A tunable single-input dual-output (SIDO) acoustic filter circuit is provided. Specifically, the tunable SIDO acoustic filter circuit includes one input port and two output ports. The input port is configured to receive a signal in a band-pass frequency range or in a band-stop frequency range outside the band-pass frequency range. When the signal is modulated in the band-pass frequency range, the acoustic band-pass and band-stop filter can output the signal via a first one of the output ports. When the signal is modulated in the band-stop frequency range, the acoustic band-pass and band-stop filter can output the signal via a second one of the output ports. In an embodiment, the band-pass frequency range, and accordingly the band-stop frequency range, can be statically or dynamically tuned by a tuning voltage. As such, the tunable SIDO acoustic filter circuit can be flexibly tuned to support a variety of band-pass and band-stop frequencies.

FIELD OF THE DISCLOSURE

The technology of the disclosure relates generally to an acoustic filter that can be tuned to output a signal in two non-overlapping frequency ranges.

BACKGROUND

Wireless devices have become increasingly common in current society. The prevalence of these wireless devices is driven in part by the many functions that are now enabled on such devices for supporting a variety of applications. In this regard, a wireless device may employ a variety of circuits and/or components (e.g., filters, transceivers, antennas, and so on) to support different numbers and/or types of applications.

Ferroelectric acoustic resonators, such as ferroelectric bulk acoustic resonators (FBARs), offer ultra-small size and can operate at frequencies up to tens of gigahertz. As such, ferroelectric resonators are widely used as miniaturized filters in many high-frequency devices, such as fifth generation (5G) and 5G new radio (5G-NR) communication and/or navigation devices. The operating frequency (a.k.a. series/parallel resonance frequency) of a ferroelectric acoustic resonator is typically determined by an inner structure (e.g., thickness and elastic properties) of the ferroelectric acoustic resonator. As such, it is desirable to electrically control the ferroelectric acoustic resonator to operate at a desired operating frequency without changing the inner structure of the ferroelectric acoustic resonator.

SUMMARY

Aspects disclosed in the detailed description include a tunable single-input dual-output (SIDO) acoustic filter circuit. Specifically, the tunable SIDO acoustic filter circuit includes one input port and two output ports. The input port is configured to receive a signal, which can be modulated in a band-pass frequency range or a band-stop frequency range outside (a.k.a. non-overlapping with) the band-pass frequency range. When the signal is modulated in the band-pass frequency range, the acoustic band-pass and band-stop filter can output the signal via a first one of the output ports. When the signal is modulated in the band-stop frequency range, the acoustic band-pass and band-stop filter can output the signal via a second one of the output ports. In an embodiment, the band-pass frequency range, and accordingly the band-stop frequency range, can be statically or dynamically tuned by a tuning voltage. As a result, the tunable SIDO acoustic filter circuit can be flexibly tuned to support a variety of band-pass and band-stop frequencies.

In one aspect, an acoustic resonator structure is provided. The acoustic resonator structure includes a ferroelectric coupling layer. The ferroelectric coupling layer is configured to tune a band-pass frequency range in response to receiving a tuning voltage. The acoustic resonator structure also includes a pair of acoustic resonators. The pair of acoustic resonators are coupled to each other via the ferroelectric coupling layer. The pair of acoustic resonators is interconnected between an input port and an output port to block a signal between the input port and the output port inside the band-pass frequency range and pass the signal from the input port to the output port outside the band-pass frequency range.

In another aspect, a tunable SIDO acoustic filter circuit is provided. The tunable SIDO acoustic filter circuit includes an input circuit. The input circuit is configured to receive a signal and output the signal in a band-pass frequency range. The tunable SIDO acoustic filter circuit also includes an output circuit. The output circuit is configured to output the signal in a band-stop frequency range outside the band-pass frequency range. The tunable SIDO acoustic filter circuit also includes an in-phase path and a quadrature path. The in-phase path and the quadrature path are provided in parallel between the input circuit and the output circuit. Each of the in-phase path and the quadrature path is configured to block the signal in the band-pass frequency range to thereby cause the signal to be outputted from the input circuit. Each of the in-phase path and the quadrature path is also configured to pass the signal in the band-stop frequency range to thereby cause the signal to be outputted from the output circuit.

In another aspect, a wireless device is provided. The wireless device includes a tunable SIDO acoustic filter circuit. The tunable SIDO acoustic filter circuit includes an input circuit. The input circuit is configured to receive a signal and output the signal in a band-pass frequency range. The tunable SIDO acoustic filter circuit also includes an output circuit. The output circuit is configured to output the signal in a band-stop frequency range outside the band-pass frequency range. The tunable SIDO acoustic filter circuit also includes an in-phase path and a quadrature path. The in-phase path and the quadrature path are provided in parallel between the input circuit and the output circuit. Each of the in-phase path and the quadrature path is configured to block the signal in the band-pass frequency range to thereby cause the signal to be outputted from the input circuit. Each of the in-phase path and the quadrature path is also configured to pass the signal in the band-stop frequency range to thereby cause the signal to be outputted from the output circuit.

In another aspect, a method for operating a tunable SIDO acoustic filter circuit is provided. The method includes providing an in-phase path and a quadrature path in parallel between an input circuit and an output circuit. The method also includes configuring each of the in-phase path and the quadrature path to block a signal in a band-pass frequency range to thereby cause the signal to be outputted from the input circuit. The method also includes configuring each of in-phase path and the quadrature path to pass the signal in a band-stop frequency range outside the band-pass frequency range to thereby cause the signal to be outputted from the output circuit.

DETAILED DESCRIPTION

Aspects disclosed in the detailed description include a tunable single-input dual-output (SIDO) acoustic filter circuit. Specifically, the tunable SIDO acoustic filter circuit includes one input port and two output ports. The input port is configured to receive a signal, which can be modulated in a band-pass frequency range or a band-stop frequency range outside (a.k.a. non-overlapping with) the band-pass frequency range. When the signal is modulated in the band-pass frequency range, the acoustic band-pass and band-stop filter can output the signal via a first one of the output ports. When the signal is modulated in the band-stop frequency range, the acoustic band-pass and band-stop filter can output the signal via a second one of the output ports. In an embodiment, the band-pass frequency range, and accordingly the band-stop frequency range, can be statically or dynamically tuned by a tuning voltage. As a result, the tunable SIDO acoustic filter circuit can be flexibly tuned to support a variety of band-pass and band-stop frequencies.

FIG.1is a schematic diagram illustrating an exemplary definition of a band-pass frequency range10and a band-stop frequency range12in context of the present disclosure. As illustrated inFIG.1, the band-stop frequency range12is located outside the band-pass frequency range10. In other words, the band-stop frequency range12does not overlap with the band-pass frequency range10.

In context of the present disclosure, the band-pass frequency range10and the band-stop frequency range12are contrary to conventional definitions of a band-pass frequency region and a band-stop frequency region. Herein, the band-pass frequency range10defines a frequency range wherein a signal will be blocked and the band-stop frequency range12defines a frequency range wherein a signal will not be blocked (a.k.a. passed). As discussed below, the band-pass frequency range10and, accordingly the band-stop frequency range12, can be tuned (a.k.a. changed) either statically or dynamically.

FIG.2Ais a schematic diagram of an exemplary acoustic resonator structure14A configured according to one embodiment of the present disclosure to block a signal16between an input port SIN and an output port Sour in the band-pass frequency range10inFIG.1and pass the signal16from the input port SIN to the output port Sour in the band-stop frequency range12inFIG.1. Common elements betweenFIGS.1and2Aare referenced therein with common element numbers and will not be re-described herein.

The acoustic resonator structure14A includes a first acoustic resonator18, a second acoustic resonator20, and a ferroelectric coupling layer22. The first acoustic resonator18includes a first electrode24, a second electrode26, and a first piezoelectric layer28provided between the first electrode24and the second electrode26. The second acoustic resonator20includes a third electrode30, a fourth electrode32, and a second piezoelectric layer34provided between the third electrode30and the fourth electrode32.

The first acoustic resonator18and the second acoustic resonator20are acoustically coupled via the ferroelectric coupling layer22. The ferroelectric coupling layer22can be tuned, either statically or dynamically, by a tuning voltage VDCto cause the first acoustic resonator18and the second acoustic resonator20to each resonate in the band-pass frequency range10.

To cause the first acoustic resonator18and the second acoustic resonator20to each block the signal16between the input port SIN and the output port Sour in the band-pass frequency range10, the acoustic resonator structure14A is configured herein to cause a first current I1in the first acoustic resonator18to have an opposite polarity from a second current I2in the second acoustic resonator20. As a result, the first current I1will offset the second current I2in the band-pass frequency range10to thereby prevent the signal16from flowing from the input port SINto the output port Sour. In a way, a nullification of the first current I1and the second current I2is equivalent to creating a high impedance between the input port SINto the output port Sour to thereby block the signal16.

Outside the band-pass frequency range10, the first current I1will not completely offset the second current I2. In other words, a lower impedance will be created between the input port SINto the output port Sour to thereby pass the signal16from the input port SINto the output port SOUT.

In an embodiment, the first electrode24of the first acoustic resonator18and the third electrode30of the second acoustic resonator20are both connected to the input port SIN, and the second electrode26of the first acoustic resonator18and the fourth electrode32of the second acoustic resonator20are both connected to the output port Sour. To nullify the first current I1and the second current I2, the first piezoelectric layer28and the second piezoelectric layer34are made with an inverted polarity material (e.g., aluminum nitride). For example, the first piezoelectric layer28can be made with a c-type piezoelectric material and the second piezoelectric layer34can be made with an f-type piezoelectric material.

FIG.2Bis a schematic diagram of an exemplary acoustic resonator structure14B configured according to another embodiment of the present disclosure to block the signal16between the input port SINand the output port SOUTin the band-pass frequency range10inFIG.1and pass the signal16from the input port SINto the output port Sour in the band-stop frequency range12inFIG.1. Common elements betweenFIGS.2A and2Bare referenced therein with common element numbers and will not be re-described herein.

The acoustic resonator structure14B includes a first acoustic resonator36, a second acoustic resonator38, and a ferroelectric coupling layer40. The first acoustic resonator36includes a first electrode42, a second electrode44, and a first piezoelectric layer46provided between the first electrode42and the second electrode44. The second acoustic resonator38includes a third electrode48, a fourth electrode50, and a second piezoelectric layer52provided between the third electrode48and the fourth electrode50.

The first acoustic resonator36and the second acoustic resonator38are acoustically coupled via the ferroelectric coupling layer40. The ferroelectric coupling layer40can be tuned, either statically or dynamically, by a tuning voltage VDCto cause the first acoustic resonator36and the second acoustic resonator38to each resonate in the band-pass frequency range10.

To cause the first acoustic resonator36and the second acoustic resonator38to each block the signal16between the input port SINand the output port Sour in the band-pass frequency range10, the acoustic resonator structure14B is also configured herein to cause the first current I1in the first acoustic resonator36to have an opposite polarity from the second current I2in the second acoustic resonator38. As a result, the first current I1will offset the second current I2in the band-pass frequency range10to thereby prevent the signal16from flowing from the input port SINto the output port Sour. In a way, a nullification of the first current I1and the second current I2is equivalent to creating a high impedance between the input port SINto the output port Sour to thereby block the signal16.

Outside the band-pass frequency range10, the first current I1will not completely offset the second current I2. In other words, a lower impedance will be created between the input port SINto the output port Sour to thereby pass the signal16from the input port SINto the output port SOUT.

In an embodiment, the first electrode42of the first acoustic resonator36and the fourth electrode50of the second acoustic resonator38are both connected to the input port SIN, and the second electrode44of the first acoustic resonator36and the third electrode48of the second acoustic resonator38are both connected to the output port SOUT. By interconnecting the first acoustic resonator36and the second acoustic resonator38between the input port SINto the output port Sour, as illustrated herein, the first current I1and the second current I2will be nullified to thereby block the signal16between the input port SINand the output port SOUT.

The acoustic resonator structure14A ofFIG.2Aand/or the acoustic resonator structure14B ofFIG.2Bcan be provided in a SIDO acoustic filter circuit to selectively output the signal16in the band-pass frequency range10or in the band-stop frequency range12.FIG.3is a schematic diagram of an exemplary tunable SIDO acoustic filter circuit54configured using the acoustic resonator structure14A inFIG.2Aand/or the acoustic resonator structure14B inFIG.2B. Common elements betweenFIGS.2A,2B, and3are referenced therein with common element numbers and will not be re-described herein.

Herein, the tunable SIDO acoustic filter circuit54includes a single input port SINand two output ports, namely a band-pass output port SOUT-BPand a band-stop output port SOUT-BS. The tunable SIDO acoustic filter circuit54is configured to receive the signal16via the input port SIN. When the signal16is modulated in the band-pass frequency range10, the tunable SIDO acoustic filter circuit54outputs the signal16via the band-pass output port SOUT-BP. When the signal16is modulated in the band-stop frequency range12, the tunable SIDO acoustic filter circuit54outputs the signal16via the band-stop output port SOUT-BS.

In an embodiment, the tunable SIDO acoustic filter circuit54includes an input circuit56and an output circuit58. Herein, the input circuit56is coupled to the input port SINand the band-pass output port SOUT-BP, and the output circuit58is coupled to the band-stop output port SOUT-BSand a terminating port STERM. The tunable SIDO acoustic filter circuit54also includes a pair of acoustic resonator structures60,62provided in parallel between the input circuit56and the output circuit58. Herein, each of the acoustic resonator structures60,62can be the acoustic resonator structure14A or the acoustic resonator structure14B. Accordingly, each of the acoustic resonator structures60,62can be tuned to block the signal16between the input circuit56and the output circuit58in the band-pass frequency range10and pass the signal16from the input circuit56to the output circuit58in the band-stop frequency range12.

The input circuit56is configured to receive the signal16via the input port SINand split the signal16into an in-phase signal16I and a quadrature signal16Q, each having an identical content and in an identical frequency range (e.g., the band-pass frequency range10or the band-stop frequency range12) as the signal16, but with less power (e.g., one-half) compared to the signal16. The input circuit56then outputs the in-phase signal16I and the quadrature signal16Q via an in-phase output64and a quadrature output66, respectively.

In an embodiment, the acoustic resonator structure60is coupled to the in-phase output64to receive the in-phase signal16I. As such, the acoustic resonator structure60is also referred to as an in-phase path60. The acoustic resonator structure62, on the other hand, is coupled to the quadrature output66to receive the quadrature signal16Q. Accordingly, the acoustic resonator structure62is also referred to as a quadrature path62.

As previously discussed inFIGS.2A and2B, the in-phase path60and the quadrature path62can each be configured to block a respective one of the in-phase signal16I and the quadrature signal16Q, and to pass the respective one of the in-phase signal16I and the quadrature signal16Q. In this regard, when the in-phase signal16I and the quadrature signal16Q fall within the band-pass frequency range10, the in-phase path60will reflect the in-phase signal16I back toward the in-phase output64and the quadrature path62will reflect the quadrature signal16Q back toward the quadrature output66. The input circuit56, in turn, will make a ninety-degree) (90° phase shift on the reflected in-phase signal16| (BP) and then combine with the reflected quadrature signal16Q (BP) to thereby output the signal16via the band-pass output port SOUT-BP.

In contrast, when the in-phase signal16I and the quadrature signal16Q fall within the band-stop frequency range12, the in-phase path60will pass the in-phase signal16I to an in-phase input68of the output circuit58and the quadrature path62will pass the quadrature signal16Q to a quadrature input70of the output circuit58. The output circuit58, in turn, will make a 90° phase shift on the in-phase signal16I (BS) and then combine with the received quadrature signal16Q (BS) to thereby output the signal16via the band-stop output port SOUT-BS.

The topology of the tunable SIDO acoustic filter circuit54may be extended to form a SIDO acoustic filter network. In this regard,FIG.4is a graphic diagram of an exemplary SIDO acoustic filter network72adapted from the tunable SIDO acoustic filter circuit54ofFIG.3. Common elements betweenFIGS.3and4are referenced therein with common element numbers and will not be re-described herein.

Herein, the SIDO acoustic filter network72includes an in-phase path74and a quadrature path76. In an embodiment, the in-phase path74includes a pair of in-phase acoustic resonator structures78,80and an in-phase acoustic shunt resonator structure82coupled between the in-phase acoustic resonator structures78,80. Each of the in-phase acoustic resonator structures78,80and the in-phase acoustic shunt resonator structure82can be configured to function as the acoustic resonator structure14A or the acoustic resonator structure14B.

The quadrature path76includes a pair of quadrature acoustic resonator structures84,86and a quadrature acoustic shunt resonator structure88coupled between the quadrature acoustic resonator structures84,86. Each of the quadrature acoustic resonator structures84,86and the quadrature acoustic shunt resonator structure88can be configured to function as the acoustic resonator structure14A or the acoustic resonator structure14B.

In an embodiment, the SIDO acoustic filter network72may provide a finer filtering in the band-stop frequency range12. As an example, the in-phase shunt acoustic resonator structure82can shunt a portion of the in-phase signal16| (BS) outputted by the in-phase acoustic resonator structure78and then provide a remainder of the in-phase signal16I (BS)′ to the in-phase acoustic resonator structure80. Likewise, the quadrature shunt acoustic resonator structure88can shunt a portion of the quadrature signal16Q (BS) outputted by the quadrature acoustic resonator structure84and then provide a remainder of the quadrature signal16Q (BS)′ to the quadrature acoustic resonator structure86.

The tunable SIDO acoustic filter circuit54ofFIG.3and the Tunable SIDO acoustic filter circuit72ofFIG.4can be provided in a communication device to support the embodiments described above. In this regard,FIG.5is a schematic diagram of an exemplary communication device100wherein the tunable SIDO acoustic filter circuit54ofFIG.3and the Tunable SIDO acoustic filter circuit72ofFIG.4can be provided.

Herein, the communication device100can be any type of communication devices, such as mobile terminals, smart watches, tablets, computers, navigation devices, access points, and like wireless communication devices that support wireless communications, such as cellular, wireless local area network (WLAN), Bluetooth, and near field communications. The communication device100will generally include a control system102, a baseband processor104, transmit circuitry106, receive circuitry108, antenna switching circuitry110, multiple antennas112, and user interface circuitry114. In a non-limiting example, the control system102can be a field-programmable gate array (FPGA), as an example. In this regard, the control system102can include at least a microprocessor(s), an embedded memory circuit(s), and a communication bus interface(s). The receive circuitry108receives radio frequency signals via the antennas112and through the antenna switching circuitry110from one or more base stations. A low noise amplifier and a filter cooperate to amplify and remove broadband interference from the received signal for processing. Downconversion and digitization circuitry (not shown) will then downconvert the filtered, received signal to an intermediate or baseband frequency signal, which is then digitized into one or more digital streams using an analog-to-digital converter(s) (ADC).

The baseband processor104processes the digitized received signal to extract the information or data bits conveyed in the received signal. This processing typically comprises demodulation, decoding, and error correction operations, as will be discussed in greater detail below. The baseband processor104is generally implemented in one or more digital signal processors (DSPs) and application specific integrated circuits (ASICs).

For transmission, the baseband processor104receives digitized data, which may represent voice, data, or control information, from the control system102, which it encodes for transmission. The encoded data is output to the transmit circuitry106, where a digital-to-analog converter(s) (DAC) converts the digitally encoded data into an analog signal and a modulator modulates the analog signal onto a carrier signal that is at a desired transmit frequency or frequencies. A power amplifier will amplify the modulated carrier signal to a level appropriate for transmission, and deliver the modulated carrier signal to the antennas112through the antenna switching circuitry110. The multiple antennas112and the replicated transmit and receive circuitries106,108may provide spatial diversity. Modulation and processing details will be understood by those skilled in the art.

In an embodiment, the tunable SIDO acoustic filter circuit54ofFIG.3and the Tunable SIDO acoustic filter circuit72ofFIG.4can be provided in the transmit circuitry106, the receive circuitry108, and/or the antenna switching circuitry110. Understandably, tunable SIDO acoustic filter circuit54and the Tunable SIDO acoustic filter circuit72may also be provided anywhere else in the communication device100.

In an embodiment, the tunable SIDO acoustic filter circuit54ofFIG.3and the SIDO acoustic filter network72ofFIG.4can be operated in accordance with a process. In this regard,FIG.6is a flowchart of an exemplary process200for operating tunable SIDO acoustic filter circuit54ofFIG.3and the SIDO acoustic filter network72ofFIG.4.

Herein, the process200includes providing the in-phase path60,74and the quadrature path62,76in parallel between the input circuit56and the output circuit58(step202). The process200also includes configuring each of the in-phase path60,74and the quadrature path62,76to block the signal16in the band-pass frequency range10to thereby cause the signal16to be outputted from the input circuit56(step204). The process200also includes configuring each of the in-phase path60,74and the quadrature path62,76to pass the signal16in the band-stop frequency range12to thereby cause the signal16to be outputted from the output circuit58(step206).