180° phase shifter based on single switch

Abstract

This invention discloses a 180° phase shifter based on a single switch, comprising a dielectric substrate, an input port, an output port, a single-pole double-throw (SPDT) switch, an input transmission line, an output transmission line, a reference transmission line, a phase-shift transmission line, a short-circuit matching stub, and a metal ground plane. The input transmission line is connected to both the reference transmission line and the phase-shift transmission line via the SPDT switch. The ends of the reference transmission line and the phase-shift transmission line are connected in parallel with the short-circuit matching stub and then connected to the output transmission line. When the SPDT switch switches between connecting to the reference transmission line and the phase-shift transmission line, the reference transmission line or the phase-shift transmission line is matched with the short-circuit matching stub, resulting in a 180° phase difference in the output signals. This invention uses only one SPDT switch and has advantages such as low insertion loss, simple structure, wide bandwidth, and good signal output amplitude balance.

Description

Technical Field

[0001] This invention relates to the technical field of microwave phase shifters, and in particular to a 180° phase shifter based on a single switch. Background Technology

[0002] In the field of microwave communication, phase shifters can adjust the phase of the output signal relative to the input signal, thus playing an important role in radar systems, satellite communications, and other applications. One of the research hotspots is how to implement a one-bit digital phase shifter with a 180° phase difference between two outputs.

[0003] An investigation and understanding of existing technologies was conducted, specifically as follows:

[0004] In 2019, Hong-Jib Yoon et al. proposed a parallel-coupled three-wire broadband 180° phase shifter. This phase shifter consists of two single-pole double-throw switches, a short-circuit coupling line, and a transmission line with a short-circuit stub. It achieves a 180° phase shift between the two outputs through a short-circuit coupling line and its equivalent circuit, and isolates the two lines through the two single-pole double-throw switches.

[0005] In 2022, Yizhan He et al. proposed an ultra-wideband microwave reconfigurable phase shifter. This phase shifter is a dual-input, dual-output system, with one input providing a 180° phase shift and the other a 90° phase shift. Each input consists of a main line and a reference line. The main line generates its phase shift relative to the reference line through a designed stub structure. Different phases are achieved by controlling a single-pole double-throw switch at the output, resulting in different polarization effects.

[0006] In 2024, Yunye Bi et al. proposed a 2.8–67 GHz 180° phase shifter based on the SISL platform. This phase shifter consists of a broadband inverter and a reference line, with a 180° output phase difference between the inverter and the reference line. The phase inverter is constructed from a conversion structure that transforms a suspended microstrip line into a substrate-integrated suspended parallel stripline. Energy is coupled through the substrate-integrated suspended parallel stripline, and when it reaches the other port, the phase flips by 180° due to the inversion of the suspended microstrip line.

[0007] In 2025, Kristen Ling et al. proposed a switchable electromagnetically coupled 180° phase-shifting filter phase shifter. This phase shifter utilizes a reconfigurable filter to control the phase shift by changing the equivalent physical geometry.

[0008] In summary, existing work includes numerous phase shifters for achieving 180° phase shift. However, most of these techniques utilize two single-pole double-throw switches. While this achieves isolation between the reference signal and the phase-shifted signal, the introduction of multiple switches increases losses. A single-switch-based phase shifter, on the other hand, can reduce insertion loss and improve the amplitude balance between the reference and phase-shifted signals. Therefore, designing a single-switch-based 180° phase shifter is of significant importance. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and to propose a 180° phase shifter based on a single switch. This phase shifter has advantages such as low insertion loss, simple structure, wide bandwidth, and good amplitude balance of the two signal outputs.

[0010] To achieve the above objectives, the technical solution provided by this invention is as follows: a 180° phase shifter based on a single switch, comprising a coplanar grounded conductor, a dielectric substrate, an input port and an output port disposed on the side of the dielectric substrate, a single-pole double-throw switch, an input transmission line, an output transmission line, a reference transmission line, a phase shift transmission line, and a short-circuit matching stub disposed on the upper surface of the dielectric substrate, and a metal ground plane disposed on the lower surface of the dielectric substrate; the input port is connected to the starting end of the input transmission line, the end of the input transmission line is connected to the input end of the single-pole double-throw switch, and the two output ends of the single-pole double-throw switch are respectively connected to the starting end of the reference transmission line and the starting end of the phase shift transmission line; the ends of the reference transmission line and the phase shift transmission line merge with one end of the short-circuit matching stub to form a parallel structure, and are connected to the starting end of the output transmission line at the merging point; the end of the output line is connected to the output port, and the other end of the short-circuit matching stub... The input transmission line, output transmission line, reference transmission line, phase shift transmission line, and short-circuit matching stub are connected to the metal ground plane through a first metallized via to form a short-circuit structure. The two sides of the input transmission line, output transmission line, reference transmission line, phase shift transmission line, and short-circuit matching stub are isolated from the coplanar grounding conductor through gaps. The coplanar grounding conductor is composed of several second metallized vias arranged at intervals and surrounding the input transmission line, output transmission line, reference transmission line, phase shift transmission line, short-circuit matching stub, coplanar grounding conductor, and short-circuit matching stub. The second metallized vias are connected to the metal ground plane to form a stable grounding condition. The input transmission line, output transmission line, reference transmission line, phase shift transmission line, short-circuit matching stub, coplanar grounding conductor, and metal ground plane together form a grounded coplanar waveguide transmission structure. The electrical lengths of the reference transmission line and the phase shift transmission line differ by 180°. When the single-pole double-throw switch conducts the reference transmission line or the phase shift transmission line, the phase of the output signal differs by 180°.

[0011] Furthermore, the short-circuit matching stub can be replaced with an open-circuit matching stub whose electrical length differs from the short-circuit matching stub by 90°.

[0012] Furthermore, the reference transmission line, the phase-shift transmission line, and the short-circuit matching stub are either linearly distributed with uniform impedance or miniaturized curved distributions.

[0013] Furthermore, the input transmission line, output transmission line, reference transmission line, phase-shift transmission line, and short-circuit matching stub have the same characteristic impedance.

[0014] Furthermore, the input transmission line is provided with a first welding connection line at its end, the reference transmission line is provided with a second welding connection line at its start end, and the phase shift transmission line is provided with a third welding connection line at its start end; the first welding connection line is connected to the second welding connection line and the third welding connection line respectively through the single-pole double-throw switch.

[0015] Furthermore, the end of the reference transmission line, the end of the phase-shift transmission line, one end of the short-circuit matching stub, and the beginning of the output transmission line converge to form a cross-shaped structure.

[0016] Further, let the electrical length of the reference transmission line be θ, the electrical length of the phase-shift transmission line be 180° + θ, and the electrical length of the short-circuit matching stub be 90° − θ. According to transmission line theory, when the output terminal of the single-pole double-throw switch is connected to the reference transmission line, the phase-shift transmission line is in an open-circuit state, and the short-circuit matching stub is in a short-circuit state. The equivalent admittance of the two connected in parallel is 0, the circuit is matched, and the phase shift of the input signal after passing through the reference transmission line with an electrical length of θ is θ, that is, the phase of the output signal is θ. This is called the 0° operating state. When the output terminal of the single-pole double-throw switch is connected to the phase-shift transmission line, the reference transmission line is in an open-circuit state, and the short-circuit matching stub is in a short-circuit state. The equivalent admittance of the two connected in parallel is 0, the circuit is matched, and the phase shift of the input signal after passing through the phase-shift transmission line with an electrical length of 180° + θ is 180° + θ, that is, the phase of the output signal is 180° + θ. This is called the 180° operating state.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] 1. This invention uses only one single-pole double-throw switch, which effectively reduces the insertion loss caused by the switch, making this invention have the characteristic of low loss.

[0019] 2. The output amplitude of this invention is very close in both the 0° and 180° operating states, and it has a good output amplitude balance.

[0020] 3. The present invention has a reflection coefficient of no more than -10dB within the working bandwidth, good matching, and a wide bandwidth.

[0021] 4. The phase difference fluctuation of the two phase states of the present invention is small, the phase stability is good, and the phase shifting accuracy is high.

[0022] 5. The present invention has a simple structure and is easy to implement. By reasonably setting the characteristic impedance and length of each transmission line segment, a 180° phase shifter based on a single switch can be obtained. The two phase states are controlled by switching the connection state of the output terminal of the single-pole double-throw switch, and the phase difference is 180°. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a 180° phase shifter based on a single switch according to an embodiment of the present invention.

[0024] Figure 2 The image shows the reflection coefficient when the phase shifter output phase is 0° or 180°, obtained from simulation in this embodiment.

[0025] Figure 3 The diagram shows the transmission coefficients when the phase shifter output phase is 0° or 180°, obtained from simulation in this embodiment.

[0026] Figure 4 The diagram shows the phase difference between the phase shifter output phase of 0° and 180° obtained from the simulation in this embodiment. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0028] See Figure 1 As shown, this embodiment discloses a 180° phase shifter based on a single switch, including a coplanar grounding conductor 9, a dielectric substrate 11, an input port 1 and an output port 2 disposed on the side of the dielectric substrate 11, a single-pole double-throw switch 3, an input transmission line 4, an output transmission line 5, a reference transmission line 6a, a phase shift transmission line 6b, and a short-circuit matching stub 7a disposed on the upper surface of the dielectric substrate 11, and a metal ground plane 12 disposed on the lower surface of the dielectric substrate 11; the input transmission line 4 has a first welding connection line 8a at its end, the reference transmission line 6a has a second welding connection line 8b at its starting end, and the phase shift transmission line 6b has a third welding connection line 8c at its starting end.

[0029] The input port 1 is connected to the starting end of the input transmission line 4. The input transmission line 4 is connected to the input end of the single-pole double-throw switch 3 via a first solder connection line 8a. The two output ends of the single-pole double-throw switch 3 are respectively connected to the second solder connection line 8b of the reference transmission line 6a and the third solder connection line 8c of the phase shift transmission line 6b. The ends of the reference transmission line 6a and the phase shift transmission line 6b merge with one end of the short-circuit matching stub 7a to form a parallel structure, and are connected to the starting end of the output transmission line 5 at the merging point to form a cross-shaped structure. The end of the output transmission line 5 is connected to the output port 2. The other end of the short-circuit matching stub 7a is connected to the metal ground plane 12 via a first metallized via 7b to form a short-circuit structure. The input transmission line 4, the output transmission line 5, the reference transmission line 6a, the phase shift transmission line 6b, and the short-circuit matching stub 7a are connected to the starting end of the output transmission line 5 to form a cross-shaped structure. The two sides of the short-circuit matching stub 7a are isolated from the coplanar grounding conductor 9 by gaps. The coplanar grounding conductor 9 is composed of several spaced second metallized vias that surround the input transmission line 4, the output transmission line 5, the reference transmission line 6a, the phase shift transmission line 6b, and the short-circuit matching stub 7a. The second metallized vias are connected to the metal ground plane 12 to form a stable grounding condition. The input transmission line 4, the output transmission line 5, the reference transmission line 6a, the phase shift transmission line 6b, the short-circuit matching stub 7a, the coplanar grounding conductor 9, and the metal ground plane 12 together form a grounded coplanar waveguide transmission structure. The electrical lengths of the reference transmission line 6a and the phase shift transmission line 6b differ by 180°. When the single-pole double-throw switch 3 conducts the reference transmission line 6a or the phase shift transmission line 6b, the phase of the output signal differs by 180°.

[0030] In a specific example, the short-circuit matching stub 7a can be replaced with an open-circuit matching stub whose electrical length differs by 90°.

[0031] In a specific example, the reference transmission line 6a, the phase-shift transmission line 6b, and the short-circuit matching stub 7a can be a linear distribution of uniform impedance or a miniaturized distribution of curves.

[0032] In a specific example, the input transmission line 4, output transmission line 5, reference transmission line 6a, phase shift transmission line 6b, and short-circuit matching stub 7a have the same characteristic impedance.

[0033] In a specific example, let the electrical length of the reference transmission line 6a be θ, the electrical length of the phase-shift transmission line 6b be 180° + θ, and the electrical length of the short-circuit matching stub 7a be 90° − θ. According to transmission line theory, when the output terminal of the single-pole double-throw switch 3 is connected to the reference transmission line 6a, the phase-shift transmission line 6b is in an open-circuit state, and the short-circuit matching stub 7a is in a short-circuit state. The equivalent admittance of the two connected in parallel is 0, the circuit is matched, and the phase shift of the input signal after passing through the reference transmission line 6a with an electrical length of θ is θ, that is, the phase of the output signal is θ. This is called the 0° operating state. When the output terminal of the single-pole double-throw switch 3 is connected to the phase-shift transmission line 6b, the reference transmission line 6a is in an open-circuit state, and the short-circuit matching stub 7a is in a short-circuit state. The equivalent admittance of the two connected in parallel is 0, the circuit is matched, and the phase shift of the input signal after passing through the phase-shift transmission line 6b with an electrical length of 180° + θ is 180° + θ. θ means the phase of the output signal is 180° + θ, which is called the 180° operating state. Therefore, this invention can achieve two operating states with a phase difference of 180°.

[0034] In one specific example, the dielectric substrate 11 uses WL-CT350 material with a thickness of 0.168 mm; the impedance of the input port 1 and the output port 2 is 50 Ω; the center frequency is determined to be 1 GHz; the characteristic impedance of the reference transmission line 6a is 50 Ω, and its electrical length at 1 GHz is 45°; the characteristic impedance of the phase-shift transmission line 6b is 50 Ω, and its electrical length at 1 GHz is 225°; the characteristic impedance of the short-circuit matching stub 7a is 50 Ω, and its electrical length at 1 GHz is 45°.

[0035] The 180° phase shifter described in this embodiment was simulated using ADS simulation software. Based on the connection position of the switch's output terminal, the single-pole double-throw switch 3 was defined as operating at 0° when connected to the reference transmission line 6a and operating at 180° when connected to the phase shift transmission line 6b. The reflection coefficient S, expressed in decibels, was obtained from the simulation for both the 0° and 180° operating states. 11 Amplitude curve, such as Figure 2 As shown in the figure, the dashed line represents S when the working state is 0°. 11 The curve, the solid line represents S when the working state is 180°. 11 Curve. From Figure 2 As can be seen from the data, the operating center frequency of this embodiment is 1 GHz, the operating bandwidth is 0.910-1.106 GHz, and the in-band reflection coefficient is no higher than −10 dB, indicating good matching. Simulations obtained at 0° and 180° operating states yielded the transmission coefficient S in decibels for both states. 21 Amplitude parameter curve, such as Figure 3 As shown in the figure, the dashed line represents S when the working state is 0°. 21 The curve, the solid line represents S when the working state is 180°. 21 Curve. From Figure 3 As can be seen, the difference in output amplitude between the two operating states in this embodiment does not exceed 0.6 dB, and the insertion loss in the passband is less than -1.3 dB. This indicates that the amplitude transmission balance of this embodiment is very good under different states. Figure 4 This is a phase difference diagram obtained from the simulation of the 0° and 180° operating states in this embodiment. From... Figure 4 As can be seen, within the operating bandwidth range of 0.910-1.106 GHz, the phase difference between the two operating states fluctuates by no more than 7°, indicating good phase stability.

[0036] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A 180° phase shifter based on a single switch, characterized in that, Includes a coplanar grounding conductor (9), a dielectric substrate (11), an input port (1) and an output port (2) disposed on the side of the dielectric substrate (11), a single-pole double-throw switch (3), an input transmission line (4), an output transmission line (5), a reference transmission line (6a), a phase-shift transmission line (6b), and a short-circuit matching stub (7a) disposed on the upper surface of the dielectric substrate (11), and a metal ground plane (12) disposed on the lower surface of the dielectric substrate (11); the input port (1) is connected to the starting end of the input transmission line (4), and the end of the input transmission line (4) is connected to The input terminal of the single-pole double-throw switch (3) and the two output terminals of the single-pole double-throw switch (3) are respectively connected to the starting end of the reference transmission line (6a) and the starting end of the phase shift transmission line (6b); the end of the reference transmission line (6a) and the end of the phase shift transmission line (6b) merge with one end of the short-circuit matching stub (7a) to form a parallel structure, and are connected to the starting end of the output transmission line (5) at the merging point. The end of the output transmission line (5) is connected to the output port (2), and the other end of the short-circuit matching stub (7a) is connected to the metallized via (7b). The ground plane (12) forms a short-circuit structure; the input transmission line (4), the output transmission line (5), the reference transmission line (6a), the phase shift transmission line (6b), and the short-circuit matching stub (7a) are isolated from the coplanar grounding conductor (9) by gaps on both sides. The coplanar grounding conductor (9) is composed of several second metallized vias arranged at intervals and surrounding the input transmission line (4), the output transmission line (5), the reference transmission line (6a), the phase shift transmission line (6b), and the short-circuit matching stub (7a). The second metallized vias are connected to the metal ground. Plane (12) to form a stable grounding condition, the input transmission line (4), the output transmission line (5), the reference transmission line (6a), the phase shift transmission line (6b), the short-circuit matching stub (7a), the coplanar grounding conductor (9) and the metal ground plane (12) together form a grounded coplanar waveguide transmission structure; the electrical lengths of the reference transmission line (6a) and the phase shift transmission line (6b) are 180° apart, and when the single-pole double-throw switch (3) turns on the reference transmission line (6a) or the phase shift transmission line (6b), the phase of the output signal is 180° apart.

2. The 180° phase shifter based on a single switch according to claim 1, characterized in that, The short-circuit matching stub (7a) can be replaced with an open-circuit matching stub whose electrical length differs from that of the short-circuit matching stub by 90°.

3. The 180° phase shifter based on a single switch according to claim 1, characterized in that, The reference transmission line (6a), the phase-shift transmission line (6b), and the short-circuit matching stub (7a) are either linearly distributed with uniform impedance or miniaturized curved distributions.

4. The 180° phase shifter based on a single switch according to claim 1, characterized in that, The input transmission line (4), output transmission line (5), reference transmission line (6a), phase shift transmission line (6b), and short-circuit matching stub (7a) have the same characteristic impedance.

5. The 180° phase shifter based on a single switch according to claim 1, characterized in that, The input transmission line (4) is provided with a first welding connection line (8a) at its end, the reference transmission line (6a) is provided with a second welding connection line (8b) at its beginning end, and the phase shift transmission line (6b) is provided with a third welding connection line (8c) at its beginning end; the first welding connection line (8a) is connected to the second welding connection line (8b) and the third welding connection line (8c) respectively through the single-pole double-throw switch (3).

6. The 180° phase shifter based on a single switch according to claim 1, characterized in that, The end of the reference transmission line (6a), the end of the phase-shift transmission line (6b), one end of the short-circuit matching stub (7a), and the beginning of the output transmission line (5) form a cross-shaped structure at their junction.

7. The 180° phase shifter based on a single switch according to claim 1, characterized in that, Let the electrical length of the reference transmission line (6a) be θ, the electrical length of the phase-shift transmission line (6b) be 180° + θ, and the electrical length of the short-circuit matching stub (7a) be 90° − θ. According to transmission line theory, when the output terminal of the single-pole double-throw switch (3) is connected to the reference transmission line (6a), the phase-shift transmission line (6b) is in an open-circuit state, and the short-circuit matching stub (7a) is in a short-circuit state. The equivalent admittance of the two connected in parallel is 0, the circuit is matched, and the phase shift of the input signal after passing through the reference transmission line (6a) with an electrical length of θ is θ, that is, the phase of the output signal is θ. This is called the 0° working state. When the output terminal of the single-pole double-throw switch (3) is connected to the phase-shift transmission line (6b), the reference transmission line (6a) is in an open-circuit state, and the short-circuit matching stub (7a) is in a short-circuit state. The equivalent admittance of the two connected in parallel is 0, the circuit is matched, and the phase shift of the input signal after passing through the reference transmission line (6a) with an electrical length of 180° + θ is θ. The phase shift transmission line (6b) of θ experiences a phase shift of 180° + θ, that is, the phase of the output signal is 180° + θ, which is called the 180° working state.

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