Ultra-wideband phase shifter based on bandpass filter network
By employing a bandpass filter network and an improved magnetic coupling network in the phase shifter, combined with single-pole double-throw switching, the bandwidth and loss limitations in the prior art are solved, realizing a passive ultrawideband phase shifter with wide bandwidth, low loss, and small area, suitable for phased array antennas and microwave communication systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD
- Filing Date
- 2022-12-19
- Publication Date
- 2026-06-02
Smart Images
Figure CN115967369B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to phase shifters, and more particularly to an ultrawideband phase shifter based on a bandpass filter network. Background Technology
[0002] In recent years, communication and detection technologies have developed rapidly. As a key device in communication and detection, phased array antennas require increasingly wider bandwidths and smaller sizes. Phase shifters are one of the key components in phased array antennas and microwave wireless communication systems. Their operating bandwidth and size directly limit the performance of phased array antennas. Therefore, exploring phase shifters with wider bandwidth, lower loss, and smaller area plays an important role in improving the integration of phased array systems.
[0003] Currently, there are two main methods for implementing monolithically integrated ultra-wideband phase shifters: active and passive. Active methods have limited power linearity and high power consumption, making them unsuitable for applications requiring high linearity. Passive methods include reflective and switching types. Reflective phase shifters have low losses but limited bandwidth. Switching phase shifters can achieve ultra-wideband coverage using an all-pass network. Chinese patent application publication CN 112271419A proposes an ultra-wideband phase shifter using a magnetically coupled all-pass network structure, but this requires multiple all-pass or high-low-pass network structures cascaded to achieve a 180° phase shift, resulting in a still large circuit area and high losses. Chinese patent application publication CN111082765A proposes a two-bit active phase shifter capable of covering nine octaves, employing a differential amplifier and an active balun structure; however, due to the use of an RC network, power consumption is high, and power linearity is significantly limited. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide an ultrawideband phase shifter based on a bandpass filter network, which has a wide phase shift bandwidth, low loss, small footprint, and large phase shift angle.
[0005] Technical solution: The ultra-wideband phase shifter of the present invention includes a first and a second single-pole double-throw switch, a reference state network module, and a phase-shifting state network module; the input terminal of the first single-pole double-throw switch is connected to the input port of the phase shifter, the first output terminal is connected to the input terminal of the reference state network module, and the second output terminal is connected to the input terminal of the phase-shifting state network module; the input terminal of the second single-pole double-throw switch is connected to the output port of the phase shifter, the first output terminal is connected to the output terminal of the reference state network module, and the second output terminal is connected to the output terminal of the phase-shifting state network module.
[0006] The phase-shifting function is achieved by switching between the reference state and the phase-shifting state using the first and second single-pole double-throw switches.
[0007] Furthermore, the reference state network module is composed of multiple cascaded T-type bandpass filter units, and the number of T-type bandpass filter units can be increased or decreased according to the bandwidth requirements;
[0008] The T-type bandpass filter unit consists of a first series network and a first parallel network. The first and second series networks are connected in series in sequence, and their first and last ends are connected to the input and output ends of the T-type bandpass filter unit, respectively. The first end of the first parallel network is connected to the common endpoint between the first and second series networks, and the other end is grounded.
[0009] Furthermore, the first and second series networks are inductor-capacitor series networks; the first parallel network is an inductor-capacitor parallel network.
[0010] Furthermore, the phase-shifting network module is composed of a bandpass filter unit improved based on a magnetic coupling network. The bandpass filter unit includes a third to fourth series network, a second parallel network, a first to second inductor, and a first capacitor.
[0011] The first end of the third series network is connected to the input port of the bandpass filter unit, and the second end of the third series network is connected to the first end of the first spiral inductor; the first end of the fourth series network is connected to the output port of the bandpass filter unit, and the second end of the fourth series network is connected to the first end of the second spiral inductor; the first spiral inductor and the second spiral inductor are intertwined to form a negative mutual inductance coefficient, and the second ends of the first spiral inductor and the second spiral inductor are connected as the third common port; the first capacitor is connected in series between the first ends of the first spiral inductor and the first ends of the second spiral inductor, the first end of the second parallel network is connected to the third common port, and the other end of the second parallel network is grounded.
[0012] Furthermore, the third and fourth series networks are inductor-capacitor series networks; the second parallel network is an inductor-capacitor parallel network.
[0013] Compared with the prior art, the significant advantages of this invention are as follows:
[0014] 1. This invention utilizes scalable T-type filter network units and all-pass network unit structures to achieve flexible structural changes under different bandwidth requirements. It features wide phase-shifting bandwidth, low loss, small footprint, and large phase-shifting angle. At the same time, it adopts a passive structure and has high power linearity.
[0015] 2. This invention combines an inductor-capacitor bandpass network with a magnetic coupling network, which reduces the loss of the phase-shifting circuit compared to using a magnetic coupling network alone, while further widening the bandwidth, achieving a maximum of more than 9 octaves.
[0016] 3. The number of bandpass filter units in the circuit of this invention can be increased or decreased according to the bandwidth requirements. The structure is flexible and easy to design, which is conducive to the miniaturization of the circuit and is suitable for engineering practice. Attached Figure Description
[0017] Figure 1(a) is the overall circuit schematic diagram of the present invention.
[0018] Figure 1(b) is a schematic diagram of the reference state network module of the present invention.
[0019] Figure 1(c) is a schematic diagram of the phase-shifting network module of the present invention;
[0020] Figure 2 This is a circuit diagram of Embodiment 1 of the present invention;
[0021] Figure 3 This is a circuit diagram of Embodiment 2 of the present invention;
[0022] Figure 4 This is a circuit diagram of Embodiment 3 of the present invention;
[0023] Figure 5 This is a simulation result diagram of the input-output VSWR in Embodiment 2 of the present invention;
[0024] Figure 6 The figures show the simulation results of insertion loss in the reference state and shift state of Embodiment 2 of this invention.
[0025] Figure 7 This is a simulation result diagram of the phase shift accuracy in Embodiment 2 of the present invention. Detailed Implementation
[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0027] As shown in Figure 1(a), the ultra-wideband phase shifter of the present invention includes first and second single-pole double-throw switches SPDT1 and SPDT2, a reference state network module, and a phase-shifting state network module. The input terminal of the first single-pole double-throw switch SPDT1 is connected to the input port of the phase shifter, its first output terminal is connected to the input terminal of the reference state network module, and its second output terminal is connected to the input terminal of the phase-shifting state network module. The input terminal of the second single-pole double-throw switch SPDT2 is connected to the output port of the phase shifter, its first output terminal is connected to the output terminal of the reference state network module, and its second output terminal is connected to the output terminal of the phase-shifting state network module. The phase-shifting function is achieved by switching between the reference state and the phase-shifting state using the first and second single-pole double-throw switches SPDT1 and SPDT2.
[0028] As shown in Figure 1(a), the reference state network module is composed of multiple cascaded T-type bandpass filter units (PSAs). The number of T-type bandpass filter units (PSAs) can be increased or decreased according to bandwidth requirements. As shown in Figure 1(b), the T-type bandpass filter unit (PSA) consists of a first series network A1-A2 and a first parallel network B1. The first series network A1-A2 is connected in series sequentially, with its left and right ends connected to the unit's input and output terminals, respectively. The first end of the first parallel network B1 is connected to the common endpoint between the first and second series networks A1-A2, and the other end is grounded.
[0029] The first and second series networks A1 and A2 are composed of inductors and capacitors connected in series, while the first parallel network B1 is composed of inductors and capacitors connected in parallel. This parallel or series connection of inductors and capacitors can generate a wider frequency passband than using inductors or capacitors alone. At the same time, it can also form more zero points of phase difference change rate with the phase-shifting network, which can effectively improve the phase-shifting accuracy.
[0030] As shown in Figure 1(a), the phase-shifting network module is composed of multiple cascaded bandpass filter units (PSBs) improved from magnetically coupled all-pass networks. The number of units can be increased or decreased according to bandwidth requirements. As shown in Figure 1(c), the bandpass filter unit (PSB) includes the third to fourth series networks A3 to A4, the second parallel network B2, the first to second inductors L1 to L2, and the first capacitor C1. The first end of the third series network A3 is connected to the input port of the bandpass filter unit PSB, and the second end of the third series network A3 is connected to the first end of the first spiral inductor L1; the first end of the fourth series network A4 is connected to the output port of the bandpass filter unit PSB, and the second end of the fourth series network A4 is connected to the first end of the second spiral inductor L2; the first spiral inductor L1 and the second spiral inductor L2 are intertwined, forming a negative mutual inductance coefficient, and the second ends of the first spiral inductor L1 and the second spiral inductor L2 are connected as their common port; the first capacitor C1 is connected in series between the first end of the first spiral inductor L1 and the first end of the second spiral inductor L2, the first end of the second parallel network B2 is connected to the common port of the first spiral inductor L1 and the second spiral inductor L2, and the other end of the second parallel network B2 is grounded.
[0031] The third and fourth series networks, A3 and A4, are composed of inductors and capacitors connected in series, while the second parallel network, B2, is composed of inductors and capacitors connected in parallel. Due to the influence of circuit parasitic parameters, traditional magnetically coupled all-pass networks often exhibit bandpass characteristics in practical applications, limiting their bandwidth. The use of series networks A3 and A4 and parallel network B2 can further extend the bandwidth of the all-pass network, giving the phase shifter a wider passband response.
[0032] The present invention will be further described below with reference to specific embodiments.
[0033] Example 1
[0034] like Figure 2 As shown, the ultra-wide phase shifter of this embodiment includes third to fourth single-pole double-throw switches SPDT3 to SPDT4, a first reference state network, and a first phase-shifting state network. The third to fourth single-pole double-throw switches SPDT3 to SPDT4 are responsible for switching the phase-shifting state.
[0035] The first reference state network consists of only one T-type bandpass filter unit PSA0, including first and second series inductors LA1 to LA2 and first and second series capacitors CA1 to CA2, first parallel inductor LB1 and first parallel capacitor CB1.
[0036] The first series inductor LA1 has its first end connected to the input terminal of the first reference state network and its second end connected to the first end of the first series capacitor CA1; the second series inductor LA2 has its first end connected to the output terminal of the first reference state network and its second end connected to the first end of the second series capacitor CA2; the second end of the first series capacitor CA1 is connected to the second end of the second series capacitor CA2; the first parallel inductor LB1 and the first parallel capacitor CB1 are connected in parallel, and the first common port formed therebetween is connected to the common terminal of the first series capacitor CA1 and the second series capacitor CA2, and the second common port is grounded.
[0037] The first phase-shifting network consists of only one bandpass network unit PSB0, including a third series capacitor CA3, a fourth series capacitor CA4, a second parallel capacitor CB2, first and second spiral inductors L1 and L2, and a first capacitor C1.
[0038] The first end of the third series capacitor CA3 is connected to the input port of the first phase-shifted network, and the second end of the third series capacitor CA3 is connected to the first end of the first spiral inductor L1; the first end of the fourth series capacitor CA4 is connected to the output port of the first phase-shifted network, and the second end of the fourth series capacitor CA4 is connected to the first end of the second spiral inductor L2; the first spiral inductor L1 and the second spiral inductor L2 are intertwined to form a negative mutual inductance coefficient, and the second ends of the first spiral inductor L1 and the second spiral inductor L2 are connected as the first common port; the first capacitor C1 is connected in series between the first end of the first spiral inductor L1 and the first end of the second spiral inductor L2, the first end of the second parallel capacitor CB2 is connected to the first common port, and the other end of the second parallel capacitor CB2 is grounded.
[0039] In this embodiment, the third series capacitor CA3, the fourth series capacitor CA4, and the second parallel capacitor CB2 correspond to the series network A3, series network A4, and parallel network B2 in Figure 1(c), respectively. This can be considered a simplification of the original series and parallel inductor-capacitor configurations. When bandwidth requirements are not too wide, this structure can reduce the circuit area. This embodiment can achieve large-angle (90° or 180°) phase shifts of 3-4 octaves, featuring small area and low loss.
[0040] Example 2
[0041] The ultra-wide phase shifter based on a bandpass filter network provided in this embodiment can achieve a phase shift function of up to 9 octaves. Its structure includes the fifth and sixth single-pole double-throw switches SPDT5-SPDT6, a second reference state network, and a second phase-shifting state network.
[0042] like Figure 3 As shown, the second reference state network includes four T-type filter networks PSA1 to PSA4 (i.e., four series networks), which are connected in sequence between the input and output ports of the second reference state network. The first T-type filter network PSA1 includes a first zero-series inductor LA10, a first zero-parallel inductor LB10, a second zero-series inductor LA20, and a first zero-series capacitor CA10; the second filter network PSA2 includes a second zero-series inductor LA20, a first zero-series capacitor CA10, a second zero-parallel capacitor CB20, a second zero-parallel inductor LB20, a third zero-series inductor LA30, and a second zero-series capacitor CA20; the third filter network PSA3 includes a fourth zero-series inductor LA40, a second zero-series capacitor CA20, a third zero-parallel capacitor CB30, a third zero-parallel inductor LB30, a fifth zero-series inductor LA50, and a third zero-series capacitor CA30; the fourth filter network PSA4 includes a fifth zero-series inductor LA50, a third zero-series capacitor CA30, a fourth zero-parallel inductor LB40, and a sixth zero-series inductor LA60.
[0043] The second zero-series inductor LA20 and the first zero-series capacitor CA10 are common components of the first T-type filter network PSA1 and the second T-type filter network PSA2; the second zero-series capacitor CA20 is a common component of the second T-type filter network PSA2 and the third T-type filter network PSA3; the fifth zero-series inductor LA50 and the third zero-parallel capacitor CA30 are common components of the third T-type filter network PSA3 and the fourth T-type filter network PSA4. The reason for the formation of common components is that the first to fourth T-type filter networks PSA1 to PSA4 have been simplified by merging the original series inductors and capacitors.
[0044] The first zero-series inductor LA10 and the first zero-parallel inductor LB10 belonging to the first T-type filter network PSA1 can be considered as simplifications of the inductor-capacitor series and inductor-capacitor parallel methods described in the implementation scheme; the fourth zero-parallel inductor LB40 and the sixth zero-series inductor LA60 belonging to the fourth T-type filter network PSA4 are also considered as simplifications in the same way. Simplifying parts of the circuit and reducing the number of components while ensuring bandwidth can reduce the circuit area.
[0045] As a specific example, combined Figure 3The component connection sequence is as follows: the second reference state network is connected in series from the input terminal with the first zero-series inductor LA10, the second zero-series inductor LA20, the first zero-series capacitor CA10, the third zero-series inductor LA30, the second zero-series capacitor CA20, the fourth zero-series inductor LA40, the third zero-series capacitor CA30, the fifth zero-series inductor LA50, and the sixth zero-series inductor LA60. The other end of the sixth zero-series inductor LA60 is connected to the output terminal of the second reference state network. The first zero-parallel inductor LB10 has its first terminal connected to the common terminal between the first zero-series inductor LA10 and the second zero-series inductor LA20, and its second terminal grounded. The second zero-parallel capacitor CB20 and the second zero-parallel inductor LB20 are connected in parallel, and the first common terminal formed is connected to the common terminal between the first zero-series capacitor CA10 and the third zero-series inductor LA30, and its second common terminal grounded. The third zero-parallel capacitor CB30 and the third zero-parallel inductor LB30 are connected in parallel, and the first common terminal formed is connected to the common terminal between the fourth zero-series inductor LA40 and the third zero-series capacitor CA30, and its second common terminal grounded. The first terminal of the fourth zero-parallel inductor LB40 is connected to the common terminal between the fifth zero-series inductor LA50 and the sixth zero-series inductor LA60, and its second terminal grounded.
[0046] like Figure 3 As shown, the second phase-shifting network has only one bandpass filter unit PSB1, which includes the seventh zero-series inductor LA70, the fourth zero-series capacitor CA40, the first to second zero spiral inductors L10 to L20, the first zero capacitor C10, the third zero parallel capacitor CB30, the fifth zero parallel inductor LB50, the fifth zero series capacitor CA50, and the eighth zero-series inductor LA80.
[0047] The first end of the seventh zero-series inductor LA70 is connected to the input port of the second phase-shifted network, and the second end is connected to the first end of the fourth zero-series capacitor CA40. The second end of the fourth zero-series capacitor CA40 is connected to the first end of the first zero-spiral inductor L10. The first end of the eighth zero-series inductor LA80 is connected to the output port of the second phase-shifted network, and the second end is connected to the first end of the fifth zero-series capacitor CA50. The second end of the fifth zero-series capacitor CA50 is connected to the first end of the second zero-spiral inductor L20. The first zero-spiral inductor L10 and the second zero-spiral inductor L20 are intertwined, forming a negative mutual inductance coefficient. The second ends of the first zero-spiral inductor L10 and the second zero-spiral inductor L20 are connected together. The first zero capacitor C10 is connected in series between the first ends of the first zero-spiral inductor L10 and the first ends of the second zero-spiral inductor L20. The fifth zero-parallel capacitor CB50 and the fifth zero-parallel inductor LB50 are connected in parallel to form two common terminals. The first common terminal is connected to the common port of the first zero-spiral inductor L10 and the second zero-spiral inductor L20, and the second common terminal is grounded.
[0048] like Figures 5-7The figures show the simulation results for the input-output voltage standing wave ratio (VSWR), insertion loss, and phase difference of Example 2. As can be seen from the figures, within the nine octaves of the set operating frequency range of 2GHz to 18GHz, the phase shift error of the phase shifter is within 3.5°, the insertion loss is less than 3.2dB, the parasitic amplitude modulation is less than 0.25dB, and the input-output VSWR is less than 1.35. Therefore, the structure proposed in this invention can achieve a bandwidth covering nine octaves while maintaining low loss and good matching performance.
[0049] Example 3
[0050] like Figure 4 As shown, based on Embodiment 2, some structural changes have been made to adapt to phase shifter design requirements of up to 9 octaves or more. The third reference state network includes four T-type filter networks PSA31 to PSA34, which are connected in series sequentially between the input and output ports of the third reference state network. Compared with Embodiment 2, Embodiment 3 differs only in the structure of the fifth T-type filter network PSA31 and the eighth T-type filter network PSA34. Specifically, a parallel capacitor (CB10 and CB40) is added to the parallel-to-ground circuit of the fifth T-type filter network PSA31 and the eighth T-type filter network PSA34, and a series capacitor (CA10 and CA50) is added to the series circuit of each, connected to the input and output terminals of the reference state network. Other components and connections in the reference state network in Embodiment 3 are the same as in Embodiment 2. The added components can increase the number of resonant units in the phase shift circuit, further widening the bandwidth.
[0051] like Figure 4 As shown, the third phase shifter network is composed of two filter networks, PSB31 and PSB32, cascaded sequentially. The circuit structures of the second and third filter networks, PSB31 and PSB32, are basically the same as those of the bandpass filter unit PSB1 in Embodiment 2. The difference lies in that the series capacitors at the connection points of the second and third filter networks, PSB31 and PSB32, are combined into a seventh zero-series capacitor, CA70, which is connected between the eighth zero-series inductor LA80 and the ninth zero-series inductor LA90. Compared with a single filter network unit, the cascaded layout of the two filter networks reduces the coupling inductance of each unit, making circuit layout more convenient.
Claims
1. An ultra-wideband phase shifter based on a bandpass filter network, characterized in that, It includes a first and second single-pole double-throw switch (SPDT1~SPDT2), a reference state network module, and a phase-shifting network module; the input terminal of the first single-pole double-throw switch (SPDT1) is connected to the input port of the phase shifter, the first output terminal is connected to the input terminal of the reference state network module, and the second output terminal is connected to the input terminal of the phase-shifting network module; the input terminal of the second single-pole double-throw switch (SPDT2) is connected to the output port of the phase shifter, the first output terminal is connected to the output terminal of the reference state network module, and the second output terminal is connected to the output terminal of the phase-shifting network module. The phase-shifting function is achieved by switching between the reference state and the phase-shifting state using the first and second single-pole double-throw switches (SPDT1~SPDT2); The phase-shifting network module is composed of a bandpass filter unit (PSB) improved on the basis of a magnetic coupling network. The bandpass filter unit (PSB) includes a third to fourth series network (A3 to A4), a second parallel network (B2), a first to second inductor (L1 to L2), and a first capacitor (C1). The first end of the third series network (A3) is connected to the input port of the bandpass filter unit (PSB), and the second end of the third series network (A3) is connected to the first end of the first spiral inductor (L1); the first end of the fourth series network (A4) is connected to the output port of the bandpass filter unit (PSB), and the second end of the fourth series network (A4) is connected to the first end of the second spiral inductor (L2); the first spiral inductor (L1) and the second spiral inductor (L2) are intertwined to form a negative mutual inductance coefficient, and the second ends of the first spiral inductor (L1) and the second spiral inductor (L2) are connected together as the third common port; the first capacitor (C1) is connected in series between the first end of the first spiral inductor (L1) and the first end of the second spiral inductor (L2), the first end of the second parallel network (B2) is connected to the third common port, and the other end of the second parallel network (B2) is grounded; The third to fourth series networks (A3 to A4) are inductor-capacitor series networks; the second parallel network (B2) is an inductor-capacitor parallel network.
2. The ultra-wideband phase shifter based on a bandpass filter network according to claim 1, characterized in that, The reference state network module is composed of multiple cascaded T-type bandpass filter units (PSA). The number of T-type bandpass filter units (PSA) can be increased or decreased according to the bandwidth requirements. The T-type bandpass filter unit (PSA) consists of a first and a second series network (A1~A2) and a first parallel network (B1). The first and second series networks (A1~A2) are connected in series in sequence, and their first and last ends are connected to the input and output terminals of the T-type bandpass filter unit, respectively. The first end of the first parallel network (B1) is connected to the common terminal between the first and second series networks (A1~A2), and the other end is grounded.
3. The ultra-wideband phase shifter based on a bandpass filter network according to claim 2, characterized in that, The first and second series networks (A1~A2) are inductor-capacitor series networks; the first parallel network (B1) is an inductor-capacitor parallel network.