Miniaturized ultra-wideband high-precision six-bit digital phase shifter

Abstract

The application discloses a kind of miniaturized ultra-wideband high-precision six digit controlled phase shifter, it is related to microwave millimeter wave integrated circuit technical field, solve the problem that existing technology cannot simultaneously consider ultra-wideband, high phase shift accuracy, miniaturization in digit controlled phase shifter, and high process technology requirement, high production cost problem.The six digit controlled phase shifter of the application is made of 6 cascaded phase shift units, can realize 5.625 ° phase step, 0 ° ~ 360 ° phase shift range;5.625 ° and 11.25 ° small phase shift unit of which adopts improved embedded magnetic coupling all-pass network structure, cancels redundant capacitor, completes matching compensation using coil parasitic capacitor, reduces chip area;22.5 °, 45 °, 90 ° and 180 ° large phase shift unit adopts improved switch selection type magnetic coupling all-pass network structure, optimizes phase characteristics by switch parallel compensation resistance, improves phase shift accuracy and bandwidth, reduces process requirement.The application can realize more than 9 times frequency ultra-wideband work.

Description

Technical Field

[0001] This invention relates to the technical field of numerically controlled phase shifters, and particularly to a miniaturized, ultra-wideband, high-precision six-digit numerically controlled phase shifter. Background Technology

[0002] Phased array systems, with their superior long-range detection capabilities, rapid beam scanning capabilities, strong anti-interference capabilities, high reliability, and flexible multi-functionality, have been widely used in military radar, satellite communications, and civilian 5G / 6G communications. Their core consists of a large array of transceiver (T / R) modules, with the phase shifter, as the core component of the T / R module's radio frequency channel, primarily functioning to change the phase of the transmitted electromagnetic wave. Its operating bandwidth, phase shifting accuracy, insertion loss, layout area, and echo characteristics directly determine the upper limit of the entire phased array system's performance.

[0003] To meet the demands of radar systems for long-range detection, high data update rates, multi-target tracking, and high-precision measurement, active phased array radar technology has developed rapidly, with ultra-wideband and multi-band coverage becoming core directions. Traditional active phased array radars employ a band overlay scheme, expanding the operating bandwidth through the parallel combination of multiple narrowband T / R component channels. However, this scheme significantly increases system size, weight, and cost, failing to meet the stringent requirements of modern radar for compactness and economy. Therefore, optimizing the ultra-wideband performance of the phase shifter, the core of beamforming in a phased array system, is crucial for achieving ultra-wideband multi-band coverage, miniaturization, and low-cost design.

[0004] Currently, the mainstream implementation schemes for digitally controlled phase shifters include high-pass and low-pass filter structures, switch-line structures, and magnetically coupled all-pass network structures. In existing technologies, patent application number 201010555904.2 describes a microwave / millimeter-wave ultra-wideband six-bit MMIC digital phase shifter that uses a high-pass and low-pass filter and a 3dB Lange bridge coupler structure to achieve microwave / millimeter-wave wideband phase shifting. However, the 3dB Lange bridge coupler suffers from low coupling coefficient, large chip area, and poor phase flatness within the bandwidth. Patent application number 201611240279.6 describes a transmission-type ultra-wideband digital phase shifter that uses a magnetically coupled all-pass network and a multi-filter structure to implement a six-bit digitally controlled phase shifter, where all phase shifting units are... A switch-selection structure achieves phase change between the reference state and the phase-shifted state by switching between two RF paths. However, this structure contains two independent RF paths, resulting in a large number of components and a large chip area. Patent application number 202311666823.3 describes a six-bit broadband digital phase shifter that uses an all-pass filter and a multi-filter structure to design the six-bit digital phase shifter. It replaces the 180° phase shift unit with two 90° phase shift units with a third-order filter structure, simplifying the design through unit multiplexing, but further increasing the chip layout area of ​​the phase shifter.

[0005] Reference AppendixFigure 1-5 As shown, existing magnetically coupled all-pass network structures are mainly divided into two categories: embedded and switch-selective. Embedded magnetically coupled all-pass network structures have small phase shifts, high phase shift accuracy, and fewer components, making them suitable for small phase-shifting units. However, traditional structures suffer from numerous redundant components, high design complexity, and large layout area. Switch-selective magnetically coupled all-pass network structures have large phase shifts and high phase shift accuracy, making them suitable for large phase-shifting units. However, traditional structures contain two RF paths, resulting in a large number of components, large inductance values, and high insertion losses. Furthermore, to achieve ultra-wideband operation, the manufacturing process requirements for the switching transistors are extremely high—typically requiring on-resistance as low as a few ohms and off-capacitance as low as tens of femtofarads—significantly increasing chip manufacturing costs. In summary, existing numerically controlled phase shifter solutions cannot simultaneously achieve ultra-wideband, high phase shift accuracy, miniaturization, and low cost, making it difficult to meet the large-scale application requirements of broadband phased array systems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing CNC phase shifters, which cannot simultaneously achieve ultra-wideband operation, high phase shifting accuracy, and chip miniaturization, and which have stringent requirements for semiconductor manufacturing processes and high chip production costs. This invention provides a miniaturized, ultra-wideband, high-precision six-digit CNC phase shifter. Through structural improvements to embedded magnetically coupled all-pass networks and switch-selective magnetically coupled all-pass networks, combined with optimized unit cascade topology, it achieves ultra-wideband operation at frequencies above 9 times the normal frequency while significantly improving phase shifting accuracy, reducing chip area, and lowering process requirements and manufacturing costs. It is perfectly suited for ultra-wideband applications of active phased array radar T / R components.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A miniaturized, ultra-wideband, high-precision six-digit digital phase shifter is composed of six cascaded phase shifting units. It can achieve a phase step of 5.625° and a continuous phase shift range of 0° to 360° through 6-bit digital control level.

[0008] The six phase-shifting units are 5.625°, 11.25°, 22.5°, 45°, 90°, and 180° phase-shifting units. Among them, the 5.625° and 11.25° phase-shifting units are small-phase-shifting units, which adopt an improved embedded magnetic coupling full-pass network structure. The 22.5°, 45°, 90°, and 180° phase-shifting units are large-phase-shifting units, which adopt an improved switch-selective magnetic coupling full-pass network structure.

[0009] Furthermore, the improved embedded magnetically coupled all-pass network structure eliminates the redundant series capacitor C1 connected in parallel with the magnetically coupled coil in the traditional structure, achieving impedance matching and phase compensation through the parasitic capacitance of the magnetically coupled coil itself. The parasitic capacitance of the magnetically coupled coil mainly includes two types: first, the planar capacitance and edge capacitance between the metal line and the semiconductor substrate; second, the edge capacitance between adjacent coupled metal lines. The edge capacitance between adjacent metal lines can be equivalent to being connected in parallel with the coupled metal lines, and its circuit function is completely consistent with the redundant series capacitor C1 in the traditional structure. Through coil structure optimization, it can completely replace the redundant capacitor to achieve matching and phase compensation without the need for additional capacitor components.

[0010] Furthermore, the improved switch-selective magnetically coupled all-pass network structure incorporates a phase compensation resistor connected in parallel between the source and drain of the series switch in the RF path. This phase compensation resistor adjusts the phase difference between the reference state and the phase-shifted state of the phase-shifting unit, optimizing phase flatness across the entire frequency band and improving phase-shifting accuracy and operating bandwidth. The phase compensation resistor has a resistance value in the hundreds of ohms range, far exceeding the on-resistance of the switch (several ohms). Therefore, when the switch is on, the compensation resistor has almost no effect on the path. When the switch is off, it functions as a turn-off parasitic capacitance. The compensation resistor and the turn-off parasitic capacitance form a parallel RC network, which can differentially adjust the phase characteristics of the reference state branch and the phase-shifted state branch, compensating for phase deviations caused by switch parasitic effects. This eliminates the need for high-precision, low-parasitic switching transistors, significantly reducing the requirements for manufacturing processes.

[0011] Furthermore, the six phase-shifting units are cascaded sequentially in the order of 45° phase shifting unit, 90° phase shifting unit, 11.25° phase shifting unit, 5.625° phase shifting unit, 22.5° phase shifting unit, and 180° phase shifting unit. This cascaded topology can effectively mitigate the drastic impedance changes caused by the path switching of the switching phase-shifting unit, improve the inter-stage matching between phase-shifting units, avoid impedance mismatch, optimize the full-band echo characteristics, and achieve good impedance matching over the ultra-wideband range.

[0012] Furthermore, the six-digit digital phase shifter of the present invention is fabricated based on GaAsPHEMT (gallium arsenide pseudo-high electron mobility transistor) technology, with an operating frequency band covering 2GHz~18GHz and a bandwidth of more than 9 times the frequency. It can cover S-band, C-band, X-band and Ku-band with a single chip, perfectly adapting to the application requirements of ultra-wideband phased array systems.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects: This invention employs an improved embedded magnetically coupled full-pass network structure for small phase-shifting units, eliminating redundant capacitors in traditional structures. It utilizes the parasitic capacitance of the magnetically coupled coil itself to achieve impedance matching and phase compensation. Without affecting phase-shifting accuracy and broadband characteristics, it significantly reduces the number of circuit components, lowers design complexity, greatly reduces the chip layout area of ​​the phase-shifting unit, and realizes miniaturized design of the phase shifter. At the same time, it effectively improves the return performance of the circuit. This invention employs an improved switch-selective magnetically coupled full-pass network structure for large-phase shift units. By connecting a 100-ohm-level phase compensation resistor in parallel with the source and drain of the series switch, and utilizing the RC network formed by the resistor and the switch turn-off parasitic capacitance, the phase deviation caused by the switch parasitic effect is effectively compensated, optimizing the phase flatness across the entire frequency band and significantly improving the phase shift accuracy and operating bandwidth. At the same time, this improvement significantly reduces the stringent requirements on the on-resistance and turn-off capacitance of the switch, making it compatible with low-precision process technology and effectively reducing the chip manufacturing cost. This invention employs a combined design scheme of an improved embedded structure with small-shift phase unit matching and an improved switch-selection structure with large-shift phase unit matching. Combined with an optimized cascaded topology of phase-shift units, it effectively solves the impedance mismatch problem caused by path switching in the switch-type structure, improves inter-stage matching and full-band echo characteristics, and can achieve ultra-wideband operation from 2GHz to 18GHz and more than 9 times the frequency. At the same time, it has the advantages of low insertion loss, high phase shift accuracy, and high phase flatness. A single chip can cover S-band, C-band, X-band, and Ku-band, fully meeting the ultra-wideband application requirements of broadband phased array radar T / R components. Attached Figure Description

[0014] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the invention and, together with the specification, further serve to explain the principles of the invention and enable those skilled in the art to practice and use the invention.

[0015] Figure 1 A block diagram of the transceiver channels of an active phased array radar T / R module in the prior art; Figure 2 A schematic diagram of an active phased array system architecture in the prior art; Figure 3 This is a circuit schematic of a traditional embedded magnetically coupled all-pass network structure. Figure 4 This is a circuit schematic of a traditional switch-selective magnetically coupled all-pass network structure, where both the reference state and phase-shifting state branches adopt a magnetically coupled all-pass structure. Figure 5 This is a circuit schematic of a traditional switch-selective magnetically coupled full-pass network structure. The reference state and phase-shifted state branches adopt magnetically coupled full-pass structure and multi-order high-pass and low-pass filter structure, respectively. Figure 6 This is a block diagram of the overall cascaded structure of the miniaturized ultra-wideband high-precision six-digit digital phase shifter proposed in this invention; Figure 7 This is a circuit schematic diagram of the improved embedded magnetically coupled all-pass network structure of the present invention; Figure 8 This is a circuit diagram of the improved switch-selective magnetically coupled all-pass network structure of the present invention. Both the reference state and phase-shifting state branches adopt a magnetically coupled all-pass structure. Figure 9 This is a circuit diagram of the improved switch-selective magnetically coupled all-pass network structure of the present invention. The reference state and phase-shifting state branches adopt magnetically coupled all-pass structure and multi-order high-pass and low-pass filter structure, respectively. Figure 10 This is a comparison curve of the phase characteristics before and after the improvement of the 11.25° phase shifting unit of this invention; Figure 11 This is a comparison curve of the phase characteristics of the 90° phase shifting unit before and after the improvement of the present invention.

[0016] As shown in the figure, specific structures and devices are marked in the figure to clearly illustrate the structure of the embodiments of the present invention. However, this is only for illustrative purposes and is not intended to limit the present invention to this specific structure, device and environment. Those skilled in the art can adjust or modify these devices and environments according to specific needs. Detailed Implementation

[0017] The miniaturized ultra-wideband high-precision six-digit digital phase shifter provided by the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0018] Please refer to the attached document. Figure 6-11 The miniaturized ultrawideband high-precision six-digit digital phase shifter disclosed in this invention is primarily used in the radio frequency front-end transmission module of active phased array radar T / R components. It can achieve a phase step of 5.625° and a full phase shift range of 0°~360°, with an operating frequency band covering 2GHz~18GHz, achieving ultrawideband operation of more than 9 times the frequency. It also has the advantages of high phase shift accuracy, low insertion loss, miniaturization, and low cost.

[0019] The six-digit digital phase shifter of the present invention consists of six cascaded phase shifting units, namely 5.625°, 11.25°, 22.5°, 45°, 90° and 180° phase shifting units; each phase shifting unit is controlled by a corresponding digital control signal to switch phases, and through the combination of 6-bit control levels, any phase value in the range of 0° to 360° in steps of 5.625° can be output.

[0020] The 5.625° and 11.25° phase shift units are small-shift phase shift units, employing an improved embedded magnetically coupled full-pass network structure; the 22.5°, 45°, 90°, and 180° phase shift units are large-shift phase shift units, employing an improved switch-selective magnetically coupled full-pass network structure. The six phase shift units are cascaded sequentially in the order of 45°, 90°, 11.25°, 5.625°, 22.5°, and 180°. The RF signal is output from the input terminal after passing through these six phase shift units. This cascading sequence effectively mitigates impedance fluctuations in switch-type phase shift units, improves inter-stage matching, and optimizes return loss across the entire frequency band.

[0021] Appendix Figure 7 This is a circuit schematic of the improved embedded magnetically coupled all-through network structure of the present invention, applicable to small phase shift units of 5.625° and 11.25°. Specifically, the structure includes a magnetically coupled coil U1, a first switch M1, a second switch M2, a first series matching network, a second series matching network, a first grounding capacitor C2, a second grounding capacitor C3, an input microstrip line WL1, and an output microstrip line WL2.

[0022] The magnetic coupling coil U1 consists of two mutually coupled inductor coils, with one end of the two coils connected to form a common terminal. The non-common terminals are connected to the input microstrip line WL1 and the output microstrip line WL2, respectively. The drain and source of the first switch M1 are connected to the first series matching network and the second series matching network, respectively. The source of the second switch M2 is connected to the second grounding capacitor C3, and the drain is connected to the common terminal of the magnetic coupling coil U1 and the first grounding capacitor C2.

[0023] Among them, the coupling coefficient K of the magnetic coupling coil U1 determines the phase shifting accuracy of the phase shifting unit. The larger the coupling coefficient, the higher the phase shifting accuracy. The first grounding capacitor C2 and the second grounding capacitor C3 are used to compensate for the low-frequency phase. The first series matching network, the second series matching network, the input microstrip line WL1 and the output microstrip line WL2 are used to achieve impedance matching and compensate for the high-frequency phase.

[0024] Compared to the conventional embedded magnetically coupled all-pass network structure shown, the improved structure of this invention eliminates the redundant series capacitor C1 connected in parallel with the magnetically coupled coil U1. Specifically, the principle is as follows: there are plate capacitance and edge capacitance between the metal wires of the magnetically coupled coil U1 and the substrate, and edge capacitance between adjacent coupled metal wires. These parasitic capacitances can be equivalent to capacitors connected in parallel with the magnetically coupled coil U1, and their circuit function is completely consistent with the redundant series capacitor C1 in the conventional structure. By optimizing the linewidth, line spacing, coil length, and stacking structure of the magnetically coupled coil U1, the capacitance value of the parasitic capacitors can be adjusted, completely replacing the redundant series capacitor C1 to achieve impedance matching and phase compensation.

[0025] Reference Appendix Figure 10 The phase characteristic comparison curves of the 11.25° phase shifter before and after the improvement show that the improved phase shifter has better phase flatness in the full frequency band of 2~18GHz, and its wideband characteristics are consistent with the traditional structure. At the same time, it reduces the number of components, significantly reduces the layout area, and realizes miniaturized design.

[0026] Referring to the circuit diagram of the improved switch-selective magnetically coupled all-pass network structure, it is suitable for large phase shift units of 22.5°, 45°, 90° and 180°. This structure includes parallel reference state branches and phase-shifting state branches. The switching between the reference state and the phase-shifting state is achieved by turning on and off the switching transistors, thereby realizing the phase change.

[0027] Reference Appendix Figure 8 Both the reference state and phase-shifting state branches adopt a magnetically coupled all-pass topology, which is suitable for phase-shifting units with medium phase shifts of 22.5°, 45°, and 90°. The reference state branch adopts a magnetically coupled all-pass topology, while the phase-shifting state branch adopts a multi-order high-pass and low-pass filter topology, which is suitable for phase-shifting units with large phase shifts of 180°. This avoids the problems of increased area and deteriorated insertion loss caused by large inductance.

[0028] Reference Appendix Figure 9 The reference state branch consists of a magnetically coupled coil U1, series switches M1 and M4, parallel switches M2 and M3, a series matching network 1, and a series capacitor C1; the phase-shifting state branch consists of a magnetically coupled coil U2, series switches M5 and M8, parallel switches M6 and M7, a series matching network 2, a grounding capacitor C2, and a grounding inductor L3. Phase compensation resistors R1, R2, R3, and R4 are connected in parallel between the source and drain of series switches M1, M4, M5, and M8, respectively.

[0029] In this embodiment, the resistance values ​​of the phase compensation resistors R1, R2, R3, and R4 are all in the hundreds of ohms range, while the on-resistance of the switching transistor is only a few ohms. Therefore, when the switch is on, the parallel compensation resistors have almost no effect on the insertion loss and impedance characteristics of the conduction path; when the switch is off, the switching transistor is equivalent to a turn-off parasitic capacitance of tens of femtofarads, at which point the compensation resistors and this parasitic capacitance form a parallel RC network.

[0030] The specific working process is as follows: When the reference state branch is on, series switches M1 and M4 are on, and M5 and M8 are off. At this time, R1 and R2 have no effect on the conduction path. The parasitic capacitances of R3 and M5, and R4 and M8 respectively form parallel RC networks, adjusting the phase characteristics of the phase-shifted branch in the off state. When the phase-shifted branch is on, series switches M5 and M8 are on, and M1 and M4 are off. At this time, R3 and R4 have no effect on the conduction path. The parasitic capacitances of R1 and M1, and R2 and M4 respectively form parallel RC networks, adjusting the phase characteristics of the reference state branch in the off state.

[0031] The above design allows for differentiated adjustment of the phase characteristics of the reference state and the phase-shifted state, compensating for phase deviations across the entire frequency band caused by parasitic effects of the switching transistor, optimizing phase flatness, and significantly improving phase-shifting accuracy and operating bandwidth. Furthermore, this design eliminates the need for ultra-low parasitic high-precision switching transistors, drastically reducing the requirements for GaAs PHEMT process technology and effectively lowering chip manufacturing costs.

[0032] Furthermore, corresponding auxiliary compensation resistors can also be connected in parallel between the source and drain of parallel switches M2, M3, M6, and M7 to improve the isolation between the reference state and the phase-shifted state branches and further optimize the phase-shifting accuracy.

[0033] Referring to the phase characteristic comparison curves before and after the improvement of the 90° phase shifting unit, it can be seen that the improved phase shifting unit has better broadband characteristics, higher phase shifting accuracy, and significantly improved phase flatness in the 2~18GHz full frequency band.

[0034] In this embodiment, the 180° phase-shifting unit can be constructed by cascading two 90° phase-shifting units, reusing the circuit topology of the 90° phase-shifting unit to simplify the design; by using the magnetically coupled all-pass structure of the reference state branch and the multi-order high-pass and low-pass filter structure of the phase-shifting state branch, the layout area caused by the large inductor is reduced.

[0035] The six-digit digital phase shifter of this invention is fabricated based on GaAs PHEMT technology, with an operating frequency band covering 2GHz~18GHz, achieving ultra-wideband operation of more than 9 times the frequency. It can cover S-band, C-band, X-band and Ku-band with a single chip. The phase shift accuracy is better than ±3° across the entire frequency band, the insertion loss is better than 8dB, and the input and output return loss is better than 15dB. At the same time, the chip layout area is significantly reduced, perfectly adapting to the application requirements of ultra-wideband and miniaturization of active phased array radar T / R components.

[0036] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0037] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A miniaturized, ultra-wideband, high-precision six-digit digital phase shifter, characterized in that, The six-digit digital phase shifter consists of six cascaded phase shifting units, enabling a phase step of 5.625° and a continuous phase shift range of 0° to 360°. The six phase shifting units are 5.625°, 11.25°, 22.5°, 45°, 90°, and 180° phase shifting units. The 5.625° and 11.25° phase shifting units employ an improved embedded magnetically coupled full-pass network structure. The 22.5°, 45°, 90°, and 180° phase shifting units... An improved switch-selective magnetically coupled full-pass network structure is adopted. This improved embedded magnetically coupled full-pass network structure eliminates the redundant capacitor connected in parallel with the magnetic coupling coil, achieving impedance matching and phase compensation through the parasitic capacitance of the magnetic coupling coil itself. In this improved switch-selective magnetically coupled full-pass network structure, a phase compensation resistor is connected in parallel between the source and drain of the series switch in the RF path. This phase compensation resistor has a resistance value in the hundreds of ohms range and is used to form an RC network with the parasitic capacitance when the series switch is turned off, compensating for the phase deviation between the reference state and the phase-shifted state caused by the switch parasitic effect and optimizing phase flatness.

2. The miniaturized ultra-wideband high-precision six-digit digital phase shifter according to claim 1, characterized in that, The six phase-shifting units are cascaded in the following order: 45° phase-shifting unit, 90° phase-shifting unit, 11.25° phase-shifting unit, 5.625° phase-shifting unit, 22.5° phase-shifting unit, and 180° phase-shifting unit.

3. The miniaturized ultra-wideband high-precision six-digit digital phase shifter according to claim 1, characterized in that, The improved embedded magnetically coupled all-through network structure includes a magnetically coupled coil, a first switching transistor, a second switching transistor, a first series matching network, a second series matching network, a first grounding capacitor, and a second grounding capacitor. The magnetically coupled coil consists of two mutually coupled inductors, with one end of the two inductors connected to form a common terminal. The non-common terminals of the two inductors are respectively connected to the input microstrip line and the output microstrip line. The drain and source of the first switching transistor are respectively connected to the first series matching network and the second series matching network. The source of the second switching transistor is connected to the second grounding capacitor, and the drain of the second switching transistor is connected to the common terminal of the magnetically coupled coil and the first grounding capacitor. The parasitic capacitance of the magnetically coupled coil consists of the planar capacitance between the metal line and the substrate, the edge capacitance, and the edge capacitance between adjacent metal lines. The parasitic capacitance is equivalent to a capacitor connected in parallel with the magnetically coupled coil, replacing redundant capacitors to complete matching and phase compensation.

4. The miniaturized ultra-wideband high-precision six-digit digital phase shifter according to claim 1, characterized in that, The improved switch-selective magnetically coupled full-pass network structure includes a reference state branch and a phase-shifting state branch connected in parallel. Each of the reference state branch and the phase-shifting state branch is connected in series with a series switch for path switching. The phase compensation resistor is connected in parallel between the source and drain of each series switch.

5. The miniaturized ultra-wideband high-precision six-digit digital phase shifter according to claim 4, characterized in that, Both the reference state branch and the phase-shifting branch adopt a magnetically coupled full-pass network structure; or the reference state branch adopts a magnetically coupled full-pass network structure, and the phase-shifting branch adopts a multi-order high-pass and low-pass filter structure.

6. The miniaturized ultra-wideband high-precision six-digit digital phase shifter according to claim 4, characterized in that, The reference state branch and the phase-shifting state branch are also equipped with parallel switches, and an auxiliary compensation resistor is connected in parallel between the source and drain of the parallel switches to improve channel isolation and phase-shifting accuracy.

7. The miniaturized ultra-wideband high-precision six-digit digital phase shifter according to claim 1, characterized in that, The six-digit digital phase shifter is fabricated using GaAsPHEMT technology, and its operating frequency band covers 2GHz~18GHz, with a bandwidth of more than 9 times the frequency.

8. The miniaturized ultra-wideband high-precision six-digit digital phase shifter according to claim 1, characterized in that, The 180° phase shifting unit is composed of two cascaded 90° phase shifting units, reusing the circuit topology of the 90° phase shifting unit.

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