A 360° continuously tunable phase shifter based on artificial surface plasmons

Abstract

The application discloses a 360-degree continuous adjustable phase shifter based on artificial surface plasmons, which is obtained by cascading a SSPP phase shifter loaded with a variable capacitance diode and a reflection type phase shifter loaded with a PIN diode, fully utilizes the flexible adjustable advantage of the dispersion characteristics of artificial surface plasmons and the different regulation characteristics of the two types of adjustable elements, and realizes continuous adjustment of the equivalent capacitance by the variable capacitance diode, so that the dispersion characteristics and the phase constant of the SSPP unit are finely and continuously regulated, the continuous phase transformation from 0 to 180 degrees is completed, the PIN diode can be switched between the on and off states, the reflection type phase shifter generates accurate 0 / 180 discrete phase inversion; after cascading, the continuous phase shift in the range of 180 degrees is obtained by using the variable capacitance diode first, then the 180-degree phase inversion is realized by switching the PIN diode to achieve the superposition of the 180-degree phase inversion, and the remaining 180-degree phase can be completed by adjusting the variable capacitance diode again, so that the 0 to 360 degree continuous and accurate phase regulation is realized by the cooperative work.

Description

Technical Field

[0001] This invention relates to the field of microwave and millimeter-wave device design technology, and in particular to a 360° continuously adjustable phase shifter based on artificial surface plasmons. Background Technology

[0002] Phase shifters are crucial microwave control devices that manipulate the phase of signals, playing a central role in systems such as signal modulation, intelligent sensing, beamforming, and phased array antennas. Phase shifters are designed to enable precise control of the electromagnetic wave phase, meeting the diverse signal processing precision and flexibility requirements of various applications. Whether in communication systems, radar systems, electronic countermeasures, or radio astronomy, phase shifters play a vital role.

[0003] In recent years, with the rapid development of communication technology, the application scenarios of phase shifters have become increasingly complex, placing higher demands on their performance, size, and control capabilities. A wider phase shift coverage range enables finer beam scanning and higher-order signal modulation, improving system flexibility and information capacity; a smaller size facilitates the integration and miniaturization of communication systems; and continuous and precise phase control capabilities can cope with complex and ever-changing application scenarios. Currently, traditional phase shifters often require large circuit sizes to achieve a wide phase shift range, while miniaturized phase shifters struggle to achieve wide continuous phase shift coverage, making it difficult to reconcile a wide phase shift range with a compact circuit size. Furthermore, traditional phase shifter design methods lack flexibility in phase control, often requiring redesign with high complexity to meet different functional requirements.

[0004] Artificial surface plasmon metamaterials are periodic structures that support surface wave mode transmission in the microwave and millimeter-wave bands, exhibiting low transmission loss, strong field confinement capability, and flexible dispersion characteristics. Applying artificial surface plasmons to phase shifter design leverages their tunable dispersion to continuously control the phase constant by altering the equivalent circuit parameters of each unit. This allows for high-performance phase modulation with a relatively simple structure, reducing design complexity and improving device integration. Summary of the Invention

[0005] Purpose of the invention: This invention provides a 360° continuously adjustable phase shifter based on artificial surface plasmons, which can solve the problem that existing adjustable phase shifters cannot simultaneously meet the requirements of continuous phase shift and miniaturization.

[0006] Technical solution: The present invention provides a 360° continuously adjustable phase shifter based on artificial surface plasmons, comprising: a transmission layer, a dielectric layer, and a ground layer stacked sequentially from top to bottom;

[0007] The transport layer includes SSPP phase shifters and reflective phase shifters, with the SSPP phase shifters and reflective phase shifters cascaded together;

[0008] The SSPP phase shifter includes a 50Ω microstrip line, a transition structure, several SSPP units, a first positive choke structure, a negative choke structure, a first positive feed structure, and vias; the 50Ω microstrip line is connected to the SSPP units through the transition structure to achieve impedance matching.

[0009] The SSPP unit includes a central conductor, parallel stubs, and a varactor diode. The parallel stubs are symmetrically loaded on both sides of the central conductor. The varactor diode is laterally connected across the central conductor and connected in series with adjacent SSPP units. The bias voltage is input through the first positive electrode feeding structure to control the capacitance value of the varactor diode, dynamically adjust the dispersion characteristics of the SSPP, and achieve 180° continuous phase control. The negative electrode of the varactor diode is connected to the ground plane through a via. The first positive electrode choke structure and the negative electrode choke structure are used to isolate the RF signal from the DC bias signal.

[0010] The reflective phase shifter includes a 50Ω microstrip line, a 35Ω microstrip line, a quarter-wavelength stub, a PIN diode, a second positive choke structure, and a second positive feed structure. The quarter-wavelength stub and PIN diode are loaded at the through port and coupling port of the 3dB coupler. The bias voltage is input through the second positive feed structure to control the on / off state of the PIN diode, realizing the switching between open and short circuits, thereby achieving 0° or 180° phase switching. The second positive choke structure is used to isolate the RF signal from the DC bias signal.

[0011] By jointly controlling the SSPP phase shifter and the reflective phase shifter, the phase shifter achieves continuous phase control in the range of 0° to 360°.

[0012] Furthermore, 50Ω microstrip lines are placed at the input and output terminals of the SSPP phase shifter, as well as at the input and output terminals of the reflective phase shifter.

[0013] Furthermore, several SSPP units are arranged periodically, with gaps between the center conduction bands of adjacent SSPP units. Varactor diodes are connected across the gaps between adjacent center conduction bands to achieve electrical connection and dispersion control between adjacent SSPP units.

[0014] Furthermore, the 3dB coupler of the reflective phase shifter is composed of 50Ω and 35Ω microstrip lines, and has an input terminal, a through terminal, a coupling terminal, and an isolation terminal; a quarter-wavelength stub is connected to the through terminal or the coupling terminal through a PIN diode; by controlling the on / off state of the PIN diode, the terminal reflection coefficient of the corresponding port is changed, so that the signal output from the isolation terminal produces a discrete phase switch of 0° or 180° relative to the input terminal.

[0015] Furthermore, both the first and second positive choke structures employ a fan-shaped stub structure to suppress interference from AC radio frequency signals on the DC bias network.

[0016] Furthermore, the dielectric layer is made of Rogers RT 5880 substrate, while the ground layer and transport layer are made of metal.

[0017] Furthermore, the varactor diode is selected as MAVR-011020-1411, and the PIN diode is selected as MA4AGP907.

[0018] Furthermore, the SSPP phase shifter can achieve continuous phase transformation from 0° to 180° by adjusting the bias voltage of the varactor diode; the reflective phase shifter can achieve discrete phase transformation from 0° to 180° by switching the on / off state of the PIN diode; the two work together in cascade to achieve continuous phase control in the range of 0° to 360°.

[0019] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: By cascading an SSPP phase shifter loaded with a varactor diode and a reflective phase shifter loaded with a PIN diode, the present invention fully utilizes the advantages of the flexible and adjustable dispersion characteristics of artificial surface plasmon resonance (ASPR) and the different control characteristics of the two types of adjustable elements. The varactor diode can achieve continuous adjustment of the equivalent capacitance, thereby enabling fine and continuous control of the dispersion characteristics and phase constant of the SSPP unit, completing a continuous phase transformation from 0° to 180°. The PIN diode can switch between on and off states, enabling the reflective phase shifter to produce... It generates precise 0° / 180° discrete phase flips; after cascading the two, it first uses a varactor diode to obtain continuous phase shift within a 180° range, and then uses a PIN diode to switch to achieve 180° phase flip superposition. Adjusting the varactor diode again can complete the remaining 180° phase, thus working together to achieve continuous and precise phase control within a 0° to 360° range; while achieving full phase coverage, it maintains a compact circuit size, solving the technical problem that existing adjustable phase shifters based on artificial surface plasmons cannot simultaneously meet the requirements of continuous and adjustable 360° full phase shift and miniaturization. Attached Figure Description

[0020] Figure 1 This is a front view of the structure of the present invention.

[0021] Figure 2 This is a side view of the structure of the present invention.

[0022] Figure 3 This is a schematic diagram of the SSPP unit structure of the present invention.

[0023] Figure 4This invention relates to the effect of the capacitance value of the varactor diode on the unit dispersion characteristics.

[0024] Figure 5 This is a simulation diagram of the return loss of the diode under different conditions according to the present invention.

[0025] Figure 6 This is a simulation diagram of the insertion loss of the diode under different conditions according to the present invention.

[0026] Figure 7 This is a simulation diagram of the phase shift of the diode under different states according to the present invention.

[0027] The layers are: 1. Transport layer; 2. Medium layer; 3. Ground layer;

[0028] 1.1 SSPP phase shifter; 1.1.1 50Ω microstrip line; 1.1.2 Transition structure; 1.1.3 SSPP unit; 1.1.4 First positive choke structure; 1.1.5 Negative choke structure; 1.1.6 First positive feed structure; 1.1.7 Through-hole; 1.1.3.1 Center conductor; 1.1.3.2 Parallel stub; 1.1.3.3 Varactor diode;

[0029] 1.2 Reflective phase shifter; 1.2.1 35Ω microstrip line; 1.2.2 Quarter-wavelength stub; 1.2.3 PIN diode; 1.2.4 Second positive choke structure; 1.2.5 Second positive feed structure. Detailed Implementation

[0030] like Figure 1 and Figure 2 As shown, a 360° continuously adjustable phase shifter based on artificial surface plasmon resonances (ASPR) comprises a transmission layer 1, a dielectric layer 2, and a ground layer 3 stacked sequentially from top to bottom. The transmission layer 1 includes an SSPP phase shifter 1.1 and a reflective phase shifter 1.2. The output of the SSPP phase shifter 1.1 and the input of the reflective phase shifter 1.2 are cascaded via a 50Ω microstrip line 1.1.1. The SSPP phase shifter 1.1 is used to achieve a first continuous phase transformation, and the reflective phase shifter 1.2 is used to achieve a second discrete phase transformation. They work together to achieve continuous phase control from 0° to 360° through joint modulation. The parameter settings of the phase shifter are shown in Table 1.

[0031] Table 1 SSPP Phase Shifter Parameter Settings

[0032]

[0033] The transmission layer of the SSPP phase shifter 1.1 includes a 50Ω microstrip line 1.1.1, a transition structure 1.1.2, several SSPP units 1.1.3, a first positive choke structure 1.1.4, a negative choke structure 1.1.5, a first positive feed structure 1.1.6, and a via 1.1.7. The 50Ω microstrip line 1.1.1 is located at both ends of the SSPP phase shifter 1.1 and is used for excitation and reception of electromagnetic signals. The transition structure 1.1.2 is a matching transformation section, connecting the 50Ω microstrip line 1.1.1 and the SSPP units 1.1.3 to achieve impedance matching between them.

[0034] Several SSPP units 1.1.3 are arranged periodically, and the structure of each SSPP unit 1.1.3 is arranged axially symmetrically, such as... Figure 3 As shown, SSPP unit 1.1.3 includes a central conductor 1.1.3.1, a parallel stub 1.1.3.2, and a varactor diode 1.1.3.3. The parallel stub 1.1.3.2 is symmetrically loaded on both sides of the central conductor 1.1.3.1, extending outward from the central conductor. There is a gap between the central conductors 1.1.3.1 of adjacent SSPP units 1.1.3; they are not directly physically connected but are electromagnetically coupled through the gap. The varactor diode 1.1.3.3 is laterally connected across the central conductor 1.1.3.1. Specifically, the varactor diode 1.1.3.3 is bridged across the gap between adjacent central conductors, connecting adjacent SSPP units 1.1.3 in series, thus achieving electrical connection between adjacent units.

[0035] The equivalent circuit of varactor diode 1.1.3.3 can be considered as an RC series circuit, whose capacitance changes with the bias voltage. The bias voltage is input through the first positive terminal feed structure 1.1.6 and applied to the positive terminal of varactor diode 1.1.3.3. The negative terminal of varactor diode 1.1.3.3 is connected to ground plane 3 through via 1.1.7, forming a complete DC bias loop. To simplify the bias network, the feed lines of the positive terminals of each varactor diode converge at the edge of the dielectric layer for unified DC feed; the feed lines of each negative terminal are collectively grounded through metallized vias.

[0036] The DC bias network includes a first positive choke structure 1.1.4 and a negative choke structure 1.1.5, both of which employ a fan-shaped stub structure. This fan-shaped stub structure effectively suppresses interference from AC radio frequency signals to the DC bias network, ensuring isolation between the DC bias signal and the radio frequency signal.

[0037] The working principle of SSPP phase shifter 1.1 is as follows: When different DC bias voltages are applied through the first positive electrode feeding structure 1.1.6, the varactor diode 1.1.3.3 exhibits different capacitance values. According to the equivalent circuit model of SSPP unit 1.1.3, the change in the capacitance value of the varactor diode will change the equivalent admittance of the parallel branch, thus affecting the dispersion equation of the entire periodic structure. The dispersion curves obtained by simulating SSPP unit 1.1.3 under different capacitance values ​​using the CST intrinsic mode solver are shown below. Figure 4 As shown, the SSPP wave propagates in a higher-order mode in this structure, exhibiting bandpass characteristics. As the capacitance of the varactor diode changes, both the upper and lower cutoff frequencies of the SSPP unit change, causing a shift in the entire passband. According to the dispersion relation, this passband shift directly alters the phase constant at a fixed frequency, resulting in a continuous phase difference. Therefore, by continuously adjusting the bias voltage of the varactor diode within a certain range, the SSPP phase shifter 1.1 can achieve continuous phase transitions from 0° to 180°.

[0038] The reflective phase shifter 1.2 is based on a 3dB coupler design and consists of a 50Ω microstrip line 1.1.1 and a 35Ω microstrip line 1.2.1. It has four ports: an input port, a through port, a coupling port, and an isolation port. The input port is connected to the output of the SSPP phase shifter 1.1 via the 50Ω microstrip line, while the isolation port serves as the output of the reflective phase shifter. A quarter-wavelength stub 1.2.2 and a PIN diode 1.2.3 are respectively loaded at the through port and the coupling port of the 3dB coupler.

[0039] The bias voltage of the PIN diode 1.2.3 is input through the second positive electrode feed structure 1.2.5. In the bias network, a second positive electrode choke structure 1.2.4 is provided, which also adopts a fan-shaped stub structure, to suppress the crosstalk of the AC radio frequency signal to the DC bias network and realize the isolation between the radio frequency signal and the DC bias signal.

[0040] The working principle of the reflective phase shifter 1.2 is as follows: Different DC bias voltages are applied through the second positive electrode feeding structure 1.2.5 to control the on / off state of the PIN diode 1.2.3. When the PIN diode is in the off state, the through port and the coupling port are respectively open-circuit. When the PIN diode is in the on state, the terminal is short-circuited, and the phase of the output signal is flipped by 180°. Therefore, by switching the on / off state of the PIN diode, the reflective phase shifter 1.2 can make the signal output from the isolation terminal produce a discrete phase switch of 0° or 180° relative to the input terminal.

[0041] By cascading the SSPP phase shifter 1.1 and the reflective phase shifter 1.2, continuous phase shifting across the entire range of 0° to 360° can be achieved through joint control of these two adjustable elements. The specific control process is as follows: First, the PIN diode is fixed in the off state, at which point the reflective phase shifter contributes 0° phase shift. By continuously adjusting the bias voltage of the varactor diode to change its capacitance value, the phase shift of the SSPP phase shifter continuously changes from 0° to 180°, thus achieving a continuous phase shift from 0° to 180°. Then, the capacitance value of the varactor diode is adjusted to its initial value, and the PIN diode is switched from the off state to the on state, causing the reflective phase shifter to contribute 180° phase shift, resulting in a jump to 180° phase shift for the entire phase shifter. Finally, the capacitance value of the varactor diode is continuously adjusted again, causing the phase shift of the SSPP phase shifter to continuously change from 0° to 180°. After superimposing the 180° phase shift from the reflective phase shifter, the entire phase shifter achieves a continuous phase shift from 180° to 360°. In summary, through the synergistic control of varactor diodes and PIN diodes, the phase shift of the phase shifter can cover the full range from 0° to 360°.

[0042] The dielectric layer 2 is made of Rogers RT 5880 substrate, and the ground layer 3 and transport layer 1 are made of copper. The varactor diode is MAVR-011020-1411, and the PIN diode is MA4AGP907.

[0043] To verify the performance of the phase shifter of this invention, a full-wave simulation of the S-parameters and phase response of the phase shifter under different diode control states was performed using the time-domain solver of the CST Microwave Studio. The simulation results are as follows: Figure 5 , Figure 6 and Figure 7 As shown. Figure 5 The simulation results of the return loss of the diode under different states are shown. It can be seen that within the expected operating frequency band, the return loss of the phase shifter under all control states is better than 10 dB, indicating that the SSPP phase shifter and the reflective phase shifter have good impedance matching. Figure 6 The simulation results of the insertion loss of the diodes under different states are shown in the present invention. Due to the ohmic loss of multiple diodes, there is a certain insertion loss after cascading, but the results are better than 5 dB in all states. Figure 7 The simulation results of phase shift under different diode states are presented in this invention. With the varactor diode capacitance value of 0.11 pF and the PIN diode off as the reference state, the phase shift is set to 0. It can be observed that by jointly controlling the varactor diode capacitance value and the on / off state of the PIN diode, the phase shifter can achieve continuous phase control from 0° to 360°, which verifies the effectiveness of the present invention.

Claims

1. A 360° continuously adjustable phase shifter based on artificial surface plasmons, characterized in that it comprises: a transmission layer (1), a dielectric layer (2), and a ground layer (3) stacked sequentially from top to bottom; The transmission layer (1) includes an SSPP phase shifter (1.1) and a reflective phase shifter (1.2), which are cascaded together. The SSPP phase shifter (1.1) includes a 50Ω microstrip line (1.1.1), a transition structure (1.1.2), several SSPP units (1.1.3), a first positive choke structure (1.1.4), a negative choke structure (1.1.5), a first positive feed structure (1.1.6), and a via (1.1.7); the 50Ω microstrip line (1.1.1) is connected to the SSPP units (1.1.3) through the transition structure (1.1.2) to achieve impedance matching; The SSPP unit (1.1.3) includes a central conductive strip (1.1.3.1), parallel stubs (1.1.3.2), and a varactor diode (1.1.3.3); the parallel stubs (1.1.3.2) are symmetrically loaded on both sides of the central conductive strip (1.1.3.1); the varactor diode (1.1.3.3) is laterally connected across the central conductive strip (1.1.3.1). On 1.1.3.1), adjacent SSPP units (1.1.3) are connected in series; the bias voltage is input through the first positive electrode feeding structure (1.1.6) to control the change of the capacitance value of the varactor diode (1.1.3.3), dynamically adjust the dispersion characteristics of the SSPP, and realize continuous phase control of 180°; the negative electrode of the varactor diode (1.1.3.3) is connected to the ground plane (3) through the through hole (1.1.7); the first positive electrode choke structure (1.1.4) and the negative electrode choke structure (1.1.5) are used to realize the isolation between the radio frequency signal and the DC bias signal; The reflective phase shifter (1.2) includes a 50Ω microstrip line (1.1.1), a 35Ω microstrip line (1.2.1), a quarter-wavelength stub (1.2.2), a PIN diode (1.2.3), a second positive choke structure (1.2.4), and a second positive feed structure (1.2.5). The quarter-wavelength stub (1.2.2) and the PIN diode (1.2.3) are loaded at the through port and the coupling port of the 3dB coupler. The bias voltage is input through the second positive feed structure (1.2.5) to control the on / off state of the PIN diode (1.2.3), thereby switching between open and short circuits and achieving phase switching of 0° or 180°. The second positive choke structure (1.2.4) is used to isolate the RF signal from the DC bias signal. By jointly controlling the SSPP phase shifter (1.1) and the reflective phase shifter (1.2), the phase shifter achieves continuous phase control in the range of 0° to 360°.

2. The 360° continuously adjustable phase shifter based on artificial surface plasmons as described in claim 1, characterized in that, A 50Ω microstrip line (1.1.1) is placed at the input and output of the SSPP phase shifter (1.1) and at the input and output of the reflective phase shifter (1.2).

3. The 360° continuously adjustable phase shifter based on artificial surface plasmons as described in claim 1, characterized in that, Several SSPP elements (1.1.3) are arranged periodically, with the central conduction bands of adjacent SSPP elements (1.1.3) being... There is a gap between 1.1.3.1), and the varactor diode (1.1.3.3) is connected across the adjacent center conduction band ( ). Electrical connection and dispersion control of adjacent SSPP units (1.1.3) are achieved in the gap between 1.1.3.1).

4. The 360° continuously adjustable phase shifter based on artificial surface plasmons as described in claim 1, characterized in that the 3dB coupler of the reflective phase shifter (1.2) is composed of a 50Ω microstrip line ( It consists of an input terminal, a through terminal, a coupling terminal, and an isolation terminal, and a 35Ω microstrip line (1.2.1). A quarter-wavelength stub (1.2.2) is connected to the through terminal or the coupling terminal via a PIN diode (1.2.3). By controlling the on / off state of the PIN diode (1.2.3), the terminal reflection coefficient of the corresponding port is changed, so that the signal output from the isolation terminal produces a discrete phase switch of 0° or 180° relative to the input terminal.

5. The 360° continuously adjustable phase shifter based on artificial surface plasmons as described in claim 1, characterized in that, Both the first positive choke structure (1.1.4) and the second positive choke structure (1.2.4) adopt a fan-shaped stub structure to suppress the interference of AC radio frequency signals on the DC bias network.

6. The 360° continuously adjustable phase shifter based on artificial surface plasmons as described in claim 1, characterized in that, The dielectric layer (2) is made of Rogers RT 5880 substrate, and the ground layer (3) and transport layer (1) are made of metal.

7. The 360° continuously adjustable phase shifter based on artificial surface plasmons as described in claim 1, characterized in that, The varactor diode (1.1.3.3) is MAVR-011020-1411, and the PIN diode (1.2.3) is MA4AGP907.

8. The 360° continuously adjustable phase shifter based on artificial surface plasmons as described in claim 1, characterized in that, The SSPP phase shifter (1.1) can achieve continuous phase transformation from 0° to 180° by adjusting the bias voltage of the varactor diode (1.1.3.3); the reflective phase shifter (1.2) can achieve discrete phase transformation from 0° to 180° by switching the on / off state of the PIN diode (1.2.3); the two work together in cascade to achieve continuous phase control in the range of 0° to 360°.

Images