Millimeter wave phase shifter based on 45-degree vector synthesis and phased array system
By using 45° vector synthesis technology in the millimeter wave phase shifter, eight different phase signal outputs are formed, and gain control and signal synthesis are carried out, the problems of insufficient phase resolution and bandwidth limitation in the prior art are solved, and high-precision and stable phase control are achieved.
Patent Information
- Application Number
- CN202411972374.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-04-11
AI Technical Summary
Existing active vector modulated millimeter wave phase shifters have limitations in phase control accuracy and performance improvement, especially in cases where phase resolution is insufficient and bandwidth is limited.
Using 45° vector synthesis technology, eight different signal outputs with phase difference of 45° are formed through orthogonal couplers and 45° phase shifters, and gain control and signal synthesis are used to improve phase resolution and accuracy.
It effectively improves the root mean square phase error of the phase shifter, improves the accuracy and stability of phase control, and makes the phase shifter have higher accuracy and more stable performance.
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Figure CN119812702A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of millimeter wave integrated circuits, and in particular to a 45° vector synthesized millimeter wave phase shifter and a phased array system. Background Art
[0002] With the development and progress of science and technology, the millimeter wave frequency band (30GHz to 300GHz) has attracted widespread attention due to its rich spectrum resources. The industry is increasingly interested in exploring the phased array technology in the millimeter wave frequency band in the fields of 5G communication, radar detection and sensor applications. This type of system cleverly uses phased array technology to accurately adjust the direction of the beam by electronic means, effectively improving the equivalent isotropic radiated power (EIRP) of the transmitter and the signal-to-noise ratio (SNR) of the receiver, thereby optimizing performance. In the process of realizing this technology, phase shifters (PS) play a vital role. They are the core components for realizing the beam deflection of millimeter wave phased arrays. Specifically, the directional angle θ of the beam in the phased array is mainly determined by the precisely controlled phase difference between each antenna unit. In order to achieve high-precision control of the beam direction, it is necessary to rely on phase shifters with low phase error and high phase resolution. This requirement is crucial for the successful application of phased array technology.
[0003] Currently, phase shifters are mainly divided into two categories according to whether they require external energy supply: passive phase shifters and active phase shifters. Compared with passive phase shifters, especially those facing the challenges of limited bandwidth and insufficient phase resolution, active vector modulation phase shifters, although introducing a small amount of power consumption, can significantly improve the accuracy of phase control and external calibration of the active synthesis part, thus improving the performance of the phase shifter.
[0004] Most of the existing active vector modulation phase shifter implementations are to weight and synthesize the amplitudes of four orthogonal signals (0°, 90°, 180°, 270°). First, an orthogonal signal generator is used to generate two orthogonal signals, I and Q. Then, these signals are controlled and synthesized by a variable gain amplifier (VGA) module with amplitude control and synthesis. The variable gain amplifier is controlled by an external DAC to weight the signal amplitude. This type of vector synthesis phase shifter is a traditional orthogonal vector synthesis.
[0005] The development of 5G millimeter wave communication and phased array antenna technology is gradually deepening, promoting the innovation and progress of mobile communication technology. Therefore, how to improve the accuracy and performance of phase shifters is of great significance to the development of phased array technology. Summary of the invention
[0006] The purpose of the embodiments of the present disclosure is to provide a 45° vector synthesized millimeter-wave phase shifter and a phased array system to solve the problems existing in the prior art.
[0007] The embodiment of the present disclosure adopts the following technical solution: a 45° vector synthesized millimeter wave phase shifter, comprising at least: an input balun, an orthogonal coupler, a 45° phase shifter, an amplitude-phase control circuit and an output balun; wherein the input balun is used to convert a single-ended input signal into a differential input signal; the orthogonal coupler is used to convert the differential input signal into four vector signals with phases of 0°, 180°, 90° and 270° respectively; the 45° phase shifter is used to phase-shift all the vector signals by 45° respectively, and after the signal of the orthogonal coupler passes through the 45° phase shifter, four vector signals with phases of 45°, 225°, 135° and 315° are output; the amplitude-phase control circuit is used to gain control and synthesize eight vector signals with different phases, and output differential output signals; the output balun is used to convert the differential output signal into a single-ended output signal.
[0008] In some embodiments, the amplitude and phase control circuit includes: a first control subcircuit, a second control subcircuit, a third control subcircuit and a fourth control subcircuit; wherein the first control subcircuit, the second control subcircuit, the third control subcircuit and the fourth control subcircuit are used to synthesize the phase and control the gain of the vector signal.
[0009] In some embodiments, each control subcircuit includes at least: a digital-to-analog converter DAC, a current mirror and a variable gain amplifier; the analog-to-digital converter is used to provide different input currents to the current mirror, and the current mirror copies the different input currents to the constant current source tube of the variable gain amplifier according to a preset ratio to drive the variable gain amplifier for gain control and synthesis.
[0010] In some embodiments, the current value of the input current provided by the digital-to-analog converter DAC in the second control subcircuit and the fourth control subcircuit is greater than the current value of the input current provided by the digital-to-analog converter DAC in the first control subcircuit and the third control subcircuit, and is used to compensate for the loss caused by the 45° phase shifter.
[0011] In some embodiments, the input signal of the first control subcircuit is a signal with phases of 0° and 180° respectively among the eight vector signals with different phases, and the input signal of the third control subcircuit is a signal with phases of 90° and 270° respectively among the eight vector signals with different phases.
[0012] In some embodiments, the input signal of the second control subcircuit is a signal with phases of 45° and 225° respectively among the eight vector signals with different phases, and the input signal of the fourth control subcircuit is a signal with phases of 135° and 315° respectively among the eight vector signals with different phases.
[0013] In some embodiments, the output balun includes at least a tap for providing an operating voltage to the variable gain amplifier through the tap.
[0014] In some embodiments, the 45° phase shifter is a low-pass π-type network phase shifter.
[0015] In some embodiments, the input balun and the output balun are both transformers.
[0016] The disclosed embodiment also provides a phased array system, comprising at least the millimeter wave phase shifter as described above.
[0017] The beneficial effects of the embodiments of the present disclosure are as follows: based on the principle of vector synthesis technology and the source of phase shifter errors, an orthogonal coupler is used in conjunction with a 45° phase shifter to form eight signal outputs with different phases and a phase difference of 45°, and vectors with a smaller phase difference are used for synthesis to improve the phase resolution, reduce the sensitivity of the phase shifter to the phase error and amplitude mismatch of the vector signal, achieve high-precision phase control, effectively improve the root mean square phase error of the phase shifter, and make the phase shifter have higher accuracy and more stable performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0019] FIG. 1( a ) is a schematic diagram of the traditional orthogonal vector synthesis technology;
[0020] Figure 1(b) shows the principle of 45° vector synthesis technology;
[0021] FIG1( c ) is a schematic diagram of eight different phase non-orthogonal vector synthesis techniques;
[0022] Figure 2 It is a schematic structural diagram of a millimeter wave phase shifter in the first embodiment of the present disclosure;
[0023] Figure 3 is a circuit schematic diagram of an orthogonal coupler in the first embodiment of the present disclosure;
[0024] Figure 4 This is a circuit schematic diagram of a 45° phase shifter in the first embodiment of the present disclosure;
[0025] Figure 5 Schematic diagram of the circuit structure of four control sub-circuits in the first embodiment of the present disclosure;
[0026] Figure 6 is a circuit schematic diagram of a variable gain amplifier in the first embodiment of the present disclosure;
[0027] Figure 7 1 is a circuit structure diagram of the millimeter wave phase shifter in the first embodiment of the present disclosure. DETAILED DESCRIPTION
[0028] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the following will be combined with the drawings in one or more embodiments of this specification to clearly and completely describe the technical solutions in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this document.
[0029] With the development and progress of science and technology, the millimeter wave frequency band (30GHz to 300GHz) has attracted widespread attention due to its rich spectrum resources. The industry is increasingly interested in exploring the phased array technology in the millimeter wave frequency band in the fields of 5G communications, radar detection and sensor applications. This type of system cleverly uses phased array technology to accurately adjust the direction of the beam by electronic means, effectively improving the equivalent omnidirectional radiated power of the transmitter and the signal-to-noise ratio of the receiver, thereby optimizing performance. In the process of realizing this technology, phase shifters play a vital role. They are the core components for realizing millimeter wave phased array beam deflection. Specifically, the directional angle θ of the beam in the phased array is mainly determined by the precisely controlled phase difference between each antenna unit. In order to achieve high-precision control of the beam direction, it is necessary to rely on phase shifters with low phase error and high phase resolution. This requirement is crucial for the successful application of phased array technology.
[0030] Currently, phase shifters are mainly divided into two categories according to whether they require external energy supply: passive phase shifters and active phase shifters. Compared with passive phase shifters, especially those facing the challenges of limited bandwidth and insufficient phase resolution, active vector modulation phase shifters, although introducing a small amount of power consumption, can significantly improve the accuracy of phase control and external calibration of the active synthesis part, thus improving the performance of the phase shifter.
[0031] Most of the existing active vector modulation phase shifters are implemented by weighting and synthesizing the amplitudes of four orthogonal signals (0°, 90°, 180°, 270°). First, an orthogonal signal generator is used to generate I and Q orthogonal signals, and then these signals are controlled and synthesized by a variable gain amplifier module with amplitude control and synthesis. The variable gain amplifier is controlled by an external DAC to weight the signal amplitude. This type of vector synthesis phase shifter is a traditional orthogonal vector synthesis. The development of 5G millimeter wave communication and phased array antenna technology has gradually deepened, driving the innovation and progress of mobile communication technology. Therefore, how to improve the accuracy and performance of phase shifters is of great significance to the development of phased array technology.
[0032] In order to solve the above problems, the first embodiment of the present disclosure provides a 45° vector synthesized millimeter wave phase shifter, which improves the root mean square error of the phase shifter by synthesizing eight different phases of non-orthogonal vectors (45° vectors). The principle of the traditional four-channel orthogonal signal vector synthesis technology and the principle of the eight different phase orthogonal signal vector synthesis technology of this embodiment are shown in Figure 1, where Figure 1(a) is the principle of the traditional orthogonal vector synthesis technology, Figure 1(b) is the principle of the 45° vector synthesis technology, and Figure 1(c) is a schematic diagram of the eight different phase non-orthogonal vector synthesis technology, wherein the phase resolution Δφ of the phase shifter is related to the phase difference θ between the vectors and the number N of the amplitude ratios generated by the VGA, which is specifically expressed as:
[0033]
[0034] In the traditional phase shifter design, an orthogonal vector is used, that is, θ is 90°, and the resolution is usually improved by adjusting the value of N. However, in this embodiment, the phase resolution is optimized by changing the phase difference θ.
[0035] Figure 2 FIG. 2 shows a schematic diagram of the structure of the millimeter wave phase shifter in this embodiment. Figure 2 As shown, the millimeter wave phase shifter of this embodiment at least includes: an input balun 10, an orthogonal coupler 20, a 45° phase shifter 30, an amplitude-phase control circuit 40 and an output balun 50; wherein, the input balun 10 is used to convert a single-ended input signal into a differential input signal; the orthogonal coupler 20 is used to convert the differential input signal into two differential orthogonal signals, that is, four vector signals with phases of 0°, 180°, 90° and 270° respectively; the 45° phase shifter 30 is used to phase-shift all vector signals by 45° respectively, and output four vector signals with phases of 45°, 225°, 135° and 315° respectively; the amplitude-phase control circuit 40 is used to gain control and synthesize the above eight vector signals with different phases, and output differential output signals; the output balun 50 is used to convert the differential output signal into a single-ended output signal.
[0036] Specifically, both the input balun 10 and the output balun 50 can be implemented by transformers to achieve conversion between single-ended signals and differential signals; the orthogonal coupler 20 cooperates with the 45° phase shifter 30 to generate eight signals with different phases, namely 0°, 45°, 90°, 135°, 180°, 225°, 270° and 315°, wherein the four vector signals directly output by the orthogonal coupler 20 are signals of 0°, 90°, 180° and 270°, and the 45° phase shifter 30 performs 45° phase shift on the above four vector signals, respectively, to generate four vector signals of 45°, 135°, 225° and 315°; the amplitude-phase control circuit 40 uses a variable gain amplifier, combined with a current steering structure and a digital-to-analog converter DAC, to achieve gain control and signal synthesis of the above eight signals with different phases.
[0037] Combine the following Figures 3 to 7 The working principle of the millimeter wave phase shifter in this embodiment is described.
[0038] Figure 3 The circuit schematic diagram of the orthogonal coupler 20 is shown, wherein IN+ and IN- are differential signal input terminals, THRU+ and THRU- are through terminals, CPL+ and CPL- are coupling terminals, ISO+ and ISO- are isolation terminals connected to 100 ohm resistors, and Cp is an interlayer coupling capacitor. Within the operating frequency range, the output signals of the THRU and CPL ports are 90° out of phase and have balanced amplitudes. The differential input signal (0°, 180°) can generate a set of differential through signals (0°, 180°) and a set of differential orthogonal signals (90°, 270°) through the coupler, forming a total of four vector signal outputs.
[0039] The 45° phase shifter 30 can actually be implemented by using a low-pass ∏-type network phase shifter, and its circuit schematic diagram is shown in FIG. Figure 4 As shown, in represents the input end of the vector signal, and out represents the output end of the phase-shifted vector signal. The circuit can realize phase shift control by directly controlling the closing and conducting of transistors M1 and M2 through digital signals Vc+ and Vc-. There is no need to integrate additional digital-to-analog conversion circuits, which greatly reduces the complexity of large-scale phased array systems and has the advantages of low power consumption and high linearity. However, due to the insertion loss of active devices such as transistors and inductors, there is an amplitude imbalance problem between the vector signal output by the 45° phase shifter 30 and the input vector signal. It is necessary to use a digital-to-analog converter DAC and a current mirror circuit in the variable gain amplifier part to perform amplitude calibration and compensation.
[0040] After being processed by the orthogonal coupler 20 and the 45° phase shifter 30, eight vector signals with different phases (0°, 45°, 90°, 135°, 180°, 225°, 270° and 315°) are generated and input to the amplitude and phase control circuit 40. The amplitude and phase control circuit 40 mainly includes a first control subcircuit 41, a second control subcircuit 42, a third control subcircuit 43 and a fourth control subcircuit 44; wherein the first control subcircuit 41, the second control subcircuit 42, the third control subcircuit 43 and the fourth control subcircuit 44 are used to perform phase synthesis and gain control on the differential signal passing through the orthogonal coupler and the 45° phase shifter. Figure 5 The circuit structure diagram of four control sub-circuits is shown, wherein each control sub-circuit includes a digital-to-analog converter DAC, a current mirror and a variable gain amplifier. The circuit schematic diagram of the variable gain amplifier is shown in FIG. Figure 6 As shown, transistors M1 to M4 are transconductors responsible for gain amplification and synthesis, M5 and M6 are constant current source tubes responsible for gain control, corresponding to Figure 5 In the figure, transistors M1 to M16 are transconductors of the variable gain amplifier, transistors M17 to M24 are constant current sources of the variable gain amplifier, and transistors M25 to M32 connected to the constant current sources are current mirrors. The current mirrors receive different input currents provided by the analog-to-digital converters DAC in their respective control subcircuits, and copy the different input currents to the constant current sources of the variable gain amplifier according to preset proportions, so as to drive the variable gain amplifier to perform gain control and synthesis.
[0041] When synthesizing in practice, each control subcircuit finds the gate of the transconductance transistor of the variable gain amplifier as the input end of the signal, wherein the input signal of the first control subcircuit 41 is one of eight vector signals with different phases, such as signals with phases of 0° and 180°, and the input signal of the third control subcircuit is one of eight vector signals with different phases, such as signals with phases of 90° and 270°; the input signal of the second control subcircuit 42 is one of eight vector signals with different phases, such as signals with phases of 45° and 225°, and the input signal of the fourth control subcircuit 44 is one of eight vector signals with different phases, such as signals with phases of 135° and 315°. The outputs of the above four variable gain amplifiers are then connected to the primary end of the output balun 50 after being synthesized in pairs.
[0042] like Figure 6As shown, eight vector signals with different phases enter the gate inputs of variable gain amplifier transconductance transistors M1 to M16 respectively, and the DAC outputs current values under different phase shift working states, which are copied to constant current source transistors M17 to M24 through transistors M25 to M32, thereby changing the output gain and achieving gain control and synthesis. Among them, the current value of the input current provided by the digital-to-analog converter DAC in the second control subcircuit 42 and the fourth control subcircuit 44 should be greater than the current value of the input current provided by the digital-to-analog converter DAC in the first control subcircuit 41 and the third control subcircuit 43, that is, the output current of the digital-to-analog converter DAC should be additionally expanded for compensation of the signal branches of 45°, 135°, 225° and 315°, in order to compensate for the amplitude imbalance problem caused by adding 45° phase shifters to these branches.
[0043] Figure 7 A circuit structure diagram of the millimeter wave phase shifter of this embodiment is shown. The single-ended input signal is converted into a differential input signal through the input balun 10 and enters the orthogonal coupler 20. The signal generates signals (V0°, V90°, V180°, V270°) through the orthogonal coupler 20. Each port directly outputs or connects to the 45° phase shifter 50 to obtain a vector signal output (V45°, V135°, V225°, V315°). The above eight signals enter the gate input of the variable gain amplifier transconductance stage M1-M16 respectively. The output of the variable gain amplifier adopts a balun to directly realize the function of converting the differential signal to a single-ended signal, and the balun tap is used to power the drain of the transconductor tube M1-M16. The DAC outputs the current value under different phase shift working states, which is copied to the constant current source tube M17-M24 through the tube M25-M32, thereby changing the output gain and realizing gain control and synthesis.
[0044] This embodiment is based on the principle of vector synthesis technology and the source of phase shifter errors. It uses an orthogonal coupler in conjunction with a 45° phase shifter to form eight signal outputs with different phases and a phase difference of 45°. It uses vectors with a smaller phase difference for synthesis to improve the phase resolution, reduce the sensitivity of the phase shifter to the phase error and amplitude mismatch of the vector signal, and effectively improve the root mean square phase error of the phase shifter.
[0045] Based on the same inventive concept, the second embodiment of the present disclosure provides a phased array system, which at least includes the millimeter-wave phase shifter provided in the first embodiment of the present disclosure. The millimeter-wave phase shifter using the 45° vector synthesis technology can improve the phase shifting accuracy from a non-traditional perspective and reduce the sensitivity to vector signal phase error and amplitude mismatch. Through the synthesis of signals with eight different phases, high-precision phase control is achieved, so that the phase shifter has higher accuracy and more stable performance, effectively improving the stability of the phased array system and promoting the innovation and progress of mobile communication technology.
[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present disclosure.
Claims
1. A 45° vector synthesized millimeter wave phase shifter, characterized in that: At least: Input balun, orthogonal coupler, 45° phase shifter, amplitude and phase control circuit and output balun; wherein, The input balun is used to convert the single-ended input signal into a differential input signal; The orthogonal coupler is used to convert the differential input signal into four vector signals with phases of 0°, 180°, 90° and 270° respectively; The 45° phase shifter is used to phase shift all the vector signals by 45° respectively, and after the signal of the orthogonal coupler passes through the 45° phase shifter, four vector signals with phases of 45°, 225°, 135° and 315° are output; The amplitude-phase control circuit is used to perform gain control and synthesis on eight vector signals with different phases, and output a differential output signal; The output balun is used to convert the differential output signal into a single-ended output signal.
2. The millimeter wave phase shifter according to claim 1, characterized in that: The amplitude and phase control circuit includes: a first control subcircuit, a second control subcircuit, a third control subcircuit and a fourth control subcircuit; wherein the first control subcircuit, the second control subcircuit, the third control subcircuit and the fourth control subcircuit are used to synthesize the phase and control the gain of the vector signal.
3. The millimeter wave phase shifter according to claim 2, characterized in that: Each control subcircuit includes: a digital-to-analog converter DAC, a current mirror and a variable gain amplifier; The analog-to-digital converter is used to provide different input currents to the current mirror, and the current mirror copies the different input currents to the constant current source tube of the variable gain amplifier according to a preset ratio to drive the variable gain amplifier to perform gain control and synthesis.
4. The millimeter wave phase shifter according to claim 3, characterized in that: The current value of the input current provided by the digital-to-analog converter DAC in the second control subcircuit and the fourth control subcircuit is greater than the current value of the input current provided by the digital-to-analog converter DAC in the first control subcircuit and the third control subcircuit, and is used to compensate for the loss caused by the 45° phase shifter.
5. The millimeter wave phase shifter according to claim 2, characterized in that: The input signal of the first control subcircuit is a signal with phases of 0° and 180° respectively among the eight vector signals with different phases, and the input signal of the third control subcircuit is a signal with phases of 90° and 270° respectively among the eight vector signals with different phases.
6. The millimeter wave phase shifter according to claim 2, characterized in that: The input signal of the second control subcircuit is a signal with phases of 45° and 225° respectively among the eight vector signals with different phases, and the input signal of the fourth control subcircuit is a signal with phases of 135° and 315° respectively among the eight vector signals with different phases.
7. The millimeter wave phase shifter according to claim 3, characterized in that: The output balun includes at least a tap for providing an operating voltage to the variable gain amplifier through the tap.
8. The millimeter wave phase shifter according to claim 1, characterized in that: The 45° phase shifter is a low-pass π-type network phase shifter.
9. The millimeter wave phase shifter according to any one of claims 1 to 8, characterized in that: The input balun and the output balun are both transformers.
10. A phased array system, characterized in that: At least comprises the millimeter wave phase shifter as claimed in any one of claims 1 to 9.