TSV phase shifter

A phase shifter includes functional actively controlled phase-shift elements formed with TSVs. The phase shifter may include plural phase shifter elements each including: a signal line including a signal line through-substrate-via (TSV) in a substrate; a ground return line including a ground return line TSV in the substrate; a capacitance control line including a capacitance control line TSV in the substrate; and an inductance control line including an inductance control line TSV in the substrate, wherein the phase shifter element has one of a first phase shift and a second phase shift, different from the first phase shift, based on a capacitance and an inductance of the signal line TSV.

BACKGROUND

The present invention relates generally to wireless communication systems and, more particularly, to a system that utilizes through-substrate-vias (TSVs) in phase shifter elements of a phased array antenna to achieve a desired direction of a beam formed by the phased array antenna.

Phase shifters are a component of phased array antenna systems which are used to directionally steer radio frequency (RF) beams for electronic communications or radar. A phased array antenna is a group of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions. The relative amplitudes of, and constructive and destructive interference effects among, the signals radiated by the individual antennas determine the effective radiation pattern of the array. By controlling the radiation pattern through the constructive and destructive superposition of signals from the different antennas in the array, phased array antennas electronically steer the directionality of the antenna system, referred to as beam forming or beam steering. In such systems, the direction of the radiation (i.e., the beam) can be changed by manipulating the phase of the signal fed into each individual antenna of the array, e.g., using a phase shifter.

Beam steering advantageously increases the signal to noise ratio (SNR) of the antenna system up to an order of magnitude or more compared to antenna systems that do not employ beam steering. An increased SNR reduces the amount of power used by the antenna system to transmit the radiation to a receiving antenna, and also permits a higher bandwidth in communication. As a result, beam steering systems have become a focus of the next-generation wireless communication systems including 5G and 6G. For example, it is envisioned that 5G and 6G systems will utilize fixed-location base stations (e.g., antennas) that steer beams toward users' wireless devices (e.g., smartphones, etc.) on an as-needed basis.

SUMMARY

In a first aspect of the invention, there is a phase shifter element including: a signal line including a signal line through-substrate-via (TSV) in a substrate; a ground return line including a ground return line TSV in the substrate; a capacitance control line including a capacitance control line TSV in the substrate; and an inductance control line including an inductance control line TSV in the substrate, wherein the phase shifter element has one of a first phase shift and a second phase shift, different from the first phase shift, based on a capacitance and an inductance of the signal line TSV.

In another aspect of the invention, there is a phased array including: plural phase shifters respectively connected to plural antenna elements, wherein: each of the plural phase shifters comprises plural phase shifter elements; and each respective one of the plural phase shifter elements comprises a signal line through-substrate-via (TSV) whose phase shift is configurable using an inductance switch and a capacitance switch in the respective phase shifter element.

In another aspect of the invention, there is a method including: determining a desired direction of a phased array antenna; and controlling switches in plural phase shifter elements in plural phase shifters of the phased array antenna to set respective phase shifts in the plural phase shifters to achieve the desired direction of the phased array antenna, wherein each respective one of the plural phase shifter elements comprises a signal line through-substrate-via (TSV) whose phase shift is configurable using an inductance switch and a capacitance switch in the respective phase shifter element.

DETAILED DESCRIPTION

The present invention relates generally to wireless communication systems and, more particularly, to a system that utilizes through-substrate-vias (TSVs) in phase shifter elements of a phased array antenna to achieve a desired direction of a beam formed by the phased array antenna. Utilizing TSVs as functional phase shifters and tunable matching circuits offers several advantages. First, from a practical standpoint, TSVs are often much larger than on-chip interconnects and therefore have lower metallic RF loss compared to on chip conduction paths (of course this is material dependent; but generally the cross-sectional area and cross-sectional perimeter of TSVs is much larger than the on-chip equivalent). Recognizing that the large cross-sectional area of TSVs provides lower loss per unit length, implementations of the invention utilize TSVs to provide lower loss phase shifters and impedance tuning networks. Second, circuits implemented using TSVs offer the potential of on-chip area reduction as the functional circuit components are now vertical instead of horizontal. For example, a TSV can typically be around 200 μm in length for a 200 mm wafer diameter process but can be shorter and longer in other processes. In the example of a 200 μm TSV, a system achieves 200 μm worth of phase shift in a relatively small area on chip. Third, the TSV configurations possible to control inductance and capacitance are not possible with conventional on-chip interconnect and allow different fundamental design choices that allow greater/more-effective inductance and capacitance tuning than is possible in on-chip designs. These advantages lead to overall system performance improvements. These devices may be able to achieve 60 degrees/dB phase change per dB of loss and have inductance tuning high-low ratios in excess of 3.

Implementations of the invention include phase shifters that use TSVs as the functional control elements of both phase and characteristic impedance (Zo). TSV phase shifters made in accordance with aspects of the invention provide several advantages: reduced area makes it compatible with 6G/high-MMW frequencies such as 77 GHz and above; allows greater phase tuning range than normally possible per unit substrate area, which results in lower loss per degree phase change; lower RF loss assuming using low resistivity substrates and typical TSV cross sections; offers great design flexibility connecting to antenna array, particularly for 6G antenna elements whose antenna arrays are chip scale; and is compatible with construction of multi-band phased array using common chip and antenna array.

As described herein, implementations of the invention provide: a phase shifter whose with functional actively controlled phase-shift elements are formed with TSVs; a phase shifter whose characteristic impedance is controlled actively controlled using elements formed from TSVs; an antenna array assembly whose actively controlled phase shift elements are formed using TSVs; an antenna controlled matching network whose impedance matching circuits are controlled using TSV elements; and a multiband phased array assembly whose functional control elements are formed of TSVs.

FIG.1shows an exemplary phased array antenna system that may be used with aspects of the invention. In the example shown inFIG.1, the phased array antenna system10comprises a 4×4 array of antenna elements15-1,15-2, . . . ,15-iincluded in a coin-shaped sensor20. In this example “i” equals sixteen; however, the number of antenna elements shown inFIG.1is not intended to be limiting, and the phased array antenna system10may have a different number of antenna elements. Similarly, the implementation in the coin-shaped sensor20is only for illustrative purposes, and the phased array antenna system10may be implemented in different structures.

Still referring toFIG.1, the arrow “A” represents a direction of the beam that is formed by the phased array antenna system10using constructive and destructive superposition of signals from the antenna elements15-1,15-2, . . . ,15-iusing beam steering principles. Angle θ represents the polar angle and angle φ represents the azimuth angle of the direction of the arrow A relative to a frame of reference25defined with respect to the phased array antenna system10.

FIG.2shows a block diagram of an arrangement of components within the phased array antenna system10in accordance with aspects of the invention. In embodiments, a respective phase shifter PS-1, PS-2, . . . , PS-i and amplifier A-1, A-2, . . . , A-i are connected to each respective one of the antenna elements15-1,15-2, . . . ,15-i. In particular embodiments, the respective phase shifter PS-1, PS-2, . . . , PS-i and amplifier A-1, A-2, . . . , A-i are connected in series upstream of the respective one of the antenna elements15-1,15-2, . . . ,15-ias shown inFIG.2. In implementations, a respective transmission signal is provided to each of the phase shifters PS-1, PS-2, . . . , PS-i, e.g., from a power splitter30such as one or more Wilkinson power dividers. In accordance with aspects of the invention, a respective phase shifter (e.g., PS-i) shifts the phase by a predefined amount, the amplifier (A-i) amplifies the phase shifted signal, and the antenna element (15-i) transmits the amplified and phase shifted signal.

FIG.3shows a block diagram of an arrangement of phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n within a respective one of the phase shifters PS-i in accordance with aspects of the invention. In embodiments, the phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n are electrically connected in series in the phase shifter PS-i as depicted inFIG.3. The number “n” of phase shifter elements may be any desired number. In a particular embodiment n=14; however, other numbers of phase shifter elements may be used in implementations of the invention. According to aspects of the invention, each one of the phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n comprises a respective structure as described with respect toFIG.4.

FIG.4shows a diagram of an exemplary structure of a phase shifter element40of a representative one of the phase shifter elements PSE-i,n in accordance with aspects of the invention. In embodiments, the phase shifter element40comprises a signal line45, at least one ground return line50, a capacitance control line55, and an inductance control line60. In embodiments, the signal line45is configured to conduct an RF signal such as that used in 5G and 6G wireless communication systems. The ground return line50can be representative of a non-switchable conductor connected to ground. The capacitance control line55can be representative of a switchable conductor connected to ground. The inductance control line60can be representative of a switchable conductor that is connected between ground lines and provides a conditional ground return path.

In accordance with aspects of the invention, the signal line45includes at least one signal line TSV46that extends through a substrate67from a first side68to a second side69of the substrate67. In embodiments, the signal line45includes a first signal line portion47connected to a first side of the signal line TSV46, and a second signal line portion48connected to a second side of the signal line TSV46that is opposite the first side of the signal line TSV46. The components of the signal line45, including the signal line TSV46, the first signal line portion47, and the second signal line portion48, are composed of metal or other electrical conductor material. As shown inFIG.4, node84represents a “signal in” node and node86represents a “signal out” node for the phase shifter element40.

In accordance with aspects of the invention, the at least one ground return line50includes at least one ground return line TSV51that extends through the substrate67from the first side68to the second side69of the substrate67. In embodiments, the ground return line50includes a first ground return line portion52connected to a first side of the ground return line TSV51, and a second ground return line portion53connected to a second side of the ground return line TSV51that is opposite the first side of the ground return line TSV51. The components of the ground return line50, including the ground return line TSV51, the first ground return line portion52, and the second ground return line portion53, are composed of metal or other electrical conductor material.

In accordance with aspects of the invention, the capacitance control line55includes at least one capacitance control line TSV56that extends through the substrate67from the first side68to the second side69of the substrate67. In embodiments, the capacitance control line55includes a first capacitance control line portion57connected to a first side of the capacitance control line TSV56. In embodiments, a second side of the capacitance control line TSV56, opposite the first side of the capacitance control line TSV56, is not connected to any conductive material. The components of the capacitance control line55, including the capacitance control line TSV56and the first capacitance control line portion57are composed of metal or other electrical conductor material.

In embodiments, the capacitance control line55includes a switch circuit SC that includes at least one switch and at least one capacitor. An example of the switch circuit SC is shown inFIG.5. In accordance with aspects of the invention, the switch circuit SC is used to control a capacitance state of the signal line TSV46in the manner described with respect toFIG.5.

In accordance with aspects of the invention, the inductance control line60includes at least one inductance control line TSV61that extends through the substrate67from the first side68to the second side69of the substrate67. In embodiments, the inductance control line60includes a first inductance control line portion62connected to a first side of the inductance control line TSV61, and a second inductance control line portion63connected to a second side of the inductance control line TSV61that is opposite the first side of the inductance control line TSV61. The components of the inductance control line60, including the inductance control line TSV61, the first inductance control line portion62, and the second inductance control line portion63, are composed of metal or other electrical conductor material.

In embodiments, the inductance control line60includes a switch96, which may be a FET (field effect transistor), for example. In accordance with aspects of the invention, the switch96is used to control an inductance state of the signal line TSV46in the manner described with respect toFIG.5.

In embodiments, the first signal line portion47, the first ground return line portion52, the first capacitance control line portion56, and the first inductance control line portion61are all located in one or more layers (e.g., back end of line (BEOL) layers) on the first side68of the substrate67. In embodiments, the second signal line portion48, the second ground return line portion53, and the second inductance control line portion62are all located in one or more layers (e.g., BEOL layers) on the second side69of the substrate67.

The substrate67may be composed of any suitable material or combination of materials, such as diamond, doped or undoped silicon, glass, sapphire, ceramic, etc. In embodiments, the substrate67has a thickness in a range of 100 μm to 400 μm between the first side68and the second side69in the z direction shown inFIG.4.

In embodiments, a cross sectional area of individual ones of the TSVs46,51,56,61is much larger than a cross sectional area of transmission lines that are conventionally used in phase shifters. For example, transmission lines that are conventionally used in phase shifters typically have a thickness of 1.2 μm and a width of 6 μm, for a cross sectional area of 7.2 μm2measured in a plane perpendicular to the primary direction of current flow. However, in embodiments described herein, the TSVs have a length of 5 μm in the x direction and a width of 20 μm in the y direction, for a cross sectional area of 100 μm2(also measured in a plane perpendicular to the primary direction of current flow), which is more than ten times greater than the cross sectional area of conventional transmission lines. This larger cross section per unit length for the TSVs means that the TSVs has less loss per unit length than do the conventional transmission lines. As a result, a phase shifter that includes one or more TSVs in the signal line has less loss than a phase shifter than uses only smaller transmission lines. Although rectangular TSV are described herein for purposes of illustrating aspects of the invention, embodiments are not limited to any particular shape of TSV. Instead, any desired shape TSV may be utilized.

FIG.5shows a schematic diagram of the phase shifter element40ofFIG.4in accordance with aspects of the invention. An inductance72represents the self-inductance of the signal line45, an inductance74represents the self-inductance of the ground return line50, and an inductance76represents the self-inductance of the inductance control line60. Coupling inductances exist between these lines as well, with a mutual inductance between the signal line45and the inductance control line60, a mutual inductance between the signal line45and the ground lines50, and a mutual inductance between the ground lines50and the inductance control line60.

Still referring toFIG.5, resistance78represents the resistance of the signal line45, resistance80represents the resistance of the ground return line50, and resistance82represents the resistance of the inductance control line60, as defined by their materials and geometries. Capacitance90(with a value of Ca) represents a capacitance between the signal line TSV46and the capacitance control line TSV56, and capacitance92(with a value of Cb) represents a capacitance between the capacitance control line TSV56and the ground return line TSV51plus any other ground metal in the phase shifter element40.

In embodiments, the inductance and the capacitance of the phase shifter element40are controlled through separate networks and are controlled independently. In operation, the open or closed state of the inductance switch96affects the signal inductance (L) in the signal line TSV46, and the open or closed state of a capacitance switch98in the switch circuit SC affects the signal capacitance (C) in the signal line TSV46.

For example, when the inductance switch96is in an ON state (i.e., closed), return current flows in the inductance control line TSV61and signal inductance (L) is in a low state (Llow). On the other hand, when the inductance switch96is in an OFF state (i.e., open), return current does not flow in the inductance control line TSV61such that signal inductance (L) is in a high state (Lhigh).

Similarly, when the capacitance switch98is in an ON state (i.e., closed), the signal capacitance (C) is equal to that of capacitance90(e.g., Ca), which is a high capacitance state (Chigh). On the other hand, when the capacitance switch98is in an OFF state (i.e., open), then the signal capacitance (C) equals (Ca*Ceff)/(Ca+Ceff), which equals Ca/2 when Ca=Ceff, and which is a low capacitance state (Clow), where Ceffequals Cb+CFETwhere CFETequals the capacitance of the switch in the OFF state. This is summarized in Table 1.

The phase shift (also referred to as the delay) of the signal travelling from node84to node86is affected by the signal inductance (L) and the signal capacitance (C) according to the relation: delay∝SQRT(L*C). Therefore, the phase shift of the signal travelling from node84to node86can be changed by opening or closing the inductance switch96, which changes the value of the signal inductance (L), and/or opening or closing the capacitance switch98, which changes the value of the signal capacitance (C).

In a particular embodiment, in order to maintain a substantially constant characteristic impedance of the signal line45, the elements of the phase shifter element40are sized and shaped such that (Lhigh/Llow)=(Chigh/Clow). The characteristic impedance of the signal line45is defined as Zo=SQRT(Llow/Clow)=SQRT(Lhigh/Chigh). In this embodiment, to maintain a substantially constant characteristic impedance for different amounts of delay, the phase shifter element40of the phase shifter element PSE-i,n is programmed in only one of two configurations: (i) the inductance switch96is ON and the capacitance switch98is OFF to provide a fast state, e.g., a smaller delay given by delay=SQRT(Llow*Clow); and (ii) the inductance switch96is OFF and the capacitance switch98is ON to provide a slow state, e.g., a larger delay given by delay=SQRT(Lhigh*Chigh). In this manner, the phase shifter element40has one of a first phase shift and a second phase shift, different from the first phase shift, based on a capacitance and an inductance of the signal line TSV46. This is summarized in Table 2.

In accordance with aspects of the invention, the phase shifter element40may be used as a TSV impedance matching circuit. In one example, the “signal out” terminal (i.e., node86) is eventually terminated to ground, and the RF impedance seen from the “signal in” terminal (i.e. node84) can be dynamically tuned for optimal RF performance. The device would be suited for dynamic impedance correcting/matching for RF/MMW amplifiers and phased array antenna elements. In this example, the “signal out” terminal (i.e., node86) may be eventually terminated to ground after passing through plural phase shifter elements40connected in series, e.g., in a serpentine fashion as shown inFIG.6.

With continued reference toFIG.5, node84represents the “signal in” node and node86represents the “signal out” node for the phase shifter element40for this phase shifter element PSE-i,n. When the phase shifter elements PSE-i,1, PSE-i,2, PSE-i,n are electrically connected in series in the phase shifter PS-i as depicted inFIG.3, the node86of phase shifter element PSE-i,1is connected to node84of phase shifter element PSE-i,2and so on. Moreover, the input node84of phase shifter element PSE-i,1is connected to (and receives the signal from) the power splitter30as shown inFIG.2. Additionally, the output node86of the phase shifter element PSE-i,n is connected to (and provides the phase shifted signal to) the amplifier A-i as shown inFIG.2. In this manner, the phase shift of the signal passing through any one phase shifter PS-i is the cumulative result of all the phase shifts applied by the respective phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n within that phase shifter PS-i.

In a particular embodiment, a memory included in the phased array antenna system10(ofFIG.1) stores data that defines which switches96,98to open and close for plural different combinations of values of angle θ (i.e., the polar angle of the direction of the arrow A) and angle φ (i.e., the azimuth angle of the direction of the arrow A). In this embodiment, for a desired combination of values of angles θ and φ, a control circuit in the system uses the stored data to determine which switches96,98to open and close (for each of the phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n included in each of the phase shifters PS-1, PS-2, . . . , PS-i) to achieved the desired combination of values of angles θ and cp. In this manner, once the desired direction of the phased array antenna system10is determined (e.g., as defined by particular a combination of values of angles θ and φ), the system controls the switches96,98in the phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n included in each of the phase shifters PS-1, PS-2, . . . , PS-i to achieve this desired direction. Subsequently, the system may determine a different direction A with a different combination of values of angles θ and φ, and the system may then control the switches96,98in the phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n included in each of the phase shifters PS-1, PS-2, . . . , PS-i to achieve this different direction. In embodiments, the phased array antenna system10is configured for automatically determining the direction A as defined by particular a combination of values of angles θ and φ. Such automatic determination of a direction of a phased array antenna system is sometimes referred to as “self-installation” and/or “tracking” and is described, for example, in United States Patent Application Publication No. 2019/0089434, published Mar. 21, 2019, the contents of which are expressly incorporated by reference herein in their entirety. Based on such automatic determination of the direction A, the system may control the switches96,98in the phase shifter elements PSE-i,1, PSE-i,2, . . . , PSE-i,n included in each of the phase shifters PS-1, PS-2, . . . , PS-i to achieve this desired direction, in the manner described herein.

FIG.6shows a phase shifter comprising plural phase shifter elements in accordance with aspects of the invention. In particular,FIG.6shows a chain of six phase shifter elements40.1,40.2,40.3,40.4,40.5,40.6connected in series to form a phase shifter PS-i as shown inFIG.3, for example. Each of the six phase shifter elements40.1-40.6may comprise an instance of the phase shifter element40shown inFIG.4, with the signal in node of one of the phase shifter elements connected to the signal out node of the next one of the phase shifter elements, e.g., as described herein. The signal in node of the first phase shifter element40.1is an “in” terminal of the phase shifter PS-i, and the signal out node of the last phase shifter element40.6is an “out” terminal of the phase shifter PS-i. In embodiments, when the “out” terminal is grounded, the “in” terminal is a tunable load connection.

As shown inFIG.6, in embodiments the phase shifter elements40.1-40.6are formed in a substrate67having a first side68and a second side69. In embodiments, the wiring connections between respective ones of the phase shifter elements40.1-40.6are formed in one or more layers (e.g., BEOL wiring layers) formed on the first side68and a second side69of the substrate67.

The number of phase shifter elements shown inFIG.6is exemplary and not limiting. Phase shifters PS-i may be made in accordance with aspects of the invention with other numbers of phase shifter elements.

FIG.7shows a system in accordance with aspects of the invention. In embodiments, the system includes the phase shifter shown inFIG.6including plural phase shifter elements connected in series, with each of the phase shifter elements comprising TSVs in the substrate67. In embodiments, a heat sink120is arranged at the first side68of the substrate67, and an antenna substrate125is arranged at the second side69of the substrate67. For example, the heat sink120may be connected to the outermost layer on the first side68of the substrate67, and the antenna substrate125may be connected to the outermost layer on the second side69of the substrate67.

In embodiments, the antenna substrate125includes the antenna elements15-1through15-ishown inFIGS.1and2. Although not shown, the substrate67may include plural individual phase shifters PS-1through PS-i, the number of phase shifters matching the number of antenna elements in the antenna substrate125, with respective ones of the phase shifters being operatively connected (e.g., by wiring, transmission lines, etc.) to respective ones of the antenna elements, e.g., as depicted inFIG.2.

In embodiments, the system ofFIG.7is constructed such that a majority of the active circuitry of the phased array antenna system (e.g., amplifiers) is at the second side68of the substrate67. In this manner, a majority of the primary heat-generating elements are closer to the heat sink120, which can more effectively dissipate the heat generated by such elements.

It is envisioned that 6G phased array antennas will look similar to that shown inFIG.7and that TSVs will be present in the array to take signals from one side of the chip to the other side where the antenna array is. This configuration allows the hotter IC circuitry to be placed closer to the heat sink as depicted inFIG.7. Implementations of the invention utilize the TSVs to provide phase shifting functionality. Having functional elements (such as phase shifters) within the TSV paths is advantageous because it reduces the size of the system and gives RF/MMW designers design flexibility on where to locate elements in the system.

FIG.8shows an embodiment of a phase shifter element in accordance with aspects of the invention. In this embodiment, the phase shifter element40′ comprises: a signal line45′, a ground return line50′, two inductance control lines60′ and60″. In this example, the signal line45′ comprises signal line TSVs46.1,46.2,46.3,46.4formed in the substrate (e.g., substrate67as inFIG.4) and connected with conductive line portions as shown inFIG.8. In this example, the ground return line50′ comprises ground return line TSVs51.1,51.2formed in the substrate (e.g., substrate67as inFIG.4) and connected with conductive line portions as shown inFIG.8. In this example, a first capacitance TSV56.1is connected to the ground return line50′ by a first switch circuit SC1, and a second capacitance TSV56.2is connected to the ground return line50′ by a second switch circuit SC2. The switch circuits SC1and SC2may be similar to switch circuit SC ofFIGS.4and5. In embodiments, the capacitance is controlled using the TSV pairs56.1/46.3and56.2/46.4.

Still referring to the example shown inFIG.8, the first inductance control line60′ includes a first inductance TSV61.1and a switch96.1(which may be similar to switch96ofFIG.4), and the second inductance control line60″ includes a second inductance TSV61.2and a switch96.2(which may be similar to switch96ofFIG.4). The switches96.1,96.2(like the switch96ofFIG.4) may be FETs and can be made from multiple materials such as Si, GaAs, SiN, GaN, etc.) The switches96.1,96.2(like the switch96ofFIG.4) may be fabricated in the substrate67with the TSVs or may be fabricated in another electrically connected substrate such as a multi-tiered substrate package stack.

In operation, the inductance of the exemplary phase shifter element shown inFIG.8is controlled by the switches96.1,96.2. When the switches96.1,96.2are closed, the inductance is decreased (e.g., Llowas described above) due to ground return current flowing in the inductance control lines60′ and60″. When the switches96.1,96.2are open, the inductance is increased (e.g., Lhighas described above). Likewise, the switch circuits SC1, SC2can be controlled to achieve a low capacitance state (e.g., Clowas described above) or a high capacitance state (e.g., Chighas described above). In this exemplary implementation, by controlling the switches96.1,96.2to achieve one of four possible inductance states and the switch circuits SC1, SC2to achieve one of four possible capacitance states, multiple delay and impedance states can be achieved with the phase shifter element shown inFIG.8.

FIG.9shows a plan view of an embodiment of a phase shifter element in accordance with aspects of the invention. In particular,FIG.9shows a plan, cross-sectional view of the phase shifter element40ofFIG.4, including the signal line TSV46, the ground return line TSV51, the capacitance control line TSV56, and the inductance control line TSV61.

In the example shown inFIG.9, the capacitance control line TSV56is located on one side of the signal line TSV46in the y direction, and the ground return line TSV51and the inductance control line TSV61are located on the opposite side of the signal line TSV46in the y direction. There is a distance d1between the ground return line TSV51and the inductance control line TSV61, a distance d2between the inductance control line TSV61and the signal line TSV46, and a distance d3between the signal line TSV46and the capacitance control line TSV56. In one exemplary implementation, each of the TSVs46,51,56,61has a length of 20 μm in the x direction and a width of 5 μm in the y direction, and the distances are: d1=40 μm, d2=60 μm, d3=20 μm. These dimensions are exemplary and not intended to be limiting, and other dimensions may be used. In embodiments, a distance between the ground return line TSV51and the signal line TSV46(shown as d4inFIG.9) is greater than a distance between the inductance control line TSV61and the signal line TSV46(shown as d2inFIG.9). In embodiments, a distance between the ground return line TSV51and the signal line TSV46(shown as d4inFIG.9) is greater than a distance between the capacitance control line TSV56and the signal line TSV46(shown as d3inFIG.9).

FIG.10shows a plan view of an embodiment of a phase shifter element in accordance with aspects of the invention. In particular,FIG.10shows a plan, cross-sectional view of another configuration of a phase shifter element40″ including signal line TSVs46″ and46′″, ground return line TSVs51″, a capacitance control line TSV56″, and inductance control line TSVs61″ formed in the substrate67. In the example shown inFIG.10, the signal line TSVs46′ are inductance invisible TSVs, and the signal line TSVs46′″ are inductance visible TSVs.

As described herein, the cross-sectional area of TSVs (such as the TSVs ofFIG.10) can be larger than conductors on the chip which helps reduce loss. Also, the relative positions and orientations of the conductors is much more flexible than in a normal/conventional metal-dielectric stack on chips where the conductors only exist in a few allowed layers with common heights and thicknesses and whose surfaces are largely parallel to each other.

As shown inFIG.10, the capacitance-control TSV56″ is effectively surrounded by multiple signal line TSVs46″ and46′ (e.g., the same signal in multiple paths) and therefore has little parasitic capacitance to ground which will decrease Cb (in the diagram ofFIG.5) and increase the capacitance tuning range. The dedicated ground return line TSVs51″ provide a controlled impedance path for the signal and also can connect top and bottom ground metal planes to reduce unintended RF modes. Inductance control line TSVs61″ provide the inductance tuning paths. Although two inductance control line TSVs61″ are shown, the phase shifter element40″ could be implemented with only one. Likewise, although two dedicated ground return line TSVs51″ are shown, the phase shifter element40″ could be implemented with only one. Using two has the advantage of providing a bit of shielding for other nearest-neighbor TSV phase shifters.

In accordance with further aspects of the invention, there is a method of manufacturing a phase shifter element as described herein. In accordance with further aspects of the invention, there is a method of manufacturing a phased array antenna that includes one or more phase shifter elements as described herein. The structures of the present invention, including the phase shifter element PSE-i,n comprising a phase shifter element40, can be manufactured in a number of ways using a number of different tools. In some embodiments that utilize semiconductor structures, the methodologies and tools are used to form structures with dimensions in the micrometer and nanometer scale. The methodologies, i.e., technologies, employed to manufacture the structures of the present invention have been adopted from integrated circuit (IC) technology. For example, the structures of the present invention are built on wafers and are realized in films of material patterned by photolithographic processes on the top of a wafer. In particular, the fabrication of the structures of the present invention uses three basic building blocks: (i) deposition of thin films of material on a substrate, (ii) applying a patterned mask on top of the films by photolithographic imaging, and (iii) etching the films selectively to the mask.