An ultra-wideband digital phase shifter covering K and Ka bands
By designing 5.625° and 11.25° phase shifting units combining magnetically coupled full-pass networks and parallel capacitors, 45° and 90° phase shifting units combining coupled and uncoupled full-pass networks, and a switch-selectable 180° phase shifting unit, the problems of large performance dispersion and low switch isolation of phase shifters in the K and Ka bands were solved, achieving a high-precision and stable 360° phase shifting effect.
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
- 2022-11-10
- Publication Date
- 2026-06-12
Smart Images
Figure CN115566379B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to digital phase shifters, and more particularly to an ultra-wideband digital phase shifter covering the K and Ka bands. Background Technology
[0002] Phase shifters are key components in phased array antenna systems. They control the phase changes of microwave signals in antenna elements, thereby controlling the antenna beam pointing and enabling target search and tracking. The performance of phase shifters plays a crucial role in the search and positioning capabilities of phased arrays. With the development of communication technology and increasingly higher communication frequencies, phase shifters are also gradually evolving towards higher frequency and wider bandwidth.
[0003] Phase shifters on integrated chips can be implemented using both active and passive methods. Active methods often employ vector synthesis, offering advantages such as high phase-shifting accuracy and low loss, but often suffer from limited power linearity and high power consumption. Passive methods include reflective and switching-mode phase shifters. However, in the K and Ka bands, reflective phase shifters are highly sensitive to changes in component size, exhibiting significant performance variations and fluctuations between different chips. Switching-mode phase shifters, by utilizing the phase difference between the reference state and the shifted state, offer more stable phase-shifting performance. Ultra-wideband phase shifters covering the K and Ka bands can be implemented using switching-mode all-pass or bandpass networks. However, traditional all-pass or bandpass network phase-shifting structures face challenges such as low switching isolation in the K and Ka bands and the significant impact of parasitic parameters of inductors and capacitors on performance, requiring specialized structures to address these issues. The literature (Eduardo VP Anjos, Dominique MM-P. Schreurs, Guy A.E. Vandenbosch, etc., A 14–50-GHz Phase Shifter With All-Pass Networks for 5G Mobile Applications, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL.68, NO.2, FEBRUARY 2020) implemented a two-way phase shifter in the 14–50 GHz range using an all-pass network structure. However, it uses a large number of all-pass network units, resulting in a complex structure that is not conducive to miniaturization, and it does not cover 360° phase shifting. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide an ultra-wideband digital phase shifter covering the K and Ka bands with high phase shifting accuracy, low parasitic amplitude modulation, and simple circuit structure.
[0005] Technical solution: The ultra-wideband digital phase shifter of the present invention includes a 180° phase shifting unit, a 45° phase shifting unit, a 22.5° phase shifting unit, a 5.625° phase shifting unit, an 11.25° phase shifting unit, and a 90° phase shifting unit, the six phase shifting units being connected in any order.
[0006] The 5.625° phase shift unit, 11.25° phase shift unit, and 22.5° phase shift unit adopt a structure combining a magnetically coupled all-pass network with a parallel capacitor; the 45° phase shift unit and 90° phase shift unit adopt a structure combining coupled and uncoupled all-pass networks; and the 180° phase shift unit adopts a switch-selective bandpass network structure. The 5.625° and 11.25° phase shift units have the same phase shift structure, and the 45° and 90° phase shift units have the same phase shift structure.
[0007] A 360° phase shift is achieved by using a step value of 5.625°.
[0008] Furthermore, the 5.625° phase shifting unit and the 11.25° phase shifting unit have the same phase shifting structure, both adopting a structure combining a magnetically coupled all-through network and parallel reactance, including first to fourth switches, first to second spiral inductors, first to second capacitors, first to fourth reactance elements, and first to second microstrip lines;
[0009] The first end of the first microstrip line is connected to the input port of the first phase shifting unit, the second end of the first microstrip line is connected to the first end of the first switch, the second end of the first switch is connected to ground through the first reactive element, and the first end of the first spiral inductor is connected to the second end of the first microstrip line.
[0010] The first end of the second microstrip line is connected to the output port of the first phase shifting unit, the second end of the second microstrip line is connected to the first end of the second switch, the second end of the second switch is connected to ground through the second reactance element, and the first end of the second spiral inductor is connected to the second end of the second microstrip line.
[0011] The first spiral inductor and the second spiral inductor are intertwined to form a negative mutual inductance coefficient. The second end of the first spiral inductor is connected to the second end of the second spiral inductor as the first common port.
[0012] The two ends of the first capacitor are respectively connected to the first end of the first spiral inductor and the first end of the second spiral inductor; one end of the second capacitor is connected in parallel to ground, and the other end is connected to the first common port; the first end of the third switch is connected to the first common port, the second end is connected to the first end of the third reactance element, and the second end of the third reactance element is grounded; the first end of the fourth switch is connected to the first common port, the second end is connected to the first end of the fourth reactance element, and the second end of the fourth reactance element is grounded.
[0013] Furthermore, the first to fourth switches are field-effect transistors or PIN diode switches;
[0014] The first to fourth reactive components can be a single capacitor or any one of three types: inductor-capacitor series or inductor-capacitor parallel.
[0015] The first to fourth switches operate in the same state. When the first to fourth switches are off, the phase-shifting structure is in the reference state; when the first to fourth switches are on, the phase-shifting structure is in the phase-shifting state.
[0016] Furthermore, the 22.5° phase-shifting unit structure includes fifth to eighth switches, third to fourth spiral inductors, third to fifth capacitors, fifth to sixth reactive elements, and third to fourth microstrip lines;
[0017] The first end of the fifth switch is connected to the input port of the 22.5° phase shift unit, and the second end of the fifth switch is grounded through the fifth reactance element; one end of the third microstrip line is connected to the input port of the 22.5° phase shift unit, and the other end is connected to the first end of the third spiral inductor.
[0018] The first end of the eighth switch is connected to the output port of the 22.5° phase shift unit, and the other end of the eighth switch is grounded through the sixth reactance element; one end of the fourth microstrip line is connected to the output port of the 22.5° phase shift unit, and the other end is connected to the first end of the fourth spiral inductor;
[0019] The third spiral inductor and the fourth spiral inductor are intertwined, forming a negative mutual inductance coefficient; the second end of the third spiral inductor and the second end of the fourth spiral inductor are connected as a second common port;
[0020] The two ends of the fourth capacitor are respectively connected to the first end of the third spiral inductor and the first end of the fourth spiral inductor; one end of the fifth capacitor is connected to ground and the other end is connected to the second common port; the sixth switch, the third capacitor and the seventh switch are connected in series and then connected between the first end of the third spiral inductor and the first end of the fourth spiral inductor.
[0021] Furthermore, the fifth to eighth switches are field-effect transistors or PIN diode switches;
[0022] The fifth and sixth reactance elements can be a single capacitor or any one of three types: inductor-capacitor series or inductor-capacitor parallel.
[0023] The fifth to eighth switches have the same operating state. When the fifth to eighth switches are off, the phase-shifting structure is in the reference state; when the fifth to eighth switches are on, the phase-shifting structure is in the phase-shifting state.
[0024] Furthermore, the 45° phase-shifting unit and the 90° phase-shifting unit have the same phase-shifting structure, which is a switch-selection type structure, including a first to a second single-pole double-throw switch, a fifth to a sixth microstrip line, a first reference state network, and a first phase-shifting state network;
[0025] The first end of the fifth microstrip line is connected to the input terminal of the second phase shifting unit, and the other end is connected to the input terminal of the first single-pole double-throw switch network; the first end of the sixth microstrip line is connected to the output terminal of the second phase shifting unit, and the other end is connected to the input terminal of the second single-pole double-throw switch network.
[0026] The first reference state network is connected in series between the first output terminal of the first single-pole double-throw switch network and the first output terminal of the second single-pole double-throw switch network; the first phase-shifting state network is connected in series between the second output terminal of the first single-pole double-throw switch network and the second output terminal of the second single-pole double-throw switch network.
[0027] Furthermore, the first reference state network includes a fifth to a sixth spiral inductor, a sixth to a seventh capacitor, and a first to a second impedance matching line.
[0028] The first end of the first impedance matching line is connected to the first output port of the first single-pole double-throw switch network, and the second end of the first impedance matching line is connected to the first end of the fifth spiral inductor; the first end of the second impedance matching line is connected to the first output port of the second single-pole double-throw switch network, and the second end of the second impedance matching line is connected to the first end of the sixth spiral inductor.
[0029] The fifth and sixth spiral inductors are intertwined, forming a negative mutual inductance coefficient; the second end of the fifth spiral inductor is connected to the second end of the sixth spiral inductor, serving as the third common port.
[0030] The sixth capacitor is connected in series between the first end of the fifth spiral inductor and the first end of the sixth spiral inductor; one end of the seventh capacitor is connected to the third common terminal, and the other end is grounded.
[0031] Furthermore, the first phase-shifting network includes a seventh to eighth spiral inductor, an eighth to ninth capacitor, and a third to fourth impedance matching line.
[0032] The first end of the third impedance matching line is connected to the second output port of the first single-pole double-throw switch network, and the second end of the third impedance matching line is connected to the first end of the seventh spiral inductor; the first end of the fourth impedance matching line is connected to the second output port of the second single-pole double-throw switch network, and the second end of the fourth impedance matching line is connected to the first end of the eighth spiral inductor.
[0033] The second end of the seventh spiral inductor is connected to the second end of the eighth spiral inductor, serving as the fourth common port; the seventh spiral inductor and the eighth spiral inductor have no mutual inductance.
[0034] The eighth capacitor is connected in series between the first end of the seventh spiral inductor and the first end of the eighth spiral inductor; one end of the ninth capacitor is connected to the third common terminal, and the other end is grounded.
[0035] The first to fourth impedance matching lines are either single characteristic impedance microstrip lines or two microstrip lines with different characteristic impedances connected in series.
[0036] The first and second single-pole double-throw switch circuits are reflective single-pole double-throw switch circuits composed of field-effect transistors or PIN diodes; when the first and second single-pole double-throw switches point to the first reference state network at the same time, the phase shifter operates in the reference state; when the first and second single-pole double-throw switches point to the second phase-shifting state network PS2 at the same time, the phase shifter operates in the phase-shifting state.
[0037] Furthermore, the phase-shifting structure of the 180° phase-shifting unit is a switch-selection type structure, including the third to fourth single-pole double-throw switches, the seventh to eighth microstrip lines, the second reference state network, and the second phase-shifting state network;
[0038] The first end of the seventh microstrip line is connected to the signal input terminal of the 180° phase shifting unit, and the second end is connected to the input terminal of the third single-pole double-throw switch; the first end of the eighth microstrip line is connected to the signal output terminal of the 180° phase shifting unit, and the second end is connected to the input terminal of the fourth single-pole double-throw switch; the second reference state network is connected between the first output terminal of the third single-pole double-throw switch and the first output terminal of the fourth single-pole double-throw switch; the second phase shifting state network is connected between the second output terminal of the third single-pole double-throw switch and the second output terminal of the fourth single-pole double-throw switch.
[0039] Furthermore, the second reference state network is a T-type bandpass network, including a fifth and a sixth impedance matching line and a seventh reactive element; the fifth and sixth impedance matching lines are connected in series between the input and output ports of the second reference state network, and one end of the seventh reactive element is grounded and the other end is connected to the common terminal of the fifth and sixth impedance matching lines;
[0040] The second phase-shifting network is a coupler network consisting of two parallel coupling lines; the through port and coupling port of the coupler are grounded respectively, and the input port and isolation port serve as the input and output ports of the second phase-shifting network.
[0041] The third and fourth single-pole double-throw switch circuits are reflective single-pole double-throw switch circuits composed of field-effect transistors or PIN diodes; when the third and fourth single-pole double-throw switches point to the second reference state network at the same time, the phase shifter operates in the reference state; when the third and fourth single-pole double-throw switches point to the second phase-shifting state network at the same time, the phase shifter operates in the phase-shifting state.
[0042] The fifth and sixth impedance matching lines can be either two microstrip lines with different characteristic impedances connected in series or a capacitor and inductor connected in series.
[0043] The seventh reactance element can be either a single capacitor or an inductor and capacitor connected in parallel.
[0044] Compared with the prior art, the significant advantages of this invention are as follows:
[0045] 1. This invention improves the all-pass network structure used in the 5.625°, 11.25° and 22.5° phase shifting units, combining the all-pass network with the parallel capacitor structure, which can improve the phase shifting port matching effect, improve the phase shifting accuracy and reduce parasitic amplitude modulation;
[0046] 2. The 45° and 90° phase shifting units in this invention adopt a combination of coupled inductor full-pass network and uncoupled inductor full-pass network structure. Both the reference state and the phase shifting state use only one full-pass structure, which effectively simplifies the circuit and uses impedance matching lines to improve the port mismatch problem caused by the low isolation of high-frequency switching, thereby improving the matching effect.
[0047] 3. In this invention, the 45°, 90° and 180° phase shifting units adopt a switch selection type, which ensures the stability of the large phase shifting performance. Attached Figure Description
[0048] Figure 1 This is a principle block diagram of Embodiment 1 of the present invention;
[0049] Figure 2 This is a schematic diagram of the 5.625 and 11.25 degree phase shifting circuits in this invention;
[0050] Figure 3 This is a schematic diagram of the 22.5-degree phase-shifting circuit in this invention;
[0051] Figure 4 This is a schematic diagram of the 45-degree and 90-degree phase shifting circuits in this invention;
[0052] Figure 5 This is a schematic diagram of the 180-degree phase-shifting circuit in this invention;
[0053] Figure 6 (a) is a schematic diagram of the circuit implementation of the reactive elements Z1-Z6 in this invention.
[0054] (b) is a schematic diagram of the circuit implementation of the reactive element Z7 in this invention;
[0055] Figure 7 (a) is a schematic diagram of the impedance matching lines TR1-TR4 implemented in this invention.
[0056] (b) is a schematic diagram of the impedance matching line TR5-TR6 implementation circuit in this invention;
[0057] Figure 8 The figure shows the simulation results of the input voltage standing wave ratio under 64 phase-shifting states of this invention;
[0058] Figure 9 The figure shows the simulation results of the output voltage standing wave ratio under 64 phase shift states of this invention;
[0059] Figure 10 The figure shows the simulation results of insertion loss under 64 phase-shifting states of this invention;
[0060] Figure 11 The figure shows the simulation results of the root mean square value of phase shift accuracy under 64 phase shift states in this invention;
[0061] Figure 12 This is a principle block diagram of Embodiment 2 of the present invention. Detailed Implementation
[0062] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0063] Example 1
[0064] like Figure 1 As shown, the ultra-wideband digital phase shifter covering the K and Ka bands implemented in Embodiment 1 includes six phase shifting units: 180°, 45°, 22.5°, 5.625°, 11.25°, and 90°. The six phase shifting units are cascaded sequentially. The switches are field-effect transistors using 0.15µm GaAs pHEMT technology, with an operating frequency of 18GHz-40GHz and a step value of 5.625°, enabling the phase shifter to achieve 360° phase shift.
[0065] like Figure 2 As shown, the phase shifting structures of the 5.625° and 11.25° phase shifting units are the same, adopting a structure combining a magnetically coupled all-pass network and parallel capacitors, including the first to fourth switches SW1 to SW4, the first to second spiral inductors L1 to L2, the first to second capacitors C1 to C2, the first to fourth reactive elements Z1 to Z4, and the first to second microstrip lines TL1 to TL2.
[0066] The first end of the first microstrip line TL1 is connected to the input port RF1 of the first phase-shifting unit. The second end of the first microstrip line TL1 is connected to the first end of the first switch SW1. The other end of the first switch SW1 is connected to ground through the first reactive element Z1. The first end of the first spiral inductor L1 is connected to the second end of the first microstrip line TL1. The first end of the second microstrip line TL2 is connected to the output port RF2 of the first phase-shifting unit. The second end of the second microstrip line TL2 is connected to the first end of the second switch SW2. The other end of the second switch SW2 is connected to ground through the second reactive element Z2. The first end of the second spiral inductor L2 is connected to the second end of the second microstrip line TL2. The first spiral inductor L1 and the first microstrip line TL2 are connected to the first phase-shifting unit input port RF2. Two spiral inductors L2 are intertwined, forming a negative mutual inductance coefficient. The second end of the first spiral inductor L1 is connected to the second end of the second spiral inductor L2, serving as the first common port. The two ends of the first capacitor C1 are respectively connected to the first end of the first spiral inductor L1 and the first end of the second spiral inductor L2. One end of the second capacitor C2 is connected in parallel to ground, and the other end is connected to the first common port. The first end of the third switch SW3 is connected to the first common port, and the second end is connected to the first end of the third reactance element Z3, with the second end of the third reactance element Z3 grounded. The first end of the fourth switch SW4 is connected to the first common port, and the second end is connected to the first end of the fourth reactance element Z4, with the second end of the fourth reactance element Z4 grounded.
[0067] like Figure 6 As shown in (a), the first to fourth reactance elements Z1 to Z4 can be any one of three types: a single capacitor, an inductor-capacitor series connection, or an inductor-capacitor parallel connection.
[0068] The first to fourth switches SW1 to SW4 in the phase shifting structures of the 5.625° and 11.25° phase shifting units have the same working state; when the first to fourth switches SW1 to SW4 are off, the phase shifting structure is in the reference state, and when the first to fourth switches SW1 to SW4 are on, the phase shifting structure is in the phase shifting state.
[0069] like Figure 2 As shown, traditional all-pass network phase-shifting structures often achieve small phase shift angles such as 5.625° and 11.25° by adding a switching network to form parallel networks with the first capacitor C1 in series and the second capacitor C2 in parallel. In the K and Ka bands, the reactance value in parallel with the first capacitor C1 in series changes little at small phase shift angles, making it difficult to change precisely and increasing phase shift error and return loss. By using a reactance network switched by the first switch SW1 and the second switch SW2, the reactance value can change more significantly and is easier to achieve, thereby improving phase shift accuracy and matching performance.
[0070] like Figure 3As shown, the 22.5° phase-shifting unit structure includes fifth to eighth switches SW5 to SW8, third to fourth spiral inductors L3 to L4, third to fifth capacitors C3 to C5, fifth to sixth reactive elements Z5 to Z6, and third to fourth microstrip lines TL3 to TL4. The first terminal of the fifth switch SW5 is connected to the 22.5° phase-shifting unit input port RF3, and the second terminal of the fifth switch SW5 is grounded through the fifth reactive element Z5. One end of the third microstrip line TL3 is connected to the 22.5° phase-shifting unit input port RF3, and the other end is connected to the first terminal of the third spiral inductor L3. The first terminal of the eighth switch SW8 is connected to the 22.5° phase-shifting unit output port RF4, and the other end of the eighth switch SW8 is grounded through the sixth reactive element Z6. One end of the fourth microstrip line TL4 is connected to the 22.5° phase-shifting unit output port RF4, and the other end is connected to the fourth spiral inductor L4. The first end of 4; the third spiral inductor L3 and the fourth spiral inductor L4 are intertwined, forming a negative mutual inductance coefficient. The second end of the third spiral inductor L3 and the second end of the fourth spiral inductor L4 are connected as the second common port; the two ends of the fourth capacitor C4 are respectively connected to the first end of the third spiral inductor L3 and the first end of the fourth spiral inductor L4; one end of the fifth capacitor C5 is connected to ground, and the other end is connected to the second common port; the sixth switch SW6, the third capacitor C3 and the seventh switch SW7 are connected in series in sequence and then connected between the first end of the third spiral inductor L3 and the first end of the fourth spiral inductor L4.
[0071] like Figure 6 As shown in (a), the fifth to sixth reactance elements Z5 to Z6 can be any one of three types: a single capacitor, an inductor-capacitor series connection, or an inductor-capacitor parallel connection.
[0072] In the phase-shifting structure of the 22.5° phase-shifting unit, the fifth to eighth switches SW5 to SW8 have the same working state; when the fifth to eighth switches SW5 to SW8 are off, the phase-shifting structure is in the reference state, and when the fifth to eighth switches SW5 to SW8 are on, the phase-shifting structure is in the phase-shifting state.
[0073] like Figure 3As shown, traditional all-pass network phase-shifting structures often achieve a 22.5° phase shift angle by adding a switching network, forming parallel networks with the fourth capacitor C4 in series and the fifth capacitor C5 in parallel. In the K and Ka bands, the reactance values of these two values change relatively significantly when achieving larger phase shift angles, causing mismatch at the phase shifter ports and worsening return loss. The improved structure combines the reactance networks of the third microstrip line TL3 and the fourth microstrip line TL4, as well as the fifth switch SW5 and the eighth switch SW8, effectively improving the mismatch during phase shifting while achieving partial phase shift. Furthermore, the series-connected third capacitor C3, linked by the sixth switch SW6 and the seventh switch SW7, forms a switching network with the series-connected fourth capacitor C4, compensating for the phase shift angle and achieving good matching. This eliminates the need for a separate switching reactance structure for the fifth capacitor C5 in parallel.
[0074] like Figure 4 As shown, the phase-shifting structures of the 45° and 90° phase-shifting units are the same, which are switch-selection type structures, including the first to second single-pole double-throw switches SPDT1 to SPDT2, the fifth to sixth microstrip lines TL5 to TL6, the reference state network PS1, and the phase-shifting state network PS2.
[0075] The first end of the fifth microstrip line TL5 is connected to the input terminal RF5 of the second phase-shifting unit, and the other end is connected to the input terminal of the first single-pole double-throw (SPDT) switch network SPDT1; the first end of the sixth microstrip line TL6 is connected to the output terminal RF6 of the second phase-shifting unit, and the other end is connected to the input terminal of the second single-pole double-throw (SPDT) switch network SPDT2; the first reference state network PS1 is connected in series between the first output terminal of the first single-pole double-throw (SPDT) switch network SPDT1 and the first output terminal of the second single-pole double-throw (SPDT) switch network SPDT2; the first phase-shifting state network PS2 is connected in series between the second output terminal of the first single-pole double-throw (SPDT) switch network SPDT1 and the second output terminal of the second single-pole double-throw (SPDT) switch network SPDT2.
[0076] The first reference state network PS1 includes fifth and sixth spiral inductors L5-L6, sixth and seventh capacitors C6-C7, and first and second impedance matching lines TR1-TR2. The first end of the first impedance matching line TR1 is connected to the input port of the first reference state network PS1, and the second end of the first impedance matching line TR1 is connected to the first end of the fifth spiral inductor L5. The first end of the second impedance matching line TR2 is connected to the output port of the first reference state network PS1, and the second end of the second impedance matching line TR2 is connected to the first end of the sixth spiral inductor L6. The fifth spiral inductor L5 and the sixth spiral inductor L6 are intertwined, forming a negative mutual inductance coefficient. The second ends of the fifth spiral inductor L5 and the sixth spiral inductor L6 are connected together as a third common port. The sixth capacitor C6 is connected in series between the first ends of the fifth spiral inductor L5 and the sixth spiral inductor L6. The first end of the seventh capacitor C7 is connected to the third common port, and the other end of the seventh capacitor C7 is grounded.
[0077] The first phase-shifting network PS2 includes seventh and eighth spiral inductors L7-L8, eighth and ninth capacitors C8-C9, and third and fourth impedance matching lines TR3-TR4. The first end of the third impedance matching line TR3 is connected to the input port of the first phase-shifting network PS2, and the second end of TR3 is connected to the first end of the seventh spiral inductor L7. The first end of the fourth impedance matching line TR4 is connected to the output port of the first phase-shifting network PS2, and the second end of TR4 is connected to the first end of the eighth spiral inductor L8. The seventh spiral inductor L7 and the eighth spiral inductor L8 have no mutual inductance, and their second ends are connected as the fourth common port. The eighth capacitor C8 is connected in series between the first ends of the seventh spiral inductor L7 and the eighth spiral inductor L8. The first end of the ninth capacitor C9 is connected to the third common port, and the other end is grounded.
[0078] like Figure 7 As shown in (a), the first to fourth impedance matching lines TR1 to TR4 are either single characteristic impedance microstrip lines or two microstrip lines with different characteristic impedances connected in series.
[0079] The first and second single-pole double-throw switches SPDT1 and SPDT2 are reflective single-pole double-throw switch circuits composed of field-effect transistors. When the first and second single-pole double-throw switches SPDT1 and SPDT2 simultaneously point to the first reference state network PS1, the phase shifter operates in the reference state. When the first and second single-pole double-throw switches SPDT1 and SPDT2 simultaneously point to the first phase-shifting state network PS2, the phase shifter operates in the phase-shifting state.
[0080] In the K and Ka bands, the spiral inductance values used are relatively small, and due to the limitation of coupling length, the achievable coupling coefficient is also smaller. Simultaneously, the isolation of the switch decreases with increasing frequency. These factors cause problems such as poor phase shift accuracy, structural mismatch, and high return loss when traditional all-pass network structures achieve 45° and 90° phase shifts in switching. Through structural improvements, the inductor in the phase-shifting state is uncoupled, while the reference state is coupled. This allows the reference state network to achieve good phase shift performance even with a low coupling coefficient. Furthermore, adding the first to fourth impedance matching lines TR1 to TR4 can improve the port mismatch problem caused by low switch isolation, reduce return loss, and allow for fine-tuning of the phase, thus improving phase shift accuracy.
[0081] like Figure 5 As shown, the phase-shifting structure of the 180° phase-shifting unit is a switch-selection type structure that switches between two bandpass networks, including the third to fourth single-pole double-throw switches SPDT3 to SPDT4, the seventh to eighth microstrip lines TL7 to TL8, the second reference state network PS3, and the second phase-shifting state network PS4.
[0082] The first end of the seventh microstrip line TL7 is connected to the signal input terminal RF7 of the 180° phase shifting unit, and the second end is connected to the input terminal of the third single-pole double-throw switch SPDT3; the first end of the eighth microstrip line TL8 is connected to the signal output terminal RF8 of the 180° phase shifting unit, and the second end is connected to the input terminal of the fourth single-pole double-throw switch SPDT4; the second reference state network PS3 is connected between the first output terminal of the third single-pole double-throw switch SPDT3 and the first output terminal of the fourth single-pole double-throw switch SPDT4; the second phase shifting state network PS4 is connected between the second output terminal of the third single-pole double-throw switch SPDT3 and the second output terminal of the fourth single-pole double-throw switch SPDT4.
[0083] The second reference state network PS3 is a T-type bandpass network, including the fifth and sixth impedance matching lines TR5 and TR6, and the seventh reactance element Z7. The fifth and sixth impedance matching lines TL5 and TL6 are connected in series between the input and output ports of the second reference state network PS3. The first end of the seventh reactance element Z7 is grounded, and the other end is connected to the common terminal of the fifth and sixth impedance matching lines TR5 and TR6. The second phase-shifting network PS4 is composed of a coupler network consisting of two parallel coupling lines. The through port and coupling port of the coupler are grounded, and the input port and isolation port serve as the input and output ports of the second phase-shifting network PS4.
[0084] like Figure 7 As shown in (b), the fifth to sixth impedance matching lines TR5 to TR6 can be either two microstrip lines with different characteristic impedances connected in series, or a capacitor and inductor connected in series; as shown in (b). Figure 6 As shown in (b), the seventh reactance element Z7 can be either a single capacitor or an inductor and capacitor in parallel.
[0085] The third and fourth single-pole double-throw switches SPDT3 to SPDT4 are reflective single-pole double-throw switch circuits composed of field-effect transistors. When the third and fourth single-pole double-throw switches SPDT3 to SPDT4 simultaneously point to the second reference state network PS3, the phase shifter operates in the reference state. When the third and fourth single-pole double-throw switches SPDT3 to SPDT4 simultaneously point to the second phase-shifting state network PS4, the phase shifter operates in the phase-shifting state.
[0086] The 180° reference state and phase-shifting state structure, which combines a T-type network and a parallel coupled-line network, has lower losses than a single all-pass network structure or a parallel coupled-line network structure. At the same time, due to the higher frequency of the K and Ka bands, the circuit can maintain a smaller area. The mismatch and phase-shifting errors caused by the low switching isolation can be corrected by adjusting the parameter values of the fifth impedance matching line TR5, the sixth impedance matching line TR6, and the seventh impedance matching line Z7.
[0087] Figures 8-11 These are the simulation results for the input / output port voltage standing wave ratio, insertion loss, and phase shift accuracy in this embodiment. Figure 8 , Figure 9 It can be seen that in the K and Ka bands, the voltage standing wave ratio (VSWR) at the input and output ports of the phase shifter is less than 1.65; Figure 10 It can be seen that the insertion loss is less than 12.5 dB; from Figure 11 It can be seen that the parasitic amplitude modulation is less than ±0.8dB and the phase shift error is within 3°.
[0088] Therefore, this invention has the advantages of high operating frequency, wide phase shift bandwidth, high phase shift accuracy, and simple structure, and has good engineering application value in the K and Ka operating frequency bands.
[0089] Example 2
[0090] like Figure 12 As shown in Embodiment 2, the ultra-wideband digital phase shifter covering the K and Ka bands also includes six phase shifting units, but the connection order is different from that in Embodiment 1. From the input port to the output port, the phase shifting units are connected in the order of 90°, 45°, 5.625°, 11.25°, 22.5° and 180°.
[0091] The 90°, 45°, 5.625°, 11.25°, and 22.5° unit structures in Example 2 are the same as in Example 1; the 180° unit structure adopts the following... Figure 4 The network structure shown is the same as the 90° and 45° structures in Example 1, and will not be described again here.
Claims
1. An ultra-wideband digital phase shifter covering the K and Ka bands, characterized in that, It includes a 180° phase shifting unit, a 45° phase shifting unit, a 22.5° phase shifting unit, a 5.625° phase shifting unit, an 11.25° phase shifting unit, and a 90° phase shifting unit, with the six phase shifting units connected in any order. The 5.625° phase shift unit, 11.25° phase shift unit, and 22.5° phase shift unit adopt a structure combining a magnetically coupled all-pass network with a parallel capacitor; the 45° phase shift unit and 90° phase shift unit adopt a structure combining coupled and uncoupled all-pass networks; and the 180° phase shift unit adopts a switch-selective bandpass network structure. The 5.625° and 11.25° phase shift units have the same phase shift structure, and the 45° and 90° phase shift units have the same phase shift structure. A 360° phase shift is achieved using a step value of 5.625°; The 5.625° phase shifting unit and the 11.25° phase shifting unit have the same phase shifting structure, both adopting a structure combining a magnetically coupled all-pass network and parallel reactance, including the first to fourth switches (SW1 to SW4), the first to second spiral inductors (L1 to L2), the first to second capacitors (C1 to C2), the first to fourth reactance elements (Z1 to Z4), and the first to second microstrip lines (TL1 to TL2). The first end of the first microstrip line (TL1) is connected to the input port (RF1) of the first phase shifting unit, the second end of the first microstrip line (TL1) is connected to the first end of the first switch (SW1), the second end of the first switch (SW1) is connected to ground through the first reactive element (Z1), and the first end of the first spiral inductor (L1) is connected to the second end of the first microstrip line (TL1). The first end of the second microstrip line (TL2) is connected to the output port (RF2) of the first phase shifting unit, the second end of the second microstrip line (TL2) is connected to the first end of the second switch (SW2), the second end of the second switch (SW2) is connected to ground through the second reactance element (Z2), and the first end of the second spiral inductor (L2) is connected to the second end of the second microstrip line (TL2). The first spiral inductor (L1) and the second spiral inductor (L2) are intertwined to form a negative mutual inductance coefficient. The second end of the first spiral inductor (L1) and the second end of the second spiral inductor (L2) are connected as the first common port. The two ends of the first capacitor (C1) are respectively connected to the first end of the first spiral inductor (L1) and the first end of the second spiral inductor (L2); one end of the second capacitor (C2) is connected in parallel to ground, and the other end is connected to the first common port; the first end of the third switch (SW3) is connected to the first common port, the second end is connected to the first end of the third reactor element (Z3), and the second end of the third reactor element (Z3) is grounded; the first end of the fourth switch (SW4) is connected to the first common port, the second end is connected to the first end of the fourth reactor element (Z4), and the second end of the fourth reactor element (Z4) is grounded.
2. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 1, characterized in that, The first to fourth switches (SW1 to SW4) are field-effect transistors or PIN diode switches; The first to fourth reactance elements (Z1 to Z4) can be any one of three types: a single capacitor, an inductor-capacitor series connection, or an inductor-capacitor parallel connection. The first to fourth switches (SW1 to SW4) have the same operating state. When the first to fourth switches (SW1 to SW4) are off, the phase-shifting structure is in the reference state; when the first to fourth switches (SW1 to SW4) are on, the phase-shifting structure is in the phase-shifting state.
3. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 1, characterized in that, The 22.5° phase shift unit includes the fifth to eighth switches (SW5 to SW8), the third to fourth spiral inductors (L3 to L4), the third to fifth capacitors (C3 to C5), the fifth to sixth reactive elements (Z5 to Z6), and the third to fourth microstrip lines (TL3 to TL4). The first terminal of the fifth switch (SW5) is connected to the input port (RF3) of the 22.5° phase shift unit, and the second terminal of the fifth switch (SW5) is grounded through the fifth reactance element (Z5); one end of the third microstrip line (TL3) is connected to the input port (RF3) of the 22.5° phase shift unit, and the other end is connected to the first terminal of the third spiral inductor (L3); The first end of the eighth switch (SW8) is connected to the output port (RF4) of the 22.5° phase shift unit, and the other end of the eighth switch (SW8) is grounded through the sixth reactor element (Z6); one end of the fourth microstrip line (TL4) is connected to the output port (RF4) of the 22.5° phase shift unit, and the other end is connected to the first end of the fourth spiral inductor (L4); The third spiral inductor (L3) and the fourth spiral inductor (L4) are intertwined to form a negative mutual inductance coefficient; the second end of the third spiral inductor (L3) and the second end of the fourth spiral inductor (L4) are connected as a second common port; The two ends of the fourth capacitor (C4) are respectively connected to the first end of the third spiral inductor (L3) and the first end of the fourth spiral inductor (L4); one end of the fifth capacitor (C5) is connected to ground, and the other end is connected to the second common port; the sixth switch (SW6), the third capacitor (C3) and the seventh switch (SW7) are connected in series and then connected between the first end of the third spiral inductor (L3) and the first end of the fourth spiral inductor (L4).
4. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 3, characterized in that, The fifth to eighth switches (SW5 to SW8) are field-effect transistors or PIN diode switches; The fifth to sixth reactance elements (Z5 to Z6) can be any one of three types: a single capacitor, an inductor-capacitor series connection, or an inductor-capacitor parallel connection. The fifth to eighth switches (SW5 to SW8) have the same operating state. When the fifth to eighth switches (SW5 to SW8) are off, the phase-shifting structure is in the reference state; when the fifth to eighth switches (SW5 to SW8) are on, the phase-shifting structure is in the phase-shifting state.
5. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 1, characterized in that, The 45° phase shifting unit and the 90° phase shifting unit have the same phase shifting structure, which is a switch selection type structure, including the first to second single-pole double-throw switches (SPDT1 to SPDT2), the fifth to sixth microstrip lines (TL5 to TL6), the first reference state network (PS1), and the first phase shifting state network (PS2). The first end of the fifth microstrip line (TL5) is connected to the input terminal of the second phase shifting unit (RF5), and the other end is connected to the input terminal of the first single-pole double-throw switch network (SPDT1); the first end of the sixth microstrip line (TL6) is connected to the output terminal of the second phase shifting unit (RF6), and the other end is connected to the input terminal of the second single-pole double-throw switch network (SPDT2); The first reference state network (PS1) is connected in series between the first output terminal of the first single-pole double-throw switch network (SPDT1) and the first output terminal of the second single-pole double-throw switch network (SPDT2); the first phase-shifting state network (PS2) is connected in series between the second output terminal of the first single-pole double-throw switch network (SPDT1) and the second output terminal of the second single-pole double-throw switch network (SPDT2).
6. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 5, characterized in that, The first reference state network (PS1) includes the fifth to sixth spiral inductors (L5 to L6), the sixth to seventh capacitors (C6 to C7), and the first to second impedance matching lines (TR1 to TR2). The first end of the first impedance matching line (TR1) is connected to the first output port of the first single-pole double-throw switch network (SPDT1), and the second end of the first impedance matching line (TR1) is connected to the first end of the fifth spiral inductor (L5); the first end of the second impedance matching line (TR2) is connected to the first output port of the second single-pole double-throw switch network (SPDT2), and the second end of the second impedance matching line (TR2) is connected to the first end of the sixth spiral inductor (L6); The fifth spiral inductor (L5) and the sixth spiral inductor (L6) are intertwined to form a negative mutual inductance coefficient; the second end of the fifth spiral inductor (L5) and the second end of the sixth spiral inductor (L6) are connected as the third common port; The sixth capacitor (C6) is connected in series between the first end of the fifth spiral inductor (L5) and the first end of the sixth spiral inductor (L6); one end of the seventh capacitor (C7) is connected to the third common port, and the other end is grounded.
7. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 5, characterized in that, The first phase-shifting network (PS2) includes the seventh to eighth spiral inductors (L7 to L8), the eighth to ninth capacitors (C8 to C9), and the third to fourth impedance matching lines (TR3 to TR4). The first end of the third impedance matching line (TR3) is connected to the second output port of the first single-pole double-throw switch network (SPDT1), and the second end of the third impedance matching line (TL3) is connected to the first end of the seventh spiral inductor (L7); the first end of the fourth impedance matching line (TR4) is connected to the second output port of the second single-pole double-throw switch network (SPDT1), and the second end of the fourth impedance matching line (TR4) is connected to the first end of the eighth spiral inductor (L8); The second terminal of the seventh spiral inductor (L7) is connected to the second terminal of the eighth spiral inductor (L8) as the fourth common port; the seventh spiral inductor (L7) and the eighth spiral inductor (L8) have no mutual inductance; The eighth capacitor (C8) is connected in series between the first end of the seventh spiral inductor (L7) and the first end of the eighth spiral inductor (L8); one end of the ninth capacitor (C9) is connected to the third common terminal, and the other end is grounded; The first to fourth impedance matching lines (TR1 to TR4) are either single characteristic impedance microstrip lines or two microstrip lines with different characteristic impedances connected in series. The first and second single-pole double-throw (SPDT1 to SPDT2) circuits are reflective single-pole double-throw switch circuits composed of field-effect transistors or PIN diodes; when the first and second single-pole double-throw (SPDT1 to SPDT2) simultaneously point to the first reference state network (PS1), the phase shifter operates in the reference state; when the first and second single-pole double-throw (SPDT1 to SPDT2) simultaneously point to the second phase-shifting state network (PS4), the phase shifter operates in the phase-shifting state.
8. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 1, characterized in that, The phase-shifting structure of the 180° phase-shifting unit is a switch-selection type structure, including the third to fourth single-pole double-throw switches (SPDT3 to SPDT4), the seventh to eighth microstrip lines (TL7 to TL8), the second reference state network (PS3), and the second phase-shifting state network (PS4). The first end of the seventh microstrip line (TL7) is connected to the signal input terminal (RF7) of the 180° phase shift unit, and the second end is connected to the input terminal of the third single-pole double-throw switch (SPDT3); the first end of the eighth microstrip line (TL8) is connected to the signal output terminal (RF8) of the 180° phase shift unit, and the second end is connected to the input terminal of the fourth single-pole double-throw switch (SPDT4); the second reference state network (PS3) is connected between the first output terminal of the third single-pole double-throw switch (SPDT3) and the first output terminal of the fourth single-pole double-throw switch (SPDT4); the second phase shift state network (PS4) is connected between the second output terminal of the third single-pole double-throw switch (SPDT3) and the second output terminal of the fourth single-pole double-throw switch (SPDT4).
9. The ultra-wideband digital phase shifter covering K and Ka bands according to claim 8, characterized in that, The second reference state network (PS3) is a T-type bandpass network, including the fifth and sixth impedance matching lines (TR5 to TR6) and the seventh reactance element (Z7); the fifth and sixth impedance matching lines (TL5 to TL6) are connected in series between the input and output ports of the second reference state network (PS3), and one end of the seventh reactance element (Z7) is grounded and the other end is connected to the common terminal of the fifth and sixth impedance matching lines (TR5 to TR6); The second phase-shifting network (PS4) is a coupler network consisting of two parallel coupling lines; the through port and coupling port of the coupler are grounded respectively, and the input port and isolation port serve as the input and output ports of the second phase-shifting network (PS4); The third and fourth single-pole double-throw (SPDT3-SPDT4) circuits are reflective single-pole double-throw (SPDT) circuits composed of field-effect transistors or PIN diodes. When the third and fourth SPDT3-SPDT4 simultaneously point to the second reference state network (PS3), the phase shifter operates in the reference state; when the third and fourth SPDT3-SPDT4 simultaneously point to the second phase-shifting state network (PS4), the phase shifter operates in the phase-shifting state. The fifth to sixth impedance matching lines (TR5 to TR6) can be either two microstrip lines with different characteristic impedances connected in series or a capacitor and inductor connected in series. The seventh reactor element (Z7) can be either a single capacitor or an inductor-capacitor in parallel.