X-band miniaturized programmable microstrip phase shifter

Abstract

The application discloses a miniaturized programmable microstrip phase-shifting circuit for X-band, which is used in X-band and has four encoding states of "00", "10", "01" and "11", and realizes relative phase shifts of 45 degrees, 90 degrees and 135 degrees correspondingly; the circuit is composed of PIN diodes, DC isolation capacitors and metal patch structures, wherein the 45-degree phase-shifting structure is composed of a rectangular patch and a ground via, the 90-degree phase-shifting structure is realized by combining multiple rectangular patches, and the required phase-shifting function is achieved after two-stage cascading; the PIN diodes control the phase response, and the DC isolation device prevents control signal crosstalk; the circuit has a high phase resolution of 45 degrees, the overall electrical size is smaller than the working wavelength, and the requirement of super-surface sub-wavelength integration is met; the driving voltage is lower than 1.2 V, the response reaches the level of nanoseconds, and the speed is faster than that of a traditional variable capacitance tube scheme; the microstrip line design is adopted, the structure is compact, the standard PCB process is compatible, the cost is low, the integration is easy, and the circuit is suitable for a high-performance phase control array system.

Description

Technical Field

[0001] This invention relates to the field of microstrip phase-shifting circuit technology, and more particularly to a miniaturized programmable microstrip phase-shifting circuit for the X-band. Background Technology

[0002] X-band is widely used in radar detection, electronic reconnaissance, electronic jamming, and radar countermeasures. As related electromagnetic systems evolve towards miniaturization, arraying, and intelligence, there is a need to integrate a large number of phase-shifting, amplitude-modulating, and digital control circuits within limited space. This places higher demands on the integration, size, and cost of these circuits. Traditional microwave RF chips and high-precision modulation devices are expensive, and their application in large-scale arrays significantly increases the overall system cost. Integrating the RF hardware structure, drive control circuitry, and transceiver units onto the same substrate, and utilizing mature printed circuit board technology for mass production, can meet the X-band system's requirements for high integration, miniaturization, and low cost.

[0003] As radar, electronic warfare, and intelligent sensing systems further evolve towards lower latency and lower power consumption, the traditional "RF front-end—ADC / DAC—DSP" chain processing architecture is increasingly facing challenges such as complex hardware structures, high data conversion rate requirements, high system power consumption, and increased processing latency. The current technological bottleneck lies in the fact that, in scenarios requiring high-bit-level or continuous phase modulation on metasurfaces, conventional microstrip phase-shifting circuits using PIN diodes as switching devices rely on changing the electrical length of the switch to regulate the phase difference between two ports, making it difficult to improve phase modulation accuracy at the subwavelength scale of metasurfaces. Using varactor diodes places high technical demands on the driving circuit, and due to their physical properties, the modulation rate is also insufficient to meet the requirements of spatiotemporally coded metasurface air interface computing and electronic warfare scenarios. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a miniaturized programmable microstrip phase-shifting circuit for the X-band, which solves the problem that current programmable metasurfaces based on phase-shifting circuits cannot simultaneously achieve high phase modulation accuracy, low insertion loss, and modulation rate within the subwavelength dimension.

[0005] Technical Solution: The present invention provides a miniaturized programmable microstrip phase-shifting circuit for the X-band, characterized in that it includes a metal patch structure composed of multiple rectangular patches disposed on a dielectric substrate. The metal patch structure includes a first phase modulation unit and a second phase modulation unit cascaded in series. The first phase modulation unit provides a first phase adjustment amount, and the second phase modulation unit provides a second phase adjustment amount, wherein the second phase adjustment amount is twice the first phase adjustment amount. An electronic switching device is also included, comprising a first switching device, a second switching device, and a third switching device. The first switching device is disposed in the first phase modulation unit, and the second and third switching devices are disposed in the second and third switching units respectively. The switching devices are located in the second phase modulation unit to receive the same control signal and are synchronously in the on or off state. By switching the on and off states of each switching device, the equivalent electrical length of the corresponding phase modulation unit is changed. A DC isolation device is located in the metal patch structure to isolate the DC control signal of each switching device. The phase shifting circuit forms four discrete phase states at the output port through different on / off combinations of the three switching devices. The four states are sequentially increased in a predetermined coding order with the first phase adjustment amount as the step. The overall structure size of the phase shifting circuit is smaller than the operating wavelength and is integrated on the dielectric substrate using a microstrip line structure.

[0006] Furthermore, the first phase modulation structure unit includes a first rectangular patch, a second rectangular patch, a third rectangular patch with a grounding through hole, and a fourth rectangular patch connected in sequence. A first electronic switch is connected between the second and third rectangular patches, and the equivalent electrical length of the first phase modulation structure unit is changed by switching the first electronic switch on and off.

[0007] Furthermore, the second phase-modulation structure unit includes a fifth rectangular patch, a sixth rectangular patch, a seventh rectangular patch, an eighth rectangular patch with a grounding through hole, a ninth rectangular patch, and a tenth rectangular patch connected in sequence. A second electronic switch is connected between the sixth and ninth rectangular patches, and a third electronic switch is connected between the seventh and eighth rectangular patches. The equivalent electrical length of the second phase-modulation structure unit is changed by simultaneously controlling the on and off switching of the second and third electronic switches.

[0008] Furthermore, the DC isolation electronic device includes a first DC isolation electronic device and a second DC isolation electronic device. The first DC isolation electronic device is connected between the first phase modulation structure unit and the second phase modulation structure unit, and the second DC isolation electronic device is connected between the seventh rectangular patch and the ninth rectangular patch inside the second phase modulation structure unit.

[0009] Furthermore, by using different combinations of the on and off states of the first, second, and third electronic switches, the phase-shifting circuit forms four encoded states. Specifically, when all three electronic switches are off, the output port outputs the first phase state; when the first electronic switch is on and the second and third electronic switches are off, the output port outputs the second phase state; when the first electronic switch is off and the second and third electronic switches are on, the output port outputs the third phase state; and when all three electronic switches are on, the output port outputs the fourth phase state.

[0010] Furthermore, taking the third phase state as a reference, the fourth phase state, the first phase state, and the second phase state are respectively increased by the first phase adjustment amount, the second phase adjustment amount, and the sum of the first phase adjustment amount and the second phase adjustment amount relative to the reference, so that the output phase of the four coding states forms a uniform step in sequence.

[0011] Furthermore, the electronic switching device is a PIN diode, with a switching time between the on and off states of the PIN diode being less than 100 nanoseconds and a driving voltage of less than 1.2 volts, in order to achieve fast, low-voltage phase modulation.

[0012] Furthermore, the phase-shifting circuit adopts a microstrip transmission line structure, and the dielectric substrate, metal patch structure, and electronic switching devices are integrated on the same dielectric substrate through printed circuit board technology.

[0013] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: The core objective of this invention is to design a phase-shifting circuit with a microstrip structure that operates in the X-band. Through electronic switching devices in both on and off states, it forms two-bit codes "00", "01", "10", and "11". At the output port of the phase-shifting circuit, four phase states with approximately 45°, 90°, and 135° phase differences are achieved within a specified operating frequency band. The "00", "01", "10", and "11" codes control the switching of the electronic switching devices between on and off states. The phase-shifting circuit can achieve four phase shift states with approximately 45°, 90°, and 135° phase differences within the specified X-band operating frequency band. The phase-shifting circuit has a compact structure, cascading two different microstrip circuits within the subwavelength dimension, and exhibits low insertion loss. PIN diodes have a fast modulation rate and low driving voltage, suitable for the rapid modulation requirements of spatiotemporal encoded metasurfaces. The phase-shifting circuit achieves multi-bit modulation using only PIN diodes. The X-band microstrip structure design utilizes mature printed circuit board (PCB) technology for processing, offering advantages such as low processing cost and mature technology. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the phase-shifting circuit structure of the present invention; Figure 2 This is a side view of the phase-shifting circuit of the present invention; Figure 3 This is a schematic diagram of the equivalent circuit of the phase-shifting circuit of the present invention; Figure 4 The equivalent circuits for the four encoding states of this invention are: (a) "00" (b) "10" (c) "01" (d) "11"; Figure 5 The simulation results of the S21 amplitude curve of the phase-shifting circuit of the present invention under four coding controls from 9.6 to 10.8 GHz are shown. Figure 6 The simulation results of the S11 amplitude curve of the phase-shifting circuit of the present invention under four coding controls from 9.6 to 10.8 GHz are shown. Figure 7 The simulation results of the S21 phase curve of the phase-shifting circuit of the present invention under four coding modulation methods from 9.6 to 10.8 GHz are shown. Figure 8 The simulation results of the phase shifting circuit of the present invention in the S21 phase RMS error and average insertion loss curves at 9.6-10.8GHz are shown. Detailed Implementation

[0015] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0016] like Figure 1As shown, this embodiment of the invention provides a miniaturized programmable microstrip phase-shifting circuit for the X-band. This circuit has four coded states—"00," "10," "01," and "11"—at a specified operating frequency in the X-band, and relative phase shifts of approximately 45°, 90°, and 135° can be achieved between different coded states, respectively. The phase-shifting circuit includes electronic switching devices, DC-isolated electronic devices, and a metal patch structure. The electronic switching devices include a first electronic switching device 41, a second electronic switching device 42, and a third electronic switching device 43; the DC-isolated electronic devices include a first DC-isolated electronic device 44 and a second DC-isolated electronic device 45. The metal patch structure includes rectangular patches 11 and 12, rectangular patches with grounding vias 13 and 14, collectively forming a 45° phase-shifting structure. Where l1=4.5mm, l2=2.4mm, w1=0.75mm; rectangular patches 15, 16, 17, and 18, 19, and 20 together form a 90° phase shifting structure. Where l3=5.9mm, l4=4mm, l5=1mm, w2=0.5mm, w3=0.8mm. Cascading the 45° and 90° phase shifting structures can achieve 45°, 90°, and 135° phase shifting functions. The first electronic switch 41, the second electronic switch 42, and the third electronic switch 43 are used to control the phase shifting circuit to generate corresponding phase responses under different encoding states; the first DC isolation electronic device 44 and the second DC isolation electronic device 45 are used to isolate DC control signals, avoiding mutual interference between the two DC control signals, thereby improving the accuracy of the encoding state. This invention has the following advantages: 1. The phase-shifting circuit has high phase control accuracy, with a minimum phase resolution of 45°, meeting the requirements for high-precision phase control; 2. The phase-shifting circuit has a compact structure, with an overall physical size smaller than the operating wavelength, meeting subwavelength size requirements and applicable to metasurface design; 3. The phase-shifting circuit uses PIN diodes for phase control, which, compared to the varactor diodes used in traditional high-bit modulation, requires a lower driving voltage (below 1.2 V, while varactor diodes typically require above 12 V), and also has a faster control speed, achieving nanosecond-level response; 4. This invention operates in the X-band and is designed using a microstrip transmission line structure. Microstrip lines are characterized by simple structure, compact size, and ease of integration, enabling the integration of PIN diodes and metasurface transmitter / receiver units on the same dielectric substrate. Furthermore, it can be fabricated using mature printed circuit board (PCB) technology, offering advantages such as low processing cost and mature technology.

[0017] The overall structure of the phase-shifting circuit is as follows: Figure 1As shown. The phase-shifting circuit, from left to right, includes: rectangular patch 11, rectangular patch 12, rectangular patch with grounding via 13, and rectangular patch 14 forming a 45° phase-shifting structure. Phase modulation is achieved by controlling the first electronic switch 41 to turn on or off, changing the equivalent electrical length of the 45° phase-shifting structure. A first DC isolation electronic device 44 isolates the DC control signal. Rectangular patches 15, 16, 17, rectangular patch with grounding via 18, rectangular patch 19, and rectangular patch 20 form a 90° phase-shifting structure, simultaneously controlling the second electronic switch 42 and the third electronic switch 43 to change the equivalent electrical length of the 90° phase-shifting structure. A second DC isolation electronic device 45 is used to isolate the DC control signal. The combined control of these two phase-shifting structures achieves the encoded phase shift of the input electromagnetic wave. With the output phase of the “01” encoding state as a reference, the output phases of the “11”, “00”, and “10” encoding states are increased by approximately 45°, 90°, and 135° respectively relative to the reference phase. The four encoding states form a phase step of approximately 45° in the order of “01”, “11”, “00”, and “10”.

[0018] In this circuit, the positive terminal of the first electronic switch 41 is soldered to patch 12, and the negative terminal is soldered to rectangular patch 13; the positive terminal of the second electronic switch 42 is soldered to rectangular patch 16, and the negative terminal is soldered to patch 19; the positive terminal of the third electronic switch 43 is soldered to rectangular patch 17, and the negative terminal is soldered to patch 18. The first, second, and third electronic switches 41, 42, and 43 provide different phase responses for the phase-shifting circuit under different operating conditions. A first DC-isolated electronic device 44 is soldered between rectangular patches 14 and 15, and a second DC-isolated electronic device 45 is soldered between rectangular patches 17 and 19. Figure 2 As shown, the microstrip circuit dielectric substrate uses F4BTM320, with a dielectric constant of 3.2 and a board thickness of 1.575mm.

[0019] A signal is input to port 1 of the phase-shifting circuit. Three electronic switches, operating in both on and off states, generate four different phase-response output signals at the output port of the phase-shifting circuit. When the first electronic switch 41 is off, and the second and third electronic switches 42 and 43 are off, the output port outputs a "00" electromagnetic wave phase. When the first electronic switch 41 is on, and the second and third electronic switches 42 and 43 are off, the output port outputs a "10" electromagnetic wave phase. When the first electronic switch 41 is off, and the second and third electronic switches 42 and 43 are on, the output port outputs a "01" encoded electromagnetic wave phase. When the first electronic switch 41 is on, and the second and third electronic switches 42 and 43 are on, the output port outputs an "11" encoded electromagnetic wave phase. When the electronic switches of the phase-shifting circuit operate in different states, the phase difference output from the output port is the subtraction of the phases of the electromagnetic waves in the two encoded states.

[0020] Phase-shifting circuit working principle: Electromagnetic waves are input from port 1 (input port) and output from port 2 (output port). This example illustrates the working principle using port 1 as input and port 2 as output. According to equivalent circuit theory, when electronic switching devices, such as PIN diodes, are subjected to positive or negative bias voltages, they can be equivalent to different circuits, such as... Figure 4 As shown. When the three PIN diodes are controlled by voltage to operate in the on or off state, the phase-shifting circuit responds differently to the input signal at port 1, resulting in a certain transmission phase difference. For example... Figure 4 As shown in (c), the first electronic switch 41 operates in the off state, while the second electronic switch 42 and the third electronic switch 43 operate in the on state. That is, when the circuit operates in the "01" encoded state, the two PIN diodes on the right side of the circuit short-circuit the bent microstrip line, and the grounded microstrip line is open-circuited on the left side of the circuit. The phase of the electromagnetic wave output from port 2 is... ;like Figure 4 As shown in (a), the first electronic switch 41, the second electronic switch 42, and the third electronic switch 43 all operate in the off state, that is, when the circuit operates in the "00" encoded state. The tortuous microstrip line on the right side of the circuit acts as a transmission line to provide phase delay, and the phase of the electromagnetic wave output from port 2 is... When the PIN diode operates in different encoding states, the electrical length of the path and the phase delay are different. Therefore, the phase shifter can achieve four different phase responses, with the phase difference at port 2 being... 3D electromagnetic simulation was performed using CST Studio Suite 2025 software. Figure 5 The simulation curves of the S21 amplitude of the phase-shifting circuit from 9.6 to 10.8 GHz under four coding modulation methods are shown. Figure 6The simulation curves of the S11 amplitude of the phase-shifting circuit from 9.6 to 10.8 GHz under four coding modulation methods are shown. Figure 7 The phase simulation curves of the S21 phase shift circuit under four coding modulation methods from 9.6 to 10.8 GHz are shown. Figure 8 Simulations of the S21 phase RMS error and average insertion loss of the phase-shifting circuit in the 9.6-10.8 GHz range under four coding modulation conditions reveal that the phase-shifting circuit can achieve 45°, 90° and 135° phase shifts near the X-band center frequency of 10 GHz, with low loss and a certain operating bandwidth, meeting the requirements of spatiotemporal coding metasurface phase modulation.

[0021] In this invention, the first electronic switch 41 can be a MADP-000907-14020x manufactured by MACOM, and the second and third electronic switches 42 and 43 can be SMP1340 manufactured by SKYWORKS, with operating states including on and off. Other models or PIN diodes from other suppliers can also be used. For other models of electronic switches, by appropriately adjusting parameters such as coupling transmission and stub length and width, the phase-shifting circuit can achieve good encoding results. The DC isolation electronic devices 44 and 45 can be RF high-Q surface-mount ceramic capacitors GJM1555C1H390GB01D manufactured by Murata Manufacturing Co., Ltd. In this invention, the microstrip circuit substrate is F4BTM320 with a relative permittivity of 3.2. Other types of substrates can also be used to implement this programmable phase-shifting circuit.

Claims

1. A miniaturized programmable microstrip phase-shifting circuit for the X-band, characterized in that, The system includes a metal patch structure composed of multiple rectangular patches disposed on a dielectric substrate. The metal patch structure comprises a first phase modulation unit and a second phase modulation unit cascaded in series. The first phase modulation unit provides a first phase adjustment amount, and the second phase modulation unit provides a second phase adjustment amount, which is twice the first phase adjustment amount. It also includes electronic switching devices, including a first switching device, a second switching device, and a third switching device. The first switching device is disposed in the first phase modulation unit, and the second and third switching devices are disposed in the second phase modulation unit. These devices receive the same control signal and are synchronously in an on or off state. By switching the on and off states of each switching device, the equivalent electrical length of the corresponding phase modulation unit is changed. A DC isolation device is disposed in the metal patch structure to isolate the DC control signals of each switching device. The phase-shifting circuit forms four discrete phase states at the output port through different on / off combinations of the three switching devices. The four states are sequentially incremented according to a predetermined encoding order with the first phase adjustment amount as the step size. The overall structural size of the phase-shifting circuit is smaller than the operating wavelength and is integrated on the dielectric substrate using a microstrip line structure.

2. The miniaturized programmable microstrip phase-shifting circuit for the X-band according to claim 1, characterized in that, The first phase modulation structure unit includes a first rectangular patch, a second rectangular patch, a third rectangular patch with a grounding through hole, and a fourth rectangular patch connected in sequence. A first electronic switch is connected between the second and third rectangular patches. The equivalent electrical length of the first phase modulation structure unit is changed by switching the first electronic switch on and off.

3. The miniaturized programmable microstrip phase-shifting circuit for the X-band according to claim 1, characterized in that, The second phase-modulation structure unit includes a fifth rectangular patch, a sixth rectangular patch, a seventh rectangular patch, an eighth rectangular patch with a grounding through hole, a ninth rectangular patch, and a tenth rectangular patch connected in sequence. A second electronic switch is connected between the sixth and ninth rectangular patches, and a third electronic switch is connected between the seventh and eighth rectangular patches. The equivalent electrical length of the second phase-modulation structure unit is changed by simultaneously controlling the on and off switching of the second and third electronic switches.

4. The miniaturized programmable microstrip phase-shifting circuit for the X-band according to claim 1, characterized in that, The DC isolation electronic device includes a first DC isolation electronic device and a second DC isolation electronic device. The first DC isolation electronic device is connected between the first phase modulation structure unit and the second phase modulation structure unit, and the second DC isolation electronic device is connected between the seventh rectangular patch and the ninth rectangular patch inside the second phase modulation structure unit.

5. The miniaturized programmable microstrip phase-shifting circuit for the X-band according to claim 1, characterized in that, By using different combinations of the on and off states of the first, second, and third electronic switches, the phase-shifting circuit forms four encoded states. Specifically, when all three electronic switches are off, the output port outputs the first phase state; when the first electronic switch is on and the second and third electronic switches are off, the output port outputs the second phase state; when the first electronic switch is off and the second and third electronic switches are on, the output port outputs the third phase state; and when all three electronic switches are on, the output port outputs the fourth phase state.

6. The miniaturized programmable microstrip phase-shifting circuit for the X-band according to claim 1, characterized in that, With the third phase state as the reference, the fourth phase state, the first phase state, and the second phase state are respectively increased by the first phase adjustment amount, the second phase adjustment amount, and the sum of the first phase adjustment amount and the second phase adjustment amount relative to the reference, so that the output phase of the four coding states forms a uniform step in sequence.

7. The miniaturized programmable microstrip phase-shifting circuit for the X-band according to claim 1, characterized in that, The electronic switching device is a PIN diode. The switching time between the on and off states of the PIN diode is less than 100 nanoseconds, and the driving voltage is less than 1.2 volts, so as to achieve fast and low-voltage phase control.

8. A miniaturized programmable microstrip phase-shifting circuit for the X-band according to claim 1, characterized in that, The phase-shifting circuit adopts a microstrip transmission line structure, and the dielectric substrate, metal patch structure and electronic switching devices are integrated on the same dielectric substrate through printed circuit board technology.

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