High-power microwave amplitude limiting protection circuit with high power capacity

Abstract

The invention relates to a high-power microwave amplitude limiting protection circuit with high power capacity, and belongs to the field of strong electromagnetic pulse protection. The three-level PIN pair transistor amplitude limiting circuit and the eight-order hairpin type microstrip filter circuit are carried on the dielectric substrate, the first blocking capacitor is connected between the input end of the amplitude limiting protection circuit and the three-level PIN pair transistor amplitude limiting circuit, and the second blocking capacitor is connected between the three-level PIN pair transistor amplitude limiting circuit and the eight-order hairpin type microstrip filter circuit. The output end of the amplitude limiting protection circuit is connected with the eight-order hairpin type microstrip filter circuit. The invention has the advantages of large power capacity, small peak leakage, small starting limit level and low amplitude limiting level, can effectively suppress interference signals coupled into the receiving end of the wireless communication equipment by high-power microwaves, and improves the anti-interference capability of the wireless communication equipment under the radiation of the high-power microwaves.

Description

Technical Field

[0001] The invention belongs to the field of strong electromagnetic pulse protection, and in particular relates to a high-power microwave limiting protection circuit with large power capacity, which is suitable for high-power microwave protection at a receiving end of a wireless communication device. Background Art

[0002] High-power microwave is a strong electromagnetic pulse with high power and wide spectrum. Its frequency range covers 300MHz~300GHz, the pulse rising edge can reach nanosecond level, and the radiation power can reach tens of gigawatts (GW). With the continuous development of communication technology, wireless communication equipment is more and more widely used. The application of high-density integrated components and the rapid development of microelectronics technology have increased the density of components per unit size of wireless communication equipment, increased the operating frequency, and further reduced the operating voltage. While meeting the high-performance and low-power development needs of military and civilian communication equipment, it also makes wireless communication equipment and systems more and more sensitive to the external electromagnetic environment.

[0003] The limiter has a strong protective effect against the interference of high-power microwaves and is an effective means of protecting the receiving end of wireless communication equipment. Limiters include high-temperature superconducting limiters, ferrite limiters, plasma limiters and solid-state limiters. The first three limiters are limited in application due to high requirements for the use environment, complex processing technology and high cost. Common components of solid-state limiters are: field effect transistors, Schottky diodes and PIN diodes. PIN diodes have the advantages of small insertion loss, strong limiting capability and large power capacity.

[0004] The working principle of the PIN limiter is: based on the nonlinear limiting mechanism of microwave semiconductor diodes, under the action of high-power microwave signals, due to the unique I region of the PIN diode, conductivity modulation will occur, the circuit will be mismatched, most of the energy will be reflected, a small part of the energy will be dissipated by the PIN diode, and the remaining energy will be output at the output port, while the small signal is not enough to turn on the PIN diode. Due to the low insertion loss of the limiting circuit, almost all the energy passes. Therefore, the PIN diode can protect the circuit components from being damaged by high-power microwaves while ensuring the normal operation of wireless communication equipment. Since the carrier movement of the PIN diode takes time, spike leakage will occur when it is not fully turned on.

[0005] Microstrip bandpass filters have the advantages of simple design, convenient manufacturing, small size and easy integration, and are widely used in microstrip circuits. Among them, the hairpin bandpass filter is composed of hairpin resonators arranged side by side and the coupled resonators folded into a "U" shape. Its coupling topology is cross-coupling. The hairpin resonator achieves filtering through an appropriate coupling topology. The coupling line terminal is open-circuited and does not require grounding vias, thereby eliminating the processing error introduced by the ground vias. It has good electrical properties and has good application prospects in the design of microwave planar circuits.

[0006] Publication No. CN118432564A discloses a high-power clipping circuit for L-band, which adopts multi-stage PIN diodes for clipping design. However, since no microstrip filter circuit is used in the circuit, out-of-band signals are not effectively removed. Publication No. CN115865021A discloses a high-power capacity clipper, but since its filter circuit is composed of lumped elements, parasitic effects are easily generated in the high frequency band and cannot be applied to wireless communication equipment working in the high frequency band. Publication No. CN117220625A discloses a power clipping circuit composed of PIN diodes, which adopts a plurality of diodes in parallel and series for clipping design. However, since it does not have a bandpass filter circuit and uses a large number of PIN diodes in the circuit, its protection circuit has high cost and out-of-band interference signals are not effectively removed, and it is difficult to achieve the expected protection effect in practical applications. Summary of the invention

[0007] The present invention provides a high-power microwave limiting protection circuit with large power capacity to solve the problems that the current limiting circuit protection circuit has high cost, the filter circuit uses lumped elements that are not suitable for high-frequency wireless communication equipment, and the out-of-band interference signal cannot be effectively removed.

[0008] The technical scheme adopted by the present invention is to include a dielectric substrate, an input end of a limiting protection circuit, a first DC blocking capacitor, a three-level PIN pair limiting circuit, a second DC blocking capacitor, an eighth-order hairpin type microstrip filter circuit and an output end of the limiting protection circuit, wherein the three-level PIN pair limiting circuit and the eighth-order hairpin type microstrip filter circuit are both mounted on the dielectric substrate, the first DC blocking capacitor is connected between the input end of the limiting protection circuit and the three-level PIN pair limiting circuit, the second DC blocking capacitor is connected between the three-level PIN pair limiting circuit and the eighth-order hairpin type microstrip filter circuit, and the output end of the limiting protection circuit is connected to the eighth-order hairpin type microstrip filter circuit.

[0009] The three-stage PIN pair limiting circuit of the present invention is used to realize power limiting and voltage clamping of high-power microwave interference signals. The three-stage PIN pair limiting circuit comprises a PIN pair limiting circuit input end, a first-stage PIN pair limiting circuit, a second-stage PIN pair limiting circuit, a third-stage PIN pair limiting circuit, a microstrip transmission line T1, a microstrip transmission line T2 and a PIN pair limiting circuit output end, wherein the first-stage PIN limiting circuit is composed of two identical PIN diodes D1 and D2 connected in parallel, the opposite polarity ends of the PIN diodes D1 and D2 are connected and the other end is grounded, the second-stage PIN limiting circuit is composed of two identical PIN diodes D3 and D4 connected in parallel, the opposite polarity ends of the PIN diodes D3 and D4 are connected and the other end is grounded, and the third-stage PIN pair limiting circuit is composed of It is composed of two identical PIN diodes D5 and D6 connected in parallel, the opposite polarity ends of the PIN diodes D5 and D6 are connected and the other end is grounded, the connection point of the PIN diodes D1 and D2 is connected to the input end of the PIN pair tube limiting circuit and one end of the microstrip line T1, the connection point of the PIN diodes D3 and D4 is connected to the other end of the microstrip line T1 and one end of the microstrip line T2, the connection point of the PIN diodes D5 and D6 is connected to the other end of the microstrip line T2 and the output end of the PIN pair tube limiting circuit, the microstrip line T1 connects the first-stage PIN limiting circuit and the second-stage PIN limiting circuit, the microstrip line T2 connects the second-stage PIN limiting circuit and the third-stage PIN limiting circuit, the input end of the PIN pair tube limiting circuit is connected to the first DC blocking capacitor, and the output end of the PIN pair tube limiting circuit is connected to the second DC blocking capacitor.

[0010] The three-stage PIN-pair limiting circuit of the present invention adopts PIN triodes with gradually decreasing I layers between stages, wherein the I layer thickness of the PIN diode used in the first-stage PIN limiting circuit is 7um and has a large power capacity, and can be used for power limiting of a high-power signal in the previous stage; the I layer thickness of the PIN diode used in the second-stage PIN limiting circuit is 2um, and since its I layer is thinner, it is suitable as an intermediate stage for further clamping the signal voltage and reducing the starting limit level; the I layer thickness of the PIN diode used in the third-stage PIN limiting circuit is 1.5um, and as the last stage of the three-stage PIN-pair limiting circuit, it can further improve the overall power tolerance of the circuit and reduce the limiting level, thereby achieving a better limiting effect.

[0011] The eighth-order hairpin-type microstrip filter circuit of the present invention is used for filtering out harmonic components generated by a front-stage three-stage PIN pair tube limiting circuit and filtering out-of-band interference, and comprises an eighth-order microstrip filter circuit input end, a first resonator, a second resonator, a third resonator, a fourth resonator, a fifth resonator, a sixth resonator, a seventh resonator, an eighth resonator and an eighth-order microstrip filter circuit output end, wherein the eighth-order microstrip filter circuit input end is connected to two phases of a DC blocking capacitor, the eighth-order microstrip filter circuit output end is connected to the limiting protection circuit output end, eight resonators are arranged side by side, and the opening directions of two adjacent resonators are opposite, and two adjacent hairpin-type resonators have a parallel coupling microstrip line with the same arm length and line width, and the coupling mode between them is cross coupling.

[0012] The first resonator of the present invention is composed of a right-angle corner microstrip line and a hairpin arm connected, and the right-angle corner microstrip line is connected above the hairpin arm. The eighth resonator is composed of a right-angle corner microstrip line and a hairpin arm connected, and the right-angle corner microstrip line is connected below the hairpin arm.

[0013] The second resonator, the third resonator, the fourth resonator, the fifth resonator, the sixth resonator and the seventh resonator of the present invention are all of U-shaped hairpin type structure, which are composed of two left and right hairpin arms, two right-angle corner microstrip lines and a middle microstrip line. The left and right hairpin arms are connected between the right-angle corner microstrip line and the middle microstrip line. The opening directions of two adjacent resonators are opposite and they are arranged side by side. The adjacent hairpin arms are parallel to each other and have the same arm length and arm width. The second resonator opens upward, and the sixth resonator opens downward. The right-angle corner microstrip line of the first resonator is connected to the input end of the eighth-order hairpin microstrip filter circuit, and the right-angle corner microstrip line of the eighth resonator is connected to the output end of the eighth-order hairpin microstrip filter circuit.

[0014] The advantages of the present invention are: 1. The three-stage PIN pair limiting circuit adopts a three-stage PIN pair limiting structure, so it has a large power capacity. Since the thickness of the PIN diode I layer used in each stage decreases successively, it can effectively clamp the high-power microwave at a low limiting level and effectively reduce the starting limit level. Based on the PIN diode conductivity modulation effect and the three-stage limiting unit and the design of the adjacent two stages using microstrip transmission lines, the limiting circuit has good limiting performance and avoids the parasitic effects of ordinary metal connecting lines at high frequencies.

[0015] 2. The eighth-order hairpin microstrip filter circuit has the advantages of compact circuit structure and strong out-of-band interference suppression performance, which can effectively filter out the out-of-band interference received by wireless communication equipment. It is smaller than the parallel coupled microstrip line filter structure, and compared with the interdigital and comb line structures, it does not use a via structure, so it can avoid the interference caused by vias when applied to high-frequency wireless communication equipment. Since lumped components are not used, the influence of parasitic effects of the filter circuit composed of traditional lumped components is avoided, and it has good performance with low insertion loss and strong out-of-band interference suppression performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 This is the principle diagram of the three-level PIN pair tube limiting circuit of the present invention; Figure 3 It is the S parameter diagram of the three-level PIN pair tube limiting circuit of the present invention; Figure 4 This is a comparison diagram of input and output power of the three-level PIN pair tube limiting circuit of the present invention; Figure 5 This is the waveform of a sinusoidal modulation wave with a rated power of 50dBm; Figure 6 This is the output waveform of the three-level PIN-pair limiting circuit injecting a sinusoidal modulation wave with a rated power of 50dBm; Figure 7 It is the schematic diagram of the eighth-order hairpin microstrip filter circuit; Figure 8 This is the structural dimension diagram of the eighth-order hairpin microstrip filter circuit; Fig. 9 This is the S-parameter diagram of the eighth-order hairpin microstrip filter circuit; Fig.10 It is the input and output power diagram of the high power microwave limiting protection circuit; Fig.11 It is the waveform diagram of high-power microwave interference signal coupled by the antenna of wireless communication equipment; Fig.12 It is the voltage output waveform diagram of the high-power microwave limiting protection circuit under the action of coupled interference signal; Wherein: 1. dielectric substrate, 2. input end of limiter protection circuit, 3. first DC blocking capacitor, 4. third-level PIN-pair limiter circuit, 5. second DC blocking capacitor, 6. eighth-order hairpin-type microstrip filter circuit, 7. output end of limiter protection circuit, 401. input end of PIN-pair limiter circuit, 402. first-level PIN-pair limiter circuit, 403. second-level PIN-pair limiter circuit, 404. third-level PIN-pair limiter circuit, 405. output end of PIN-pair limiter circuit, 601. input end of eighth-order microstrip filter circuit, 602. first resonator, 603. second resonator, 604. third resonator, 605. fourth resonator, 606. fifth resonator, 607. sixth resonator, 608. seventh resonator, 609. eighth resonator, 610. output end of eighth-order microstrip filter circuit. DETAILED DESCRIPTION

[0017] like Figure 1 As shown, an embodiment of the present invention provides a schematic diagram of the structure of a high-power microwave limiting protection circuit with high power capacity, which includes a dielectric substrate 1, a limiting protection circuit input terminal 2, a DC blocking capacitor 1 3, a three-stage PIN pair tube limiting circuit 4, a DC blocking capacitor 2 5, an eighth-order hairpin microstrip filter circuit 6, and a limiting protection circuit output terminal 7; Specifically, 1 is a dielectric substrate, which can be but not limited to a ROGERS 4350B dielectric substrate. In this case, the three-stage PIN pair tube limiting circuit 4 and the eighth-order hairpin type microstrip filter circuit 6 are both mounted on the dielectric substrate 1, so that the protection circuit provided in this embodiment forms an integrated structure. Among them, the relative dielectric constant of the dielectric substrate 1 in this embodiment is is 3.66, the loss tangent is 0.002, and the thickness H is 1 mm to ensure the reliability of the circuit during operation. The DC blocking capacitor 3 is connected between the input terminal 2 of the limiting protection circuit and the three-stage PIN pair limiting circuit 4, the DC blocking capacitor 2 5 is connected between the three-stage PIN pair limiting circuit 4 and the eighth-order hairpin type microstrip filter circuit 6, and the output terminal 7 of the limiting protection circuit is connected to the eighth-order hairpin type microstrip filter circuit 6.

[0018] In this embodiment, the three-stage PIN pair limiting circuit 4 is used to achieve power limiting and voltage clamping of high-power microwave interference signals. Figure 2 The three-stage PIN-pair limiting circuit includes a PIN-pair limiting circuit input terminal 401, a first-stage PIN-pair limiting circuit 402, a second-stage PIN-pair limiting circuit 403, a third-stage PIN-pair limiting circuit 404, microstrip transmission lines T1 and T2, and a PIN-pair limiting circuit output terminal 405.

[0019] Specifically, the first-stage PIN limiter circuit 402 is composed of two identical PIN diodes D1 and D2 connected in parallel, the opposite polarity ends of D1 and D2 are connected and the other end is grounded, the second-stage PIN limiter circuit 403 is composed of two identical PIN diodes D3 and D4 connected in parallel, the opposite polarity ends of D3 and D4 are connected and the other end is grounded, and the third-stage PIN pair tube limiter circuit 404 is composed of two identical PIN diodes D5 and D6 connected in parallel, the opposite polarity ends of D5 and D6 are connected and the other end is grounded. The connection point of D1 and D2 is connected to the input end 401 of the PIN pair tube limiter circuit and one end of the microstrip line T1, the connection point of D3 and D4 is connected to the other end of the microstrip line T1 and one end of the microstrip line T2, and the connection point of D5 and D6 is connected to the other end of the microstrip line T2 and the output end 405 of the PIN pair tube limiter circuit. The microstrip line T1 connects the first-stage PIN limiter circuit 402 and the second-stage PIN limiter circuit 403, and the microstrip line T2 connects the second-stage PIN limiter circuit 403 and the third-stage PIN limiter circuit 404. The length of the microstrip line is 10 mm and the width is 1.07 mm. The input end 401 of the PIN pair limiter circuit is connected to the DC blocking capacitor 13, and the output end 405 of the PIN pair limiter circuit is connected to the DC blocking capacitor 25.

[0020] In this embodiment, the three-stage PIN-pair limiting circuit uses PIN triodes with gradually decreasing I layers between stages. The first-stage PIN limiting circuit 402 uses a PIN diode of model CLA4607-085LF of SKYWORKS. The I layer thickness of the PIN diode is 7um and has a large power capacity, which can be used for power limiting of high-power signals in the previous stage. The second-stage PIN limiting circuit 403 uses a PIN diode of model CLA4605-085LF of SKYWORKS. The PIN diode has an I layer of 2um. Since its I layer is thinner, it is suitable as an intermediate stage to further clamp the signal voltage while reducing the starting limit level. The third-stage PIN limiting circuit 404 uses a PIN diode of model CLA4603-085LF of SKYWORKS. The I layer thickness of this model of PIN diode is 1.5um. As the last stage of the three-stage PIN-pair limiting circuit 4, it can further improve the power tolerance of the circuit as a whole and reduce the limiting level, so as to achieve a better limiting effect.

[0021] The above three-level PIN-pair limiter circuit 4 is debugged in the circuit simulation software ADS and analyzed by simulation. The S parameter diagram of the three-level PIN-pair limiter circuit 4 is as follows: Figure 3 As shown, its input and output power diagram is as follows Figure 4As shown. S parameters are used to describe the reflection characteristics, transmission characteristics and isolation of circuit networks. The commonly used S parameter ‌S11 is the input return loss, which represents the reflection coefficient of the input port. The commonly used S parameter ‌S21 is the insertion loss, which represents the transmission coefficient of the signal from port 1 to port 2, and measures the power attenuation of the signal after passing through the system. Figure 3 It can be seen that the circuit's return loss S11 parameter can be lower than -7.8dBm in the 2.4GHz center frequency band, and its insertion loss, i.e. |S21|, is about 0.8dBm. Figure 4 As shown, the starting level of the three-stage PIN pair limiting circuit is 9dBm, the limiting level is 6.3dBm, and the power capacity can reach 44dBm.

[0022] In order to further verify the actual effect of the three-level PIN limiter circuit 4, the circuit is further simulated and analyzed in the ADS software. Figure 5 As shown in the figure, it is a modulated sine wave signal with a rated power of 50dBm, which is injected into the three-stage tube limiting circuit as an interference signal. The output waveform is as follows Figure 6 As shown, its peak leakage is less than 2.2V, the clamping voltage is less than 1V, and it has good limiting performance for high-power signals.

[0023] In this embodiment, the eighth-order hairpin microstrip filter circuit 6 is used to filter out the harmonic components generated by the front-stage three-stage PIN pair tube limiter circuit 4 and filter out the out-of-band interference. Figure 7 The eighth-order hairpin microstrip filter circuit 6 includes an eighth-order microstrip filter circuit input terminal 601, a first resonator 602, a second resonator 603, a third resonator 604, a fourth resonator 605, a fifth resonator 606, a sixth resonator 607, a seventh resonator 608, an eighth resonator 609, and an eighth-order microstrip filter circuit output terminal 610. The eighth-order microstrip filter circuit input terminal 601 is connected to the DC blocking capacitor 5, and the eighth-order microstrip filter circuit output terminal 610 is connected to the limiting protection circuit output terminal 7.

[0024] Specifically, the first resonator 602 is composed of a right-angle corner microstrip line and a hairpin arm connected, and the right-angle corner microstrip line is connected above the hairpin arm. The eighth resonator 609 is composed of a right-angle corner microstrip line and a hairpin arm connected, and the right-angle corner microstrip line is connected below the hairpin arm. The second resonator 603, the third resonator 604, the fourth resonator 605, the fifth resonator 606, the sixth resonator 607, and the seventh resonator 608 are all U-shaped hairpin-shaped structures, consisting of two left and right hairpin arms, two right-angle corner microstrip lines and a middle microstrip line, and the left and right hairpin arms are connected between the right-angle corner microstrip line and the middle microstrip line. The opening directions between two adjacent resonators are opposite and side by side. Adjacent hairpin arms are parallel to each other and have the same arm length and arm width. The second resonator 603 opens upward, the sixth resonator 607 opens downward, the right-angle corner microstrip line of the first resonator 602 is connected to the input end 601 of the eighth-order hairpin microstrip filter circuit, and the right-angle corner microstrip line of the eighth resonator 609 is connected to the output end 610 of the eighth-order hairpin microstrip filter circuit.

[0025] In this embodiment, the coupling topology of the hairpin type microstrip filter circuit 6 is cross-coupling, and the cross-coupling between adjacent resonators improves the ability to suppress out-of-band signals. The second resonator 603 to the sixth resonator 607 are all coupled resonators folded into a U-shape. Figure 8 As shown, the length of the middle microstrip line of the U-shaped hairpin structure from the second resonator to the seventh resonator is Lx, and in this embodiment, Lx is set to 17.39 mm. The hairpin arm of the first resonator and the left arm of the adjacent second resonator form a parallel coupled microstrip line structure, and the arm length and the hairpin arm line width are equal. The arm length of the parallel coupled microstrip line structure is L1, the microstrip line spacing is S1, and the hairpin arm line width is W1. And so on, Figure 8 The arm length parameters of the adjacent resonator parallel coupled microstrip line structure are L1 to L7, the microstrip line spacing is S1 to S7, and the hairpin line width is W1 to W7. The arm length is determined by formula (1): (1) in, is the wavelength corresponding to the center frequency of the eighth-order hairpin microstrip filter, which is 2.4 GHz. When the ratio of the resonator line width W and the dielectric substrate thickness H is less than 2, the effective dielectric constant Determined by formula (2): ,i=1,2,...,7 (2) in is the relative dielectric constant of the substrate and is 3.66 mm in this embodiment, and H is the thickness of the dielectric substrate and is 1 mm in this embodiment.

[0026] The eighth-order hairpin microstrip filter adopts a U-shaped structure, and a right-angle corner microstrip line is used at the corner, where the miter M is defined according to formula (3): (3) In this embodiment, the width W of the right-angle corner microstrip line is 1.11 mm. The length L of the right-angle corner microstrip line is determined by formula (4): (4) After completing the calculation of the arm lengths between all resonators and the length of the right-angle corner microstrip lines, the ADS software is used to simulate and optimize the designed microstrip filter structure.

[0027] As a preferred embodiment, Figure 8 The structural dimension diagram of the eighth-order hairpin type microstrip filter circuit shown in the figure, the dimension parameters of each structure in the eighth-order hairpin type microstrip filter circuit in this embodiment are shown in the following Table 1: Table 1 Dimensional parameters (unit: mm)

[0028] The ADS software is used to simulate and analyze the transmission characteristic S parameters of the above eighth-order hairpin microstrip filter circuit 6, as shown in Fig. 9 As shown, within 2.35-2.45GHz, the insertion loss |S21| is less than 0.1dB. The return loss S11 is less than -20dBm. It can be seen that the eighth-order hairpin microstrip filter circuit provided in this embodiment can effectively suppress out-of-band interference.

[0029] In this embodiment, when the protection circuit is working, the first-stage PIN-pair limiter circuit 402 is mainly used to limit the power of the high-power signal and suppress transients. The second-stage PIN-pair limiter circuit 403 further clamps the signal voltage while reducing the threshold level. The third-stage PIN-pair limiter circuit 404 can further improve the overall power tolerance of the circuit, reduce peak leakage, and reduce the limit level. Finally, the out-of-band signal is further filtered out by the eighth-order microstrip filter circuit 6 at the subsequent stage.

[0030] In order to further verify the overall performance of the high-power microwave limiting protection circuit provided in this embodiment, power simulation is performed in ADS simulation software. The input and output power curves of the high-power microwave limiting protection circuit are shown in FIG. Fig.10 Its threshold level is about 8dBm, power tolerance is about 46dBm, and limit level is about 2.3dBm, which has good anti-interference ability.

[0031] Fig.11The voltage waveform of the wireless communication device antenna coupled with broadband high-power microwaves is obtained by simulation in CST software when the broadband high-power microwave strong electromagnetic pulse radiation field intensity is 150kV / m. The absolute value of the pulse peak voltage reaches 375V. In ADS software, the coupling voltage waveform is used as interference to simulate the interference injection of the high-power microwave limiting protection circuit. The output voltage waveform is as follows: Fig.12 As shown, the induced voltage waveform is suppressed to a peak voltage less than 1.2V. It can be seen that the high-power microwave limiting protection circuit of the present invention has a significant effect in suppressing high-power microwave interference and can effectively improve the anti-interference ability of the receiving end of the wireless communication device under high-power microwave radiation.

[0032] In summary, the high-power microwave limiting protection circuit with high power capacity proposed by the present invention adopts a multi-stage structure design of "three-stage PIN pair tube limiting circuit + eighth-order hairpin type microstrip filter circuit". Among them, the three-stage PIN pair tube limiting circuit is used for pre-stage voltage clamping and power limiting, and the three-stage PIN pair tube limiting structure can ensure low peak leakage and clamping voltage while small insertion loss. The three-stage PIN pair tube limiting structure uses a decreasing I-layer PIN diode between the stages, which can clamp and limit the high-power interference signal step by step, and finally achieve good limiting performance. The power limiting performance of the three-stage PIN pair tube is further verified in the ADS software, which can play a good protective role in practical applications. The hairpin structure adopted by the eighth-order hairpin type microstrip filter circuit can further filter out out-of-band interference while ensuring a compact structure, low insertion loss and no need for vias. The eighth-order hairpin type microstrip filter circuit has good out-of-band suppression capability. The power simulation analysis of the high-power microwave limiting protection circuit design was carried out through the simulation software ADS. The results show that the high-power microwave limiting protection circuit proposed in the present invention has large power capacity, small peak leakage, small starting limit level and low limiting level. It can effectively suppress the interference signal of high-power microwave coupled into the receiving end of the wireless communication device, thereby improving the anti-interference ability of the wireless communication device under high-power microwave radiation.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-power microwave limiting protection circuit with high power capacity, characterized in that: The invention comprises a dielectric substrate, an input end of a limiting protection circuit, a first DC blocking capacitor, a three-level PIN pair limiting circuit, a second DC blocking capacitor, an eighth-order hairpin type microstrip filter circuit and an output end of the limiting protection circuit, wherein the three-level PIN pair limiting circuit and the eighth-order hairpin type microstrip filter circuit are both mounted on the dielectric substrate, the first DC blocking capacitor is connected between the input end of the limiting protection circuit and the three-level PIN pair limiting circuit, the second DC blocking capacitor is connected between the three-level PIN pair limiting circuit and the eighth-order hairpin type microstrip filter circuit, and the output end of the limiting protection circuit is connected to the eighth-order hairpin type microstrip filter circuit.

2. A high-power microwave limiting protection circuit with high power capacity according to claim 1, characterized in that: The three-stage PIN pair limiting circuit is used to achieve power limiting and voltage clamping of high-power microwave interference signals. The three-stage PIN pair limiting circuit includes a PIN pair limiting circuit input end, a first-stage PIN pair limiting circuit, a second-stage PIN pair limiting circuit, a third-stage PIN pair limiting circuit, a microstrip transmission line T1, a microstrip transmission line T2 and a PIN pair limiting circuit output end, wherein the first-stage PIN limiting circuit is composed of two identical PIN diodes D1 and D2 connected in parallel, the PIN diodes D1 and D2 are connected at opposite polarity ends and the other end is grounded, the second-stage PIN limiting circuit is composed of two identical PIN diodes D3 and D4 connected in parallel, the PIN diodes D3 and D4 are connected at opposite polarity ends and the other end is grounded, and the third-stage PIN pair limiting circuit is composed of two The same PIN diode D5 and PIN diode D6 are connected in parallel, the opposite polarity ends of the PIN diode D5 and the PIN diode D6 are connected and the other end is grounded, the connection point of the PIN diode D1 and the PIN diode D2 is connected to the input end of the PIN pair tube limiting circuit and one end of the microstrip line T1, the connection point of the PIN diode D3 and the PIN diode D4 is connected to the other end of the microstrip line T1 and one end of the microstrip line T2, the connection point of the PIN diode D5 and the PIN diode D6 is connected to the other end of the microstrip line T2 and the output end of the PIN pair tube limiting circuit, the microstrip line T1 connects the first-stage PIN limiting circuit and the second-stage PIN limiting circuit, the microstrip line T2 connects the second-stage PIN limiting circuit and the third-stage PIN limiting circuit, the input end of the PIN pair tube limiting circuit is connected to the first DC blocking capacitor, and the output end of the PIN pair tube limiting circuit is connected to the second DC blocking capacitor.

3. A high-power microwave limiting protection circuit with high power capacity according to claim 2, characterized in that: The three-stage PIN-pair limiting circuit uses PIN triodes with gradually decreasing I layers between stages, wherein the I layer thickness of the PIN diode used in the first-stage PIN limiting circuit is 7um and has a large power capacity, and can be used for power limiting of a high-power signal in the previous stage; the I layer thickness of the PIN diode used in the second-stage PIN limiting circuit is 2um, and since its I layer is thinner, it is suitable as an intermediate stage for further clamping the signal voltage while reducing the starting limit level; the I layer thickness of the PIN diode used in the third-stage PIN limiting circuit is 1.5um, and as the last stage of the three-stage PIN-pair limiting circuit, it can further improve the overall power tolerance of the circuit and reduce the limiting level, thereby achieving a better limiting effect.

4. The high-power microwave limiting protection circuit with high power capacity according to claim 1, characterized in that: The eighth-order hairpin-type microstrip filter circuit is used to filter out the harmonic components generated by the front-stage three-stage PIN pair tube limiting circuit and filter out-of-band interference, and comprises an eighth-order microstrip filter circuit input end, a first resonator, a second resonator, a third resonator, a fourth resonator, a fifth resonator, a sixth resonator, a seventh resonator, an eighth resonator and an eighth-order microstrip filter circuit output end, wherein the eighth-order microstrip filter circuit input end is connected to the second phase of the DC blocking capacitor, the eighth-order microstrip filter circuit output end is connected to the limiting protection circuit output end, eight resonators are arranged side by side, and the opening directions of two adjacent resonators are opposite, and two adjacent hairpin-type resonators have a parallel coupling microstrip line with the same arm length and line width, and the coupling mode between them is cross coupling.

5. A high-power microwave limiting protection circuit with high power capacity according to claim 4, characterized in that: The first resonator is composed of a right-angle corner microstrip line connected to a hairpin arm, the right-angle corner microstrip line is connected above the hairpin arm, and the eighth resonator is composed of a right-angle corner microstrip line connected to a hairpin arm, the right-angle corner microstrip line is connected below the hairpin arm.

6. A high-power microwave limiting protection circuit with high power capacity according to claim 4, characterized in that: The second resonator, the third resonator, the fourth resonator, the fifth resonator, the sixth resonator and the seventh resonator are all of U-shaped hairpin type structure, which are composed of two left and right hairpin arms, two right-angle corner microstrip lines and a middle microstrip line. The left and right hairpin arms are connected between the right-angle corner microstrip line and the middle microstrip line. The opening directions of two adjacent resonators are opposite and they are side by side. The adjacent hairpin arms are parallel to each other and have the same arm length and arm width. The second resonator opens upward, and the sixth resonator opens downward. The right-angle corner microstrip line of the first resonator is connected to the input end of the eighth-order hairpin microstrip filter circuit, and the right-angle corner microstrip line of the eighth resonator is connected to the output end of the eighth-order hairpin microstrip filter circuit.

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