module90A includes three resonators80A,80B, and80C, resistors94A,94B, and a signal generator92A. In an embodiment, the signal generator92A may represent a TX signal to be communicated via an antenna50, the resistor94A may represent the load of the TX signal, and the resistor94B may represent the load of an antenna50. In an embodiment, the resonators80A,80B,80C form a T-shape between the signal to be transmitted and the antenna (source load94A and antenna load94B). The resonators80A,80B,80C may be SAW devices. A resonator80A,80B,80C commonly has a fixed resonate frequency and anti-resonate frequency similar to a pass band and stop band of a common inductor-capacitor type filter.

An acoustic wave resonator80A,80B,80C may be represented by corresponding electrical components according to various embodiments such as shown inFIG.2B. As shown inFIG.2B, a resonator80A may be represented by a first capacitor82A in parallel with a series coupling of an inductor86A, a second capacitor82B, and a resistor84A where the capacitors82A,82B may have a capacitance of Co, Cm, respectively, inductor86A may have an inductance of Lm and the resistor84A may have a resistance of Rm in an embodiment. Modeling of resonators or SAW devices via electrical components is described in the reference entitled “Surface Acoustic Wave Devices in Telecommunications: Modeling and Simulation” by Ken-Ya Hashimoto, published by Springer on Jul. 31, 2000, ISBN-10: 354067232X and ISBN-13:978-3540672326.

The Cm and Lm may be related to the elasticity and inertia of an AW device80A,80B,80C. Co may represent the effective capacitance of the transverse electric fingers in the piezoelectric material of the AW80A,80B,80C. Rm may represent the heat generated by mechanical motion in the AW80A,80B,80C (the effective quality or Q limiter of the AW). Using the values Co, Cm, Lm, and Rm for first capacitor82A, inductor86A, second capacitor82B, and resistor84A, the resonance wrand the anti-resonance waof an acoustic wave (AW) device80A may be defined by the following equations:

wr≡1Lm⁢Cm⁢and⁢wa≡1Lm⁢Cm⁢Co/(Cm+Co).

Using these equations AW80C may form a short path and the resultant filter formed by the AW80A, AW80B, and AW80C may have a pass band about the wrof80A,80B and waof80C (77C as shown inFIG.1D), a first notch before the pass band at wrof80C (77A inFIG.1D), and a second notch after the pass band at waof80A,80B (77B inFIG.1D). These resonators AW80A,80B,80C resonate and anti-resonate values wrand waare fixed as a function of the physical characteristics of the AW80A,80B,80C.

It may be desirable to shift the wrand waof AW80A,80B,80C to shift the pass-band or stop-bands to tune to specific sub-bands74A,74B,74C,75A,75B,75C or different TX or RX bands73A,73B. It is also noted that the wrand waof AW80A,80B,80C may vary as a function of the temperature of the AW, respectively. In such an embodiment it may be desired to correct for temperature variations accordingly. It is also noted that the wrand waof AW80A,80B,80C may vary due to manufacturing variances, respectively. In such an embodiment it may be desirable to correct for manufacturing variances accordingly. In an embodiment various capacitors98A may be coupled in parallel or serially with a AW80A,80B,80C to be able to shift, tune, or modulate the wror waof the AW80A,80B,80C and accordingly its pass-band and stop-band(s).

FIGS.2C and21are block diagrams of modulated or tunable resonator modules96A,96G according to various embodiments. The module96A shown inFIG.2Cmay include a variable capacitor98A in parallel with an AW80A. Based on the above equations, the anti-resonate wamay be modulated by the variable capacitor98A having a capacitance Cv(effective Co of an AW may be Co+Cvfor module96A). The module96G shown inFIG.2Imay include a variable capacitor98G in parallel with an AW80G and a variable capacitor98H in series with the AW80G. Based on the above equations, the anti-resonate wamay be modulated by the variable capacitor98G having a capacitance Cv1and the variable capacitor98H having a capacitance Cv2. Similarly, the resonate wrmay be modulated by the variable capacitor98H having the capacitance Cv2.

FIG.2Dis a block diagram of an electrical signal filter module90B including tunable or modulated resonator modules96A.96B,96C according to various embodiments. The module90B is similar to module90A shown inFIG.2Ain that it includes three resonators80A,80B, and80C in a similar T-configuration where the resonators80A,80B,80C have a fixed resonate frequency and anti-resonate frequency similar to a pass band and stop band of a common inductor-capacitor type filter where the anti-resonate frequency for each resonator80A,80B,80C is modulated or tuned by a variable capacitor98A,98B,98C.

As noted above AW80C may form a short path and the resultant filter formed by the AW80A, AW80B, and AW80C may have a pass band about the wrof80A,80B and waof80C (77C as shown inFIG.1D), a first notch before the pass band at wrof80C (77A inFIG.1D), and a second notch after the pass band at waof80A,80B (77B inFIG.1D). By varying the capacitors98A,98B,98C, the pass band77C and second notch77B shown inFIG.1Dmay be varied.

FIGS.2E-Hare block diagrams of tunable filter modules including tunable or modulated resonators or AW that may be employed for various operations including filtering an RX band73B or sub-band75A,75B,75C in an embodiment. As shown inFIG.2Ethe tunable filter module90C may include tunable resonate or AW modules96D,96E,96F, and96G, resistor94C, and resistor94B. Similar to above, resistor94B may represent the antenna50load and resistor94C may represent a signal (RX or TX) load. In an embodiment, the module90C may include two tunable shorts96G and96F and two tunable pass AW modules96D,96E in series. Module90C is similar to module90A (T-configuration) with the addition of a second short96G that includes a capacitor98G designed to effect the anti-resonate frequency and a second tunable capacitor98H in series with the AW80G to further effect the resonate frequency of the AW80G.

FIG.2Fis a block diagram of an electrical signal filter module90D including a first tunable filter module95A and a second tunable filter module95B according to various embodiments. The module90D includes a first filter module95B, a second filter module95B, a first signal source92A and a resistor load94A, a second signal source92B and resistor load94C, and antenna load resistor94B. Module95A is similar to module90B and module95B is similar to module90C where module95A is a T-configuration module and module95B is a modified T-configuration with a second short (with a series tunable capacitor98H). In an embodiment, the module90D may be employed as a tunable duplexer20inFIG.1A.

FIGS.2G,2H,2Jare block diagrams of tunable filter modules95C,95D,95E including tunable or modulated resonators or AW that may be employed for various operations including filtering a RX band73B or sub-band75A,75B.75C in an embodiment. As shown inFIG.2Gthe tunable filter module90E may include tunable resonate or AW modules96D,96G,96F, resistor94C, resistor94B, and effective capacitance97A,97B. Similar to above, resistor94B may represent the antenna50load and resistor94C may represent a signal (RX or TX) load and92B a signal source. In an embodiment, the module90E may include two shorts96G and96F and a single tunable AW module96D in series with the loads94C.94B. Module90E is similar to module90D with the elimination of the second module96E in series with the first module96D.

As shown inFIG.2Hthe tunable filter module90F may include tunable resonate or AW modules96D,96G,96F,96H, tunable capacitor98H, resistor94C, resistor94B, and effective capacitance97A,97B. Similar to above, resistor94B may represent the antenna50load and resistor94C may represent a signal (RX or TX) load and92B a signal source. In an embodiment, the module90F may include three tunable shorts96G,96F, and96H and a single tunable AW module96D in series with the loads94C,94B. Module90F is similar to module90F with the addition of a third short module96H.

As shown inFIG.2Jthe tunable filter module95E may include tunable resonate AW modules96B,96F, and a plurality of AW modules80A,80C,80D,80E,80G,80H,80I. In the filter module95E, tunable resonate AW modules96B,96F, and a plurality of AW modules80A,80C,80D,80E,80G,80H,80I form a series of “T” sub-filters such as80A,96B, and80C. As explained above each T sub-filter may create a frequency response with two passband (AW80A,96B) and a stopband (80C). In the embodiment one or more AW80A to80I may not be tunable (AW modules80A,80C,80D,80E,80G,80H,80I inFIG.2J) while one or more AW80A to80I may be tunable (80B and80F inFIG.2J). A tunable capacitor98B,98F may be coupled (in parallel) to an AW80A to80I when one or more AW80A to80I may be desirably tunable to modulate the AW80A to80I for temperature or process variations or provide frequency adjustments to the AW80A to80I.

FIG.3A-3Care diagrams of capacitor modules according to various embodiments where the modules may be used as capacitors98A to98G (in parallel to an AW80A to80F) and98H (in series with an AW80G). As shown inFIG.3C, the module120C includes a single capacitor104A. The capacitor104A capacitance may be determined after the physical characteristics of an AW80A to80G are measured (to account for process variations or operating temperature variance). The capacitor104A capacitance may also be varied for different TX or RX bands73A,73B to be filtered by the module96A to96G including the module120C.

As shown inFIG.3B, the module120B includes the capacitor104A and a second capacitor104B and resistor106A parallel to the first capacitor104A. The additional capacitor104B may further shift the AW80A to80G anti-resonate or resonate frequency to tune to a second band or sub-band. As shown inFIG.3A, the module120A includes the capacitor104A, the second capacitor104B and a resistor106A parallel to the first capacitor104A, and a third capacitor104C and a second resistor106B parallel to the first capacitor104A (and second capacitor104B and resistor106A). The additional capacitor104C may still further shift the AW80A to80G anti-resonate or resonate frequency to tune to a third band or sub-band when the modules120A to120D are employed in parallel or series with a AW80A to80G as shown in modules96A to96G.

FIG.3Dis a diagram of a tunable capacitance module according to various embodiments. As shown inFIG.3D, the module120D includes the capacitor104A, the second capacitor104B and resistor106A selectively parallel (via a switch105A) to the first capacitor104A, and a third capacitor104C and a second resistor106B selectively parallel (via the second switch105B) to the first capacitor104A (and second capacitor104B and resistor106A). The module120D may shift the AW80A to80H anti-resonate or resonate frequency to tune to a first, second, or third band or sub-band as a function of the switches105B.105A when coupled in parallel or series with the AW80A to80H as shown in modules96A to96G. The module120D may also shift an AW80A to80H anti-resonate or resonate frequency to account for temperature or manufacturing variants.

FIG.3Eis a diagram of a tunable capacitor module600according to various embodiments. The tunable capacitor module600includes a plurality of capacitor banks602, each switchable in operation via control lines640,642, and644. In an embodiment each successive capacitor bank has twice the capacitance of the previous bank602so that each control line640,642, and644is a digit of a binary number. In an embodiment, the capacitor banks are formed of CMOS FETs having their source and drain coupled via a resistor RDSto effectively form capacitors in parallel. Each gate of the CMOS FETs606,608,610,612,614is coupled to the respective control lines640,642,644. Accordingly a tunable AW module96A to96G using the tunable capacitor600(in series or parallel) may have N2−1 (where N is the number of control lines) different tunable anti-resonance or resonate frequencies based on the N2−1 effective capacitances of the module600. Further details of digitally tunable capacitors are recited in commonly assigned PCT application entitled “METHOD AND APPARATUS FOR USE IN DIGITALLY TUNING A CAPACITOR IN AN INTEGRATED CIRCUIT DEVICE”, Filed Mar. 2, 2009, and International Application Number PCT/US2009/001358, the entire contents of which are hereby incorporated herein by reference.

FIG.4is a block diagram of a configuration of a tunable filter module130including tunable resonators according to various embodiments. The filter module130may have a common circuit board or module132, a resonance or AW board or module150, and electrical component board or module140. The AW module150may include two or more resonators or AW80A,80B,80C.80I. In an embodiment, the AW80A,80B,80C may form the T-configuration90A shown inFIG.2A. The AW module150may further include a bias AW80I.

The electrical component board or module140may include three tunable capacitors98A,98B,98C, a control logic module146, and an oscillator144. Each tunable capacitor98A,98B,98C may be coupled in parallel to an AW80A,80B,80C, respectively via two conductance lines134between the modules140,150. Accordingly, the combination of an AW80A and a tunable capacitor98A may form a tunable AW module96A as shown inFIG.2B. The oscillator144may be coupled to the bias AW80I via a conductance line134. The effective resonate frequency of the bias AW80I may modulate the oscillation of the oscillator144in a known and measurable way.

The control logic module146may receive control signals SPI for controlling the capacitance of tunable capacitors98A,98B, and98C and a stable clock or reference frequency (such a phase lock loop signal). In an embodiment, the AW80I resonate or anti-resonate frequencies may vary as function of temperature. Similarly the oscillator144frequency may vary as the AW80I resonate or anti-resonate frequencies fluctuate with temperature. The control logic146may monitor the change of oscillator frequency144via the stable reference frequency signal. The control logic146may then modulate the tunable capacitor's capacitance based on known deltas to account for the oscillator frequency and thereby corresponding AW80A,80B,80C resonate or anti-resonate frequencies. In an embodiment, the delta may be added to the SPI control signals as needed to adjust for temperature effects of the AW80A.80B,80C.

FIG.5Ais a block diagram of an electrical signal filter module190A including switchable resonator modules (SRM) according to various embodiments. The module190A includes three switchable resonators modules (SRM)180A,180B, and180C, resistors94A,94B, and a signal generator92A. In an embodiment, the signal generator92A may represent a TX signal to be communicated via an antenna50, the resistor94A may represent the load of the TX signal, and the resistor94B may represent the load of an antenna50. In an embodiment, the switchable resonators modules (SRM)180A,180B,180C may form a T-shape between the signal to be transmitted and the antenna (source load94A and antenna load94B). The switchable resonators modules (SRM)180A,180B,180C may include one or more resonator devices or modules where one or more of the modules may include switchable resonators. The one or more resonators may have a fixed resonate frequency and anti-resonate frequency similar to a pass band and stop band of a common inductor-capacitor type filter.

FIG.5B to5Dare block diagrams of SRM184A to184C according to various embodiments. As shown inFIGS.5B to5D, a resonator module184A,184B,184C may include several (acoustic wave) resonators82A to82N where the resonators82A to82N may be bypassed or activated via one or more switches182A to182N.

InFIG.5Ba switchable resonator module (SRM)184A may include two resonators82A,82B, and two switches182A,182B. The resonators82A,82B are coupled in series. A switch182A,182B may be coupled in parallel to resonator82A,82B, respectively. When a switch182A,182B is closed, the corresponding resonator82A,82B may be bypassed and inoperative. When a switch182A,182B is open, the corresponding resonator82A,82B may be active. In an embodiment each switch182A,182B may be controlled by a control signal S1A, S1B. In an embodiment, resonator82A and82B may operate exclusively or in tandem as a function of the control signals S1A, S1B. In a further embodiment a single signal may control the switches182A,182B where in a first signal state switch182A is open and switch182B is closed and in a second signal state switch182A is closed and switch182B is open.

InFIG.5Cthe switchable resonator module (SRM)184B includes three resonators82A,82B,82C and three switches182A,182B, and182C. The resonators82A,82B,82C are coupled in series. A switch182A,182B,182C may be coupled in parallel to a resonator82A,82B,82C, respectively. When a switch182A,182B,182C is closed the corresponding resonator82A,82B,82C may be bypassed and inoperative. Conversely when a switch182A,182B,182C is open, the corresponding resonator82A,82B,82C may be active. Each switch182A,182B,182C may be controlled by an independent control signal S1A, S1B, S1C. In an embodiment, resonators82A,82B, and82C may operate exclusively or in various combinations as a function of the control signals S1A, S1B, S1C.

InFIG.5Dthe switchable resonator module (SRM)184C includes a plurality of resonators82A to82N and corresponding switches182A to182N. The resonators82A to82N may be coupled in series. A switch182A to182N may be coupled in parallel to each resonator82A to82N, respectively. When a switch182A to182N is closed the corresponding resonator82A to82N may be bypassed and inoperative. Similarly, when a switch182A to182N is open the corresponding resonator82A to82N may be active. Each switch182A to182N may be controlled by a control signal S1A to S1N. In an embodiment, the resonators82A,82B, and82C may operate exclusively or in various combinations as a function of the control signals S1A to S1N.

FIG.5Eis a block diagram of a modulated or tunable resonator module system190B according to various embodiments. The tunable resonator module system190B includes several tunable resonator modules196A,196B,196C, forming a T configuration similar toFIG.5A. Each tunable resonator module196A,196B,196C may include a variable capacitor98A,98B,98C coupled in parallel with a SRM184D,184E,184F. In each tunable modulator196A,196B,196C, the variable capacitor98A,98B,98C may modulate the anti-resonant frequency waof corresponding active resonators82A to82N,83A to83N, and84A to84N based on the capacitor's selected capacitance Cv(effective capacitance Ce of an AW device may be equal to Co+Cvfor a module196A). In an embodiment, the variable capacitor98A,98B,98C may module the anti-resonate wafor each resonator82A to82N,83A to83N, and84A to84N not bypassed by switches182A to182N,183A to183B, and185A to185N where the switches are controlled by switch control signals S1A to S1N, S2A to S2N, and S3A to S3N.

In an embodiment each resonator82A to82N,83A to83N, and84A to84N may have a different resonance in each respective SRM184D,184E, and184F. The different resonances of the SRM184D,184E, and184F may enable a system190B to tune to different channels (different resonance frequencies) as shown inFIGS.6A to6Ffor frequency responses197A to197F. In an embodiment, the variable capacitor98A and98B in parallel with the SRM184D,184E may only module or tune the anti-resonate waof the active resonators82A to82N,83A to83N respectively. By selectively bypassing resonators82A to82N and83A to83N in the SRM184D,184E, the resonate frequency or effective pass-bands of the system190B may be tuned in addition to the stop bands.

In an embodiment control signals S×N in each corresponding SRM184D,184E,184F may be similarly opened or closed, e.g., control signals182A,183A, and185A may be simultaneously opened or closed (coordinated between modules184D,184E,184F). In a further embodiment the only one switch182A to182N,183A to183N,185A, to185N may be open at any time so only one resonator82A to82N,83A to83N,84A, to84N is active at any time. In an embodiment, the variable capacitor98C in parallel with the SRM184F may only module or tune the anti-resonate waof the active resonators82A to82N,83A to83N respectively. By selectively bypassing resonators84A to84N, the anti-resonate frequency or effective pass-bands of the SRM196C may be tuned in addition to the stop bands.

FIG.5Fis similar toFIG.5Eexcept the tunable module196C is replaced by the module96G described with respect toFIGS.2E and2I. The module96G may include a variable capacitor98G in parallel with an AW80G and a variable capacitor98H in series with the AW80G. Accordingly, the anti-resonate waof96G may be modulated by the variable capacitor98G having a capacitance Cv1and the variable capacitor98H having a capacitance Cv2. Similarly, the resonate wrmay be modulated by the variable capacitor98H having the capacitance Cv2. Capacitor98H may be subject to high voltages.

FIG.5Gis a block diagram of a modulated filter system190C similar toFIG.2Dwhere the tunable resonators96A,96B,96C may be further tuned by series coupled variable capacitors98I,98J,98H. The variable capacitors981and98J may modulate or tune the resonate frequencies of the resonators80A,80B, respectively. Such modulation may enable the system190C to tune different pass-bands and stop-bands as a function of the tunable capacitors98A,98B,98C,98I,98J, and98H. The tunable capacitors981,98J in series with the resonators80A,80B may be subject to significant voltages, requiring the capacitors to be large. It is noted any resonator80A to80H shown inFIG.2A to2Hmay be replaced by a SRM184A,184B, or184C such as shown inFIG.5B to5D.

In an embodiment it may be desirable to increase the isolation and stop-band rejection of a filter module.FIG.7Ais a block diagram of a filter module202A according to various embodiments. The filter module202A includes an inductor204A and capacitor206A in series coupled in parallel to another inductor204B and capacitor206B in series. The inductors204A,204B may have an inductance L1, L2and the capacitors206A,206B may have a capacitance C1, C2. The filter module202A may have two pass bands at w1and w2surrounding a rejection point at wt. The rejection point may be limited by the quality, Q of the filter module202A. In the filter module202A the pass bands may be determined by the equations:

w1≡1L1⁢C1⁢and⁢w2≡1L2⁢C2.
The impedance of the filter module202A may be determined by the equation

zt(s)=Lts×2⁢(s2-s12)⁢(s2-s22)s2-st2
where

s1=jw1,s2=jw2,st2=(L1⁢s12+L2⁢s22L1+L2),
and

Lt=L1⁢◦L2L1+L2.

As noted with reference toFIG.2B, an AW80A may include an inductor86A in series with a capacitor82B with an inductance Lm and capacitance Cm, respectively. The resistor84A and capacitor82A may be nominal as a function of the inductor86A and capacitor82B. Accordingly, In an embodiment, the filter module202A may be represented by the parallel coupling of an AW214A,214B (the filter module212A shownFIG.7B). In this embodiment the acoustic wave module214A may represent the inductor204A and capacitor206A and the AW module214B may represent the inductor204B and capacitor206B of filter module202A.

The elasticity and inertia of an AW214A,214B may be configured or selected to have an equivalent Lm about L1or L2and Cm about C1and C2in an embodiment. In AW214A,214B, the parallel capacitance Co may represent the effective capacitance of the transverse electric fingers in the piezoelectric material and the resistance Rm may represent the heat generated by mechanical motion in the AW214A,214B (the effective quality or Q limiter of the AW). As a function of the signals to be filtered the pass bands and effective stop band between the pass bands w1and w2may need to be shifted or changed.

In an embodiment two or more inductor-capacitor filter modules (LCF)202A,202B, in series with a low resistive switch205A,205B may be coupled in parallel as shownFIG.8A, filter module208A. The switches205A,205B may include one or more CMOS or MOSFET devices that have a low resistance when closed (as a function of a control signal S1A, S1B). In an embodiment, the LCF202A may have a first desired pass-band and stop-band and the LCF202B may have a second desired pass-band and stop-band. Via the control signals S1A, S2A a signal may be processed by either the LCF202A or the LCF202B of the filter module208A. Because the modules202A,202B are placed in parallel the operative signal path will only include the resistance of a single switch205A,205B, thus increasing the quality of the filter module202A,202B and its effective rejection strength (of its stop-band).

In an embodiment it may be desirable to process signals with larger voltage or limit circuit elements. The LCF202A,202B of filter module208A may be replaced by acoustic wave filters (AWF)212A,212B as shown inFIG.8B, filter module222. Each AWF212A,212B may include two or more AW modules214A,214B coupled in parallel as shown inFIG.7B. As noted and shown inFIG.8Ca variable capacitor218A may be coupled in parallel in with AW device(s) or module(s) to provide adjustments for process variations in the AW device(s) or module(s) variations due to temperature, and enable shifting of pass-band or stop-bands of the device(s). As shown in the filter module224ofFIG.8C, a variable capacitor218A may also be placed in parallel with one or more AWF212A,212B. In filter module224, the capacitor218A capacitance may be varied as a function of the switch216A,216B control signals S1A, S1B to modulate the AWF212A or the AWF212B.

FIG.9Bis a block diagram of filter module230A according to various embodiments. The filter module230A may include a first capacitive-tunable, parallel switched AW module filter232A, a second capacitive-tunable, parallel switched AW module filter232B, a first capacitive-tunable parallel switched AWF module filter224A, a capacitive-tunable AW module234A, and impedance inversion modules228A,228B. The module232A may be coupled to the module232B via the inversion module228A and the module232B may be coupled to the module224A via the inversion module228B. The module234A may be coupled to ground and the module232A.

In an embodiment, the first capacitive-tunable, parallel switched AW module filter232A may include AW modules214A,214B, switches216A,216B, and variable capacitor218A. AW module214A is series coupled to switch216A and AW module214B is series coupled to switch216B. Each module, switch pair214A,216A,214B,216B is coupled in parallel to the variable capacitor218A. Similarly, the second capacitive-tunable, parallel switched AW module filter232B may include AW modules214C,214D, switches216C,216D, and a variable capacitor218B. AW module214C is series coupled to switch216C and AW module214D is series coupled to switch216D. Each module, switch pair214C,216C.214D,216D is coupled in parallel to the variable capacitor218B.

The capacitive-tunable, parallel switched AWF module filter224A may include AWF modules212A,212B, switches216E,216F, and variable capacitor218C. AWF module212A is series coupled to switch216E and AWF module212B is series coupled to switch216F. Each module, switch pair212A,216E,212B,216F is coupled in parallel to the variable capacitor218C. Each AWF module212A,212B includes two parallel coupled AW modules214C,214D and214E,214F, respectively. The capacitive-tunable AW module234A includes an AW module214G coupled in parallel to a variable capacitor218D.

In an embodiment, the inversion module228A,228B may be a K-filter228as shown inFIG.9A. The filter228includes two capacitors226A,226B in series with a third capacitor226C in parallel and between the series pair226A,226B. In an embodiment, the capacitors226A,226B have a capacitance of-C and the capacitor226C has a capacitance of +C. As shown in theFIG.9B, the capacitor226C of the inversion modules228A,228B is also coupled to ground.

In an embodiment, the module234A may provide a fixed high rejection and tunable pass-band, the modules232A,232B may provide a movable, switchable pass-band and tunable rejection band, and the module224A may provide a movable, switchable high rejection point and pass-band. The filter module230A ofFIG.9Bmay be employed to generate the frequency responses240A,240B shown inFIGS.10A,10Bwhere the control signals S1A, S1C, S1E may be active, inactive while the control signals S1B, SID, SIF may be inactive, active, respectively to shift the pass-bands and stop or rejection bands shown inFIGS.10A,10B(240A,240B). In an embodiment230B shown inFIG.9Cthe inversion modules228A,228B ofFIG.9Bmay be replaced by one or more capacitors226D.226E coupled to ground.

FIG.11is a diagram of filter frequency responses250according to various embodiments.FIG.11depicts a first frequency response258B and a second frequency response258A. In an embodiment a filter response258A,258B includes a passband261with a passband edge262and stopband263. Further a filter response258A,258B may have a maximum acceptable loss252in the passband area261(creating the passband edge262) and a minimum attenuation or rejection256in the stopband263. Further the minimum attenuation or rejection256in the stopband263may need to be achieved by a particular frequency254such a channel boundary or cutoff frequency. In an embodiment a filter mechanism or module such as resonator module292B ofFIG.13Bmay produce a first frequency response258B during ideal operation and fabrication conditions. The same filter module292B may generate the shifted frequency response258A due to non-ideal operation or fabrication conditions. In an embodiment, the frequency response shift from258B to258A may be due to temperature fluctuations and fabrication variations.

Given the potential filter module292B frequency response shift (from258B to258A), the passband261region or width of a signal processed by the filter module292B may be narrowed or reduced to ensure that the minimum required attenuation256is achieved by a required frequency254. The required frequency254may be the start of another channel and the filter module292B may be required to prevent signal leakage into adjacent channels. The distance between the channel boundary254and passband edge262is commonly termed the guard band of a filter or channel. In a system or architecture such as channel architecture310A,310B,310C shown inFIG.15A,15B,15Cthe guard band (316B inFIGS.15B and318BinFIG.15C) represents lost or unusable bandwidth. Accordingly it may be desirable to minimize the guard band316B,318B by reducing the effect of temperature and process or fabrication variations of filters or filter architectures that may be employed to limit or prevent signal leakage between adjacent channels (312A,314A, and312B).

FIG.12is a flow diagram of a filter configuration method270according to various embodiments. In the method270the maximum passband loss252may be selected where this loss level may be required or indicated (by a standard or other communication protocol establishment organization) (activity272). The filter response stopband minimum attenuation256needed to reduce or limit signal leakage into adjacent channels may be selected where the minimum attenuation may be required or indicated (by a standard or other communication protocol establishment organization) (activity274). Further the minimum stopband edge254for the minimum attenuation256may also be selected where the minimum stopband edge254may be required or indicated (by a standard or other communication protocol establishment organization) (activity276).

In the method270the minimum stopband edge254of a non-tunable filter292B may be pre-shifted to ensure the filter response258B when shifted due to temperature or process variations achieves the minimum attenuation256by the desired or required boundary or edge254(activity278). Further, the filter passband262edge may also be shifted, effectively reducing the usable signal bandwidth to ensure less than the maximum loss252is present in the passband (activity282). Accordingly the effective guard band316B,318B may be increased.

FIG.13Ais a simplified block diagram of a filtering architecture290A according to various embodiments. The filter architecture includes a filter292A coupled in series with a tunable filter294A. In an embodiment, the filter292A may have a desired frequency response shown as258A shown inFIG.11but be subject to temperature or process variations where the fixed filter292A frequency response may shift to the filter response300A shown inFIG.14A. Such a worst case frequency response302A may be unacceptable due to potential signal leakage beyond the desired channel or signal boundary254. The frequency response302A otherwise has stable passband and stopband304A.

The tunable filter294A may have a tunable frequency response such as module294B shown inFIG.13Bwhere temperature and process variations are corrected or modulated by an adjustable element such as a tunable capacitor218A. The tunable filter294A may have a frequency response300B inFIG.14B. As shown inFIG.14Bthe frequency response302B may achieve the desired or required maximum passband loss252with an edge262than is greater in frequency than the filter302A (when adjusted to account for potential shifts) and correspondingly a smaller needed guard band316B,318B. The filter response302B for tunable filter294A may also meet the minimum attenuation256by the frequency boundary254(point303B inFIG.14B). The tunable filter294A filter response302B may have a second, unacceptable passband304B within the adjacent channel305and thus be unacceptable as a single filter.

In an embodiment, the filter module292A,292B and tunable filter294A,294B,290A,290B respectively, in combination may create the frequency response300C shown inFIG.14C. As shown inFIG.14Cthe net frequency response300C may include the desirable stopband of filter294A, B without the subsequent passband304B due the filter292A, B stopband304A. Further, while the filter292A, B stopband edge303A may vary with temperature and process variations it is sufficient to suppress the filter294A, B undesirable second passband304B. The resultant frequency response300C may have an acceptable passband loss252and minimum stopband attenuation256by the desired boundary or frequency cutoff254without temperature and process variations.

FIG.13Bis a block diagram of a filter architecture290B including a modulated or tunable resonator module294B and a resonator module292B according to various embodiments. The resonator module292B may be a non-tunable filter that may be configured to a frequency response similar to frequency response300A shown inFIG.14A. The resonator module292B may include surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices where the device enables the transduction of acoustic waves. In an acoustic wave device electrical energy is transduced to mechanical energy back to electrical energy via piezoelectric materials. The piezoelectric materials may include quartz, lithium niobate, lithium tantalate, and lanthanum gallium silicate. One or more transverse fingers of conductive elements may be placed in the piezoelectric materials to convert electrical energy to mechanical energy and back to electrical energy.

In an embodiment, the tunable resonator294B may include one or more acoustic wave modules or devices214A,214B, and a tunable capacitor218A. The AW modules214A,214B, and tunable capacitor218A may be coupled in parallel in an embodiment as shown inFIG.13B. As noted this configuration may have two pass bands at w1and w2surrounding a rejection point at wt. The pass bands at w1and w2may correspond to filter response components302B and304B shown inFIG.14Band the rejection point at wtmay correspond to the component303B. The variable capacitor218A coupled in parallel with the AW modules214A,214B may tune or modulate the filter module294B frequency response300B to correct for temperature or process variations. Other resonator filters such as shown inFIGS.2A to2H,FIG.4,FIGS.5A to5G,FIGS.7B to8C, andFIGS.9B-9Cmay be employed in whole or part as a tunable resonator or filter294B.

The filter architecture290A may be modified such as shown inFIGS.16A,16B,16C, and16Dfor different filter requirements or parameters. As shown inFIG.16A, the filter architecture330A may include a switchable and tunable filter module334A. Such a module334A and resulting architecture (and switchable frequency response) may be employed in communication architectures requiring varying filters to process one or more signals. As shown inFIG.16B, a switchable, tunable filtering architecture330B may include a first switchable tunable filter module335A and a second switchable tunable filter module335B. Each module335A,335B may include a filter module332B,332C similar to module292B (FIG.13B). Each switchable, tunable module335A,335B may also include an AWF212A, AWF212B, switch pairs216E,217E and216F,217F, and a AW module96C.96F.

Each AWF module212A,212B may include two AW modules214C,2124D, and214E,214F coupled in parallel and a variable capacitor218C.218D further coupled in parallel to the two AW modules214C,214D and214E,214F, respectively. The tunable modules335A,335B may include the AW module96C,96D located between the AW332B,332C and212A,212B and ground. Each AW module96C,96D may include an AW module80C,80F and a tunable capacitor98C,98F coupled in parallel to the AW module80C,80F. Each switchable, tunable module335A,335B may be coupled in parallel. As noted above each AWF module212A,212B may have a frequency response that includes two pass bands at w1and w2surrounding a rejection point at wt. In an embodiment, the switchable, tunable architecture330B may operate in two modes: mode 1 (switch pair216E,217E closed and switch pair216F.217F open) (frequency responses320A and320B shown inFIGS.17A and17Bmay combine to create response320C shown in17C) and mode 2 (switch pair216E,217E open and switch pair216F,217F closed), frequency response320D and320E shown inFIGS.17D and17Emay combine to create response320F shown in17F.

The AW module332B,332C may have a frequency response320A.320D shown inFIG.17A,FIG.17D, respectively. When this frequency response320A,320D is combined with the switchable, tunable AW module's335A frequency response mode 1320B-FIG.17Bor tunable AW module's335B, mode 2320D-FIG.17E, the resultant frequency response may be combined mode 1320C-FIG.17Cor mode 2320F-FIG.17F. Such a switchable, tunable filter architecture330A,330B may be applied in a channel architecture requiring different filter operation modes such as shown inFIGS.15A to15C. The AWF96C,96F may provide an additional stop band as a function of the AW80C,80F configuration.

In the channel configuration310A shown inFIG.15Aa time division multiplex (TDD) band38is located between a transmit channel of band7and a receive channel of band7. In an embodiment band7may represent frequency division duplex (FDD) spectrum of a long term evolution (LTE) system and band38may represent TDD spectrum of the LTE system or architecture. In the combined LTE FDD. TDD spectrum, band38spectrum314A may be sandwiched between band7's spectrum312A312B. When the TDD channel or band38is transmitting (as shown in configuration310B shown inFIG.15B) band38should not leak into RX band7312B. In band38transmit mode310B, mode 1 of the filter architecture330B may be employed to generate the frequency response320C shown inFIG.17C.

In channel configuration310B during band38transmit mode, a guard band316B may be located between band38's transmit section or passband316A and band7's receive band312B. In mode 1 the filter architecture330B may generate the frequency response320C shown inFIG.17Cwhere the stopband324A is located in the guard band316B. When band38is in receive mode (FIG.15C.310C), the band7transmit channel312A may interfere with the band38receive channel318A. In such a configuration the filter architecture330B ofFIG.16Bmay operate in the second mode (mode 2) to generate the frequency response320F shown inFIG.17F. The frequency response320F stopband324B may be located in the guard band318B when band38is in receive mode. The architecture330B shown inFIG.16Bmay reduce the guard band size316B,318B enabling greater bandwidth utilization (of band38in the embodiment shown inFIGS.15A to15C).

Another filter embodiment330C is shown inFIG.16C. Filter330C includes a first, tunable switchable filter module334C and a second, tunable switchable filter module334D serially coupled. The first, tunable switchable filter module334C may include a first resonator332B, a first tunable resonator212A, a first, grounded tunable resonator96C, and a first opposite switch pair216E,217E. The switch217E, the first resonator332B, and the first tunable resonator212A may be serially coupled together and the serial group (217E,332B,212A) may be coupled in parallel to the switch216E. The AWF module96C may be located between the AW332B and212A and ground. The AWF96C may include an AW module80C and a tunable capacitor98C coupled in parallel to the AW module80C.

Similarly, the second, tunable switchable filter module334D may include a second resonator332C, a second tunable resonator212B, a second, grounded tunable resonator module96F, and a second opposite switch pair216F,217F. The switch217F, the second resonator332C, and the second tunable resonator212B may be serially coupled together and the serial group (217F,332C,212B) may be coupled in parallel to the switch216F. The AWF module96F may be located between the AW332C and212B and ground. The AWF96F may include an AW module80F and a tunable capacitor98F coupled in parallel to the AW module80F.

The filter module334C, when active (switch216E open, switch217E closed, switch216F closed, switch217F open (mode 1)) may produce the frequency response320C shown inFIG.17C. The filter module334D, when active (switch216E closed, switch217E open, switch216F open, switch217F closed (mode 2)) may produce the frequency response320F shown inFIG.17F. In another mode, mode 3 switches216E and216F may both be open and switches217E,217F closed (engaging both filter modules334C,334D) generating the frequency response320G shown inFIG.17G. Such a frequency response may be employed to protect bands on either side of the combined filter, such as band7transmit312A and receive312B shown inFIG.15A. The AWF96C may provide an additional stop band as a function of the AW80C configuration.

The filter system or architecture330C may have an unacceptable insertion loss in mode 1 or 2 given the potential loss and capacitance of the open switches216F.217E (mode 2), switch216E,217F (mode 1). Another filter architecture330D enabling modes 1, 2, and 3 with a lower insertion loss is show inFIG.16D. As shown inFIG.16D, the filter architecture334E includes a first filter module336A, a second filter module336B, and a third filter module336C, all coupled in parallel to each other. The first filter module336A includes a first resonator332B, a first AWF212A, a first, grounded AWF96C, and a switch pair216E,217E coupled in series where these resonators in series may produce the frequency response320C shown inFIG.17C(mode 1-switch pair216E,217E closed, switch pair216F,217F open, and switch pair216G,217G open).

The second filter module336B includes a second resonator332C, a second AWF212B, a second, grounded AWF96F, and a switch pair216F.217F coupled in series where these resonators in series may produce the frequency response320F shown inFIG.17F(mode 2-switch pair216E,217E open, switch pair216F.217F closed, and switch pair216G,217G open)). The third filter module336C may include the first resonator332B, the first AWF212A, the second resonator332C, the second AWF212B, the first, grounded AWF96C, the second, grounded AWF96F, and the switch pair216G,217G in series. In mode 3, the combined resonators332B,212A,332C, and212B may generate the frequency response320G shown inFIG.17G.

A signal processing architecture330E is shown inFIG.16E. The architecture330E may include a first filter system215A, a second filter system215B, a two position switch216H, a power amplifier (PA)12, a low noise amplifier (LNA)14, an antenna50, and a mixer60A. A signal8to be transmitted via antenna50may be amplified by PA12to produce an amplified signal22. The resultant amplified signal22may include signal content beyond the desired or permitted transmission bandwidth such as band38transmit channel316A shown inFIG.15B. The resultant signal22may filtered by the filter system215A. The filter system215A may include the first resonator module332B, a first grounded resonator module96C (including a resonator80C and a tunable capacitor98C), and a first parallel resonator module (including resonator214C,214D and a tunable capacitor218C). In an embodiment, the first filter system215A may generate the frequency response320C shown inFIG.17C.

The filtered, amplified signal may be coupled to the antenna50via the switch216H. Similarly a signal42received on the antenna50may be filtered by the second filter system215B. The filter system215B may include the second resonator module332C, a second grounded resonator module96F (including a resonator80F and a tunable capacitor98F) and a second parallel resonator module (including resonator214E,214F and a tunable capacitor218D). In an embodiment, the second filter system215B may generate the frequency response320F shown inFIG.17F. The resultant filtered, received signal may be amplified by the LNA14. The amplified, filtered, received signal may be shifted to another center frequency (such as base-band) via the mixer60A and a reference frequency signal60B to generate the frequency shifted, amplified, filtered, received signal60C. The filter architecture330E may be employed in a TDD communication system such as band38in an LTE spectrum in an embodiment.

In an embodiment, the method340shown inFIG.18may be employed to configure a filter architecture290A,290B,330A-E shown inFIGS.13A,13B, and16A-16E, respectively. In method340the maximum insertion loss (passband maximum loss)252may be selected (as required or indicated) (activity342). The stopband minimum edge(s)254may then be selected (as required or indicated) (activity344). Similarly the minimal attenuation for the stopband edge may also be selected (as required or indicated)256(activity346). Based on these requirements252,254,256, a tunable resonator filter294A,294B,334A,334B may be configured to have a stopband located at the point254and having at least the minimum attenuation256while meeting the maximum passband loss252requirement (activity348). A resonator filter292A,292B,332A,332B,332C may be configured to have stopband extend pass the initial stopband254with the minimum attenuation256and the maximum passband loss252based on the potential temperature and process variation of the filter (activity352). Activities348,352may be performed in any order or contemporaneously.

FIG.19Ais a block diagram of an electrical signal filter module360A including resonators80A,80B,80C and diagrams of filter frequency responses362A,362B,362C of resonators80A,80B,80C, respectively according to various embodiments. A resonator80A,80B,80C may be represented by corresponding electrical components according to various embodiments such as shown inFIGS.2B,20A,20B. As shown inFIG.2B,20A,20B, a resonator80A,80B,80C may be represented by a first capacitor81A,81B,81C in parallel with a series coupling of an inductor86A,86B,86C, second capacitor82A,82B,82C, and resistor84A,84B,84C where the capacitors81A,81B,81C,82A,82B,82C may have a capacitance of COA, COB, COC, CMA, CMB, CMC, respectively, inductors86A,86B,86C may have an inductance of LMA, LMB, LMCand the resistors84A,84B,84C may have a resistance of RMA, RMB, RMCin an embodiment.

The values of CMA, CMB, CMCand LMA, LMB, LMCmay be related to the elasticity and inertia of an AW80A,80B,80C in an embodiment. The values of COA, COB, COCmay represent the effective capacitance of the transverse electric fingers in the piezoelectric material of the AW80A,80B,80C in an embodiment. The values of RMA, RMB, RMCmay represent the heat generated by mechanical motion in the AW80A,80B,80C (the effective quality or Q limiter of the AW) in an embodiment. Using the values COA, CMA, LMA, and RMAfor the first capacitor81A, the inductor86A, the second capacitor82B, and the resistor84A for resonator80A, the resonance wrand the anti-resonance waof the acoustic wave (AW) device80A may be defined by the following equations:

wr⁢1≡1LMA⁢CMA⁢and⁢wa⁢1≡1LMA⁢CMA⁢COA/(CMA+COA.

Using these equations the AW80A may form the frequency response362A shown inFIG.19A, the response similar to a low pass filter with a pass band about the resonate frequency, fr1and stop band about the anti-resonance fa1. Similarly, the AW80B may form the frequency response362B shown inFIG.19A, the response similar to a low pass filter with a pass band about the resonate frequency, fr2and stop band about the anti-resonance fa2. The AW80C may form a short path and its frequency response362C shown inFIG.19Amay be similar to a high pass filter with a pass band about the anti-resonance fa3and stop band about the resonate frequency, fr3. It is noted that the resonator AW80A,80B,80C resonate and anti-resonate frequencies fr1, fr2, fr3and fa1, fa2, fa3may be fixed as a function of the physical characteristics of the AW devices80A,80B,80C. Using the resultant frequency response of an AW device80A,80B,80C based on its physical characteristics, various filter responses may be formed by various combinations of the devices80A,80B,80C.

FIG.19Bis a diagram of filter frequency responses362A,362B,362C of the electrical signal filter module360A including resonators80A,80B,80C ofFIG.19Ain a first, pass-band filter configuration364A having a center frequency fcaccording to various embodiments.FIG.19Dis a diagram of the effective combination of filter frequency responses362A,362B,362C of the electrical signal filter module360A including resonators80A,80B,80C ofFIG.19Ain the first, pass-band filter configuration364C having a center frequency fcaccording to various embodiments.

InFIGS.19B and19Dthe AW device80A frequency response362A resonate frequency, fr1may be configured to be greater than fcof the filter364A and accordingly its stop band about the anti-resonance fa1also greater than fcof the filter364A and its resonate frequency, fr1. Similarly, the AW device80B frequency response362B resonate frequency, fr2may be configured to be greater than fcof the filter364A and the AW device80A frequency response362A resonate frequency, fr1. The AW device80B stop band about its anti-resonance fa2may also be greater than fcof the filter364A, its resonate frequency, fr2and the AW device80A resonate frequency, fr1and anti-resonate frequency, fa1. The short part AW device80C frequency response362C anti-resonate frequency, fa3may be configured to be less than fcof the filter364A and accordingly its stop band about the resonance fr3also less than fcof the filter364A and its anti-resonate frequency, fa3. As shown inFIG.19Dthe effective combination of the AW devices80A,80B,80C having the frequency responses362A,362B,362C as shown inFIG.19B(based on the AW devices physical characteristics) may form the band pass filter364C with bandwidth366A.

FIG.19Cis a diagram of filter frequency responses362A,362B,362C of the electrical signal filter module360A including resonators80A,80B,80C ofFIG.19Ain a notch filter configuration364B having a center frequency fcaccording to various embodiments.FIG.19Eis a diagram of the effective combination of filter frequency responses362A,362B,362C of the electrical signal filter module360A including resonators80A,80B,80C ofFIG.19Ain the notch filter configuration364E having a center frequency fcaccording to various embodiments.

InFIGS.19C and19Ethe AW device80A frequency response362A anti-resonate stop-band frequency, fa1may be configured to be less than fcof the filter364A and accordingly its pass band about the resonance fr1also less than fcof the filter364A and its anti-resonate frequency, fa1. The AW device80B frequency response362B anti-resonate frequency, fa2may be configured to be about the center frequency, fcof the filter364B and greater than the AW device80A frequency response362A anti-resonate frequency, fa1. The AW device80B pass band about its resonance fr2may also be less than fcof the filter364B, its anti-resonate frequency, fa2and the AW device80A anti-resonate frequency, fa1. The AW device80B pass band about its resonance fr2may be greater the AW device80A resonate frequency, fr1.

The short part AW device80C frequency response362C stop-band resonate frequency, fr3may be configured to be greater than fcof the filter364A and accordingly its pass-band about the anti-resonance fa3also greater than fcof the filter364A and its resonate frequency, fr3. As shown inFIG.19Ethe effective combination of the AW devices80A,80B,80C having the frequency responses362A,362B,362C as shown inFIG.19C(based on the AW devices physical characteristics) may form the notch filter364D with bandwidth366B.

FIG.21Ais a block diagram of a tunable electrical signal filter module380A including resonators80A,80C,80D, variable capacitors98A,98C, and98D, and diagrams of filter frequency responses362A,362C,362D of resonators80A,80C,80D, respectively according to various embodiments. In an embodiment, the variable capacitor98A may be coupled in parallel to the AW device80A. The variable capacitor98C may be coupled in series with the AW device80C. The variable capacitor98D may be coupled in series with the AW device80D. The AW device80C coupled in series with the variable capacitor98C may form a first short path. The AW device80D coupled in series with the variable capacitor98D may form a second short path.

Similar toFIG.19Athe AW80A may form the frequency response362A shown inFIG.21A, the response similar to a low pass filter with a pass band about the resonate frequency, fr1and stop band about the anti-resonance fa1. The AW80C may form a short path and its frequency response362C shown inFIG.21Amay be similar to a high pass filter with a pass band about its anti-resonance fa3and a stop band about its resonate frequency, fr3. The AW80D may also form a short path and its frequency response362D shown inFIG.21Amay be similar to a high pass filter with a pass band about its anti-resonance fa4and a stop band about its resonate frequency, fr4.

It is noted that the resonator AW devices80A,80C,80D resonate and anti-resonate frequencies fr1, fr3, fr4and fa1, fa3, fa4may be fixed as a function of the physical characteristics of the AW devices80A,80C,80D. The variable capacitors98A,98C,98D may shift the device80A,80C,80D characteristics as described above. Using the resultant frequency response of a AW device80A,80C,80D based its physical characteristics various filter responses may be formed by various combinations of the devices80A,80C,80D.

FIG.21Bis a diagram of filter frequency responses362A,362C,362D of the electrical signal filter module380A (FIG.21A) including resonators80A,80C,80D ofFIG.21Ain a notch filter configuration380B having a center frequency fcaccording to various embodiments.FIG.21Cis a diagram of the effective combination380C of filter frequency responses362A,362C,362D of the electrical signal filter module380A including resonators80A,80C,80D ofFIG.21Ain the notch configuration380C having a center frequency fcand bandwidth386C according to various embodiments.

InFIGS.21B and21Cthe AW device80A frequency response362A anti-resonate stop-band frequency, fa1may be configured to be less than fcof the filter380B and accordingly its pass band about the resonance fr1also less than fcof the filter380B and its anti-resonate frequency, fa1. The short part AW device80C frequency response362C stop-band resonate frequency, fr3may be configured to be about the fcof the filter380A and accordingly its pass-band about the anti-resonance fa3greater than fcof the filter380A and its resonate frequency, fr3. The second short part AW device80D frequency response362D stop-band resonate frequency, fr4may be configured to be greater than the fcof the filter380A and accordingly its pass-band about the anti-resonance fa3greater than fcof the filter380A and its resonate frequency, fr3. As shown inFIG.21Cthe effective combination of the AW devices80A,80C,80D having the frequency responses362A,362C,362D as shown inFIG.21C(based on the AW devices physical characteristics) may form the notch filter380C with bandwidth386C.

FIG.20Ais a block diagram of a tunable filter module370A including electrical elements representing the characteristics of tunable resonators80A,80B,80C according to various embodiments. As shown inFIG.20A, the filter module370A may include AW devices80A,80B,80C, variable capacitors98A,98B, and98C, a signal source or generator92A, resistors94A representing an input load, and a resistor94B representing an antenna load. The variable capacitor98A may be coupled in parallel to the AW device80A. The variable capacitor98B may be coupled in parallel to the AW device80B. The variable capacitor98C may be coupled in series with the AW device80C.

As shown in20A a resonator80A,80B,80C may be represented by a first capacitor81A,81B.81C in parallel with a series coupling of an inductor86A.86B,86C, second capacitor82A,82B,82C, and resistor84A,84B,84C where the capacitors81A,81B,81C,82A,82B,82C may have a capacitance of COA, COB, COC, CMA, CMB, CMC, respectively, inductors86A,86B,86C may have an inductance of LMA. LMB, LMCand the resistors84A,84B,84C may have a resistance of RMA, RMB, RMCin an embodiment. As noted the AW devices80A,80B,80C physical characteristics may be selected to create one or filter modules (band-pass364C ofFIG.19Dand notch364D ofFIG.19E). In order for the variable capacitors98A,98B,98C to have a desired tuning effect on the corresponding AW device80A,80B,80C, their capacitance range may need to be significant relative the effective inductance LMA, LMB. LMCof the AW devices80A,80B,80C.

A variable capacitor98A,98B,98C may consume significant die area of a semiconductor including the capacitors and affect the Q (quality) of a filter370A including the capacitors98A,98B,98C. In an embodiment a filter364D ofFIG.19Emay have a center frequency of about 800 MHZ. The AW80A,80B,80C may be selected to have resonate frequencies fr1, fr2, fr3of about 797 MHz, 818 MHZ, and 800 MHz, respectively. For such a filter the modeled AW devices80A,80B,80C inductance LMA, LMB, LMCmay be about 30 nH, 30 nH, and 132 nH, respectively. In order to effectively tune the AW devices80A,80B,80C, the98A,98B,98C capacitance range may need to be about 4-9.5 pF. 3.5-13 pF, and 2-10 pF in an embodiment. In this example the Q of the resonators may be about 500 and the Q of the variable capacitors98A,98B, and98C may be about 100.

In an embodiment, the AW device80A may be similar to the AW device80B. In this embodiment the variable capacitor98A may also be similar to the variable capacitor98B. As shown inFIG.20Ba single variable capacitor98D may be used to effectively tune both the AW device80A and the AW device80B. In the filter module370B, the variable capacitor98D is coupled in parallel to the serial coupled AW devices80A,80. Using the filter module370B ofFIG.20B, the AW80A,80B,80C may be selected to have resonate frequencies fr1, fr2, fr3of about 800 MHZ, 805 MHz, and 800 MHz, respectively. For such a filter the modeled AW devices80A,80B,80C inductance LMA, LMB, LMCmay be about 46 nH, 77 nH, and 44 nH, respectively. In order to effectively tune the AW devices80A,80B,80C of filter370B, the98D and98C capacitance range may need to be about 2-4 pF and 2.5-3.3 pF in an embodiment, a substantial reduction in capacitance relative to the capacitors98A.98B,98C of filter module370A ofFIG.20A. The filter module or configuration370B ofFIG.20Bmay lower the insertion loss of the filter and improved the Q of the filter module370B. In an embodiment, the AW devices80A.80B, and80C may include 41 degree lithium niobate (LiNbO3).

As noted above an acoustic wave (AW) device such as80A,80B,80C shown inFIG.4, resonate and anti-resonate frequencies fr0, fa0may vary due to manufacturing variants and operating temperature. In addition a variable capacitor such as device such as98A,98B,98C shown inFIG.4, selected or variable capacitance cx0m (where x is variable capacitance selection x) may vary due to manufacturing variants and operating temperature. In an embodiment, a system such as430shown inFIG.23may adjust one or more variable capacitors tuning signals442A,442B,442C based on measured manufacturing variants for AW devices80A,80B,80C and variable capacitors98A,98B,98C and the operating temperature of the system430near the AW modules98A,98B.98C.

In an embodiment a temperature sensor module444A electrically coupled to a contact444B near the AW modules98A,98B,98C may calculate the temperature near the AW modules98A,98B,98C. A control logic module446may use the calculated temperature and known manufacturing variants for the system430components to control or modulate one or more variable capacitors98A,98B,98C via their control signals442A,442B,442C.

In an embodiment, the AW modules98A,98B,98C may be configured to operate at a nominal operating temperature where the actual environmental temperature may be below or above the nominal operating temperature. The control logic module446may determine the differential between the AW modules'98A,98B,98C nominal operating temperature and the calculated or determined environmental temperature. An AW modules'98A,98B,98C nominal operating temperature may be stored in the PROM448(FIG.23). Further a SPI signal may provide desired settings for the variable capacitors98A,98B,98C. The control logic module446may adjust the SPI based settings for the variable capacitors98A,98B,98C based on the calculated environmental temperature and known manufacturing variants for the system430components.

In an embodiment a programmable read only memory (PROM)448may include manufacturing variance characteristics for one or more components80A to80C and98A to98C of the system430. The PROM448characteristics may include the possible resonate and anti-resonate frequencies fr0, fa0for each AW module80A to80C or a delta between the optimal or normal resonate and anti-resonate frequencies fr0, fa0and the probable resonate and anti-resonate frequencies fr0, fa0for each AW module80A to80C. The control logic module446may use the delta or differential frequency or probable frequency for each AW module80A to80C to calculate a desired correction to be achieved by modulating a corresponding variable capacitor98A to98C.

FIG.22Ais a diagram of a resonant frequency fr0probably function Pr(f)392A representing manufacturing variations for an acoustic wave (AW) module according to various embodiments.FIG.22Bis a diagram of an anti-resonant frequency fa0probably function Pa(f)392B representing manufacturing variations for an acoustic wave (AW) module according to various embodiments.FIG.22Dis a diagram of a capacitance per unit area co probably function Pc(f)392D representing manufacturing variations for a capacitor module according to various embodiments. In an embodiment, the PROM448may include data representing each Pr(f)392A, Pa(f)392B, Pc(f)392C including the measured standard deviation Δfr0, Δfa0, Δfc0for each function392A to392C where the functions are approximately Gaussian in nature (as measured or sampled).

In an embodiment a programmable read only memory (PROM)448may also include temperature variance characteristics for one or more components80A to80C of the system430. The PROM448characteristics may include the possible resonate and anti-resonate frequencies fr0, fa0for each AW module80A to80C or a delta between the optimal or normal resonate and anti-resonate frequencies fr0, fa0and the probable resonate and anti-resonate frequencies fr0, fa0for each AW module80A to80C based on temperature. The control logic module446may use the temperature delta or differential frequency or probable frequency for each AW module80A to80C to calculate a desired correction to be achieved by modulating a corresponding variable capacitor98A to98C.

In an embodiment, the resonant and anti-resonant frequency variation392C for an AW module80A to80C may be linear as shown inFIG.22C. As shown inFIG.22Cfor a positive temperature delta ΔT0from a nominal temperature (such as room temperature), an AW module80A to80C resonant or anti-resonant frequency may be reduced by a predetermined number based on the slope of the temperature function392C and magnitude of the temperature delta ΔT0. Similarly, as shown inFIG.22Cfor a negative temperature delta −ΔT0from a nominal temperature (such as room temperature), an AW module80A to80C resonant or anti-resonant frequency may be increased by a predetermined number based on the slope of the temperature function392C and magnitude of the negative temperature delta −ΔT0.

In an embodiment, the control logic module446may combine manufacturing variation deltas and temperature variation deltas provided by the PROM448for a component80A to80C to determine or calculate an overall delta or correction for corresponding variable capacitor98A to98C. In a further embodiment the control logic module446may combine manufacturing variation deltas and temperature variation deltas provided by the PROM448for a component80A to80C and a manufacturing variation deltas provided by the PROM448for a corresponding variable capacitor98A to98C to determine or calculate an overall delta or correction for the corresponding variable capacitor98A to98C.

In an embodiment, the PROM448data may be updatable via one or more methods. In such an embodiment the PROM448characteristic data for temperature or manufacturing variants for one or more components80A to80C may be updated based on measured response or updated component testing. Similarly characteristic data for manufacturing variants for one or more capacitors98A to98C may be updated based on measured response or updated component testing. In an embodiment, the system430control logic module446may include memory for storing temperature and manufacturing characteristics for components80A to80C and manufacturing characteristics for components98A to98C.

In order to produce AW modules80A to80C or variable capacitors98A to98C or other components having possible variable system characteristics due to manufacturing a process400shown inFIG.24may be employed.FIG.24is a flow diagram of a component modeling, manufacturing, and configuration method according to various embodiments. In the process400general component characteristics of an AW module80A to80C or variable capacitor module98A to98C may be determined. In order to design and manufacture an AW module80A to80C or variable capacitor module98A to98C having desired parameters, test devices or related modules may be produced and its characteristics evaluated (activity402). In particular, key or critical parameters may be checked for the test devices including resonant and anti-resonant frequencies for an AW module related device and capacitance per unit area for a capacitor or series of capacitors forming a digital, variable capacitor related device.

Based on the test devices and a consistent or well behaved manufacturing process, probability curves or standard deviations for critical parameters of the test devices may be determined. In an embodiment, a Gaussian distribution may be applied and first standard deviations may be determined for each critical parameter probability function. Using correlation(s) between the test devices and an AW module or variable capacitor module to be designed and produced, probability functions (such as each Pr(f)392A, Pa(f)392B, Pc(f)392C) may be determined for the AW module or variable capacitor modules.

Based on the correlations between the test devices and resultant probability functions for critical parameters, an AW module or capacitor module may be designed (activity404). Without compensating modules or methods as recited by the present invention, an AW module or capacitor module design parameters may be required to be loose to compensate for the manufacturing variants. Employing the AW modules or capacitors in a system430(with compensating modules) of the present invention may enable tighter design parameters given the ability to compensate for variants of the system430. In an embodiment initial, final components (AW module or capacitor modules) based on a design may be produced (activity406). Then, the initial components based on the associated design may be tested to determine the probability characteristics for key or critical parameters (activity408).

The determined probability characteristics for the initial final, designed components may be compared to the determined probability characteristics for the test devices. Where the characteristics are correlated as expected, larger quantities of the final, design components may be produced and randomly tested (activity412). Where the manufacturing process and source is controlled and well-behaved only sparse or random components may need to be tested to confirm correlation to the previously determined probability functions Pr(f)392A, Pa(f)392B, Pc(f)392C. For temperature sensitive components including AW modules, the temperature effects may also be modeled (activity402) and considered during the component design (activity404). The temperature characteristics of initial, final components may also be determined (activity408) prior to producing higher quantities of temperature sensitive components (activity412). In an embodiment each or batch groups of final, designed component (AW module or variable capacitor module) may be tested and resultant probability function determined for key or critical module characteristics. As noted the determined probability functions may be stored in a system430employing a corresponding module (80A to80C,98A to98C).

In addition to adjusting for AW modules' performance variants due manufacturing variants and operating temperature, impedances present at a filter module452A input or output port may affect the filter module452A (FIG.25A) performance. In particular a filter module452A may be designed for a particular load at its input node and a particular load at its output node. In an embodiment a differential between the target/designed load94A on the input node or the target/designed load94B on the output node of a filter module452A may affect its performance.FIG.25Ais block diagram of signal filter architecture450A. Architecture450A includes a filter module452A, an input load94A represented by a resistor and an output load94B represented by a resistor. The filter module452A may be configured to have a balanced load where the input load impedance94A and the output load impedance94B are about equal and have a predetermined level such as 50 ohms in an embodiment.

The ratio between target loads94A,94B is related to the Voltage Standing Wave Ratio (VSWR) for the module. As noted, a filter module452A may be configured for a common VSWR of 1:1 (where the input load94A is about equal to the output load94B). For a filter module452A configured for a VSWR of 1:1 an input-output mismatch (VSWR other than 1:1) may result in a greater input signal insertion loss (greater filter passband loss).FIG.25Bis a block diagram of a signal filter architecture450B including a tunable filter module452B that may be configured to reduce effects of impedance mismatches between loads94A,94B (VSWR other than expected by filter module452A,452B nominally).

As shown in theFIG.25Bthe signal filter architecture450B includes an input load94A, an output load94B, and a tunable filter module452B. The tunable filter module452B includes multiple tunable AW modules96A.96C,96D,96E. Each tunable AW module96A,96C,96D,96E may include an AW device80A,80C,80D,80E, and80F (represented by their electrical component equivalents) coupled in parallel to a variable capacitor98A,98C,98D,98E, and98F, respectively. The tunable AW module96C may be coupled to the input load94A and ground. One or more sub-filter modules454A,454B may be coupled between the tunable AW module96C and the output load94B.

Each sub-filter module454A,454B may include a first tunable AW module96C,96E and a second tunable AW module96D,96F coupled to ground, respectively. As noted above an AW device80A,80C,80D,80E,80F may be modeled from a series of a inductor86A,86C,86D,86E,86F, capacitor82A,82C,82D,82E,82F, resistor84A,84C,84D,84E,84F coupled in parallel with a capacitor81A,81C,81D,81E,81F, respectively. Each variable capacitor98A,98C,98D,98E, and98F coupled in parallel with an AW device80A,80C,80D,80E, and80F may be varied to affect the filter characteristics of the AW device80A,80C.80D,80E, and80F.

As noted previously a variable capacitor98A,98C,98D,98E, and98F may be employed to modulate an AW device80A,80C,80D,80E, and80F to shift a resonant or anti-resonant frequency to select different bands, sub-bands, correct for manufacturing variants, and temperature shifts. A variable capacitor98A,98C,98D,98E, and98F may also be employed to modulate an AW device80A,80C,80D,80E, and80F to reduce a input signal insertion loss due to an unexpected or non-conforming VSWR (not equal to VSWR the filter model452B was designed to process).

In an embodiment, the filter module452B may be designed for a VSWR of about 1:1 and the variable capacitors98A,98C.98D,98E, and98F may be modulated to reduce insertion loss due to a VSWR other than 1:1 (non-forming). For example,FIG.26Ais a diagram of the frequency response of the filter module452B for a VSWR of 1:1 (nominal). As shown inFIG.26Athe insertion loss (passband attenuation) is about 0.5 dB.FIG.26Bis a diagram of the frequency response of the filter module452B for a VSWR of 1:1.5 and one or more variable capacitors98A,98C,98D,98E, and98F modulating a AW device80A,80C,80D,80E, and80F, respectively to reduce the insertion loss. As shown inFIG.26Bthe insertion loss (passband attenuation) is about 0.68 dB.FIG.26Cis a diagram of the frequency response of the filter module452B for a VSWR of 1:2 and one or more variable capacitors98A,98C,98D,98E, and98F modulating a AW device80A,80C,80D,80E, and80F, respectively to reduce the insertion loss. As shown inFIG.26Cthe insertion loss (passband attenuation) is about 1 dB.

In another embodiment the PROM448ofFIG.23may be configured to include variable capacitor deltas for various VSWR. A user may be indicate the output load and configure the PROM448accordingly. In another embodiment the control logic module may sense the output load, determine the VSWR differential, and choose the closest set of variable capacitor deltas from the PROM448. In a further embodiment a filter module452B may be configured or designed for a nominal VSWR (median relative to possible VSWR that the filter module452B may experience). For example in architecture450B, VSWRs of 1:1, 1:1.5 and 1:2 may be expected. The filter module452B may be configured or designed to be optimal for a VSWR of 1:1.5 and the variable capacitors98A,98C,98D,98E, and98F may be adjusted to modulate the AW device80A,80C,80D,80E, and80F, respectively when the VSWR is 1:1 or 1:2. In a further embodiment a variable capacitor may be placed in series with a AW module80C,80F (or80A,80E) (such as capacitor98C inFIG.20A). The variable capacitor in series with an AW module80C,80F may be modulated to compensate for loads94A,94B other than the target/designed loads of the filter module450B.

FIG.27Ais a diagram of the frequency response of the filter module452A for a VSWR of 1:1 where the filter module452B is optimized for VSWR of 1:1, 1:1.5, and 1:2 and one or more variable capacitors98A,98C,98D,98E, and98F modulate a AW device80A,80C,80D,80E, and80F, respectively to reduce the insertion loss for VSWR 1:1. As shown inFIG.27Athe insertion loss (passband attenuation) is about 0.65 dB.FIG.27Bis a diagram of the frequency response of the filter module452B for a VSWR of 1:1.5 where the filter module452A is optimized for VSWR of 1:1, 1:1.5, and 1:2 and one or more variable capacitors98A,98C.98D,98E, and98F modulate a AW device80A,80C,80D,80E, and80F, respectively to reduce the insertion loss for VSWR 1:1.5. As shown inFIG.27Bthe insertion loss (passband attenuation) is about 0.62 dB.FIG.27Cis a diagram of the frequency response of the filter module452B for a VSWR of 1:2 where the filter module452B is optimized for VSWR of 1:1, 1:1.5, and 1:2 and one or more variable capacitors98A,98C,98D,98E, and98F modulate a AW device80A,80C.80D,80E, and80F, respectively to reduce the insertion loss for VSWR 1:2. As shown inFIG.27Cthe insertion loss (passband attenuation) is about 0.69 dB.

As shown inFIG.26A to26Cthe average insertion loss is about 0.72 dB for a system designed for a VSWR 1:1 and adjusted for VSWR of 1:1.5 and 1:2. As shown inFIG.27A to27Cthe average insertion loss is about 0.65 dB for a system optimized for a range of VSWR from 1:1 to 1:2 and adjusted for VSWR of 1:1.0, 1:1.5, and 1:2. The insertion loss of the filter module452B optimized for VSWR 1:1 has a lower insertion loss for VSWR 1:1 than the insertion loss for the filter module452B optimized for a range of VSWR from 1:1 to 1:2 (0.5 dB versus 0.65 db) even with variable capacitor modulation. Accordingly different filter modules452B for VSWR 1:1 optimization or a range of VSWR may be selected as a function of the expected range of VSWR in a system implementation and minimal acceptable insertion loss criteria.

As noted the VSWR is based on the balance between the input load and output load of a system. As shown inFIG.1AandFIG.28A, a power amplifier12may, in part provide a load to filter module452A (FIG.28A). Power amplifiers12commonly produce very low impedance. In order to provide a desired input impedance to the filter module452A (FIG.28) or RF switch40(FIG.1A), one or more elements forming an impedance matching module470A may be placed between the PA12and filter module462A. The impedance matching module470A may provide the expected impedance at the input port of a filter module462A. When the filter module462A is tunable and support filtering different frequency bands, the matching module470A may not be effective for all the various operating/filtering modes of the tunable filter module462A.

FIG.28Ais a block diagram of a filter system architecture460A according to various embodiments. Architecture460A includes a PA12, an impedance matching module470A and a tunable/switchable filter module462A. The impedance matching module470A couples the PA12to the tunable/switchable filter module462A. In an embodiment, the tunable/switchable filter module462A includes a variable capacitor control signal SPI and a band select signal. The tunable/switchable filter module462A may produce or switch between different frequency responses to process different frequency spectrum or bands. In an embodiment, the impedance matching module470A may include an inductor464A. The PA12may receive power via input VDD in an embodiment.

The inductor464A may provide the impedance matching function of the impedance matching module470A. In an embodiment, the inductor may be about a 2 to 3 nH inductor.FIG.28Bis a block diagram of a tunable/switchable signal filter module462B that may be configured to operate in multiple bands and provide impedance matching with the matching module470A. In an embodiment, the filter module462B may be configured to operate in evolved UMTS Terrestrial Radio Access Network e-UTRAN Long Term Evolution (LTE) bands, in particular bands13and17. LTE band13may have a transmit band from 776 MHz to 787 MHz and a receive band from 746 MHz to 757 MHz. LTE band17may have a transmit band from 704 MHz to 716 MHz and a receive band from 734 MHz to 746 MHz. LTE Bands13and17are adjacent, tight bands.

As shown in theFIG.28Btunable/switchable filter module462B includes multiple tunable AW modules476C,476D,476F and multiple tunable/switchable AW modules476A,476E. Tunable AW module476C may include AW devices80C and80E coupled in parallel, the set coupled in parallel to a variable capacitor98C. The tunable AW module476C may be coupled to the impedance matching module470A and ground. Tunable AW module476D,476F may include an AW device80D,80G coupled in parallel to a variable capacitor98D.98F, respectively. One or more sub-filter modules474A,474B may be coupled between the tunable AW module96C and the output load94B.

Each sub-filter module474A,474B may include a first tunable/switchable AW module476A,476E and a second tunable AW module476D,476F coupled to ground, respectively. Tunable AW module476A may include AW device80A in series with a switch472B coupled in parallel to AW device80F in series with a switch472A, the set coupled in parallel to a variable capacitor98A. Tunable AW module476E may include AW device80H in series with a switch472C coupled in parallel to AW device80I in series with a switch472D, the set coupled in parallel to a variable capacitor98E.

In a first mode the switches474A to474D may operate to switch AW module80A and AW module80H on (closed) and AW module80F and AW module80I off (switch open) for band13or17. In a second mode the switches474A to474D may operate to switch AW module80A and AW module80H off (switch open) and AW module80F and AW module80I on or active (switch closed) for the other of band13or17. The variable capacitors98A,98E,98F, and98D may be employed to adjust the operation of the AW modules80F,80A,80I,80H,80G, and80D to correct for temperature, output impedance, and manufacturing variants. It is noted that variable capacitor98A modulates AW module80A or80F (is shared) and variable capacitor98E modulates AW module80H or80I (is shared).

The variable capacitor98C may be modulated to provide impedance matching between the filter module462B and the impedance matching module470A.FIG.29Ais a diagram of the frequency response of the tunable/switchable filter module462B operating in a first mode to pass signals for LTE band17in an embodiment.FIG.29Bis a diagram of the frequency response of the tunable/switchable filter module462B operating in a second mode to pass signals for LTE band13in an embodiment. In an embodiment, the parallel combination of AW modules80C and80E are configured to resonate about the LTE band17and thereby provide rejection below LTE band17and between LTE band17and13. The variable capacitor98C may also tune the anti-resonant point between LTE band17and13as a function of the mode of operation (mode 1 or mode 2).

In an embodiment, the switches472A to472D may be comprised of stacked CMOS FETs to pass the PA amplified signals. The use of multiple sub-filters474A,474B in series may reduce the stack size and power across the switches474A to474D as the signal is shared across the sub-filters. In a further embodiment the capacitors98A and98E may be fixed. Their capacitance may be preset based on known manufacturing variants, operating temperature variants, and impedance matching (output) corrections that are fixed for the filter module462B. In another embodiment of all the variable capacitors98A to98G described in the application capacitance range and granularity may be varied as function of corrections needed to maintain the associated AW modules80A to80G nominal resonant and anti-resonant frequencies within acceptable tolerances. The corrections may be known or calculated based on the AW modules80A to80G known manufacturing and operating temperature variants and output impedance compensation conditions.

FIG.30Ais a simplified block diagram of a signal filter architecture according to various embodiments. As shown inFIG.30Asignal filter architecture480A includes a source92A, a resistor94A, a signal processing module482A, and a resistor94B. The resistor94A may represent the input load generated by the signal92A. The signal processing module482A may modify or filter the source signal92A in a desired or predetermined way. The second resistor94B may represent the load at an output including at an antenna. As noted, a differential between the target/designed load or impedance94A on the input node or the target/designed load94B on the output node of a filter module480A may affect its performance. It is noted that the loads94A,94B may have real and imaginary components in an embodiment (x+jy) where x is the real component and y is the imaginary component.

As noted, the ratio between loads or impedance94A,94B is related to the Voltage Standing Wave Ratio (VSWR) for the module480A where a module480A may be configured for a common VSWR of 1:1 (where the input impedance94A is about equal to the output impedance94B). For a filter module482A configured for a VSWR of 1:1 an input-output mismatch (VSWR other than 1:1) may increase an input signal92A insertion loss (greater filter passband loss).

FIG.30Bis a simplified block diagram of an impedance matched (“IM”) signal filter architecture480B according to various embodiments. Architecture480B includes a signal source92A, a resistor94A, a signal processing module482A, a resistor94B, and an impedance match (“IM”) module484A. In an embodiment, the IM module484A may include one or more components that are selected or configured to provide a real or imaginary impedance balance, modification, or modulation between input and output impedance for architecture480A. In an embodiment, the IM module response or modulation may vary by frequency and thus be tuned for a range or ranges of desired frequencies such as when frequency variable components are employed in an IM module484A such as shownFIG.30C.

FIG.30Cis a simplified block diagram of an impedance matched (“IM”) signal filter architecture480C including an IM module484C according to various embodiments. As shown inFIG.30C, architecture480C includes a signal source92A, a resistor94A, a signal processing module482A, a resistor94B, and an impedance match (“IM”) module484C. In an embodiment, a IM module484C may include one or more frequency variant components that are selected or configured to provide a real or imaginary impedance balance, modification, or modulation between input and output impedance for architecture480C. In an embodiment, the IM module484C may include an L-shaped resonator circuit. The module484C may include an inductor86J coupled serially between the signal processing module (SPM)482A and the resistor94B. The module484C may further include a capacitor82J coupled between the inductor86J and resistor94B and ground.

The resultant L-C circuit formed by the inductor86J and the capacitor82J may provide balancing impedance between the source94A and output port94B. As a function of the inductance and capacitance of the inductor86J and capacitor82J and loads94A,94B, the L-C circuit of module484C may balance the impedance94A,94B at or about predetermined frequenc(ies). When the input impedance94A is about 50 ohms and the output impedance94B is about 100 ohms, the VSWR may be about 1:2 causing about a 6 dB insertion loss for an input signal92A. In an embodiment, the inductance and capacitance of the inductor86J and capacitor82J may be about 9.406 μH (micro-Henries) and 1.881 pF (pico-Farads). In such an embodiment, the IMM484C may provide an impedance of about 50 ohms about a frequency of 846 MHz. In this embodiment, the IMM484C may balance the source and output impedance so the VSWR is about 1:1 and the input signal insertion loss about 2 dB.

It is noted that the inductor86J may consume substantial real estate and lower the quality (Q) of architecture480C due to its substantial inductance. In an embodiment, it may be desirable to balance architecture impedance while not employing a large inductor as in an L-C resonator circuit shown inFIG.30Cor variants thereof including T-networks (484N inFIG.30T).FIG.30Dis a simplified block diagram of IM signal filter architecture480D including an IMM484D. Similar to architecture480C, architecture480D includes a signal source92A, an input load or impedance modeled by resistor94A, a SPM482, an IMM484D, and an output load or impedance represented by resistor94B (such as an antenna impedance in an embodiment). In an embodiment, the IMM484D may include an acoustic wave module (AWM)490A, a pre-impedance match component module (pre-IMCM)491A, and a post-impedance match component module (post-IMCM)492A. The AWM490A may be a single acoustic wave device or a plurality of devices and variable capacitors in various configurations as shown and described above.

In an embodiment, a post-IMCM492A may include one or more components configured along with the AWM490A to create a balancing impedance between94A and94B, such as492B inFIG.30F.492C inFIGS.30I, and492DinFIG.30R. Similarly, a pre-IMCM491A may include one or more components configured along with the AWM490A to create a balancing impedance (real and imaginary) between94A and94B, such as492B inFIGS.30L and492CinFIG.30O. In an embodiment, one or more components of a post-IMCM492A may be configured to resonate with an AWM490A to add impedance to architecture480D, i.e., when impedance of94B>94A. In an embodiment, one or more components of a pre-IMCM491A may be configured to resonate with an AWM490A to reduce the impedance of architecture480D, i.e., when impedance of94A>94B.

In other embodiments, an IMM's484D pre-IMCM491A and post-IMCM492A may both include one or more components configured to interact or resonate with the AWM490A to affect architecture480D input/output impedance ratios or VSWR. In an embodiment, the AWM490A of a IMM484D may be configured to filter an input signal92A in addition to resonating with one or more components of a pre-IMCM491A or post-IMCM492A to modulate or modify the impedance ratio of architecture480D for various frequencies. As a function of the pre-IMCM491A and post-IMCM492A components the resonate frequency, frand the anti-resonance faof the AWM490A may be shifted or modified in a predetermined and configurable manner. In particular, the AWM nominal resonate frequency. frand the anti-resonance famay be selected based on the known shift of these frequencies due to the interaction with components of a pre-IMCM491A or post-IMCM492A.

FIG.30Eis a simplified block diagram of IM architecture480E including an IMM484D according to various embodiments. Similar to architecture480D, architecture480E includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484D, and an output load or impedance represented by resistor94B (such as an antenna impedance in an embodiment). In an embodiment, the IMM may include an acoustic wave module (AWM)490A, a pre-impedance match component module (pre-IMCM)491A, and a post-impedance match component module (post-IMCM)492A. The AWM490A may be a single acoustic wave device or a plurality of devices and variable capacitors in various configurations as shown and described above. Architecture480E may not include a SPM482as shown inFIG.30D. It is noted that an IMM484D of the present invention may be employed in various networks or architecture to modify the architecture impedance ratio in a known or desired way.

FIG.30Fis a simplified block diagram of IM architecture480F including an IMM484F according to various embodiments. Similar to architecture480E, architecture480F includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484F, and an output load or impedance modeled by resistor94B. In an embodiment, the IMM484F may include an acoustic wave module (AWM)490A and a post-impedance match component module (post-IMCM)492B. The AWM490A may be a single acoustic wave device or a plurality of devices and variable capacitors in various configurations as shown and described above. InFIG.30F, the AWM490A is shown as a single AW device with representative electrical components or elements including capacitors81A,82A, inductor86A, and resistor84A, the capacitors81A,82A having capacitance Cr and Cm, respectively, the inductor86A inductance Lm, and resistor84resistance Rm.

In an embodiment, the IMM484F may be configured to provide a balancing impedance to architecture480F at a desired or target frequency. The IMM484F may be configured to add impedance to architecture480F when output impedance is greater than the input impedance. In IMM484F, a capacitor82J is coupled to ground and between the AWM490A and the output load94B to form a resonator circuit with the AWM490A, the resonator circuit having a desired impedance at desired frequency fr′. The AWM490A may be configured to have a nominal frequency frthat is shifted to resonate at fr′by the capacitor82J where the capacitor82J effectively borrows inductance L (represented by inductor86J inFIGS.30G and30H) from the AWM490A to resonate at the desired frequency fr′and provide the desired impedance at that the desired frequency fr′.

As shown inFIG.30H, the AWM490A provides an inductor86J having inductance L to the L-C module484C. The AWM490A is then effectively coupled to an inductor86K with inductance −L forming the modified AWM494A (balanced inductance as shown by module486A inFIG.30G). InFIG.30G, the balanced inductor pair module486A includes an inductor86K having inductance—L and an inductor86J having inductance L. The module486A represents the effect of the AWM490A losing inductance L (inductor86K) to the capacitor82J so the capacitor82J and effective inductor86J having inductance L form a desired resonator module484C. The balanced inductor pair module486A represents the net effect of capacitor82J resonating with AWM490A: the AWM490A providing inductance L to resonate with the capacitor82J (L-C module484C ofFIG.30H), while the AWM490A losses inductance L. The AWM490A resonance may be adjusted accordingly (based on modified AWM494A ofFIG.30H).

Using the values Cr, Cm, Lm, and Rm for first capacitor82A, inductor86A, second capacitor82B, and resistor84A, a AWM's490A nominal resonance frequency frmay be defined by the following equation:

fr≡12⁢π⁢Lm⁢Cm.
In an embodiment, the capacitance of Cr is modified so the modified resonator494A (with −L) resonates at fr′. Cr may be determined when

wr′2>LmL⁢(wr′2-wr2)
and

fr′>fr,then⁢Cr=L·wr′2+Lm·(wr′2-wr2)L·Lm·wr′2·(wr′2-wr2).
Accordingly based on desired effective L-R module484C having impedance at fr′, a AWM490A may be configured to provide inductance L and resonate at fr′.

In an embodiment, IMM484F may be configured to balance an input impedance94A of about 50 ohms with an output impedance94B about 100 ohms for a frequency fr′of 846 MHz. Similar to the capacitor82J of L-C module484C ofFIG.30C, capacitor82J may have a capacitance of about 1.881 pF (pico-Farads). In the L-C module484C ofFIG.30C, the inductor86J had an inductance of about 9.406 nH (nano-Henries) where the L-C module484C provided the desired impedance at 846 MHz. Accordingly the AWM490A may be provide an effective inductance of 9.406 nH (nano-Henries) to the L-C module484C shown inFIG.30Hand lose the same inductance to form the modified AWM494A shown inFIG.30H. In an embodiment, Lm may be about 100 nH (nano-Henries) and Cm may be about 0.3713 pF (pico-Farads). Using the equation for Cr above, Cr may be about 3.813 pF (pico-Farads) where the AWM490A has a nominal frequency of 826 MHz.

The IMM484F may provide an impedance of about 50 ohms about a frequency of 846 MHz. In this embodiment, the IMM484F may balance the source and output impedance so the VSWR is about 1:1 and the input signal insertion loss is nominal as shown in the frequency response graph498B inFIG.31B.FIG.31Bis a frequency response graph498A of the AWM490A alone with a balanced load applied to the AWM490A. As shown inFIG.31A, the AWM490A has a nominal resonate frequency frof about 826 MHz. When the AWM490A is coupled with the capacitor82J in architecture480F having an unbalanced input-output impedance, (1:2), the IMM484F (AWM490A and capacitor82J) may combine to have a resonate frequency frof about 846 MHz as shown inFIG.31B. As shown in Table 1 different AWM and capacitances for capacitor82J may be employed to achieve a resonate frequency of about 836 MHz and various impedances (resistance from about 82 ohms to 413 ohms.)

TABLE 1FrFaF′rLmCmCrLCRMHzMHzMHzn-Hp-Fp-Fn-Hp-FOhmsQ750800836301.50110.897.7041.86282.750.8750800836600.75015.44715.411.702181.011.67508008361000.45033.26825.681.241413.932.4

Other components may be coupled with an AWM in an embodiment for various desired impedance matches at various desired resonate frequencies.FIG.30Iis a simplified block diagram of IM architecture480I including an IMM484G according to various embodiments. Similar to architecture480F, architecture480I includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484G, and an output load or impedance modeled by resistor94B. In an embodiment, the IMM484G may include an acoustic wave module (AWM)490B and a post-impedance match component module (post-IMCM)492C. The AWM490B may be a single acoustic wave device or a plurality of devices and variable capacitors in various configurations as shown and described above. As shown inFIG.30F, the AWM490B may be described with representative electrical components or elements including capacitors81A,82A, inductor86A, and resistor84A, the capacitors81A,82A having capacitance Cr and Cm, respectively, the inductor86A inductance Lm, and resistor84resistance Rm.

In an embodiment, the IMM484G may be configured to provide a balancing impedance to architecture480I at a desired or target frequency. The IMM484G may be configured to add impedance to architecture480G when output impedance is greater than the input impedance. In IMM484G, an inductor86L is coupled to ground and between the AWM490B and the output load94B to form a resonator circuit with the AWM490B, the resonator circuit having a desired impedance at desired frequency fr′. The AWM490B may be configured to have a nominal frequency frthat is shifted to resonate at frby the inductor86L where the inductor86L effectively borrows capacitance C (represented by capacitor82K inFIGS.30J and30K) from the AWM490B to resonate at the desired frequency fr′and provide the desired impedance at that the desired frequency fr′.

As shown inFIG.30I, the AWM490B provides a capacitor82K having capacitance C to the L-C module484H. The AWM490B is then effectively coupled to a capacitor82L with capacitance −C forming the modified AWM494B (balanced capacitance is shown by module486B inFIG.30J). InFIG.30J, the balanced capacitor pair module486B includes a capacitor82K having capacitance −C and a capacitor82L having capacitance −C. The module486B represents the effect of the AWM490B losing capacitance C (capacitor82K) to the inductor86L so the inductor86L and effective capacitor82K having capacitance C form a desired resonator module484G. The balanced capacitor pair module486B represents the net effect of inductor86L resonating with AWM490B: the AWM490B providing capacitance C to resonate with the inductor86L (L-C module484H ofFIG.30K), while the AWM490B losses capacitance C. The AWM490B resonance may be adjusted accordingly (based on modified AWM494B ofFIG.30K).

In an embodiment, IMM484G may be configured to balance an input impedance94A of about 50 ohms with an output impedance94B about 414 ohms for a frequency fr′of 846 MHz. The inductor89L may have an inductance of about 29.21 nH. The capacitor82K may have an effective capacitance of about 1.411 pF and the capacitor82L may have an effective capacitance of about-1.411 pF. Accordingly, the AWM490A may provide an effective capacitance of about 1.411 pF to the L-C module484H shown inFIG.30Kand lose the same capacitance to form the modified AWM494B shown inFIG.30K. In an embodiment, Lm may be about 100 nH (nano-Henries), Cm may be about 0.4503 pF (pico-Farads), and Cr may be about 3.268 pF (pico-Farads).

The IMM484G may provide an impedance of about 364 ohms about a frequency of 836 MHz. In this embodiment, the IMM484G may balance the source and output impedance so the VSWR is about 1:1 and the input signal insertion loss is nominal as shown in the frequency response graph498C inFIG.31C. When the AWM490B is coupled with the inductor86L in architecture480I, the IMM484G (AWM490B and inductor86L) combine to have a resonate frequency fr′of about 836 MHz as shown inFIG.31C.

FIGS.30L to30Nare simplified diagrams of another embodiment480L that includes an IMM484I. Similar to architecture480F, architecture480L includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484I, and an output load or impedance modeled by resistor94B. In an embodiment, the IMM484I may include an acoustic wave module (AWM)490A and a pre-impedance match component module (pre-IMCM)491B. The AWM490A may be a single acoustic wave device or a plurality of devices and variable capacitors in various configurations as shown and described above. InFIGS.30L-30N, the AWM490A is shown as a single AW device but may be represented by electrical components or elements including capacitors81A,82A, inductor86A, and resistor84A, the capacitors81A,82A having capacitance Cr and Cm, respectively, the inductor86A inductance Lm, and resistor84resistance Rm.

In an embodiment, the IMM484I may be configured to provide a balancing impedance to architecture480L at a desired or target frequency. The IMM484I may be configured to remove impedance from architecture480L when output impedance is less than the input impedance. In IMM4841, a capacitor82J is coupled to ground and between the AWM490A and the input load94A to form a resonator circuit with the AWM490A, the resonator circuit having a desired impedance at desired frequency fr′. The AWM490A may be configured to have a nominal frequency frthat is shifted to resonate at frby the capacitor82J where the capacitor82J effectively borrows inductance L (represented by inductor86J inFIGS.30M and30N) from the AWM490A to resonate at the desired frequency fr′and provide the desired impedance at that the desired frequency fr′. As shown inFIG.30N, the AWM490A provides an inductor86J having inductance L to the L-C module484J. The AWM490A is then effectively coupled to an inductor86K with inductance −L forming the modified AWM494C (balanced inductance as shown by module486C inFIG.30M).

FIGS.300to30Qare simplified diagrams of another embodiment480M that includes an IMM484K. Similar to architecture480L, architecture480M includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484K, and an output load or impedance modeled by resistor94B. In an embodiment, the IMM484K may include an acoustic wave module (AWM)490B and a pre-impedance match component module (pre-IMCM)491C. The AWM490B may be a single acoustic wave device or a plurality of devices and variable capacitors in various configurations as shown and described above. InFIGS.300-30Q, the AWM490B is shown as a single AW device but may be represented by electrical components or elements including capacitors81A,82A, inductor86A, and resistor84A, the capacitors81A,82A having capacitance Cr and Cm, respectively, the inductor86A inductance Lm, and resistor84resistance Rm.

In an embodiment, the IMM484K may be configured to provide a balancing impedance to architecture480M at a desired or target frequency. The IMM484K may be configured to remove impedance from architecture480M when output impedance is less than the input impedance. In IMM484K, an inductor86L is coupled to ground and between the AWM490B and the input load94A to form a resonator circuit with the AWM490B, the resonator circuit having a desired impedance at desired frequency fr′. The AWM490B may be configured to have a nominal frequency frthat is shifted to resonate at frby the inductor86L where the inductor86L effectively borrows capacitance C (represented by capacitor82K inFIGS.30M and30N) from the AWM490B to resonate at the desired frequency fr′and provide the desired impedance at that the desired frequency fr′. As shown inFIG.30Q, the AWM490B may provide a capacitor82K having capacitance C to the L-C module484L. The AWM490B is then effectively coupled to a capacitor82L with capacitance −C forming the modified AWM494D (balanced capacitance as shown by module486D inFIG.30P).

FIGS.30R to30Tare simplified diagrams of another embodiment480N that includes an IMM484M. Similar to architecture480F, architecture480N includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484M, and an output load or impedance modeled by resistor94B. In an embodiment, the IMM484M may include an acoustic wave module (AWM)490A and a post-impedance match component module (post-IMCM)492D. The AWM490A may be a single acoustic wave device or a plurality of devices and variable capacitors in various configurations as shown and described above. InFIGS.30R-30T, the AWM490A is shown as a single AW device but may be represented by electrical components or elements including capacitors81A,82A, inductor86A, and resistor84A, the capacitors81A,82A having capacitance Cr and Cm, respectively, the inductor86A inductance Lm, and resistor84resistance Rm.

In an embodiment, the IMM484M may be configured to provide a balancing impedance to architecture480N at a desired or target frequency. The IMM484M may be configured to add impedance to architecture480N when output impedance is greater than the input impedance. In IMM484M, the post-IMCM492D includes a capacitor82J and inductor86N. The capacitor82J is coupled to ground and between the AWM490A and the inductor86N. The inductor86N is coupled between the AWM490A and the output load94B. The post-IMCM492D forms a T-shaped resonator circuit with the AWM490A, the resonator circuit having a desired impedance at desired frequency fr′. The AWM490A may be configured to have a nominal frequency frthat is shifted to resonate at fr′by the capacitor82J where the capacitor82J effectively borrows inductance L (represented by inductor86J inFIGS.30S and30T) from the AWM490A to resonate at the desired frequency fr′and provides the desired impedance at that the desired frequency fr′. As shown inFIG.30T, the AWM490A provides an inductor86J having inductance L to the L-C-L T-shaped resonator module484N. The AWM490A is then effectively coupled to an inductor86K with inductance −L forming the modified AWM494A (balanced inductance as shown by module486A inFIG.30S).

FIG.30Uis a simplified diagram of another embodiment480O that includes an IMM484N. Similar to architecture480F, architecture480O includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484N, and an output load or impedance modeled by resistor94B. In an embodiment, the IMM484N may include an acoustic wave module (AWM)490A coupled in parallel with a variable capacitor98A, and a post-impedance match component module (post-IMCM)492D. The variable capacitor98A may modify the capacitance of Cr and may be used to modify the impedance or resonate or anti-resonate of the AWM490A and thus the IMM484N.

FIG.30Vis a simplified diagram of another embodiment480P that includes an IMM484O. Similar to architecture480F, architecture480P includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484N, and an output load or impedance modeled by resistor94B. In an embodiment, the IMM484N may include an acoustic wave module (AWM)490A and a post-impedance match component module (post-IMCM)492D. The IMM484O may be configured to add impedance to architecture480P when output impedance is greater than the input impedance. In IMM484O, the post-IMCM492D may include a variable capacitor98C. The variable capacitor98C is coupled to ground and between the AWM490A and the output load94B. By varying the capacitor98C capacitance, the borrowed inductance from the AWM490A may also vary. Similarly the resonant frequency fr′and impedance may also vary. The variable capacitor98C may be used to tune the IMM484O resonant frequency and impedance in an embodiment.

FIG.30Wis a simplified diagram of another embodiment480Q that includes an IMM484P. Similar to architecture480N, architecture480O includes a signal source92A, an input load or impedance modeled by resistor94A, an IMM484P, and an output load or impedance modeled by resistor94B. As noted, the input load and output load94A,94B may include real and imaginary components. In an embodiment, the IMM484M may include a first acoustic wave module (AWM)490A coupled between the loads94A,94B and a second acoustic wave module (AWM)490B coupled between the first AWM490A and load94B at one end and ground at the other.

The AWM490A and AWM490B may be single acoustic wave devices or a plurality of devices and variable capacitors in various configurations as shown and described above. In an embodiment, the IMM484P may be configured to provide a balancing impedance to architecture480N at a desired or target frequency. The IMM484P may be configured to add impedance to architecture480Q when output impedance is not equal to the input impedance. As noted, input and output impedance94A,94B may include a real and imaginary imbalance. As shown inFIG.30W, the first AWM490A may provide an effective inductor86J with inductance L. The inductance L may balance a real load difference between the input and output loads94A,94B and may balance an imaginary load differential. The borrowed inductance L via inductor86J may shift the effective inductance of the AWM490A by −L (86K) as represented by the block486A.

Similarly, the second AWM490B may provide an effective capacitor82J with capacitance C. The capacitance C may balance a real load difference between the input and output loads94A,94B and may balance an imaginary load differential. The borrowed capacitance C from capacitor82J may shift the effective capacitance of the AWM490A by −C(82K) as represented by the block487A. In an embodiment, the AWM490A and AWM490B may be selected to have a desired frequency response based on the borrowed or shifted inductance (AWM490A) or capacitance (AWM490B), the effect on a resonant or anti-resonant frequency of the AWM490A,490B due to the borrowed inductance or capacitance. For example, the AWM490A be configured to have a nominal frequency frthat is shifted to resonate at fr′by the inductor86J.

Applications that may include the novel apparatus and systems of various embodiments include electronic circuitry used in high-speed computers, communication and signal processing circuitry, modems, single or multi-processor modules, single or multiple embedded processors, data switches, and application-specific modules, including multilayer, multi-chip modules. Such apparatus and systems may further be included as sub-components within a variety of electronic systems, such as televisions, cellular telephones, personal computers (e.g., laptop computers, desktop computers, handheld computers, tablet computers, etc.), workstations, radios, video players, audio players (e.g., mp3 players), vehicles, medical devices (e.g., heart monitor, blood pressure monitor, etc.) and others. Some embodiments may include a number of methods.

It may be possible to execute the activities described herein in an order other than the order described. Various activities described with respect to the methods identified herein can be executed in repetitive, serial, or parallel fashion.

A software program may be launched from a computer-readable medium in a computer-based system to execute functions defined in the software program. Various programming languages may be employed to create software programs designed to implement and perform the methods disclosed herein. The programs may be structured in an object-orientated format using an object-oriented language such as Java or C++. Alternatively, the programs may be structured in a procedure-orientated format using a procedural language, such as assembly or C. The software components may communicate using a number of mechanisms well known to those skilled in the art, such as application program interfaces or inter-process communication techniques, including remote procedure calls. The teachings of various embodiments are not limited to any particular programming language or environment.

The accompanying drawings that form a part hereof show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived there-from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. § 1.72 (b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In the foregoing Detailed Description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted to require more features than are expressly recited in each claim. Rather, inventive subject matter may be found in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.