Passive microwave pulse compression device and method based on bidirectional frequency compression
Through bidirectional frequency compression technology, the signal with a wider frequency range is synchronized by using a cyclometer, filter, delay line and power synthesizer, and combined with some medium loading rectangular waveguides for compression, the problem of limited bandwidth of the unidirectional frequency microwave pulse compression band is solved, and a higher power compression factor and a narrower output pulse signal are achieved.
Patent Information
- Application Number
- CN202510528662.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-08-08
AI Technical Summary
In the existing passive microwave pulse compression technology, the frequency band bandwidth of unidirectional frequency microwave pulse compression is limited, resulting in a small power compression factor that cannot meet the needs of high-power millimeter waves.
A passive microwave pulse compression device based on bidirectional frequency compression is adopted, and a bidirectional chirped signal with a wider frequency range is synchronized by a circular device, a filter, a delay line and a power synthesizer, and a rectangular waveguide is loaded through some medium for compression, outputting a narrow pulse signal.
A higher peak power of the output pulse signal and a narrower output pulse signal in the sub-nanosecond order are achieved, with a power compression factor of about 1.5 to 2.0 times, suitable for a wider frequency band range.
Smart Images
Figure CN120454733A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of microwave pulse compression, and in particular relates to a passive microwave pulse compression device and method based on bidirectional frequency compression. Background Art
[0002] Microwave pulse compression technology can shorten the time width of microwave pulses and increase the peak power of microwave pulses. It is widely used in microwave thermoacoustic imaging, microwave weapons, materials science and other fields.
[0003] Generally speaking, microwave pulse compression technology can be divided into active microwave pulse compression technology and passive microwave pulse compression technology. Usually, the input pulse signal of active microwave pulse compression is generally a quasi-monochromatic wave, while the input pulse signal of passive microwave pulse compression has a certain bandwidth. The basic principle of passive microwave pulse compression is: when electromagnetic waves propagate in a dispersive structure, the group velocities of electromagnetic waves of different frequencies are different. As long as the time variation characteristics of the input signal frequency are reasonably designed, the rear part of the input signal can gradually catch up with the front part during the propagation process, so that the output signal pulse width is reduced and the output power is increased. If the input power is P in , the input pulse width is τ in , the output power after compression is P peak , the output pulse width is τ c According to the law of conservation of energy, P in τ in =P peak τ c As the output pulse width becomes smaller, the output pulse power is improved, and its power compression factor is defined as Q = P peak / P in .
[0004] Current research on passive microwave pulse compression, both domestically and internationally, primarily utilizes dispersive structures such as rectangular waveguides, circular waveguides, and spiral waveguides. Unidirectional frequency microwave pulse compression is typically employed, meaning the input signal frequency increases or decreases unidirectionally over time, with the frequency variation in the time domain being monotonic. However, the bandwidth of the frequency band in which unidirectional frequency microwave pulse compression can be utilized is relatively limited, resulting in a relatively limited power compression factor.
[0005] Liang Zhang et al. from the University of Strathclyde have recently reported on passive microwave pulse compression using a five-fold spiral waveguide. By injecting chirped pulses into the waveguide, they achieved a compression factor of 25.2, a world-leading result. However, current passive microwave pulse compression using spiral waveguides relies on unidirectional frequency microwave pulse compression, and its long dispersion structure and low power compression factor make it unable to meet the recent demand for high-power millimeter waves. Therefore, a method to further improve the power compression factor of passive microwave pulse compression is urgently needed. Summary of the Invention
[0006] In order to expand the frequency band width that can be used for passive microwave pulse compression, thereby improving the power compression factor of the passive microwave pulse and reducing the time domain width of the output pulse signal, the present invention proposes a passive microwave pulse compression device and method based on bidirectional frequency compression, that is, an electromagnetic wave whose frequency increases with time and an electromagnetic wave whose frequency decreases with time simultaneously enter the dispersion structure to perform passive microwave pulse compression.
[0007] The technical solution adopted in the present invention is as follows:
[0008] In a first aspect, the present invention proposes a passive microwave pulse compression device based on bidirectional frequency compression, characterized in that the device comprises: an arbitrary waveform generator, a bidirectional frequency passive microwave pulse compression kit;
[0009] The output end of the arbitrary waveform generator is connected to the input end of the bidirectional frequency passive microwave pulse compression kit, and the generated pulse signal is input into the bidirectional frequency passive microwave pulse compression kit;
[0010] The bidirectional frequency passive microwave pulse compression kit is used to compress the pulse signal and output a compressed narrow pulse signal;
[0011] The bidirectional frequency passive microwave pulse compression kit includes: a circulator, a filter, a delay line, a power combiner, and a partially dielectric loaded rectangular waveguide;
[0012] The input port of the circulator is connected to an arbitrary waveform generator, the output port is connected to the input port of the filter, and the isolation port is connected to the input port of the delay line; the output port of the filter and the output port of the delay line are respectively connected to two input ports of the power combiner; the output port of the power combiner is connected to the input port of a partially dielectric-loaded rectangular waveguide;
[0013] The pulse signal is generated by an arbitrary waveform generator, input into a circulator, and then directly transmitted to a filter through an output port. The filter divides the pulse signal into two signals of different frequency bands, wherein the low-frequency band signal is input into a power combiner through the filter, and the high-frequency band signal is reflected back to the waveguide circulator and enters the delay line through an isolation port. After a time delay, it is synchronously input into the power combiner with the low-frequency band signal.
[0014] The power combiner combines the low-frequency signal and the high- and low-frequency signals and then inputs the combined signals into a partially dielectric-loaded rectangular waveguide;
[0015] The partially dielectric-loaded rectangular waveguide performs bidirectional frequency compression on the synthesized signal and outputs a compressed narrow pulse signal.
[0016] Furthermore, the partially dielectric-loaded rectangular waveguide is composed of a metal rectangular waveguide and at least one internally loaded dispersive dielectric layer; the dispersive dielectric layer is axially arranged and parallel to the narrow side of the metal rectangular waveguide.
[0017] Furthermore, the material of the dispersive medium layer is sapphire or diamond.
[0018] Furthermore, the filter is a low-pass filter, and its cut-off frequency is the frequency corresponding to the maximum group velocity of the partially dielectric-loaded rectangular waveguide.
[0019] Furthermore, the performance indicators of the waveguide circulator meet the following requirements: the frequency range covers the frequency band used for passive microwave pulse compression; the insertion loss is less than 0.3dB, the isolation is greater than 23dB, and the standing wave ratio is less than 1.20; the performance indicators of the filter meet the following requirements: the insertion loss is less than 0.3dB, and the standing wave ratio is less than 1.20; the performance indicators of the delay line meet the following requirements: the insertion loss is less than 0.3dB, and the standing wave ratio is less than 1.20, and the delay amount is determined by the time difference between the high-frequency band signal and the low-frequency band signal.
[0020] Furthermore, the pulse signal output by the arbitrary waveform generator is converted into a standard waveguide TE10 mode and then input into the circulator.
[0021] In a second aspect, the present invention proposes a passive microwave pulse compression method based on a bidirectional frequency microwave pulse compression device, comprising the following steps:
[0022] Step 1. Obtain the frequency range of the input pulse signal based on the frequency band of the required narrow pulse signal;
[0023] Step 2. Determine the dispersion requirements and filter cutoff frequency that the partially dielectric-loaded rectangular waveguide needs to meet based on the frequency range of the input pulse signal.
[0024] Step 3. Based on the dispersion requirements, determine the dimensions of the metal rectangular waveguide in the partially dielectric-loaded rectangular waveguide, as well as the material, thickness, and loading position of the dispersive dielectric layer. Then, theoretical calculations are performed to obtain the dispersion data of the partially dielectric-loaded rectangular waveguide and the time delay between the high-band and low-band signals.
[0025] Step 4. Based on the dispersion data of the partially dielectric-loaded rectangular waveguide, the waveform of the input pulse signal is calculated using group velocity theory.
[0026] Step 5. Build a passive microwave pulse compression device based on bidirectional frequency compression, then import the waveform data of the input pulse signal into the arbitrary waveform generator, and finally obtain the compressed narrow pulse signal at the output port of the bidirectional frequency passive microwave pulse compression kit.
[0027] The beneficial effects of the present invention are:
[0028] Compared to conventional unidirectional microwave pulse compression devices, the bidirectional frequency microwave pulse compression device used in the present invention uses a circulator, a filter, a delay line, and a power synthesizer to synchronously synthesize a bidirectional chirped signal with a wider frequency range. It also uses a partially dielectric-loaded rectangular waveguide to compress the synthesized signal, ultimately obtaining a compressed narrow pulse signal. Compared to conventional unidirectional microwave pulse compression methods, the present invention can achieve a power compression factor of approximately 1.5 to 2.0 times greater, thereby obtaining a higher peak power output pulse signal. Furthermore, compared to conventional unidirectional microwave pulse compression methods, the present invention can be applied to a wider frequency band, thereby obtaining a sub-nanosecond output pulse signal that is narrower in the time domain. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 The present invention is a schematic structural diagram of a passive microwave pulse compression device based on bidirectional frequency microwave pulse compression.
[0030] Figure 2 Schematic diagram of the first partially dielectric-loaded rectangular waveguide structure.
[0031] Figure 3 Schematic diagram of the first partially dielectric-loaded rectangular waveguide port.
[0032] Figure 4 Schematic diagram of the second partially dielectric-loaded rectangular waveguide structure.
[0033] Figure 5 Schematic diagram of the second partially dielectric-loaded rectangular waveguide port.
[0034] Figure 6 Schematic diagram of the third partially medium-loaded rectangular waveguide structure.
[0035] Figure 7 Schematic diagram of the rectangular waveguide port loaded with the third partial medium.
[0036] Figure 8 This is the dispersion data (TE10 mode) of the partially dielectric-loaded rectangular waveguide used in the design example obtained through theoretical calculation in Example 1.
[0037] Figure 9 This is the group velocity curve (TE10 mode) of the partially dielectric-loaded rectangular waveguide used in the design example obtained through theoretical calculation in Example 1.
[0038] Figure 10 It is the input pulse signal of the bidirectional frequency microwave pulse compression device calculated according to the group velocity theory in Example 1.
[0039] Figure 11 These are two synchronized signals of different frequency bands theoretically expected after the input frequency sweep signal of the bidirectional frequency passive microwave pulse compression device in Example 1 passes through a waveguide circulator, a waveguide filter and a delay line.
[0040] Figure 12 is the square of the amplitude of the output signal and the envelope of the square of the amplitude of the output signal in the first embodiment.
[0041] Figure 13 This is the dispersion data (TE10 mode) of the partially dielectric-loaded rectangular waveguide used in the design example in Example 2 obtained through theoretical calculation.
[0042] Figure 14 This is the group velocity curve (TE10 mode) of the partially dielectric-loaded rectangular waveguide used in the design example obtained through theoretical calculation in Example 2.
[0043] Figure 15 It is the input pulse signal of the bidirectional frequency microwave pulse compression device calculated according to the group velocity theory in Example 2.
[0044] Figure 16 These are two synchronized signals of different frequency bands theoretically expected after the input frequency sweep signal of the bidirectional frequency passive microwave pulse compression device in Example 2 passes through the waveguide circulator, waveguide filter and delay line.
[0045] Figure 17 is the square of the amplitude of the output signal and the envelope of the square of the amplitude of the output signal in the second embodiment.
[0046] Description of the accompanying figures: 1 is a metal rectangular waveguide, 2 is a dispersion medium layer. DETAILED DESCRIPTION
[0047] The technical solution of the present invention is further described in detail below with reference to specific embodiments and accompanying drawings:
[0048] Example 1:
[0049] In this embodiment, a passive microwave pulse compression method based on a bidirectional frequency microwave pulse compression device is provided, comprising the following steps:
[0050] Step 1: The required narrow pulse signal has a frequency band of 7.7 GHz to 13.9 GHz. Therefore, the frequency band of the input pulse signal is 7.7 GHz to 13.9 GHz.
[0051] Step 2: Based on the frequency band of the input pulse signal, the dispersion curve of the partially dielectric-loaded rectangular waveguide needs to have a maximum slope at the center frequency of 10.8 GHz and a minimum slope at 7.7 GHz and 13.9 GHz. Therefore, the cutoff frequency of the filter is set within the range of 10.8 GHz ± 0.1 GHz.
[0052] Step 3: Based on the dispersion requirements in step 2, determine the size of the metal rectangular waveguide in the partially dielectric-loaded rectangular waveguide, the material, thickness, and loading position of the dispersive dielectric layer.
[0053] Figure 2 and Figure 3 Schematic diagram of the first partially dielectric-loaded rectangular waveguide structure, where the dispersive dielectric layer is loaded at the center of the metal rectangular waveguide; Figure 4 and Figure 5 This is a schematic diagram of the second partially dielectric-loaded rectangular waveguide structure, where the dispersive dielectric layer is bonded to one of the narrow sides of the metal rectangular waveguide. Figure 6 and Figure 7 This is a schematic diagram of the third partially dielectric-loaded rectangular waveguide structure. Two dispersive dielectric layers are positioned adjacent to the narrow sides of the metal rectangular waveguide. In this embodiment, the partially dielectric-loaded rectangular waveguide adopts the third structure. The port dimensions of this partially dielectric-loaded rectangular waveguide are 21.4 mm × 8 mm, and the length is 2000 mm. The two dispersive dielectric layers, 1.7 mm thick, are positioned adjacent to the narrow sides of the rectangular waveguide. The material is sapphire, which has a relative dielectric constant of approximately 11.58.
[0054] The dispersion data of the above-mentioned dielectric-loaded rectangular waveguides are obtained through theoretical calculations, such as Figure 8 and Figure 9 As shown; the time delay between the two signals is then calculated based on the dispersion data.
[0055] Step 4: Based on the dispersion data of the partially dielectric loaded rectangular waveguide, the waveform of the input pulse signal is calculated using the group velocity theory. The waveform is as follows: Figure 10The input pulse signal includes both up-chirp and down-chirp signals. From approximately 0 ns to 4.3 ns, the input signal is an up-chirp signal with a frequency range of approximately 7.7 GHz to 10.7 GHz. After approximately 4.3 ns, the input signal becomes a down-chirp signal with a frequency range of approximately 10.9 GHz to 13.9 GHz.
[0056] Step 5: Build a device based on bidirectional frequency microwave pulse compression, import the calculated waveform data of the input pulse signal into the arbitrary waveform generator, and finally obtain the compressed narrow pulse signal at the output port of the bidirectional frequency passive microwave pulse compression kit.
[0057] Specifically, in this embodiment, due to the limitations of simulation conditions, only the bidirectional frequency passive microwave pulse simulation output results of the second half of the system including the power combiner and partially dielectric-loaded rectangular waveguide are given in this example, where the working mode is also TE10 mode.
[0058] Figure 11 are the two theoretically expected signals after the input pulse signal passes through the waveguide circulator, waveguide filter and delay line. Figure 11 (a) The frequency band corresponding to the signal is approximately 7.7 GHz to 10.7 GHz. Figure 11 (b) The frequency band corresponding to the signal is approximately 13.9 GHz to 10.9 GHz.
[0059] The two expected signals are used as the two input signals of the power combiner during simulation. The output port of the power combiner is connected to the input port of the partially dielectric loaded rectangular waveguide to perform passive microwave pulses, and the compressed simulation output result is obtained at the other port of the partially dielectric loaded waveguide. The output signal waveform obtained by simulation is as follows: Figure 12 As shown, Figure 12 (a) is the square of the amplitude of the simulated output signal, Figure 12 (b) is the envelope of the squared amplitude of the simulated output signal.
[0060] Simulation results show that in this design example, the power compression factor of bidirectional microwave pulse compression is approximately 22 times, which is approximately 1.83 times the power compression factor of unidirectional microwave pulse compression (approximately 12 times) under the same conditions. Furthermore, in this design example, the 3dB pulse width of the output signal of bidirectional microwave pulse compression is approximately 0.1271ns, which is approximately half the 3dB pulse width of the output signal of unidirectional microwave pulse compression (approximately 0.2644ns) under the same conditions.
[0061] Example 2:
[0062] In this embodiment, a passive microwave pulse compression method based on a bidirectional frequency microwave pulse compression device is provided, comprising the following steps:
[0063] Step 1: The required narrow pulse signal has a frequency band of 12 GHz to 18 GHz. Therefore, the frequency band of the input pulse signal is 12 GHz to 18 GHz.
[0064] Step 2: Based on the frequency band of the input pulse signal, determine that the dispersion curve of the partially dielectric-loaded rectangular waveguide needs to have a maximum slope at the center frequency of 15 GHz and a minimum slope at 12 GHz and 18 GHz. Therefore, the cutoff frequency of the filter is set within the range of 15 GHz ± 0.1 GHz.
[0065] Step 3: Based on the dispersion requirements in step 2, determine the size of the metal rectangular waveguide in the partially dielectric-loaded rectangular waveguide, the material, thickness, and loading position of the dispersive dielectric layer.
[0066] Specifically, in this embodiment, the partially dielectric loaded rectangular waveguide adopts the third structure, such as Figure 6 、 Figure 7 As shown, the port size of this dielectric-loaded rectangular waveguide is 13.6 mm × 6 mm, and the length is 2000 mm. The two dispersive dielectric layers are set close to the narrow side of the rectangular waveguide, with a thickness of 1.3 mm. The material is sapphire, and its relative dielectric constant is about 11.58.
[0067] The dispersion data of the above-mentioned dielectric-loaded rectangular waveguides are obtained through theoretical calculations, such as Figure 13 and Figure 14 As shown; the time delay between the two signals is then calculated based on the dispersion data.
[0068] Step 4: Based on the dispersion data of the partially dielectric loaded rectangular waveguide, the waveform of the input pulse signal is calculated using the group velocity theory. The waveform is as follows: Figure 15 The input pulse signal includes both up-chirp and down-chirp signals. From approximately 0ns to 2.6ns, the input signal is an up-chirp signal with a frequency range of approximately 12GHz to 15GHz. After approximately 2.6ns, the input signal becomes a down-chirp signal with a frequency range of approximately 18GHz to 15GHz.
[0069] Step 5: Build a device based on bidirectional frequency microwave pulse compression, import the calculated waveform data of the input pulse signal into the arbitrary waveform generator, and finally obtain the compressed narrow pulse signal at the output port of the bidirectional frequency passive microwave pulse compression kit.
[0070] Specifically, in this embodiment, due to the limitations of simulation conditions, only the bidirectional frequency passive microwave pulse simulation output results of the second half of the system including the power combiner and partially dielectric-loaded rectangular waveguide are given in this example, where the working mode is also TE10 mode.
[0071] Figure 16are the two theoretically expected signals after the input pulse signal passes through the waveguide circulator, waveguide filter and delay line. Figure 16 (a) The frequency band corresponding to the signal is approximately 12 GHz to 15 GHz. Figure 16 (b) The frequency band corresponding to the signal is approximately 15 GHz to 18 GHz.
[0072] The two expected signals are used as the two input signals of the power combiner during simulation. The output port of the power combiner is connected to the input port of the partially dielectric loaded rectangular waveguide to perform passive microwave pulses, and the compressed simulation output result is obtained at the other port of the partially dielectric loaded waveguide. The output signal waveform obtained by simulation is as follows: Figure 12 As shown, Figure 17 (a) is the square of the amplitude of the simulated output signal, Figure 17 (b) is the envelope of the squared amplitude of the simulated output signal.
[0073] Simulation results show that in this design example, the power compression factor of bidirectional microwave pulse compression is approximately 26 times, which is approximately 2.83 times the power compression factor of unidirectional microwave pulse compression (approximately 9.2 times) under the same conditions. Furthermore, in this design example, the 3dB pulse width of the output signal of bidirectional microwave pulse compression is approximately 0.1371ns, roughly half the 3dB pulse width of the output signal of unidirectional microwave pulse compression (approximately 0.2684ns) under the same conditions.
Claims
1. A passive microwave pulse compression device based on bidirectional frequency compression, characterized in that: The device includes: an arbitrary waveform generator, a bidirectional frequency passive microwave pulse compression kit; The output end of the arbitrary waveform generator is connected to the input end of the bidirectional frequency passive microwave pulse compression kit, and the generated pulse signal is input into the bidirectional frequency passive microwave pulse compression kit; The bidirectional frequency passive microwave pulse compression kit is used to compress the pulse signal and output a compressed narrow pulse signal; The bidirectional frequency passive microwave pulse compression kit includes: a circulator, a filter, a delay line, a power combiner, and a partially dielectric loaded rectangular waveguide; The input port of the circulator is connected to an arbitrary waveform generator, the output port is connected to the input port of the filter, and the isolation port is connected to the input port of the delay line; the output port of the filter and the output port of the delay line are respectively connected to two input ports of the power combiner; the output port of the power combiner is connected to the input port of a partially dielectric-loaded rectangular waveguide; The pulse signal is generated by an arbitrary waveform generator, input into a circulator, and then directly transmitted to a filter through an output port. The filter divides the pulse signal into two signals of different frequency bands, wherein the low-frequency band signal is input into a power combiner through the filter, and the high-frequency band signal is reflected back to the waveguide circulator and enters the delay line through an isolation port. After a time delay, it is synchronously input into the power combiner with the low-frequency band signal. The power combiner combines the low-frequency signal and the high- and low-frequency signals and then inputs the combined signals into a partially dielectric-loaded rectangular waveguide; The partially dielectric-loaded rectangular waveguide performs bidirectional frequency compression on the synthesized signal and outputs a compressed narrow pulse signal.
2. A passive microwave pulse compression device based on bidirectional frequency compression as claimed in claim 1, characterized in that: The partially dielectric-loaded rectangular waveguide consists of a metal rectangular waveguide and at least one internally loaded dispersive dielectric layer; the dispersive dielectric layer is arranged axially and parallel to the narrow side of the metal rectangular waveguide.
3. A passive microwave pulse compression device based on bidirectional frequency compression as claimed in claim 2, characterized in that: The material of the dispersive medium layer is sapphire or diamond.
4. A passive microwave pulse compression device based on bidirectional frequency compression as claimed in claim 3, characterized in that: The filter is a low-pass filter, and the cut-off frequency of the filter is the frequency corresponding to the maximum group velocity of the partially dielectric-loaded rectangular waveguide.
5. A passive microwave pulse compression device based on bidirectional frequency compression as claimed in claim 4, characterized in that: The performance indicators of the waveguide circulator meet the following requirements: the frequency range covers the frequency band used by passive microwave pulse compression, the insertion loss is less than 0.3dB, the isolation is greater than 23dB, and the standing wave ratio is less than 1.20; The performance indicators of the filter meet the following requirements: insertion loss is less than 0.3dB, and standing wave ratio is less than 1.20; The performance indicators of the delay line meet the following requirements: insertion loss is less than 0.3dB, and standing wave ratio is less than 1.
20.
6. A passive microwave pulse compression device based on bidirectional frequency compression as claimed in claim 5, characterized in that: The pulse signal output by the arbitrary waveform generator is converted into a standard waveguide TE10 mode and then input into the circulator.
7. A passive microwave pulse compression method based on a bidirectional frequency microwave pulse compression device, characterized in that: The following steps are involved: Step 1. Obtain the frequency range of the input pulse signal based on the frequency band of the required narrow pulse signal; Step 2. Determine the dispersion requirements and filter cutoff frequency that the partially dielectric-loaded rectangular waveguide needs to meet based on the frequency range of the input pulse signal. Step 3. Based on the dispersion requirements, determine the dimensions of the metal rectangular waveguide in the partially dielectric-loaded rectangular waveguide, as well as the material, thickness, and loading position of the dispersive dielectric layer. Then, theoretical calculations are performed to obtain the dispersion data of the partially dielectric-loaded rectangular waveguide and the time delay between the high-band and low-band signals. Step 4. Based on the dispersion data of the partially dielectric-loaded rectangular waveguide, the waveform of the input pulse signal is calculated using group velocity theory. Step 5. Build a passive microwave pulse compression device based on bidirectional frequency compression as described in any one of claims 1 to 7, then import the waveform data of the input pulse signal into an arbitrary waveform generator, and finally obtain a compressed narrow pulse signal at the output port of the bidirectional frequency passive microwave pulse compression kit.