A high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range

Abstract

The present invention discloses a high-performance, broadband, electrically adjustable phase shifter with low phase error across the entire phase domain. This device belongs to the field of radio frequency microwave technology. The electrically adjustable phase shifter comprises an upper phase shifter structure, a middle microwave dielectric substrate, and a lower grounded metal plate. The phase shifter structure includes an input port feeder with a first capacitor, a routing microstrip line with second and third DC-blocking capacitors and first and second PIN diodes, a transmission microstrip line connected at one end to a fourth DC-blocking capacitor and at the other end to a coupler, a coupler, a reflective load, and an output feeder. The reflective load employs a novel structure, specifically comprising two varactors, an inductor, and an M-shaped transmission line. The reflective load is connected to the through-port and coupled-port of the coupler via a fifth DC-blocking capacitor, respectively, and the load terminal is grounded via a metal via. While maintaining a simple overall structure and a large phase shift range, the present invention addresses the issues of conventional reflective phase shifters, such as their inability to achieve broadband and small phase error.

Description

Technical Field

[0001] The present invention belongs to the field of radio frequency microwave technology, and in particular relates to a broadband electrically adjustable phase shifter that can be used in applications such as phased arrays. Background Art

[0002] Phase shifters are two-port microwave components that can shift the phase of an input signal without attenuating signal strength. They are widely used in phase-steering arrays, beamforming networks, and other modern wireless communication systems. They are crucial components in signal transmission and reception. Their relative bandwidth, insertion loss, return loss, phase shift, phase error, and size significantly impact the overall performance of communication equipment, making them indispensable for implementing many functions in modern communication systems. Reflective phase shifters, compared to traditional phase shifters, have been widely studied due to their simpler design, convenient voltage control, and continuously adjustable phase. However, they often suffer from bandwidth limitations. Using a hybrid architecture can reduce the required phase shift range of an adjustable phase shifter, making it possible to design a phase shifter that meets these requirements.

[0003] However, although existing electronically adjustable phase shifters can simultaneously meet the characteristics of low insertion loss, broadband, small phase error, and a large phase shift range, due to the phase shift limit of existing adjustable phase shifters, only three-stage or more phase shifter structures can be used, resulting in increased insertion loss and circuit size, and also affecting the bandwidth to a certain extent, resulting in insufficient broadband performance. Summary of the Invention

[0004] Purpose of the Invention: To address the aforementioned problems existing in the prior art, the present invention aims to provide a high-performance, broadband, electrically adjustable phase shifter with low phase error across the entire phase domain. By improving upon the existing dual-resonant load and employing a cascaded structure of two phase shifters, this electrically adjustable phase shifter achieves a wider bandwidth, lower insertion loss, and a more compact circuit structure while ensuring a full 360° phase shift and acceptable phase error.

[0005] Technical Solution: To achieve the above-mentioned objectives, the present invention provides a high-performance, broadband, electrically adjustable phase shifter with low phase error across the entire phase domain, comprising an upper phase shifter structure, a middle microstrip dielectric substrate, and a lower grounded metal plate; the upper phase shifter structure comprises:

[0006] A 180° reflective phase shifter includes a 3dB quadrature coupler and two novel reflective loads. The 3dB quadrature coupler includes an input terminal for input signals, an isolation terminal for output signals, and a through terminal and a coupling terminal for reflected signals. The reflective load includes a first resonant circuit and a second resonant circuit connected in parallel. The first resonant circuit includes a first inductor and a first varactor. The second resonant circuit includes an M-type transmission line and a second varactor. The M-type transmission line is located between the through terminal or the coupling terminal of the 3dB quadrature coupler and the second varactor.

[0007] A 180° switch-type phase shifter, comprising a transmission structure from an input port feeder line to a slot line and a phase state control section, wherein an output end of the phase state control section is connected to an input end of the 3dB quadrature coupler;

[0008] The lower ground metal plate includes a slot line structure in a switch-type phase shifter.

[0009] Preferably, the transmission structure of the switching-type phase shifter includes an input port feeder, one end of which is connected to the first capacitor and the other end serves as the input port of the phase shifter. The other end of the first capacitor is grounded through a metallized via. The input signal is transmitted to the slotline structure through the input port feeder and is then transmitted to the routing microstrip line of the phase state control part through the slotline structure.

[0010] Preferably, the phase control part of the switching type phase shifter includes a routing microstrip line, the routing microstrip line includes a first branch and a second branch, the output port of the first branch is connected to the second DC blocking capacitor, and the presence or absence of the first branch signal is controlled by the first PIN diode, the output port of the second branch is connected to the third DC blocking capacitor, and the presence or absence of the second branch signal is controlled by the second PIN diode, the output signal of the phase control part is connected to the transmission microstrip line through the fourth DC blocking capacitor, one end of the transmission microstrip line is connected to the switching type phase shifter, and the other end is connected to the 3dB orthogonal coupler input end of the reflective phase shifter.

[0011] Preferably, a first signal is input into the input end of the 3dB quadrature coupler in the reflective phase shifter and decomposed into a second signal and a third signal through the coupler. The second signal and the third signal are reflected by the reflective load and combined at the output end to obtain a fourth signal. At the same time, the second signal and the third signal will cancel each other out at the input end to avoid affecting the input first signal.

[0012] Preferably, the new reflective load in the reflective phase shifter is composed of a first resonant circuit and a second resonant circuit in parallel; one end of the fifth DC blocking capacitor is connected to the reflective load, and the other end thereof is connected to the through end and the coupling end of the 3dB orthogonal coupler.

[0013] Preferably, the cathode of the first varactor in the first resonant circuit of the reflective phase shifter is connected to the fifth DC blocking capacitor, the anode is connected to the first inductor, and the other end of the first inductor is grounded; one end of the M-type transmission line in the second resonant circuit is connected to the cathode of the second varactor, and the anode of the second varactor is grounded; the inductance of the first inductor can be used to adjust the phase properties of the electronically adjustable phase shifter; increasing the inductance can increase the phase shift, but also increase the phase error, so a compromise needs to be considered in selecting the values; both the length and width of the M-type transmission line can be used to adjust the phase properties of the electronically adjustable phase shifter; adjustment can minimize the fluctuation of the phase slope at the center frequency to obtain a better result.

[0014] Preferably, the M-type transmission line has a length greater than a quarter wavelength and is located between the second varactor and the fifth DC blocking capacitor.

[0015] Preferably, the slot line structure is H-shaped and symmetrical. The frequency response and phase properties of the overall phase shifter are changed by adjusting the width of the slot line portion used for the middle connection of the slot line structure. The larger the width, the better the return loss, and the worse the insertion loss needs to be considered in a compromise. At the same time, the change will also affect the phase error property.

[0016] Preferably, the switching phase shifter adopts the signal transmission principle from slot line to transmission line, and switches the input signal between two phase states of 0 / 180° by controlling the PIN diodes on the two branches to achieve the conduction and cutoff of the corresponding branches. When in use, only one branch signal is conducted, and the other branch is in the cutoff state. The reflective phase shifter controls the change in the reactance of the reflective load by adjusting the capacitance of the varactor in the reflective load, thereby obtaining all phase values ​​from 0 to 180°, and different capacitance values ​​correspond to different phase value changes.

[0017] Preferably, when the center frequency of the broadband electrically adjustable phase shifter is 2 GHz, the capacitance range of the varactor in the reflective load is determined to be within 0.1 to 2 pF, the inductance value is selected within 1 to 5 nH, the length of the M-type transmission line is greater than a quarter wavelength, and the width is within 0.1 to 0.3 mm.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant technical effects:

[0019] 1. The present invention cascades a 180° switching phase shifter and a 180° reflective phase shifter, thereby reducing the impact of multi-stage cascading, insertion loss, and circuit size, and requires fewer control circuits and control components.

[0020] Second, the present invention improves the dual-resonant load. Considering that the phase slope fluctuation is small at the center frequency, the phase error can be more easily reduced. Moreover, due to the frequency-varying characteristics of the M-type transmission line, compared with the original fixed large inductance, the M-type transmission line can have a phase compensation effect to a certain extent, which also brings greater freedom to the load. At the same time, while ensuring the phase shift amount, it is easier to implement than the original load. The introduction of the M-type transmission line can also eliminate the parasitic parameter effects caused by the varactor in the second resonant circuit through design.

[0021] 3. The broadband electrically adjustable phase shifter proposed in the present invention has the advantages of small size and simple structure;

[0022] 4. The broadband electrically adjustable phase shifter proposed in the present invention has a large operating bandwidth, a small RMS phase error, and realizes a 360° overall phase shift while introducing a small insertion loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A perspective view of an embodiment of the present invention;

[0024] Figure 2 A top view of an embodiment of the present invention;

[0025] Figure 3 A diagram of a grounded metal plate according to an embodiment of the present invention;

[0026] Figure 4 This is the frequency response diagram of the broadband electronically adjustable phase shifter;

[0027] Figure 5 The relative phase shift diagram of the broadband electronically adjustable phase shifter;

[0028] Figure 6 This is the phase error diagram of the broadband electronically adjustable phase shifter;

[0029] In the figure: 1-upper phase shifter structure, 2-middle microstrip dielectric substrate, 3-lower ground metal plate, 4-input port feeder, 5-first capacitor, 6-slotline structure, 7-routing microstrip line, 8-second DC blocking capacitor, 9-first PIN diode, 10-third DC blocking capacitor, 11-second PIN diode, 12-fourth DC blocking capacitor, 13-transmission microstrip line, 14-3dB orthogonal coupler, 15-fifth DC blocking capacitor, 16-first varactor, 17-first inductor, 18-M-type transmission line, 19-second varactor. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention and to implement it, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. The present invention can also be implemented or applied through other different specific embodiments, and the details of this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0031] In addition, the terms "first", "second", etc. are used for descriptive purposes only and do not indicate or imply their importance. In the description of the present invention, unless otherwise specified or limited, the terms "connected" and "connected" should be understood in a broad sense.

[0032] The embodiment of the present invention provides a high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase domain, specifically Figure 1 , Figure 2 , Figure 3As shown. It includes an upper phase shifter structure 1, an intermediate microstrip dielectric substrate 2 and a lower ground metal plate 3; the upper phase shifter structure 1 includes: a 180° reflective phase shifter, including a 3dB orthogonal coupler 14 and two new reflective loads, the 3dB orthogonal coupler 14 includes an input end for the input signal, an isolation end for the output signal, and a through end and a coupling end for the reflected signal; the reflective load includes a first resonant circuit and a second resonant circuit; the first resonant circuit includes a first inductor 17 and a first varactor 16; the second resonant circuit includes an M-type transmission line 18 and a second varactor 19; a 180° switching phase shifter, including a transmission structure from an input port feeder 4 to a slot line and a phase state control circuit. The output end of the phase control part is connected to the input port of the 3dB orthogonal coupler 14; the grounded metal plate 3 includes a slot line structure 6 in the switch type phase shifter; the transmission structure of the switch type phase shifter includes an input port feeder 4, one end of which is connected to the first capacitor 5, and the other end serves as the input port of this design, the other end of the first capacitor 5 is grounded through a metallized via, and the input signal is transmitted to the slot line structure 6 through the input port feeder 4, and is transmitted to the routing microstrip line 7 through the slot line structure 6; the phase control part of the switch type phase shifter includes a first branch (a) and a second branch (b) of the routing microstrip line 7, the output port of the first branch (a) is connected to the second DC blocking capacitor 8, and is connected to the first The PIN diode 9 controls the presence or absence of the signal of the first branch (a); the output port of the second branch (b) is connected to the third DC blocking capacitor 10, and the presence or absence of the signal of the second branch (b) is controlled by the second PIN diode 11; the output signal of the phase control part is connected to the transmission microstrip line 13 through the fourth DC blocking capacitor 12; one end of the transmission microstrip line 13 is connected to the switch-type phase shifter, and the other end is connected to the input end of the 3dB orthogonal coupler 14 of the reflective phase shifter; the input end of the 3dB orthogonal coupler 14 in the reflective phase shifter inputs the first signal (1), and is decomposed into the second signal (2) and the third signal (3) through the coupler; the second signal (2) and the third signal (3) are reflected at the output end through the reflective load. The fourth signal (4) obtained by merging, and the second signal (2) and the third signal (3) will cancel each other out at the input end to avoid affecting the input first signal (1); the new reflective load in the reflective phase shifter is composed of a first resonant circuit and a second resonant circuit connected in parallel; one end of the fifth DC blocking capacitor 15 is connected to the reflective load, and the other end thereof is connected to the through end and the coupling end of the 3dB orthogonal coupler 14; one end of the first varactor 16 of the first resonant circuit in the reflective phase shifter is connected to the fifth DC blocking capacitor 15, and the positive electrode is connected to the first inductor 17, and the other end of the first inductor 17 is grounded; one end of the M-type transmission line 18 of the second resonant circuit is connected to the negative electrode of the second varactor 19, and the positive electrode of the second varactor 19 is grounded;

[0033] like Figure 3As shown, the lower ground metal plate 3 has a slot line structure 6 and a slot structure for connecting the through end of the 3dB orthogonal coupler 14.

[0034] Working principle: The present invention is mainly divided into two parts. One part is a switching phase shifter, which can realize the switching of the input signal phase between 0 / 180°, and the other part is a reflective phase shifter, which can realize the phase transformation of 0~180° continuously adjustable. The combination of the two constitutes a hybrid phase shifter with full phase shift. Among them, the switching phase shifter adopts the signal transmission principle from slot line to transmission line, and realizes the switching of the input signal 0 / 180° two phase states by controlling the PIN diodes on the two branches to realize the conduction and cutoff of the corresponding branches. When in use, only one branch signal is turned on and the other branch is in the cutoff state; while the reflective phase shifter is achieved by adjusting the reflective load The capacitance of the varactor realizes the control of the change of the reflective load reactance to obtain all phase values ​​in 0~180°. Different capacitance values ​​correspond to different phase value changes. By optimizing the component parameters of the reflective load part, better phase performance can be obtained. For example, by adjusting the inductance in the first resonant circuit or adjusting the parameters of the M-type transmission line in the second resonant circuit, increasing the inductance and reducing the transmission line length will increase the overall phase shift. Reducing the inductance and increasing the transmission line length will reduce the overall phase shift. The width of the transmission line can adjust the in-band phase error. Because the transmission line is bent into an M shape, the circuit size is also very small. The circuit size of the reflective phase shifter part is 0.081λ. g ×0.102λ g The reflective load part of the present invention adopts the same voltage regulation, so the voltage control part is relatively simple.

[0035] The substrate of the specific embodiment of the present invention adopts RogersRO4003 plate, the dielectric constant is 3.55, and the center frequency is set at 2GHz. Figure 4 It can be seen that in the 1.5GHz-2.5GHz frequency band, the return loss is less than -10dB, and the average insertion loss at the center frequency is 1.95dB. The capacitance value of the varactor in the reflective load ranges from 0.134 to 0.985pF. Figure 5 The relative phase shift in the 1.5GHz-2.5GHz frequency band reaches 360°. Figure 6 The phase error is within ±6.9° in the 1.5GHz-2.5GHz frequency band, and the circuit size is 0.151λ. g ×0.102λ g .

[0036] In summary, the broadband electrically adjustable phase shifter of the present invention has a relative bandwidth of 50%, can achieve 360° continuous phase modulation in the 1.5GHz-2.5GHz frequency band, and has a phase error of ±6.9° in the 1.5GHz-2.5GHz frequency band, making it well suited for use in broadband systems. Furthermore, the present invention has a small overall size (only 0.151 guided wave wavelengths * 0.102 guided wave wavelengths) and an average insertion loss of 1.95dB at the center frequency.

[0037] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent transformations made using the contents of the present invention specification and drawings, as well as any other changes, modifications, replacements, combinations, simplifications, and non-equivalent replacement methods made without departing from the spirit and principles of the present invention, are included in the patent protection scope of the present invention.

Claims

1. A high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range, characterized by: It comprises an upper phase shifter structure (1), an intermediate microstrip dielectric substrate (2) and a lower ground metal plate (3); The upper phase shifter structure (1) comprises: A 180° reflective phase shifter comprises a 3dB quadrature coupler (14) and two novel reflective loads, wherein the 3dB quadrature coupler (14) comprises an input end for input signals, an isolation end for output signals, and a through end and a coupling end for reflected signals; the reflective load comprises a first resonant circuit and a second resonant circuit connected in parallel; the first resonant circuit comprises a first inductor (17) and a first varactor (16); the second resonant circuit comprises an M-type transmission line (18) and a second varactor (19); the M-type transmission line (18) is located between the through end or the coupling end of the 3dB quadrature coupler (14) and the second varactor (19); A 180° switch-type phase shifter comprises a transmission structure from an input port feed line (4) to a slot line and a phase state control section, wherein the output end of the phase state control section is connected to the input end of the 3dB quadrature coupler (14); The lower grounding metal plate (3) includes a slot line structure (6) in a switch-type phase shifter.

2. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1 is characterized in that: The transmission structure of the switch-type phase shifter includes an input port feeder (4), one end of which is connected to a first capacitor (5), and the other end serves as an input port of the phase shifter. The other end of the first capacitor (5) is grounded through a metallized via. An input signal is transmitted to a slot line structure (6) through the input port feeder (4), and is then transmitted to a routing microstrip line (7) of a phase state control part through the slot line structure (6).

3. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: The phase control part of the switch-type phase shifter includes a routing microstrip line (7), the routing microstrip line (7) includes a first branch and a second branch, the output port of the first branch is connected to a second DC blocking capacitor (8), and the presence or absence of the first branch signal is controlled by a first PIN diode (9), the output port of the second branch is connected to a third DC blocking capacitor (10), and the presence or absence of the second branch signal is controlled by a second PIN diode (11), the output signal of the phase control part is connected to a transmission microstrip line (13) through a fourth DC blocking capacitor (12), one end of the transmission microstrip line (13) is connected to the switch-type phase shifter, and the other end is connected to the input end of a 3dB quadrature coupler (14) of the reflective phase shifter.

4. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: A first signal is input to the input end of a 3dB quadrature coupler (14) in the reflective phase shifter and decomposed into a second signal and a third signal through the coupler. The second signal and the third signal are reflected by a reflective load and combined at the output end to obtain a fourth signal. At the same time, the second signal and the third signal are offset at the input end to avoid affecting the input first signal.

5. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: The novel reflective load in the reflective phase shifter is formed by connecting a first resonant circuit and a second resonant circuit in parallel; one end of a fifth DC blocking capacitor (15) is connected to the reflective load, and the other end thereof is connected to a through end and a coupling end of a 3dB orthogonal coupler.

6. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: The negative electrode of the first varactor (16) of the first resonant circuit in the reflective phase shifter is connected to the fifth DC blocking capacitor (15), and the positive electrode is connected to the first inductor (17), and the other end of the first inductor (17) is grounded; one end of the M-type transmission line (18) of the second resonant circuit is connected to the negative electrode of the second varactor (19), and the positive electrode of the second varactor (19) is grounded; the inductance value of the first inductor (17) can be used to adjust the phase property of the electrically adjustable phase shifter, and the length and width of the M-type transmission line (18) can be used to adjust the phase property of the electrically adjustable phase shifter.

7. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: The M-type transmission line (18) has a length greater than a quarter wavelength and is located between the second varactor (19) and the fifth DC blocking capacitor (15).

8. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: The slot line structure (6) is an H-shaped structure and is symmetrical. The frequency response and phase properties of the overall phase shifter are changed by adjusting the width of the slot line portion used for connecting the slot line structure in the middle.

9. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: The switching phase shifter uses the signal transmission principle from slot line to transmission line. By controlling the PIN diodes on the two branches to turn the corresponding branches on and off, the input signal can switch between two phase states of 0 / 180°. During use, only one branch signal is turned on, while the other branch is in the off state. The reflective phase shifter controls the reactance change of the reflective load by adjusting the capacitance of the varactor in the reflective load, obtaining all phase values ​​from 0 to 180°. Different capacitance values ​​correspond to different phase value changes.

10. The high-performance broadband electrically adjustable phase shifter with low phase error in the entire phase range according to claim 1, characterized in that: When the center frequency of the broadband electrically adjustable phase shifter is 2 GHz, the capacitance range of the varactor in the reflective load is determined to be within 0.1 to 2 pF, the inductance value is selected within 1 to 5 nH, the length of the M-type transmission line (18) is greater than a quarter wavelength, and the width is within 0.1 to 0.3 mm.

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