CN106684573A - High-efficiency and high-power microwave space power synthesis method - Google Patents

Abstract

The invention discloses a high-efficiency high-power microwave space power synthesis method, which adopts beams radiated by multiple antennas to perform power synthesis in space. It includes the following steps: 1) Set up a time-reversal antenna array on one side of the detection area, select any antenna unit to transmit a weak signal to detect non-cooperative targets, determine the main emission direction of each antenna according to the echo, and adjust the antenna accordingly The physical direction of the unit is consistent with it, and the space-frequency polymorphic response matrix is established at the same time to obtain the time-reversed signal corresponding to the target; 2) the time-reversed antenna array increases the power to transmit the time-reversed signal obtained in step 1), and converts it to will focus on the target position. The invention proposes to use time inversion algorithm to realize spatial power combination, which improves the efficiency of combined power, has self-adaptive focusing capability, integrates non-cooperative target detection and space power combination, and efficiently realizes high-power microwave space power combination.

Description

A high-efficiency high-power microwave spatial power combining method

Technical field:

The invention relates to a high-efficiency high-power microwave space power synthesis technology, which belongs to the high-power microwave field.

Background technique:

In recent years, ultra-broadband high-power microwaves have developed rapidly in the fields of directed energy weapons, impulse radar, power transmission, high-power microwave heating, etc. With the traction of these application requirements, how to obtain high-power microwaves through power synthesis has become an urgent technology to be solved difficulty. At present, there are two methods for high-power microwave power synthesis: one is to use solid-state power synthesis technology to obtain the corresponding combined power in the microwave channel of the equipment, but due to the limitations of high-voltage power supply and high-power devices The improvement of the output power is extremely limited; the second is to combine the beams radiated by multiple antennas in space, which can greatly improve the effective radiation power of microwaves.

The main methods to achieve spatial power combining are: parallel beam method, focused beam method and cross beam method. The parallel beam method mostly uses phased array antennas, and each unit of the array can have its own independent source and transmitter, which avoids the loss of power division of a single source, and can synthesize a larger total power in a certain direction in space, but This method is only suitable for the far-field area; in the focused beam method, each antenna is placed in a different position similar to a parabola, and the beams of each antenna unit are focused on its focal point, so that the focal area reaches a high synthetic power density, but this method The method is limited by the size of the paraboloid; the cross-beam method refers to sending out several beams with the same frequency and certain power from some different positions at the same time, and by controlling the phase relationship of each beam, the beams can be synthesized with sufficient power in the predetermined crossing area. This method can effectively increase the power density in the beam intersection area, but how to precisely control the phase of each beam so that each beam reaches the designated area at the same time is a technical difficulty.

Contents of the invention

In view of the above deficiencies in the prior art, the object of the present invention is to provide a high-efficiency high-power microwave space power synthesis method that integrates target detection and space power synthesis. In this method, a time-reversal antenna is set on one side of the detection area Array, choose any antenna unit to transmit a weak signal to detect non-cooperative targets, determine the main shooting direction of each antenna according to the echo, and adjust the physical direction of the antenna unit accordingly to ensure that each antenna unit is directly facing the non-cooperative target The signal is transmitted, and the space-frequency polymorphic response matrix is established at the same time to obtain the time-reversal signal corresponding to the target; then the antenna array increases the power and transmits the time-reversal signal, and these signals will be focused on the target position. It can not only complete the detection of non-cooperative targets, but also realize space power synthesis at the target position, obtain high-power microwaves, and integrate non-cooperative target detection and space power synthesis into one.

For realizing the purpose of the present invention, the concrete measures that adopt are as follows:

A high-efficiency high-power microwave space power combining method uses beams radiated by multiple antennas to perform power combining in space. It includes the following steps: 1) Set up a time-reversal antenna array on one side of the detection area, select any antenna unit to transmit a weak signal to detect non-cooperative targets, determine the main emission direction of each antenna according to the echo, and adjust the antenna accordingly The physical direction of the unit is consistent with it, and the space-frequency polymorphic response matrix is established at the same time, and the time-reversal signal corresponding to the target is obtained; 2) the time-reversal antenna array is increased in power, and the time-reversal signal obtained in step 1) is transmitted, and the It will focus on the target location.

In actual implementation, the time-reversal antenna array is decomposed into many small antenna arrays, and the small antenna array determines the main shooting direction of each antenna according to the echo, and adjusts the physical direction of the antenna unit accordingly to ensure that each Antenna units transmit signals directly to non-cooperative targets.

By adopting the high-power microwave space power synthesis method of the present invention, the detection of non-cooperative targets can be completed, and the space power synthesis can be realized at the target position to obtain high-power microwaves. The method is simple and easy, and the power combining efficiency is high, reaching 87.39% of the ideal combining power. It is an efficient high-power microwave space power combining technology that integrates non-cooperative target detection and space power combining, and solves the problem of traditional space power combining technology. Due to positioning first and then synthesizing, it cannot be effectively connected, and the synthesis efficiency and positioning accuracy are not high. This technology can be used for the detection and removal of landmines, firstly emit weak signals to detect the orientation of landmines, and then synthesize high-power microwaves to disable the mines; it can also be used for the detection and removal of kidney stones and urinary stones, first emit weak signals to Detect the location of stones, and then synthesize higher power microwaves (laser) to break the stones and excrete them from the body, realizing lithotripsy outside the body and reducing the pain of patients. The invention proposes the use of time inversion algorithm to realize spatial power synthesis, improves the efficiency of combined power, has self-adaptive focusing capability, integrates non-cooperative target detection and spatial power synthesis, and is an efficient high-power microwave space power synthesis technology .

Description of drawings

Figure 1. Schematic diagram of antenna array and target setup.

Fig. 2 Schematic diagram of spatial power combining.

Fig. 3 is a schematic diagram of spatial power synthesis after frequency increase.

detailed description

Classical power combining refers to the in-phase superposition of multiple signals of the same frequency at the combining point. Theoretically, the amplitude of the superimposed electric field will increase linearly, while the power will increase in a quadratic relationship. When the polarization direction of each signal is the same and the time domain waveform is consistent, the maximum average power density can be obtained for multiple time domain signals.

As shown in Figure 1, a combined transceiver antenna array with N antenna units is set on one side of the detection area, and any antenna is selected to transmit an ultra-wideband pulse time-domain signal s(t), and all antenna units receive the echo signal reflected by the target. The time-domain signal k _n (t), n=1, 2,...,N received by each antenna unit is Fourier transformed to obtain the frequency-domain signal k _n (ω), n=1, 2,...,N, Then the space-frequency polymorphic response matrix is obtained:

The nth row of the matrix K corresponds to the received signal of the nth antenna unit, and is the frequency domain discrete value of the time domain signal collected by the nth antenna unit through Fourier transform. Singular value decomposition matrix K, ie K=UΛV ^H . U is a left singular vector matrix of order N×N. U _i represents the left singular vector of the i-th column of the U matrix, corresponding to the i-th target, containing the spatial information of the antenna array and the target, and reflecting the spatial relationship between the antenna array and the i-th target. Using U _i and the frequency domain signal S(ω) of the detection signal s(t), the time-reversed time-domain signal for power combination transmitted by each antenna unit is obtained as

In the formula: Represents the inverse Fourier transform; the center frequency of S(ω) and the center frequency of the detection signal can be consistent or different. N antenna units simultaneously transmit corresponding time-reversal signals, The signal peaks will arrive at the i-th target position at the same time, and the power combination will be realized at this target. Obviously, the N time-reversal signals have the same frequency and the same polarization direction. The magnitude of the combined power can be determined by the amplitude A _i of the radiated signal of each antenna unit; the irradiation direction of each antenna unit is determined according to the arrival direction of the echo.

Divide the N antenna units into (N-2) groups, the 1st, 2nd, and 3rd antenna units form a group, the 2nd, 3rd, and 4th antenna units form a group, and so on, the (N-2)th , (N-1), and N antenna elements form a group. Each group of antennas can be regarded as a small antenna array, and when the target is in the far-field area of the antenna array, the echoes reaching each small antenna array can be regarded as parallel waves. Use the multi-type signal identification method to calculate the direction of the parallel wave arriving at the small antenna array, take the direction of the arriving wave calculated by the first group of small antenna arrays as the main radiation direction of the first and second antenna units, and take the second group of small antenna arrays to obtain The obtained arrival wave direction is the main emission direction of the third antenna unit, and the arrival wave direction calculated by the third group of small antenna arrays is the main emission direction of the fourth antenna unit, and so on, the (N-2) The arrival wave direction calculated by the small antenna array is the main radiation direction of the (N-1)th and Nth antenna units, and the physical direction of the antenna units is adjusted accordingly to ensure that each antenna unit is directly facing the non-cooperative The target emits a signal.

As shown in Figure 1, set up two layers of media, one layer is air, the other layer is sand or human tissue, set a radius r = 2cm target in the sand or human tissue, the interface between the medium and air is set as x-axis, y<0 The region is the atmosphere, and 7 ideal transceiver antenna units form a time-reversal antenna array along the parallel x-axis direction. The antenna array is 10cm away from the interface of the two layers of media, that is, the vertical coordinate of the array is y=-10cm. The direction of the antenna element is parallel to the z-axis, and only s-polarized waves are considered. The distance between adjacent antennas is 0.2m, the coordinates of the central antenna unit are (1.5m,-0.1m), the average dielectric constant ε _m of the other layer of medium is 2.908, and the coordinates of the center of the cylinder are: T(1.2m, 1.5m ). The main shooting direction of all antenna units is the same. The first antenna transmits a detection signal. The signal is a Gaussian pulse wave with a center frequency of 320MHz. All antennas receive the echo signal reflected by the target. The sampling point M is 2400. Determine the main emission direction of each antenna unit according to the echo signal, adjust the antenna to make the emission direction consistent with the required direction; at the same time, establish a space-frequency polymorphic response matrix according to the echo signal, and calculate the power used for each antenna unit emission Synthesized time-reversed time-domain signal. Select the amplitude A _i =1 of the signal transmitted by each antenna unit to realize spatial power synthesis as shown in Figure 2. The ratio of the synthesized power to the peak power transmitted by the antenna unit is 0.0229; the central frequency of S(ω) in the power synthesis formula is increased to the original 4 times that of the original 320MHz to 1.28GHz, and the combined power is obtained again as shown in Figure 3. The ratio of the combined power to the peak power transmitted by the antenna unit is increased to 0.0818, and the energy is more concentrated.

Each antenna alone transmits signals to the target, and the ratio of the ideal combined power of the seven antennas to the peak power transmitted by the antenna is 0.0936. The synthesis efficiency η is defined as the ratio of the actual synthesis power to the ideal synthesis power, then η ₁ =0.0229/0.0936=24.47% and η ₂ =0.0818/0.0936=87.39%. Apparently, the efficiency of power synthesis is greatly improved after the frequency is increased, which shows the superiority of this method in power synthesis. This technology can be used for the detection and removal of landmines, firstly emit weak signals to detect the orientation of landmines, and then synthesize high-power microwaves to disable the mines; it can also be used for the detection and removal of kidney stones and urinary stones, first emit weak signals to Detect the location of stones, and then synthesize higher power microwaves (laser) to break the stones and excrete them from the body, realizing lithotripsy outside the body and reducing the pain of patients. After the frequency is increased, the synthesis power area is smaller, so that it can directly act on the calculus, which can reduce the damage to the body.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (3)

1. a kind of high-efficiency high power spatial microwave power combining methods, carry out power in space using the wave beam of multiple aerial radiations Synthesis, it is characterised in that comprising the steps：1) time reversal aerial array is set in the side of search coverage, appoints and take one Individual antenna element launches infant laser signal detection noncooperative target, determines that the master of each antenna penetrates direction according to echo, and adjusts according to this The physical direction of antenna element is consistent therewith, while setting up the polymorphic response matrix of null tone, obtains time reversal corresponding with target Signal；2) time reversal aerial array increases power emission step 1) obtained by time reversal signal, and which will be focused on into target At position.

2. high-efficiency high power spatial microwave power combining methods according to claim 1, it is characterised in that the time is anti- Drill aerial array and resolve into many miniature antenna arrays, according to echo, miniature antenna array determines that the master of each antenna penetrates direction, and The physical direction for adjusting antenna element according to this is consistent therewith, it is ensured that each antenna element is directly to noncooperative target transmission signal.

3. high-efficiency high power spatial microwave power combining methods according to claim 1, it is characterised in that in search coverage Side the transmitting-receiving of N number of antenna element is set closes and put aerial array, appoint and take an antenna transmitting ultra-wideband pulse time-domain signal s T (), all antenna elements receive the echo-signal of target reflection, the time-domain signal k received to each antenna element_n(t), n= 1,2 ..., N carry out Fourier transformation, obtain frequency-region signal k_n(ω), n=1,2 ..., N, and then obtain the polymorphic response square of null tone Battle array.