High-power fast phase inversion switch based on p-i-n diode

Abstract

The invention discloses a high-power fast phase inversion switch based on a p-i-n diode, and relates to the technical field of high-power microwave p-i-n diode phase shifting. The inverter switch comprises a rectangular waveguide, 2N loading linear p-i-n diode phase shift circuits which are symmetrically and uniformly arranged on a narrow-side waveguide wall, and a bias power supply which provides bias voltage for the phase shift circuits. According to the invention, the loading line type p-i-n diode phase shift circuit is inserted into the waveguide structure, so that a microwave signal is transmitted along the waveguide transmission line instead of being transmitted along the metal microstrip line, the influence of the power loss of the p-i-n diode on the insertion loss of the phase shift circuit can be reduced, and the overall insertion loss is reduced; and meanwhile, phase inversion is realized by controlling the bias state of a p-i-n diode in the phase shift circuit, and nanosecond switching speed can be realized.

Description

Technical Field

[0001] The present invention mainly relates to high-power microwave PIN diode phase shifting technology, and specifically designs and provides a phase-inverting switch combining a traditional PIN diode phase shifter with a waveguide structure, which can realize high-power, fast and low insertion loss applications. Background Art

[0002] In a high power microwave (HPM) system, a pulse compressor compresses the long microwave pulses generated by an HPM source into narrow pulse signals with a pulse width of hundreds or even tens of nanoseconds and a peak power increased by several times or even dozens of times, so as to generate pulse signals with higher peak power. The main principle of a microwave pulse compressor is to store microwave energy in an energy storage cavity and then release it to achieve the purpose of pulse compression. The method of extracting energy by inverting the microwave pulse before the microwave pulse ends is called a passive pulse compression method.

[0003] The phase-inverting switch is one of the key components in the passive pulse compression system, because the phase-inverting speed of the phase-inverting switch affects not only the output gain of the pulse compression, but also the efficiency of the pulse compression. In the passive pulse compressors that have been developed, the microwave source uses a klystron, because the klystron belongs to an electric vacuum amplifier. In the compression system, the phase-inverting switch is set at the front end of the klystron, which is used to control the output phase of the small signal excitation source of the klystron. Therefore, low-power fast phase-inverting switches based on semiconductor devices are used, such as pin diode phase-inverting switches. However, the cost, volume, weight, efficiency and other parameters of the klystron are at a disadvantage compared to the magnetron. Therefore, in order to develop a passive pulse compression system based on a magnetron, it is necessary to propose a high-power fast phase-inverting switch.

[0004] Since the magnetron is an oscillator, in a pulse compression system based on a magnetron, the phase-inverting switch can only be used to control the phase inversion of the output signal of the magnetron. Therefore, the power of the phase-inverting switch needs to be high enough, and the phase-inversion speed needs to be within tens of nanoseconds. The insertion loss needs to be low enough to reduce the power loss of the entire compression system and improve the system efficiency. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a high-power fast phase-reversing switch based on a pin diode. The phase-reversing switch symmetrically inserts a traditional loaded linear pin diode phase-shifting circuit into a rectangular waveguide. The insertion of the phase-shifting circuit can change the cross-section of the waveguide, thereby causing an inductive effect; by controlling the bias state of the pin diode, the equivalent impedance of the phase-shifting circuit in the waveguide transmission line is changed, thereby changing the phase of the microwave signal transmitted in the waveguide, and achieving the purpose of phase reversal. The phase-reversing switch of the present invention can reduce the power loss caused by the pin diode itself, reduce the insertion loss, and retain the nanosecond response time of the pin diode while improving the power capacity, and can be used in a high-power pulse compression system based on a magnetron.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A high-power fast phase-reversing switch based on a PIN diode comprises a rectangular waveguide, 2N loaded linear PIN diode phase-shifting circuits and a bias power supply.

[0008] 2N of the loaded linear pin diode phase shift circuits are symmetrically and evenly arranged on the narrow side waveguide wall of the rectangular waveguide.

[0009] The loaded linear pin diode phase shift circuit has an overall mirror-symmetrical structure, including a dielectric substrate, a U-shaped microstrip line arranged on the front of the dielectric substrate, two pin diodes, a bias circuit, and a current-limiting resistor; wherein the dielectric substrate is a rectangular dielectric substrate perpendicular to the wide side and narrow side of the rectangular waveguide; the U-shaped microstrip line is composed of a microstrip line Line1 and microstrip lines Line2 and Line3 connected at both ends thereof, wherein the microstrip line Line1 is parallel to the narrow side of the rectangular waveguide, and the microstrip lines Line2 and Line3 are parallel to the wide side of the rectangular waveguide, and the ends are connected to the waveguide wall; the two pin diodes are loaded on the microstrip line Line2 and the microstrip line Line3, respectively, and the negative poles face the direction of the waveguide wall; the bias circuit is a long strip microstrip line, one end of which is connected to the microstrip line Line1, a current-limiting resistor is arranged in the middle, and the other end extends out of the rectangular waveguide through a metal probe.

[0010] 2N circular holes for metal probes to extend out are arranged on the narrow side waveguide wall of the rectangular waveguide, and an insulating medium is arranged between the circular holes and the metal probes.

[0011] The bias power supply is connected to the metal probe to provide a bias voltage for controlling the bias state of the pin diode.

[0012] Furthermore, the spacing between adjacent loaded linear pin diode phase shift circuits is 1 / 5 to 1 / 4 of the waveguide wavelength.

[0013] Furthermore, the bias power supply adopts a DC voltage source or a pulse voltage source.

[0014] Furthermore, the rectangular waveguide is a standard rectangular waveguide.

[0015] In the present invention, when the positive electrode of the bias power supply is connected to the metal probe, the negative electrode is connected to the waveguide wall, and the pin diode is in a forward bias state, the pin diode is in a forward conduction state, and the loaded linear pin phase shift circuit is equivalent to connecting an equivalent admittance Y in parallel in the waveguide transmission line. F The phase of the transmitted signal is

[0016] When the negative electrode of the bias power supply is connected to the metal probe and the positive electrode is connected to the waveguide wall, the pin diode is in a reverse bias state and the pin diode is in a reverse disconnected state. The loaded linear pin diode phase shift circuit is equivalent to connecting an equivalent admittance F in parallel in the waveguide transmission line. R The phase of the transmitted signal is

[0017] By changing the positive and negative of the bias voltage, the phase difference between the two state transmission signals can be achieved. By optimizing the size of the loaded linear pin diode phase shift circuit and the specific value of N, it can be achieved In addition, by symmetrically placing the loaded linear pin diode phase shift circuit, the reactance effect of the loaded linear pin diode phase shift circuit in the waveguide is increased, thereby increasing the phase shift angle, thereby reducing the number of the loaded linear pin diode phase shift circuits and reducing the waveguide length, thereby achieving a miniaturized design.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention inserts a loaded linear PIN diode phase shift circuit into a waveguide structure, so that the microwave signal is no longer transmitted along the metal microstrip line but along the waveguide transmission line, which can reduce the influence of the power loss of the PIN diode on the insertion loss of the phase shift circuit and reduce the overall insertion loss.

[0020] (2) The present invention uses a method of controlling the change in the bias state of a PIN diode to achieve phase inversion, which can achieve a switching speed of nanoseconds.

[0021] (3) The present invention adopts a waveguide structure to design an inverting switch, which improves the power capacity and can withstand peak powers above megawatts. Combined with the nanosecond switching speed of the PIN diode, it can be used in a passive pulse compression system based on a magnetron.

[0022] (4) The present invention arranges the loaded linear pin phase shift circuits in the waveguide symmetrically rather than on one side. Under the condition of the same number of loaded linear pin diode phase shift circuits, the waveguide length can be halved, thereby realizing a miniaturized design of the inverting switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 . A schematic diagram of the structure of the inverting switch of the present invention, wherein (a) is a cross-sectional view of the inverting switch xoy surface,

[0024] (b) is a top view of the phase-inverting switch;

[0025] Figure 2 . A schematic diagram of the structure of a linear pin diode phase shift circuit loaded in the present invention;

[0026] Figure 3 . This is a simulation model diagram of an inverting switch according to an embodiment of the present invention N = 3;

[0027] Figure 4 . is the simulation result of the inverting switch of the embodiment of the present invention with N=3.

[0028] Among them: 1. Rectangular waveguide; 2. Dielectric substrate; 3. Microstrip line Line 1; 4. Microstrip line Line 2; 5. Microstrip line Line 3; 6. PIN diode; 7. Current limiting resistor; 8. Bias circuit. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] This embodiment provides a waveguide high-power fast phase-inverting switch based on a pin diode operating in the S band. Figure 1-3 As shown, the structure includes: a rectangular waveguide, 6 loaded linear pin diode phase shift circuits, and a bias power supply.

[0031] The six loaded linear PIN diode phase shift circuits are symmetrically and evenly arranged on the narrow side waveguide wall of the rectangular waveguide, and the spacing between the phase shift circuits on the same side is 32 mm.

[0032] The loaded linear pin diode phase shift circuit is a mirror-symmetrical structure as a whole, comprising a rectangular dielectric substrate, a U-shaped microstrip line arranged on the front of the rectangular dielectric substrate, two pin diodes, a bias circuit, and a current limiting resistor.

[0033] The rectangular dielectric substrate is Rogers 4350B, with a dielectric constant of 3.66, a loss tangent of 0.0037, and a dielectric substrate size of 28×43.2×0.508 mm. 3 The rectangular dielectric substrate is perpendicular to the wide side and the narrow side of the rectangular waveguide, and the three edges are in contact with and fixed to the waveguide wall.

[0034] The U-shaped microstrip line is composed of microstrip line Line1 and microstrip line Line2 and microstrip line Line3 connected at both ends; wherein microstrip line Line1 is parallel to the narrow side of the rectangular waveguide, microstrip line Line2 and microstrip line Line3 are parallel to the wide side of the rectangular waveguide, and the ends are connected to the waveguide wall; Line1 has a size of 30.4×8 mm 2 Line 2 is divided into a long section and a short section by a pin diode, and the long section size is 13×3mm 2 , the short section size is 3.85×3mm 2 .

[0035] The pin diodes are loaded on microstrip line Line2 and microstrip line Line3 respectively, and the cathode faces the waveguide wall. The pin diode in this embodiment adopts SMP1340 model diode of SKYWORKS company. The technical parameters of the diode are tested as follows: forward resistance 0.85Ω, reverse capacitance 0.21pF, package inductance 1nH, and response time less than 20ns.

[0036] The bias circuit is a long microstrip line with a line width of 1 mm, one end of which is connected to the microstrip line Line1, a current limiting resistor with a resistance of 100Ω is arranged in the middle, and the other end extends out of the rectangular waveguide through a metal probe.

[0037] The rectangular waveguide is a standard rectangular waveguide, model BJ26: wide side = 86.4 mm, narrow side = 43.2 mm, length 150 mm; 6 circular holes for metal probes to extend are arranged on the narrow side waveguide wall of the rectangular waveguide, and an insulating medium is arranged between the circular holes and the metal probes.

[0038] The bias power supply is connected to the metal probe to provide a bias voltage for controlling the bias state of the pin diode.

[0039] The forward biased SMP1340 pin diode is equivalent to a small resistor with a resistance of 0.85Ω, while the reverse biased pin diode is equivalent to a 10Ω resistor, a 0.21pF capacitor, and a 1nH inductor in parallel. By changing the equivalent parameters of the pin diode, the bias state of the circuit is changed. The S parameters and phase of the forward bias and reverse bias are calculated. The difference between the two states is the phase shift of this inverting switch. The simulation results are shown in Figure 4As shown, the insertion loss of the inverting switch at 2.856 GHz in both forward and reverse bias is 0.43 dB, and the reflection coefficient S 11 Both are less than -20dB, and the phase shift is 178.8 degrees.

[0040] The present invention designs a high-power, low-insertion-loss, fast phase-reversing switch by combining a waveguide structure with a pin diode phase-shifting circuit. The phase-reversing switch retains the fast response time of the pin diode, reduces the influence of the diode power loss on the circuit insertion loss, thereby reducing the insertion loss of the overall phase-reversing switch, and at the same time changes the signal transmission mode to transmission along the waveguide to increase the power capacity, and can be applied to a high-power microwave passive pulse compression system based on an electric vacuum oscillator such as a magnetron.

Claims

1. A high-power fast phase-inverting switch based on a pin diode, characterized in that: include: Rectangular waveguide, 2N loaded linear pin diode phase shift circuit, bias power supply; 2N of the loaded linear pin diode phase shift circuits are symmetrically and evenly arranged on the narrow side waveguide wall of the rectangular waveguide; The loaded linear pin diode phase shift circuit is a mirror-symmetrical structure as a whole, including a dielectric substrate, a U-shaped microstrip line arranged on the front of the dielectric substrate, two pin diodes, a bias circuit, and a current-limiting resistor; wherein the dielectric substrate is a rectangular dielectric substrate perpendicular to the wide side and narrow side of the rectangular waveguide; the U-shaped microstrip line is composed of a microstrip line Line1 and microstrip lines Line2 and Line3 connected at both ends thereof, wherein the microstrip line Line1 is parallel to the narrow side of the rectangular waveguide, and the microstrip line Line2 and the microstrip line Line3 are parallel to the wide side of the rectangular waveguide, and the ends are connected to the waveguide wall; the two pin diodes are loaded on the microstrip line Line2 and the microstrip line Line3, respectively, and the negative poles face the direction of the waveguide wall; the bias circuit is a long strip microstrip line, one end of which is connected to the microstrip line Line1, a current-limiting resistor is arranged in the middle, and the other end extends out of the rectangular waveguide through a metal probe; 2N circular holes for metal probes to extend out are arranged on the narrow side waveguide wall of the rectangular waveguide, and an insulating medium is arranged between the circular holes and the metal probes; The bias power supply is connected to the metal probe to provide a bias voltage for controlling the bias state of the pin diode.

2. A high-power fast phase-inverting switch based on a PIN diode as claimed in claim 1, characterized in that: The spacing between adjacent loaded linear pin diode phase shift circuits is 1 / 5 to 1 / 4 of the waveguide wavelength.

3. A high-power fast phase-inverting switch based on a pin diode as claimed in claim 1 or 2, characterized in that: The bias power supply adopts a direct current voltage source or a pulse voltage source.

4. A high-power fast phase-inverting switch based on a PIN diode as claimed in claim 3, characterized in that: The rectangular waveguide is a standard rectangular waveguide.

Images