Standing wave electrode composite loading microwave photon receiving antenna and signal receiving method thereof

Abstract

The invention provides a moving and standing wave electrode composite loading microwave photon receiving antenna and a signal receiving method thereof.The antenna comprises a dual-band combined plane patch antenna and a lithium niobate film moving and standing wave electro-optical modulation chip, a high-frequency antenna and a moving wave electrode are mutually connected through gold wire bonding, and a low-frequency antenna and a standing wave electrode are mutually connected through gold wire bonding; and a single beam of light wave is modulated by the two electrodes in sequence by using a cascade light path. The signal receiving method comprises the steps of light wave injection, dual-band signal induction and loading, sequential modulation based on the lithium niobate electro-optical effect, photoelectric conversion and signal extraction. Through the traveling wave and standing wave electrode composite loading and optical domain modulation mechanism, the bottleneck that the bandwidth of a traditional antenna is limited by impedance matching is broken through, high-sensitivity receiving is achieved within the ultra-wide band of 10 MHz to 20 GHz, and meanwhile the ultra-wide-band antenna has the advantages of being compact in structure and high in electromagnetic interference resistance and is suitable for ultra-wide-band weak field detection and high-precision electromagnetic signal receiving.

Description

Technical Field

[0001] This invention relates to the field of electric field signal measurement technology, specifically to a traveling-standing-wave electrode composite loaded microwave photonic receiving antenna and its signal receiving method. Background Technology

[0002] With the widespread application of electronic devices and the continuous expansion of spectrum resources, the electromagnetic environment is becoming increasingly complex, placing higher demands on the reception and measurement of ultra-wideband (10MHz–20GHz) electromagnetic signals. While traditional ultra-wideband antenna technology, since its development from frequency-independent theory, has achieved breakthroughs in relative bandwidth across multiple octaves, two key bottlenecks remain: First, there is an inherent contradiction in physical size. Lower frequencies require larger dimensions for efficient radiation, while higher frequencies require smaller dimensions to maintain beam directivity and pattern stability. A single structure cannot simultaneously achieve excellent electromagnetic performance across the entire frequency band. Second, impedance matching limitations are significant. Within the ultra-wideband, the antenna reactance component changes drastically with frequency, leading to severe impedance mismatch. Although partial compensation can be achieved through complex matching networks, this introduces additional losses and frequency response distortion, thus limiting further expansion of the system bandwidth.

[0003] On the other hand, while optical electric field sensors based on lithium niobate electro-optic modulation possess the potential for broadband coverage from DC to tens of GHz, their practical applications are still limited by the trade-off between sensitivity and bandwidth. Employing electrically small antenna structures can maintain a relatively wide bandwidth response, but the electromagnetic energy coupling efficiency is low, making it difficult to effectively detect weak far-field signals (<1V / m). Increasing the electrode size to improve sensitivity leads to a deterioration in the high-frequency response due to structural resonance effects, resulting in a significant decrease in bandwidth performance.

[0004] Therefore, the physical limitations of traditional ultra-wideband antennas in terms of bandwidth and the inherent defects of optical electric field sensors in terms of sensitivity together constitute the core technical obstacles faced in the development of ultra-wideband weak field detection systems. Summary of the Invention

[0005] The purpose of this invention is to provide a microwave photonic receiving antenna with a traveling-standing wave electrode composite loading and a signal receiving method thereof, so as to solve the problems of limited bandwidth, prominent contradiction between sensitivity and bandwidth, and insufficient anti-interference capability of traditional antennas.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A microwave photonic receiving antenna with a traveling-standing wave (TSW) electrode composite loading includes a dual-band combined planar patch antenna, a lithium niobate thin-film TSW electro-optic modulation chip, an input optical fiber, and an output optical fiber. The dual-band combined planar patch antenna includes a high-frequency antenna element and a low-frequency antenna element, respectively used to receive electromagnetic signals of different frequency bands. The lithium niobate thin-film TSW electro-optic modulation chip is based on a Mach-Zehnder interferometer structure, with traveling-wave electrodes and standing-wave electrodes integrated on its optical waveguide. The input optical fiber is used to couple optical signals from a continuous-wave laser source to the electro-optic modulation chip. The output optical fiber is used to transmit the modulated optical signal... The signal is output from the electro-optic modulation chip to the photodetector; the RF output port of the high-frequency antenna unit is connected to the input end of the traveling wave electrode via gold wire bonding, and the terminal of the traveling wave electrode is connected to a matching load; the RF output port of the low-frequency antenna unit is connected to the standing wave electrode via gold wire bonding, and the terminal of the standing wave electrode is set to open circuit; the input optical fiber, the optical waveguide of the electro-optic modulation chip, and the output optical fiber constitute a first-order optical path, so that a single light wave can pass through the modulation regions corresponding to the traveling wave electrode and the standing wave electrode in sequence, and be modulated by the high-frequency and low-frequency RF signals loaded on them respectively.

[0007] Furthermore, the two interferometer arms of the Mach-Zehnder interferometer structure have asymmetrical lengths so that the static operating point of the interferometer is located in the linear region of its transmission characteristics.

[0008] Furthermore, the traveling wave electrode has a push-pull electrode structure.

[0009] Furthermore, the input optical fiber is a polarization-maintaining optical fiber.

[0010] Furthermore, the high-frequency antenna unit is one of a Vivaldi antenna, a helical antenna, or a tapered slot antenna; the low-frequency antenna unit is one of a vibrating antenna, a monopole antenna, or a dipole antenna.

[0011] A method for receiving microwave photonic signals based on a microwave photonic receiving antenna with a traveling-standing wave electrode composite loading includes the following steps: S1. Connect the continuous wave laser source to the antenna through the input optical fiber, and connect the photodetector to the antenna through the output optical fiber; S2. Start the laser source to generate continuous light waves and inject them into the electro-optic modulation chip; S3. Induction of spatial electromagnetic signals through the dual-band combined planar patch antenna, and loading of high-frequency signals onto traveling wave electrodes and low-frequency signals onto standing wave electrodes; S4. The light wave is sequentially passed through the modulation regions corresponding to the traveling wave electrode and the standing wave electrode. The phase of the light wave is modulated based on the lithium niobate electro-optic effect to generate a modulated light signal containing dual-frequency information. S5. The modulated optical signal is transmitted to the photodetector via the output optical fiber and converted into an electrical signal; S6. Process the electrical signal to extract information related to the spatial electromagnetic field strength.

[0012] Furthermore, the high-frequency antenna unit operates in the frequency band of 1 GHz to 20 GHz, and the low-frequency antenna unit operates in the frequency band of 10 MHz to 1 GHz.

[0013] As can be seen from the above technical solutions, the present invention has the following technical advantages compared with the prior art: 1. In the high-frequency band, the traveling wave electrode of this invention can be freely matched with a load according to its characteristic impedance, breaking through the traditional 50Ω impedance limitation and making it easier to achieve ultra-wideband matching; at the same time, in the low-frequency band, the open-circuit matched standing wave electrode forms the maximum voltage division at the terminal, significantly improving the modulation efficiency, eliminating the need for a complex matching network, and enabling the narrowband antenna structure to work in broadband mode. 2. This invention effectively avoids the high-frequency loss problem in traditional electronic receiving links by modulating and transmitting optical signals, significantly enhancing the system's anti-interference and anti-damage capabilities in strong electromagnetic environments, and achieving high linearity and high precision electromagnetic field optical measurement; 3. This invention utilizes a single optical path to sequentially drive antenna elements covering high and low frequency bands respectively, realizing the integration and synthesis of dual-band signals in the optical domain, which is equivalent to the output of a single broadband antenna, overcoming the inherent contradiction between bandwidth and structural size. 4. By optimizing the traveling wave and standing wave electrode structures and their corresponding antenna designs respectively, this invention maintains the wideband matching characteristics of the traveling wave in the high-frequency band and enhances the voltage sensitivity by utilizing standing wave resonance in the low-frequency band, thereby achieving both high field strength sensitivity and good frequency response in an ultra-wide frequency range of 10MHz–20GHz. Attached Figure Description

[0014] Figure 1 A schematic diagram of the structure of the traveling-standing-wave electrode composite loading microwave photonic receiving antenna provided by the present invention; Figure 2 This is a schematic diagram of the equivalent circuit model of the high-frequency antenna unit and traveling wave electrode of the present invention; Figure 3 This is a schematic diagram of the equivalent circuit model of the low-frequency antenna unit and standing wave electrode of the present invention. Figure 4 This is a schematic diagram of the performance equivalence method for the microwave photonic receiving antenna system of the present invention; Figure 5 This is a physical diagram of the antenna in Example 4; Figure 6 This is a diagram showing the test results of the equivalent antenna coefficient of the antenna system in Example 4; Figure 7The diagram shows the equivalent gain test results of the antenna system in Example 4.

[0015] In the diagram: 1. Printed circuit board; 2. High-frequency antenna unit; 3. Low-frequency antenna unit; 4. Traveling wave electrode matching load; 5. Lithium niobate thin film MZI electro-optic modulation chip; 6. Traveling wave electrode; 7. Standing wave electrode; 8. Bonding wire; 9. Input optical fiber; 10. Output optical fiber; 11. RF signal line output by photodetector; 12. Measured high-frequency signal; 13. Measured low-frequency signal. Detailed Implementation

[0016] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] Example 1: Antenna Structure Composition This embodiment provides a traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna, such as... Figure 1 As shown, its specific structure includes: a printed circuit board (PCB) 1, a high-frequency antenna unit 2, a low-frequency antenna unit 3, a traveling wave electrode matching load 4, a lithium niobate thin film MZI electro-optic modulation chip 5, a traveling wave electrode 6, a standing wave electrode 7, a bonding wire 8, an input optical fiber 9, and an output optical fiber 10; the dual-band combined planar patch antenna is integrated on the printed circuit board 1.

[0018] Specifically, the traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna needs to form a complete system with a laser source and a photodetector to realize its function. During operation, the light emitted by the laser source enters the electro-optic modulation chip 5 through the input optical fiber 9, and is modulated by high-frequency signal 12 and low-frequency signal 13 in the regions of the traveling-wave electrode 6 and the standing-wave electrode 7, respectively. The modulated optical signal is transmitted to the photodetector through the output optical fiber 10, and after photoelectric conversion, it is analyzed and processed by back-end instruments (such as a spectrum analyzer or oscilloscope).

[0019] In this preferred embodiment, the high-frequency antenna unit 2 adopts a Vivaldi antenna design, with a designed operating frequency band of 1 GHz to 20 GHz; the low-frequency antenna unit 3 adopts a dipole antenna design, with a designed operating frequency band of 10 MHz to 1 GHz. These two antenna units are structurally designed independently to optimize the radiation and reception performance of their respective frequency bands.

[0020] The lithium niobate thin-film traveling-standing-wave electro-optic modulation chip described in this preferred embodiment employs a lithium niobate thin-film chip 5 based on a Mach-Zehnder interferometer (MZI) structure. The chip's optical waveguide utilizes micro-nano fabrication technology to integrate traveling-wave electrodes 6 and standing-wave electrodes 7 in parallel. The two arms of the MZI are designed with asymmetrical lengths, ensuring that its static operating point is located in the linear region of the transmission characteristics (typically set to a static phase difference of π / 2). The traveling-wave electrodes 6 employ a push-pull structure to enhance modulation efficiency and suppress common-mode noise.

[0021] Specifically, the output port of the high-frequency antenna unit 2 is connected to the input terminal of the traveling wave electrode 6 via a gold wire bonding process 8. The terminal of the traveling wave electrode is connected to a matching load 4, the impedance of which is the same as the characteristic impedance of the traveling wave electrode. The voltage is kept equal to ensure that high-frequency signals are transmitted in traveling wave mode, reducing reflections. The output port of the low-frequency antenna unit 3 is also connected to the standing wave electrode 7 via gold wire bonding 8. The electrode terminal is kept open to form the maximum voltage in the low-frequency band, improving modulation sensitivity.

[0022] In this preferred embodiment, the input optical fiber 9 is a polarization-maintaining fiber used to couple a 1550nm wavelength continuous wave laser to the input optical waveguide of the modulation chip 5. The output optical fiber 10 is used to export the modulated optical signal from the chip. The input optical fiber 9, the internal optical waveguide of the chip, and the output optical fiber 10 form a cascaded optical path, ensuring that the same light beam can pass sequentially through the modulation region above the traveling wave electrode 6 and the standing wave electrode 7.

[0023] Example 2: Microwave Photonic Signal Reception Process This embodiment provides a microwave photonic signal receiving method based on the above-mentioned antenna, specifically including the following steps: S1. System Connection: Connect the continuous wave laser source to the antenna via the input fiber optic cable, and connect the photodetector to the antenna output via the output fiber optic cable. Set the laser output wavelength to 1550nm and adjust the optical power entering the modulation chip. .

[0024] S2, Optical Wave Injection: The laser source is activated to generate a continuous optical wave, which is coupled to the Mach-Zehnder interferometer (MZI) optical waveguide of the lithium niobate modulation chip via a polarization-maintaining input fiber.

[0025] S3. Signal Sensing and Loading: The dual-band antenna senses high-frequency and low-frequency electromagnetic signals in space respectively. When the signal frequency matches the polarization direction, the voltage induced by the antenna element... With the measured electric field strength The relationship is: (1); in, This represents the effective height of the antenna element used. High-frequency signals are loaded onto the traveling wave electrode via gold wire bonding, while low-frequency signals are loaded onto the standing wave electrode.

[0026] S4. Electro-optic modulation and signal conversion: The voltage applied to the electrodes creates a modulation electric field between the electrodes. Based on the linear electro-optic effect (Pockels effect) of lithium niobate, this electric field causes a change in the refractive index of the optical waveguide. : (2); in, The effective refractive index of the optical waveguide, This represents the electro-optic coefficient of lithium niobate. When a push-pull electrode structure is used, the electric fields of the upper and lower arms of MZI are in opposite directions, resulting in refractive index changes of equal magnitude but opposite sign, thus introducing an optical phase difference between the two arms. : (3); in, The wavelength of light This represents the length of the electrode modulation region.

[0027] MZI employs an asymmetric arm length design, with its static operating point set at the orthogonal point ( After the two beams are interfered with, the phase modulation is converted into intensity modulation, and the output optical power... for: (4); in, Let be the optical insertion loss of the device. Substitute into... ,get: (5); Under the condition of small signal modulation When the above equation is true, it can be simplified to a linear relationship: (6); S5. Photoelectric Conversion: The modulated optical signal is transmitted through the output optical fiber to the photodetector and converted into an electrical signal. : (7); in, For photoelectric conversion efficiency, This represents the responsivity of the photodetector.

[0028] S6. Signal Processing and Information Extraction: [This section appears to be incomplete and requires further context.] Perform DC filtering to extract the electric field strength. proportional AC signal components : (8); By amplifying, sampling, and analyzing the signal, the intensity and frequency of the measured electromagnetic field in space can be accurately reproduced, thus achieving high linearity microwave photon signal reception.

[0029] Example 3: Analysis of Antenna Working Principle This embodiment elaborates in detail the working principle of the traveling-standing-wave electrode composite loaded microwave photonic receiving antenna in the high and low frequency bands and the equivalent evaluation method of system performance. It quantitatively explains its ultra-wideband and high-sensitivity characteristics through mathematical models.

[0030] 3.1 Working principle of high-frequency antenna unit: like Figure 2 The equivalent circuit model of the high-frequency antenna element and traveling wave electrode is shown. Among them, This indicates that the voltage generated by the high-frequency antenna element inducing the measured electric field satisfies... , The effective height of the high-frequency antenna element. The electric field strength being measured; This refers to the input impedance of the high-frequency antenna unit. The characteristic impedance of the traveling wave electrode; The electrode length is represented by ; the ab and cd terminals represent the input and output terminals of the traveling wave electrode, respectively. To match the load impedance; This refers to the input impedance as seen from terminals ab. and These are the incident voltage and the reflected voltage, respectively.

[0031] According to transmission line theory, the input impedance of the traveling wave electrode at end ab can be expressed as: (9): in, Let be the propagation constant of the electrical signal on the electrode. The attenuation constant (unit: Np / m) Let be the phase shift constant (unit: rad / m). Assuming the y-axis represents the signal propagation direction, the voltage at any position y on the electrode can be expressed as the superposition of the incident and reflected waves:

[0032]

[0033]

[0034] (10); in, The reflection coefficient. The input voltage at port ab. It can be represented as: (11); Substituting equations (9) and (10) into equation (11), we get: (12); To achieve speed matching and maintain high-frequency modulation efficiency in electro-optic modulation, microwaves need to propagate in a traveling wave manner. Therefore, impedance matching is required at the electrode terminals, i.e., ... .at this time, , Equation (12) can be simplified to: (13); Inter-electrode traveling wave electric field intensity Represented as: (14); in, The electrode gap is represented by the average value of the voltage peak distribution. Since the time it takes for light to travel through the waveguide is extremely short, the average electric field strength can be approximated by the average value of the voltage peak distribution. (15); This electric field causes a change in the refractive index of the optical waveguide: (16); The two arms of the MZI are subjected to electric fields in opposite directions, resulting in opposite signs of refractive index changes. The refractive index of lithium niobate waveguide, Its electro-optic coefficient. After modulating a waveguide of length L, the two beams generate a phase difference: (17); in Where is the wavelength of the optical signal. To maintain the MZI in the linear region, its two arms are preset with a static phase difference of π / 2, and the total phase difference is . Amplitude modulation is achieved through interference of the two optical paths, resulting in an output optical power of: (18); in, For optical insertion loss, This refers to the input optical power.

[0035] The modulated optical signal is transmitted via optical fiber with low loss to a photodetector, where it is converted into current. (19); This represents the photoelectric conversion efficiency. After passing through a transimpedance amplifier (gain R), the output voltage is: (20); In the linear modulation region (i.e., π / 2) <π / 8), can be approximated as: (twenty one); After filtering out the DC component, the result is the same as... Proportional AC voltage signal: (twenty two); Finally, substituting equation (15) into equation (22) yields: (twenty three); Therefore, the antenna coefficient in the high-frequency band It can be represented as: (twenty four); 3.2 Working principle of low-frequency antenna unit like Figure 3 The equivalent circuit model of the low-frequency antenna element and standing wave electrode is shown. Among them, This represents the voltage generated by the induced electric field in the dipole antenna element. The input impedance of the antenna element. Let be the equivalent capacitance of the standing wave electrode. The voltage across the standing wave electrode can be expressed as: (25); in, The frequency of the signal being measured. The lower the frequency, the higher the voltage on the electrodes. The closer to the induced voltage of the antenna element . Effective height of antenna element The relationship between the electric field strength E and the electric field strength E is: (26); At low frequencies, the effect of electro-optic velocity mismatch on modulation efficiency is negligible. (27); Where d is the electrode spacing. This change causes a phase difference between the two arms of the MZI: (28); Based on the foregoing derivation, the output voltage of the photodetector in the low-frequency operating range is: (29); After filtering out the DC component, the AC output signal is: (30); Therefore, the antenna coefficient in the low-frequency band It can be represented as: (31).

[0036] Example 4: Effect Verification and Test Results 4.1 System Performance Equivalence Method Based on the optoelectronic collaborative working mechanism of the microwave photonic receiving antenna system, its actual performance evaluation requires the construction of an integrated system model including a laser source, a microwave photonic receiving antenna, and a photodetector. Due to the introduction of non-thermal noise components from the light source and photodetector, the overall noise level of this system is higher than that of traditional antenna receiving systems. However, the core performance indicators of antennas, "antenna coefficient and gain," are only related to the received signal power and are independent of system noise. Therefore, directly testing the antenna coefficient or gain of this system cannot achieve a fair comparison with traditional antennas. This embodiment establishes a performance evaluation method based on signal-to-noise ratio equivalence.

[0037] In electromagnetic signal receiving systems, the received signal-to-noise ratio (SNR) is a key parameter for measuring system sensitivity. If a microwave photonic receiving antenna system and a traditional antenna have equal SNR under the same field strength, they can be considered to have equivalent antenna coefficients and gain performance; if there is a difference, it needs to be compensated for by the difference in system noise floor. Based on this principle, this invention proposes... Figure 4 The equivalent test method shown is as follows: using the noise floor N_0 (-174dBm / Hz) of the spectrum analyzer as the standard for traditional antenna receiver noise, and assuming the actual noise floor of the microwave photonic receiver antenna system is N, and the measured signal power is P_s, then the system equivalent power P_s^' can be expressed as: (32); This equivalent power can be used to further calculate antenna coefficients and gain parameters that can be directly compared with traditional antennas.

[0038] The equivalent antenna coefficient AF of a microwave photonic receiving antenna system is defined in the same way as that of a conventional antenna, namely: (33); Among them, the system's equivalent output voltage is composed of the equivalent power. It is calculated that the antenna coefficient is usually tested using the standard field method, which involves establishing a standard electromagnetic environment with a known field strength in a microwave anechoic chamber, receiving the signal through the system under test and measuring its output voltage, and finally calculating the antenna coefficient according to equation (33). The flatter the frequency response curve of the antenna coefficient, the better the broadband characteristics of the antenna in that frequency band, and the smaller the time-domain waveform distortion when receiving broadband signals.

[0039] Traditional antenna gain is defined as the ratio of radiated power in a specified direction to the radiated power of an omnidirectional antenna in the same direction (unit: dBi). Since a microwave photonic receiving antenna system is only used for receiving, its equivalent gain needs to be converted using the equivalent antenna coefficient, as follows: (34); 4.2 Performance Testing To verify the performance of the antenna of this invention, the following was fabricated: Figure 5The image shows a physical prototype of a traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna. The antenna employs a Vivaldi antenna structure for the high-frequency band and a dipole antenna structure for the low-frequency band, integrating both onto the same lithium niobate thin-film electro-optic modulation chip using gold wire bonding. The overall antenna dimensions are 60mm × 250mm × 2mm.

[0040] Based on the standard field test system, a systematic test and evaluation of the equivalent antenna coefficient and gain characteristics of the microwave photonic receiving antenna system proposed in this embodiment was conducted. The tests below 1 GHz were performed in a TEM chamber, while the 1–20 GHz band was tested using a compact field test system. The test system used a 1550 nm wavelength continuous laser source and a 20 GHz bandwidth photodetector, with the optical power entering the photodetector being 9.5 dBm.

[0041] Figure 6 The frequency response characteristics of the equivalent antenna coefficient of this antenna system were demonstrated. Test results show that within the 10MHz–20GHz frequency band, the antenna coefficient is no higher than 55dB / m, and the relative bandwidth ratio reaches 2000:1, exhibiting excellent ultra-wideband operating characteristics.

[0042] Figure 7 The equivalent gain frequency response curve of the antenna system is shown. Test data shows that within the 300MHz–20GHz frequency band, its equivalent gain is no less than 0dBi, the relative bandwidth ratio is 66.7:1, and it achieves a peak gain of 9.3dBi at 8.5GHz.

[0043] Test results show that the traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna described in this invention achieves an antenna coefficient of no more than 55 dB / m in the 10 MHz–20 GHz ultra-wideband and an equivalent gain better than 0 dBi in the 300 MHz–20 GHz ultra-wideband, with bandwidth characteristics significantly superior to traditional single-structure ultra-wideband antennas. Simultaneously, through an optoelectronic synergy mechanism, a significant improvement in the sensitivity of traditional optical sensors is achieved while maintaining a millimeter-scale compact structure, effectively resolving the inherent contradiction between broadband and high sensitivity. Furthermore, due to the use of an optical transmission mechanism, the system's high-frequency transmission loss in the 18–20 GHz band is reduced by approximately 1.5 dB / m compared to electronic links.

[0044] This embodiment fully verifies the feasibility and superiority of the described traveling / standing wave electrode composite-loaded microwave photonic receiving antenna. Through the heterogeneous integration of the dual-band antenna and traveling / standing wave electrodes, as well as optical domain modulation and signal synthesis mechanisms, the contradiction between broadband and high sensitivity is effectively resolved, achieving ultra-wideband, high-sensitivity, and strong anti-interference electromagnetic signal reception.

[0045] It should be noted that, within the scope of this invention, the high-frequency antenna unit can also be in the form of a helical antenna, a tapered slot antenna, etc., and the low-frequency antenna unit can be in the form of a monopole, a dipole, etc. The layout of the traveling wave and standing wave electrodes can also be adjusted according to the process.

[0046] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A microwave photonic receiving antenna with a traveling-standing wave electrode composite loading, characterized in that, include: A dual-band combined planar patch antenna, comprising a high-frequency antenna element and a low-frequency antenna element, used to receive electromagnetic signals of different frequency bands respectively; The lithium niobate thin film traveling-standing wave electro-optic modulation chip is based on the structure of a Mach-Zehnder interferometer, and its optical waveguide integrates traveling wave electrodes and standing wave electrodes. An input optical fiber is used to couple the optical signal from the continuous wave laser source to the electro-optic modulation chip; An output optical fiber is used to export the modulated optical signal from the electro-optic modulation chip to the photodetector. The radio frequency output port of the high-frequency antenna unit is connected to the input terminal of the traveling wave electrode via gold wire bonding, and the terminal of the traveling wave electrode is connected to a matching load. The radio frequency output port of the low-frequency antenna unit is connected to the standing wave electrode via gold wire bonding, and the terminal of the standing wave electrode is set to open circuit. The input optical fiber, the optical waveguide of the electro-optic modulation chip, and the output optical fiber constitute a first-order optical path, enabling a single light wave to pass sequentially through the modulation regions corresponding to the traveling wave electrode and the standing wave electrode, and be modulated by high-frequency and low-frequency radio frequency signals loaded thereon, respectively.

2. The traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna according to claim 1, characterized in that, The two interferometer arms of the Mach-Zehnder interferometer structure have asymmetrical lengths so that the static operating point of the interferometer is located in the linear region of its transmission characteristics.

3. The traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna according to claim 1, characterized in that, The traveling wave electrode has a push-pull electrode structure.

4. The traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna according to claim 1, characterized in that, The input optical fiber is a polarization-maintaining fiber.

5. The traveling-standing-wave electrode composite-loaded microwave photonic receiving antenna according to claim 1, characterized in that, The high-frequency antenna element is one of a Vivaldi antenna, a helical antenna, or a tapered slot antenna; the low-frequency antenna element is one of a vibrating antenna, a monopole antenna, or a dipole antenna.

6. The microwave photonic signal receiving method using a microwave photonic receiving antenna with a traveling-standing wave electrode composite loading according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Connect the continuous wave laser source to the antenna through the input optical fiber, and connect the photodetector to the antenna through the output optical fiber; S2. Start the laser source to generate continuous light waves and inject them into the electro-optic modulation chip; S3. Induction of spatial electromagnetic signals through the dual-band combined planar patch antenna, and loading of high-frequency signals onto traveling wave electrodes and low-frequency signals onto standing wave electrodes; S4. The light wave is sequentially passed through the modulation regions corresponding to the traveling wave electrode and the standing wave electrode. The phase of the light wave is modulated based on the lithium niobate electro-optic effect to generate a modulated light signal containing dual-frequency information. S5. The modulated optical signal is transmitted to the photodetector via the output optical fiber and converted into an electrical signal; S6. Process the electrical signal to extract information related to the spatial electromagnetic field strength.

7. The microwave photonic signal receiving method according to claim 6, characterized in that, The high-frequency antenna unit operates in the frequency band of 1 GHz to 20 GHz, and the low-frequency antenna unit operates in the frequency band of 10 MHz to 1 GHz.

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