A time slot excitation calibrated radiation source field intensity coherent synthesis method and system

Abstract

The present application relates to a kind of time slot excitation calibration radiation source field intensity coherent synthesis method and system, can promote the radiation field power density of target position obtains the high peak microwave field intensity of local area, for target object withstand field intensity examination and other research applications, solve the technical problem that existing vacuum electronics device needs to be attached high-voltage pulse generation device to can strong electromagnetic radiation, and its system is more complex.The time slot excitation calibration radiation source field intensity coherent synthesis method, through excitation signal excitation microwave radiation source, through specific timing strobe each microwave radiation source, to target position radiation.The present application also provides time slot excitation calibration radiation source field intensity coherent synthesis system, including frequency synthesis, N microwave radiation source arranged in any way, measuring antenna and receiver.Can carry out compensation excitation signal subsequently, realize the coherent enhancement of target position radiation field.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of time slot excitation calibration radiation source field intensity coherent synthesis method and system, can promote the radiation field power density of target position, obtain the high peak microwave field intensity of local area, for target object withstand field intensity examination and other research applications. BACKGROUND

[0002] With the rapid development of microwave technology, in microwave energy transmission and microwave energy industrial applications and other high power microwave technology field, often need to obtain as high as possible microwave power.The output power of single microwave radiation source is limited by the power capacity of device itself, using multiple microwave radiation source array in space power synthesis is an effective means that can greatly improve system transmission power, promote the radiation field power density of target position.

[0003] At present, klystron and other vacuum electronic devices are often used as microwave radiation source in laboratory, to generate strong electromagnetic radiation through power synthesis, for target withstand field intensity examination research.But, vacuum electronic devices need to be attached to high-voltage pulse generating device to generate strong electromagnetic radiation, and its system is relatively complex.

[0004] In recent years, semiconductor microwave device materials and process technology has made breakthrough progress, and the output power of semiconductor microwave device is getting higher and higher, and through the improvement of materials, process and design, it has the potential to further improve the output power.Semiconductor microwave device belongs to amplification system, and it is easier to realize waveform control, time difference control and phase difference control of radiation field signal when power synthesis is carried out. SUMMARY

[0005] The purpose of the present application is to solve the technical problems that existing vacuum electronic devices need to be attached to high-voltage pulse generating device to generate strong electromagnetic radiation, and its system is relatively complex, and provide a kind of time slot excitation calibration radiation source field intensity coherent synthesis method and system, which can promote the radiation field power density of target position, obtain the high peak microwave field intensity of local area, and realize the coherent enhancement of radiation field at target position.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is:

[0007] A kind of time slot excitation calibration radiation source field intensity coherent synthesis method, which is characterized by comprising the following steps:

[0008] S1, generate N excitation signals, N is greater than or equal to 1 positive integer;

[0009] The on-off time gate of the N excitation signals satisfies the following formula

[0010] Gate k(τ)=Gate1(τ-T 1k )

[0011] In the formula: Gate k (τ) represents the gating time gate for the k-th excitation signal, k∈[2,N]; T 1k τ is the time difference between the gating time gate of the k-th excitation signal and the gating time gate of the 1st excitation signal; τ is time.

[0012] S2, N excitation signals are respectively input into N microwave radiation sources, and the N microwave radiation sources amplify the N excitation signals and emit N radiation signals to the target position;

[0013] S3, N radiation signals are received by the measuring antenna at the target location in step S2. The measuring antenna emits N radiation field signals, which are then received by the receiver.

[0014] S4, Define the propagation of the excitation signal from the microwave radiation source to the target location as a transmission channel; calculate the time difference and phase difference of the N transmission channels respectively;

[0015] S5. Based on the time difference and phase difference obtained in step S4, compensate for the time difference and phase difference of the N excitation signals respectively, so that the amplitude and phase of the radiation field signals of the N transmission channels are consistent when they arrive at the target position, and realize the coherent synthesis of the radiation field at the target position.

[0016] Furthermore, the N excitation signals in step S1 are generated using frequency synthesis, specifically as follows:

[0017]

[0018] In the formula, S 1A (τ), ..., S NA (τ) represents the 1st, 2nd, ..., Nth excitation signals generated by the frequency synthesizer; Gate1(τ), ..., Gate N (τ) represents the gating time gate corresponding to the 1st, 2nd, ..., Nth excitation signals of the frequency synthesizer; f c The center frequency of the frequency synthesizer; It is the equivalent phase of the up-conversion of the excitation signal.

[0019] Furthermore, in step S2, the specific excitation signal sensed by each microwave radiation source is as follows:

[0020] S 1B (τ)=S 1A (τ-T 1A ),

[0021] S 2B (τ)=S 2A (τ-T2A ), ...

[0023] S NB (τ)=S NA (τ-T NA )

[0024] In the formula, S 1B (τ), ..., S NB (τ) represents S 1A (τ), ..., S NA (τ) N signals that reach the microwave radiation source after propagation; T 1A ,T 2A ,...,T NA This represents the propagation time difference of N excitation signals from the frequency synthesizer to each microwave radiation source.

[0025] Furthermore, in step S3, the N radiated signals received by the measuring antenna at the target location are specifically as follows:

[0026] S 1C (τ)=S 1B (τ-T 1B ),

[0027] S 2C (τ)=S 2B (τ-T 2B ), ...

[0029] S NC (τ)=S NB (τ-T NB )

[0030] In the formula, S 1C (τ), ..., S NC (τ) represents S 1B (τ), ..., S NB (τ) N signals that reach the measuring antenna after passing through the microwave radiation source; T 1B ,T 2B ,...,T NB This represents the time difference between the propagation of N radiation signals from the microwave radiation source to the target location.

[0031] Furthermore, in step S3, the N radiation field signals received by the receiver are specifically as follows:

[0032]

[0033] In the formula, S 1D (τ), ..., S ND (τ) represents S 1C(τ), ..., S NC (τ) N signals that propagate through the measuring antenna and reach the receiver; T L Let be the propagation time difference of N radiation field signals from the measuring antenna to the receiver.

[0034] N radiation field signals satisfy the following equation

[0035] Gate k (τ-T kA -T kB -T L )·Gate i (τ-T iA -T iB -T L ) = 0

[0036] In the formula: Gate k (τ-T kA -T kB -T L )·Gate i (τ-T iA -T iB -T L ) represents the pulse envelope signal of the k-th microwave radiation source and the i-th microwave radiation source, where k ≠ i and i ∈ [2, N]; T kA T represents the propagation time difference of the excitation signal from the frequency synthesizer to the k-th microwave radiation source; kB T represents the time difference in the propagation of the radiated signal from the k-th microwave radiation source to the target location; iA T represents the propagation time difference of the excitation signal from the frequency synthesizer to the i-th microwave radiation source; iB This represents the time difference in which the radiated signal travels from the i-th microwave radiation source to the target location.

[0037] Furthermore, step S3 also includes the receiver sequentially amplifying, filtering, down-converting, and digitally sampling the signal via an RF front-end to obtain a complex baseband signal.

[0038]

[0039] ...

[0041]

[0042] In the formula, S 1E (τ), ..., S NE (τ) represents S 1D (τ), ..., S ND (τ) is the signal obtained after compensating for the time and phase differences; j is the imaginary unit.

[0043] The common phase of N radiated signals

[0044]

[0045] This is the down-conversion reference phase for the receiver.

[0046] Furthermore, step S4 specifically includes:

[0047] 4.1) Calculate the time for each radiation field signal.

[0048]

[0049] In the formula, Let I be the time of the k-th radiation field signal; Pulsefront{} represents taking the pulse leading edge of the k-th radiation field signal; abs() represents taking the complex amplitude of the k-th radiation field signal; I k (τ) represents the in-phase channel of the orthogonal down-conversion of the k-th radiation field signal; Q k (τ) represents the orthogonal phase channel of the k-th radiation field signal;

[0050] 4.2) Calculate the phase of the radiation field signal

[0051]

[0052] In the formula, Let be the phase of the k-th radiation field signal;

[0053] 4.3) Keep the time of the first microwave radiation source unchanged, and adjust the additional time setting for the kth microwave radiation source according to step 4.1).

[0054]

[0055] In the formula, This represents the additional time difference from the kth to the Mth microwave radiation source, with the time of the first microwave radiation source as the reference. The time of the first radiation field signal is represented by M∈[2,N];

[0056] 4.4) Keeping the phase of the first microwave radiation source unchanged, add a phase setting to the kth microwave radiation source according to step 4.2).

[0057]

[0058] In the formula, This represents the additional phase difference between the kth to Mth microwave radiation sources, with the phase of the first microwave radiation source as the reference. This indicates the phase of the first radiation field signal; This represents the phase of the k-th radiation field signal.

[0059] Furthermore, step 5 specifically includes:

[0060] The time difference and phase difference of N excitation signals are compensated by using the gating switch of the frequency synthesizer and the phase shifter at the front end of the microwave radiation source:

[0061]

[0062]

[0063] ...

[0065]

[0066] After compensation, N excitation signals excite the microwave radiation source to generate N radiation signals. The amplitude and phase difference of these signals are consistent at the target location. The radiation field signal formed at the target location is specifically as follows:

[0067]

[0068] In the formula: S 1A' (τ), ..., S NA' (τ) represents the N excitation signals generated by the frequency synthesizer after compensating for the time and phase differences; S 1C' (τ), ..., S NC' (τ) represents S 1A' (τ), ..., S NA' (τ) N signals that arrive at the receiver after propagation; This represents the additional time difference from the second, ..., Nth microwave radiation sources to the Mth microwave radiation source, with the time difference of the first microwave radiation source as the reference. This represents the additional phase difference between the second, ..., Nth microwave radiation sources up to the Mth microwave radiation source, with the phase of the first microwave radiation source as the reference.

[0069] Meanwhile, the present invention also provides a coherent synthesis system for radiation source field strength of time slot excitation calibration, which is used to realize the above-mentioned coherent synthesis method for radiation source field strength of time slot excitation calibration. Its special feature is that it includes a frequency synthesizer, N microwave radiation sources arranged in an arbitrary manner, a measurement antenna and a receiver.

[0070] The frequency synthesizer is used to generate and output N different excitation signals, which are then phase-shifted and used as excitation signals for N microwave radiation sources.

[0071] The N excitation signal output terminals of the frequency synthesizer are connected to the excitation signal input terminals of N microwave radiation sources arranged in any manner through phase shifters. The frequency time reference signal output terminal of the frequency synthesizer is connected to the receiver to ensure phase locking between the receiver and the frequency synthesizer.

[0072] Each microwave radiation source receives its own excitation signal, amplifies it, generates a radiation signal, and radiates the radiation signal to the target location, forming a radiation field signal at the target location.

[0073] The measuring antenna is located at the target position and connected to the receiver; the measuring antenna is used to sense and measure the radiation field signal and transmit the radiation field signal to the receiver.

[0074] The receiver is used to receive radiation field signals and perform separation processing to obtain excitation signals corresponding to each microwave radiation source. It calculates the time difference and phase difference between the excitation signals of each frequency synthesizer and the target position. Based on the calculated time difference and phase difference, the gating time gate of the frequency synthesizer excitation signal is adjusted to achieve coherent synthesis of radiation source field strength for time slot excitation calibration.

[0075] Furthermore, it also includes a radio frequency (RF) front-end, which includes a variable attenuator, a limiting low-noise amplifier, a bandpass filter, a downconversion module, a gain control module, an AD sampling module, a digital pre-selection filter, and a digital quadrature downconversion module connected in sequence.

[0076] The measuring antenna is connected to a variable attenuator; the receiver is connected to a digital quadrature downconversion module.

[0077] A variable attenuator is used to adjust the power of the radiation field signal;

[0078] A limiting low-noise amplifier is used to amplify the radiation field signal processed by the variable attenuator;

[0079] Bandpass filters are used to filter amplified radiation field signals;

[0080] The downconversion module is used to downconvert the filtered radiation field signal;

[0081] The gain control module is used to perform automatic gain control on the down-converted radiation field signal;

[0082] The AD sampling module is used to convert the radiation field signal after automatic gain control into a digital signal.

[0083] Digital pre-selection filtering is used to suppress image interference before quadrature downconversion of digital signals;

[0084] Digital quadrature downconverter modules are used to convert digital signals into corresponding complex baseband signals.

[0085] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0086] (1) This invention excites each distributed microwave radiation source with an excitation signal, and selects each microwave radiation source through a specific timing sequence to radiate towards the target location. The radiation signals of each microwave radiation source will arrive at the target location according to a specific timing sequence. By receiving the radiation signals at the target location and calculating the time difference and phase difference of each radiation signal arriving at the target location, the excitation signal can be compensated in the subsequent process, thereby changing the time and phase of the excitation signals of each microwave radiation source, realizing coherent synthesis, and thus coherently enhancing the radiation field at the target location.

[0087] (2) The system of the present invention compensates for the time difference and phase difference between the radiation signals of each microwave radiation source at the target position by changing the time and phase of the excitation signals of each microwave radiation source, so that the amplitude and phase of each radiation signal at the target position are consistent, thereby achieving coherent enhancement of the radiation field at the target position. The method of changing the time can be achieved by modulating the time difference of the pulse (excitation signal), and the phase can be achieved by a phase shifter at the front end of the microwave source.

[0088] (3) The present invention generates strong electromagnetic radiation by means of field strength coherent synthesis. Compared with the method of generating strong electromagnetic radiation by using vacuum electronic devices as microwave radiation sources, the method of the present invention is simpler and more flexible in configuration.

[0089] (4) The method of the present invention is used to increase the power density of the radiation field at the target location and obtain the peak value of the microwave field strength in the local area. It can be used for research applications such as the field strength tolerance test of the target object. Attached Figure Description

[0090] Figure 1 A schematic diagram of the constructed radiation source field strength coherent synthesis system.

[0091] Figure 2 This is a schematic diagram illustrating the implementation of time-domain gating logic using frequency synthesizers in an embodiment of the radiation source field strength coherent synthesis method for time-slot excitation calibration of the present invention.

[0092] Figure 3 This is a schematic diagram of the time slot of a microwave radiation source transmitting a radiation signal, as shown in an embodiment of the coherent synthesis method for radiation source field strength of time slot excitation calibration according to the present invention.

[0093] Figure 4 This is a schematic diagram of adjusting the excitation signal at the front end of a microwave radiation source in an embodiment of the coherent synthesis method for radiation source field strength of time slot excitation calibration according to the present invention. Detailed Implementation

[0094] The design concept of this invention is:

[0095] Taking advantage of the stable amplitude and phase difference of the amplification system of microwave radiation sources, a phase difference and time difference measurement system is constructed to receive the radiation field signals formed at the target location by the radiation field signals emitted by each microwave radiation source. Through signal processing, the time difference and phase difference of the radiation signals emitted by each microwave radiation source to reach the target location are calculated.

[0096] To achieve the measurement of the aforementioned time and phase differences, this invention designs a time-slot excitation signal and excites each microwave radiation source separately through corresponding timing gating. The radiation field signals from each microwave radiation source arrive at the target position according to a specific timing sequence. The radiation field signals are received at the target position, and the time and phase differences of each microwave radiation source arriving at the target position are calculated through signal processing. By changing the time and phase differences of the excitation signals of each microwave radiation source, the time and phase differences of the radiation field signals arriving at the target position are compensated, ensuring that the amplitude and phase difference of the radiation field signals from each microwave radiation source are consistent at the target position, thus achieving coherent enhancement of the radiation field at the target position. The method of changing the time difference can be achieved by altering the pulse time difference of the modulation excitation signal, and the phase difference can be changed by using a phase shifter at the front end of the microwave radiation source.

[0097] like Figure 1 As shown, the invention also provides a time-slot excitation calibration radiation source field strength coherent synthesis system, including a frequency synthesizer, N microwave radiation sources arranged in an arbitrary manner, a measuring antenna, and a receiver; achieving high field strength at a certain target location.

[0098] The N excitation signal outputs of the frequency synthesizer are connected to the excitation signal inputs of N microwave radiation sources arranged in an arbitrary manner via phase shifters. The frequency and time reference signal output of the frequency synthesizer is connected to the receiver to ensure phase locking between the receiver and the frequency synthesizer. The measuring antenna is located at the target position and connected to the receiver. The frequency synthesizer generates and outputs N different excitation signals, which are then phase-shifted and used as excitation signals for the N microwave radiation sources. Each microwave radiation source receives its own excitation signal, amplifies it, and generates a radiation signal, which is then radiated to the target position, forming a radiation field signal at the target position. The measuring antenna senses and measures the radiation field signal and transmits it to the receiver. The receiver receives the radiation field signal, performs separation processing to obtain the excitation signal corresponding to each microwave radiation source, and calculates the time difference and phase difference between the excitation signals of each frequency synthesizer reaching the target position. Based on the calculated time difference and phase difference, the gating time gate of the frequency synthesizer excitation signal is adjusted to achieve coherent synthesis of the radiation source field strength for time-slot excitation calibration.

[0099] In this embodiment, an RF front-end is also provided between the measurement antenna and the receiver. The RF front-end includes a variable attenuator, a limiting low-noise amplifier, a bandpass filter, a downconversion module, a gain control module, an AD sampling module, a digital pre-selection filter, and a digital quadrature downconversion module connected in sequence. The measurement antenna is connected to the variable attenuator, and the receiver is connected to the digital quadrature downconversion module.

[0100] The frequency synthesizer generates and outputs N different excitation signals, which serve as excitation signals for N microwave radiation sources. Each microwave radiation source receives its own excitation signal, amplifies it, and generates a radiation signal, which is then radiated to the target location, forming a radiation field signal at the target location. The measuring antenna senses and measures the radiation field signal and transmits it to a variable attenuator. The variable attenuator adjusts the power of the radiation field signal. The limiting low-noise amplifier amplifies the radiation field signal processed by the variable attenuator. The bandpass filter filters the amplified radiation field signal. The down-conversion module down-converts the filtered radiation field signal. The gain control module performs automatic gain control on the down-converted radiation field signal. The AD sampling module converts the automatically gain-controlled radiation field signal into a digital signal. The digital pre-selection filter suppresses image interference before quadrature down-conversion. The digital quadrature down-conversion module converts the digital signal into a corresponding complex baseband signal.

[0101] First, physical channels for time synchronization and phase locking need to be established between the various microwave radiation sources to control the time and phase of the radiation signals from each source, thereby achieving coherent enhancement at specific locations. The system constructed in this invention consists of N microwave radiation sources distributed at different locations, a frequency synthesizer, a receiver, and a measurement antenna. The frequency time reference signal output terminal of the frequency synthesizer is connected to the receiver to ensure phase locking between the receiver and the frequency synthesizer. The N excitation signal output terminals of the frequency synthesizer are respectively connected to the excitation signal input terminals of N microwave radiation sources arranged in an arbitrary manner through phase shifters. The measuring antenna is used to sense and measure the radiation field signal and transmit the radiation field signal to the receiver. The measuring antenna is located at the target position and connected to the receiver. The frequency synthesizer is used to generate and output N different excitation signals, which are phase-shifted and used as excitation signals for the N microwave radiation sources. Each microwave radiation source receives its own excitation signal, amplifies it, generates a radiation signal, and radiates the radiation signal to the target position, forming a radiation field signal at the target position. The receiver is used to receive the radiation field signal, perform separation processing, obtain the excitation signal corresponding to each microwave radiation source, and calculate the time difference and phase difference of the excitation signal of each frequency synthesizer reaching the target position.

[0102] In this embodiment, the receiver is connected in sequence to a variable attenuator, a limiting low-noise amplifier, a bandpass filter, a downconversion module, a gain control module, an AD sampling module, a digital pre-selection filter, and a digital quadrature downconversion module;

[0103] The measuring antenna is connected to a variable attenuator for power adjustment of the radiated field signal; the frequency and time reference signal output of the frequency synthesizer is connected to the reference signal input of the receiver; the limiting low-noise amplifier amplifies the radiated field signal processed by the variable attenuator; the bandpass filter filters the amplified radiated field signal; the down-conversion module down-converts the filtered radiated field signal; the gain control module performs automatic gain control on the down-converted radiated field signal; the AD sampling module converts the automatically gain-controlled radiated field signal into a digital signal; the digital pre-selection filter suppresses image interference before quadrature down-conversion of the digital signal; and the digital quadrature down-conversion module converts the digital signal into the corresponding complex baseband signal.

[0104] The excitation signal for each microwave radiation source is generated using a frequency synthesizer. It is required that the excitation signal for each microwave radiation source be generated independently and that the waveform be fully controllable. There are no special constraints on the deployment location of the individual microwave radiation sources. Figure 1 As can be seen, the multiple microwave radiation sources of this invention are arranged in any manner. The frequency synthesizer signal output terminal is electrically connected to the signal input terminals of the N microwave radiation sources arranged in any manner; the receiving antenna is located at the target position and is electrically connected to the receiver. The receiver processes the radiation field signal at the target position and calculates the time difference and phase difference between the radiation signals emitted by each microwave radiation source and the arrival at the target position.

[0105] The method for coherent synthesis of radiation source field strength using time-slot excitation calibration according to the present invention will be described in detail below with reference to the accompanying drawings:

[0106] like Figure 2 As shown, the frequency synthesizer generates N different excitation signals, where N is a positive integer greater than or equal to 1;

[0107]

[0108] Where τ represents time; S 1A (τ), ..., S NA (τ) represents the excitation signal generated by the frequency synthesizer for the corresponding 1st, 2nd, and 3rd microwave radiation sources; Gate1(τ), ..., Gate N (τ) represents the gating time gate signal for the excitation signal generated by the frequency synthesizer for the 1st, 2nd, ..., Nth microwave radiation sources; f c The center frequency of the frequency synthesizer; It is the up-conversion equivalent phase of the frequency synthesizer.

[0109] Choose the gating time gates for each time domain of the frequency synthesizer to satisfy equation (2):

[0110] Gate k (τ)=Gate1(τ-T 1k ), k=2,3,...,N (2)

[0111] In the formula, Gate k (τ) represents the gating time gate of the excitation signal generated by the frequency synthesizer for the k-th microwave radiation source, k∈[2,N]; T 1k It is the time difference between the gating time gate of the k-th microwave radiation source and the gating time gate of the 1st microwave radiation source.

[0112] After receiving the excitation signal, each microwave radiation source amplifies the excitation signal and radiates the amplified excitation signal to the target location. In this embodiment, for ease of distinction, the signal radiated by the microwave radiation source is denoted as the radiation signal, and the signal at the target location is denoted as the radiation field signal. Because the excitation signal generated by the frequency synthesizer will have different time differences when it is transmitted to each microwave radiation source:

[0113]

[0114] In the formula, S 1B (τ), ..., S NB (τ) represents S 1A (τ), ..., S NA (τ) N signals that reach the microwave radiation source after propagation, T 1A ,T 2A ,...,T NA This represents the propagation time difference between the N excitation signals generated by the frequency synthesizer and their arrival at each microwave radiation source.

[0115] like Figure 3 As shown, the microwave radiation source amplifies the signal and radiates it to the target location. Since the distances between each microwave radiation source and the target location are different, their respective radiation signals will also have different signal propagation time differences.

[0116]

[0117] In the formula, S 1C (τ), ..., S NC (τ) represents S 1B (τ), ..., S NB (τ) N signals that reach the measuring antenna after passing through the microwave radiation source, T 1B ,T 2B ,...,T NBThis represents the time difference between the propagation of N radiation signals from the microwave radiation source to the target location.

[0118] Finally, the measuring antenna located at the target position senses and measures the radiated field signal and transmits it to the radio frequency front end. In this embodiment, the principle for selecting the measuring antenna is to use an electrically small measuring antenna to reduce the influence of the measuring antenna itself on the propagation of the electromagnetic field. At the same time, considering that the arrival directions of the various microwave radiation sources relative to the target position differ in this invention, a wide-angle receiving method should be used when selecting the measuring antenna. If necessary, the phase difference pattern of the measuring antenna can be calibrated into the system.

[0119] After the RF front-end modulates the level of the radiated field signal, it can be transmitted to the receiver via an RF cable. For situations where the target location and the receiver are far apart, the RF signal can be modulated using optical signals and transmitted through optical fiber. The propagation time difference of the radiated field signal from the receiving measurement antenna to the receiver is perfectly consistent. Therefore, the signal arriving at the receiver from the aforementioned radiated field signal is:

[0120]

[0121] In the formula, S 1D (τ), ..., S ND (τ) represents S 1C (τ), ..., S NC (τ) N signals that propagate through the measuring antenna and reach the receiver, T L Let be the propagation time difference of N radiation field signals from the measuring antenna to the receiver.

[0122] The propagation time difference of the radiated field signal from the receiving antenna to the receiver is consistent for all microwave radiation sources. To ensure that the various radiated field signals do not interfere with each other when they reach the receiver, the radiated field signals must satisfy the following equation:

[0123] Gate k (τ-T kA -T kB -T L )·Gate i (τ-T iA -T iB -T L )=0,k≠i (6)

[0124] In the formula, Gate k (τ-T kA -T kB -T L )·Gate i (τ-T iA -T iB -TL The product term is the pulse envelope signal of the k-th microwave radiation source and the i-th microwave radiation source in equation (5), where k ≠ i and i ∈ [2, N]; T kA T represents the propagation time difference of the excitation signal from the frequency synthesizer to the k-th microwave radiation source; kB T represents the time difference in the propagation of the radiated signal from the k-th microwave radiation source to the target location; iA T represents the propagation time difference of the excitation signal from the frequency synthesizer to the i-th microwave radiation source; iB This represents the time difference in the propagation of the radiated signal from the i-th microwave radiation source to the target location.

[0125] In this embodiment, the following formula is preferably used to ensure that the signals from each radiation field do not interfere with each other when they reach the receiver:

[0126]

[0127] In the formula, T 1i It is the time difference between the gating time gate of the i-th microwave radiation source and the gating time gate of the 1st microwave radiation source.

[0128] In this embodiment, by setting the time difference between the excitation signals generated by the frequency synthesizer according to equation (7), it can be ensured that each excitation signal arrives at the receiver in its own order, and no aliasing occurs in the time domain. Since the time difference between each excitation signal can be estimated by approximate cable and feeder lengths, an upwardly conservative calculation method can be used to ensure that no aliasing occurs.

[0129] The receiver's local oscillator frequency and sampling clock are required to be generated by the frequency synthesizer. The signal transmitted from the measurement antenna to the receiver is amplified, filtered, down-converted, and digitally sampled sequentially by the RF front end to obtain the complex baseband signal of equation (9):

[0130]

[0131] In the formula, S 1E (τ), ..., S NE (τ) represents S 1D (τ), ..., S ND (τ) The signal obtained after amplification, filtering, downconversion, and digital sampling; It is the down-conversion reference phase of the receiver.

[0132] Since all microwave radiation sources receive signals through the same receiving channel, the receiver's down-conversion reference phase is consistent for all radiation field signals. The fixed phase portion of the microwave radiation sources (i.e., the common phase of the radiated signals) is as follows:

[0133]

[0134] Therefore, equation (9) can be expressed as:

[0135]

[0136] In the formula, S 1E (τ), ..., S NE (τ) represents S 1D (τ), ..., S ND (τ) is the signal obtained after compensating for the time and phase differences; j is the imaginary unit.

[0137] Equation (11) is represented as I in the receiver. k Q k The data from both channels (i.e., the complex signal in the receiver is generated by in-phase I) k and quadrature Q k (Data from two channels is used to represent this); calculate the time difference and phase difference caused by the distance difference between the microwave radiation source and the target location; where the time difference is calculated as follows:

[0138]

[0139] In the formula, Let I be the time difference of the k-th radiation field signal; Pulsefront{} represents taking the pulse leading edge of the k-th radiation field signal, and abs() represents taking the complex amplitude of the k-th radiation field signal. k (τ) represents the in-phase channel of the orthogonal downconversion of the k-th radiation field signal, Q k (τ) represents the orthogonal phase channel of the k-th radiation field signal. In this embodiment, regardless of whether the pulse leading edge is taken as the pulse leading edge, pulse trailing edge, or pulse center, the method used for taking the pulse leading edge for each microwave radiation source should be consistent. It is not necessarily required to take the pulse leading edge, but the calculation method and standard for the time difference of all signals must be exactly the same.

[0140] Based on the calculation results and methods of the time difference, the effective time support for each radiation field signal is determined as follows:

[0141]

[0142] Where atan2() is the arctangent function, T set(k) It is a valid support.

[0143] Based on the previously set propagation time difference of the excitation signals of each microwave radiation source (i.e., equation (2)), we can obtain:

[0144]

[0145] Therefore, using the first microwave radiation source as a reference, the propagation time difference can be calculated:

[0146]

[0147] in, This represents the additional time difference from the k-th to the M-th microwave radiation source, with the time of the first microwave radiation source as the reference; in this embodiment, T 1k The initial set value is a known quantity.

[0148] The phase difference of the waveforms of each microwave radiation source is calculated as follows:

[0149]

[0150] in, Let be the phase of the k-th radiation field signal;

[0151] Therefore, taking the first microwave radiation source as a reference, the phase difference between each microwave radiation source can be calculated as follows:

[0152]

[0153] Based on this, the time difference and phase difference are calculated.

[0154] Keeping the time of the first microwave radiation source unchanged, the additional settings for the excitation signals of the other microwave radiation sources are as follows:

[0155]

[0156] in, This represents the additional time difference from the kth to the Mth microwave radiation source, with the time of the first microwave radiation source as the reference. The time of the first radiation field signal is represented by M∈[2,N];

[0157] Keeping the phase of the first microwave radiation source unchanged, the phase setting amount added to the excitation signals of the other microwave radiation sources is as follows:

[0158]

[0159] in, This represents the additional phase difference between the kth to Mth microwave radiation sources, with the phase of the first microwave radiation source as the reference. This indicates the phase of the first radiation field signal; This represents the phase of the k-th radiation field signal.

[0160] Based on the above calculations, the time difference and phase difference of the radiation signals from each microwave radiation source are changed by adjusting the excitation signal of the frequency synthesizer:

[0161]

[0162] Among them, S 1A' (τ), ..., S NA' (τ) represents the N excitation signals generated by the frequency synthesizer after compensating for the time and phase differences; S 1C' (τ), ..., S NC' (τ) represents S 1A' (τ), ..., S NA' (τ) N signals that arrive at the receiver after propagation; This represents the additional time difference from the second, ..., Nth microwave radiation sources to the Mth microwave radiation source, with the time difference of the first microwave radiation source as the reference. This represents the additional phase difference between the second, ..., Nth microwave radiation sources up to the Mth microwave radiation source, with the phase of the first microwave radiation source as the reference.

[0163] like Figure 4 As shown, the time difference is achieved through time adjustment of the gating switch. In this embodiment, the additional phase can be achieved by adding a phase shifter at the front end of the amplification link of the microwave radiation source. The excitation signal generated by the frequency synthesizer is transmitted to each microwave radiation source and radiated to the target location through the measuring antenna:

[0164]

[0165] Comparing equations (17), (18), and (20), it can be seen that the amplitude and phase of the microwave radiation source at the target location are consistent, thus achieving coherent enhancement.

[0166] By setting time and phase difference compensation parameters for the frequency synthesizer and adjusting its initial phase and time to radiate at the target location, phase compensation can be achieved in the intermediate frequency signal of the frequency synthesizer. The radiated signal obtained by the method of this invention can achieve coherent enhancement of the field strength at the target location.

Claims

1. A method of time-slot-stimulus-calibrated radiated source field strength coherent combining, comprising: The method comprises the following steps: S1, generating N excitation signals, N being a positive integer greater than or equal to 1; The gating time gate of the N excitation signals satisfies the following formula Gate k (τ) = Gate1(τ - T 1k ) In the formula: Gate k (k) represents the gate time of the kth excitation signal, k ∈ [2, N]; T 1k is the time difference of the gate time of the kth excitation signal relative to the gate time of the first excitation signal; τ is time; S2, the N excitation signals are respectively input into N microwave radiation sources, the N microwave radiation sources respectively amplify the N excitation signals, and emit N radiation signals to the target position; S3, the N radiation signals are inductively received by a measurement antenna at the target position in step S2, the measurement antenna emits N radiation field signals, and a receiver receives the N radiation field signals; S4, defining that the propagation of the excitation signal to the target position is a transmission channel, and respectively calculating the time difference and the phase difference of the N transmission channels; S5, according to the time difference and the phase difference obtained in step S4, respectively compensating the time difference and the phase difference of the N excitation signals, so that the amplitude and the phase of the radiation field signals of the N transmission channels reaching the target position are consistent, and the radiation field at the target position is coherently synthesized: The compensation of the time difference and the phase difference of the N excitation signals is specifically as follows: ... After compensation, the amplitude and the phase difference of the N excitation signals exciting the microwave radiation sources to generate the N radiation signals reaching the target position are consistent, and the radiation field signal formed at the target position is specifically as follows: ... where S 1A' (τ),...,S NA' (τ) represents N excitation signals generated by the frequency spectrum after compensating for the time difference and the phase difference; Gate1(τ) represents the gate time of the first excitation signal; f c is the center frequency of the frequency spectrum; is the equivalent phase of the up-conversion of the excitation signal; S 1C' (τ),...,S NC' (τ) represents S 1A' (τ),...,S NA' (τ) after propagation reaches the receiver N signals; represents the additional time difference from the second,...,Nth to the Mth microwave radiation source, based on the time of the first microwave radiation source; T 1A ,T 2A ,...,T NA represents the propagation time difference of N excitation signals from the frequency spectrum to each microwave radiation source; T 1B ,T 2B ,...,T NB represents the propagation time difference of N radiation signals from the microwave radiation source to the target position; represents the additional phase difference from the second,...,Nth to the Mth microwave radiation source, based on the phase of the first microwave radiation source.

2. The time-slot excited calibrated source field strength coherent synthesis method of claim 1, wherein, The N excitation signals in step S1 are generated by using a frequency synthesizer, and specifically as follows: ... where S 1A (τ),...,S NA (τ) represent the 1st, 2nd,..., Nth excitation signals generated by the frequency synthesizer; Gate1(τ),...,Gate N (τ) represent the 1st, 2nd,..., Nth gating time gates of the frequency synthesizer corresponding to the 1st, 2nd,..., Nth excitation signals; f c is the center frequency of the frequency synthesizer; is the equivalent phase of the up-converted excitation signal.

3. The time-slot excited calibrated source field strength coherent synthesis method of claim 2, wherein, In step S2, the corresponding excitation signal inductively received by each microwave radiation source is specifically as follows: S 1B (τ) = S 1A (τ - T 1A ), S 2B (τ) = S 2A (τ-T 2A ), ... S NB (τ) = S NA (τ-T NA ) where S 1B (τ),...,S NB (τ) represent the N signals arriving at the microwave radiation sources after propagation of S 1A (τ),...,S NA (τ); T 1A ,T 2A ,...,T NA represent the propagation time differences of the N excitation signals from the frequency spectrum to the individual microwave radiation sources.

4. The time-slot excited calibrated source field strength coherent combining method of claim 3, wherein, In step S3, the N radiation signals received by the measurement antenna at the target position are specifically as follows: S 1C (τ) = S 1B (τ - T 1B ), S 2C (τ) = S 2B (τ-T 2B ), ... S NC (τ) = S NB (τ-T NB ) where S 1C (τ),...,S NC (τ) represents S 1B (τ),...,S NB (τ) the N signals that reach the measuring antenna from the microwave radiation source; T 1B ,T 2B ,...,T NB represent the difference in propagation times of the N radiation signals from the microwave radiation source to the target location.

5. The time-slot excited calibrated source field strength coherent synthesis method of claim 4, wherein, In step S3, the N radiation field signals received by the receiver are specifically as follows: ... where S 1D (τ),...,S ND (τ) represent the N signals received at the receiver from the N signals transmitted by the measuring antenna; T 1C (τ),...,S NC (τ) represent the N signals received at the receiver from the N signals transmitted by the measuring antenna; T L is the difference in propagation time from the measuring antenna to the receiver for the N radiation field signals. The N radiation field signals satisfy the following formula: Gate k (τ-T kA -T kB -T L )·Gate i (τ-T iA -T iB -T L ) = 0 where Gate k (τ-T kA -T kB -T L )·Gate i (τ-T iA -T iB -T L ) represents the pulse envelope signal of the kth microwave radiation source and the ith microwave radiation source, where k≠i and i∈[2, N]; T kA represents the propagation time difference of the excitation signal from the frequency synthesizer to the kth microwave radiation source; T kB represents the propagation time difference of the radiation signal from the kth microwave radiation source to the target position; T iA represents the propagation time difference of the excitation signal from the frequency synthesizer to the ith microwave radiation source; T iB represents the propagation time difference of the radiation signal from the ith microwave radiation source to the target position.

6. The time-slot excited calibrated source field strength coherent synthesis method of claim 5, wherein, In step S3, the receiver sequentially performs amplification, filtering, down-conversion, and digital sampling through a radio frequency front end to obtain a complex baseband signal: ... where S 1E (τ),...,S NE (τ) represents S 1D (τ),...,S ND (τ) after compensating for the time difference and the phase difference; j is the imaginary unit; The common phase of N radiated signals The down-converted reference phase for the receiver.

7. The time-slot excited calibrated source field strength coherent synthesis method of claim 6, wherein, Step S4 is specifically as follows: 4.1) calculating the time of each radiation field signal In the formula, is the time of the kth radiation field signal; Pulsefront{k} represents the pulse front of the kth radiation field signal; abs() represents the complex amplitude of the kth radiation field signal; I k (I) is the in-phase channel of the quadrature down-conversion of the kth radiation field signal; Q k (I) is the in-phase channel of the quadrature down-conversion of the kth radiation field signal; Q 4.2) calculating the phase of the radiation field signal In the formula, is the phase of the kth radiation field signal; 4.3) keeping the time of the first microwave radiation source unchanged, and adding a time setting amount to the kth microwave radiation source according to step 4.1) In the formula, represents the additional time difference from the kth to the Mth microwave radiation source, based on the time of the first microwave radiation source; represents the time of the first radiation field signal, M ∈ [2, N]; 4.4) keeping the phase of the first microwave radiation source unchanged, and adding a phase setting amount to the kth microwave radiation source according to step 4.2) In the formula, represents the additional phase difference of the kth to Mth microwave radiation sources with respect to the phase of the 1st microwave radiation source as a reference; represents the phase of the 1st radiation field signal; represents the phase of the kth radiation field signal.

8. A time-slot-stimulated calibrated radiating source field intensity coherent synthesis system for implementing the time-slot-stimulated calibrated radiating source field intensity coherent synthesis method according to any one of claims 1 to 7, characterized in that: The frequency synthesizer, the N microwave radiation sources arranged in any manner, the measurement antenna, and the receiver are included. The frequency synthesizer is used to generate and output N different excitation signals, which are used as excitation signals of the N microwave radiation sources after phase shifting. The N excitation signal output ends of the frequency synthesizer are respectively connected with the excitation signal input ends of the N microwave radiation sources arranged in any manner through phase shifters, and the frequency time reference signal output end of the frequency synthesizer is connected with the receiver, which is used to ensure the phase locking between the receiver and the frequency synthesizer. Each microwave radiation source receives its own excitation signal, amplifies the excitation signal, generates a radiation signal, and radiates the radiation signal to the target position to form a radiation field signal at the target position. The measurement antenna is located at the target position and is connected with the receiver. The measurement antenna is used to inductively measure the radiation field signal and transmit the radiation field signal to the receiver. The receiver is used for receiving N radiation field signals, and separating and processing the N radiation field signals to obtain excitation signals corresponding to the N microwave radiation sources, and calculating time difference and phase difference of the N excitation signals of the frequency synthesizer reaching the target position; and adjusting the gating time gate of the excitation signal of the frequency synthesizer according to the calculated time difference and phase difference, so as to realize time slot excitation calibration of the radiation source field intensity coherent synthesis.

9. The time-slot-stimulated calibrated radiated source field intensity coherent combining system of claim 8, wherein: The radio frequency front end comprises a variable attenuator, an amplitude limiting low noise amplifier, a band pass filter, a down conversion module, a gain control module, an AD sampling module, digital pre-selection filtering and a digital quadrature down conversion module connected in sequence; The measurement antenna is connected with the variable attenuator; and the receiver is connected with the digital quadrature down conversion module; The variable attenuator is used for power adjustment of the radiation field signal; The amplitude limiting low noise amplifier is used for amplifying the radiation field signal processed by the variable attenuator; The band pass filter is used for filtering the amplified radiation field signal; The down conversion module is used for down conversion of the filtered radiation field signal; The gain control module is used for automatic gain control of the down-converted radiation field signal; The AD sampling module is used for converting the radiation field signal after automatic gain control into a digital signal; The digital pre-selection filtering is used for image interference suppression before quadrature down conversion of the digital signal; The digital quadrature down conversion module is used for converting the digital signal into a corresponding complex baseband signal.

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