119 results about "Directivity diagram" patented technology

The method relates to a method for designing an antenna by improving the side lobe characteristics of an array wave beam directivity diagram, belonging to the technical field of array antennae. The method comprises the following steps of: setting an expected response directivity diagram A; under the unrestraint condition, determining a array wave directivity diagram B according to a minimum mean square error criterion; selecting a side lobe S to be optimized to determine an interval Omega; under the condition of taking a principle that the directivity diagram amplitude at a k equal division point is zero in the Omega as a constrict condition, calculating an optimal weighting vector Wopt(k) of an array, approaching to the directivity diagram A, according to the minimum mean square error criterion under the corresponding constraint condition to obtain a directivity diagram Ck, and searching the peak value p1(k) and a peak value p2(k) of side lobes at the left side and the right side of the k equal division point in the Ck; and marking Mr (k)=max{pr2(k), pr1 (k)}, searching a maximum value Mr (krm) in all Mr(k), determining the corresponding Wopt (krm) and a wave beam directivity diagram D, and carrying out array antenna design according to the Wopt (krm) and D. The method disclosed by the invention is used for designing the array antenna by improving the characteristics of the side lobes at the single side or both sides without carrying out hardware improvement on the original array and has the advantages of good flexibility, low cost and good effect.

The invention discloses an interference suppression method based on a low-correlation space-time two-dimensional random directional diagram. A space-time two-dimensional random directional diagram inmicrowave staring super-resolution imaging is designed, and interference can be more effectively suppressed. The method comprises the steps of generating an orthogonal random phase sequence based on agenetic search algorithm, establishing a phased-array antenna working coordinate system for representing an array element position, calculating a phased-array far-field directional diagram function by utilizing the generated orthogonal random phase sequence, and identifying a target and interference of an array element signal in combination with a sparse reconstruction algorithm. According to theinvention, the random initial phase of the array element signal is generated by using a genetic search algorithm; the designed directional diagram has better orthogonality and performance, the orthogonality of the designed directional diagram is better, target signals and interference signals are separated through matched filtering at the receiving end of the phased array radar, and interferenceof array element signals can be suppressed more effectively. The method is used for anti-interference for radar signals.

The invention relates to a beam forming metasurface structure and method based on amplitude and phase modulation, the beam forming metasurface structure comprises a plurality of metasurface units, and the metasurface units with different structural parameters are uniformly arranged to form the metasurface structure; each metasurface unit comprises three metal layers and two dielectric layers; the first layer, the third layer and the fifth layer are metal layers from top to bottom, and the second layer and the fourth layer are dielectric layers. The metasurface capable of modulating the amplitude and the phase of the electromagnetic wave simultaneously is designed, the structure is simple, the profile is low, and the flexibility of electromagnetic wave regulation and control is improved; the excitation amplitude and phase distribution required by the target directional diagram are calculated based on the Taylor synthesis method and the superposition principle, the method is suitable for synthesis of various far-field directional diagrams, and the calculation method is simple and convenient.

The invention discloses a phase-only multi-beam directional diagram synthesis method based on separation calibration iteration FFT. The method comprises the following steps of generating an initial excitation phase, performing phase-only optimization on initial excitation and selecting an optimal excitation phase. The invention provides an iterative fast Fourier transform (FFT) technology for beam separation calibration, which is inspired by a Schirkunov unit circle, the technology decomposes a multi-beam directional diagram into a plurality of single-beam directional diagrams during each iteration, utilizes forward FFT to solve the excitation of the multiple single-beam directional diagrams, calibrates all the excitation and then adds the excitation, and a calibrated multi-beam directional diagram is obtained through reverse FFT, in addition, an amplitude directional diagram is continuously modified in iteration so as to reduce the side lobe level and lift a main lobe with a low peak value, meanwhile, multiple initial solutions are subjected to multiple times of phase-only optimization so as to achieve the lower side lobe level, and only the excitation phase of an array element is optimized in the method, and the complexity of the feed network can be effectively reduced.

The invention provides an array beam forming method based on a directional diagram reconstruction unit. The method comprises the following steps: 1) an initialization step; and 2) an iteration step: firstly, solving a convex optimization problem by traversing all different directional diagram combination modes, then, taking a directional diagram mode combination with the minimum sidelobe level asan optimal directional diagram mode combination in an iteration process, and outputting the optimal directional diagram mode combination and a corresponding optimal array weight coefficient. Through optimal selection of the array unit directional diagram mode and optimal design of the array weight coefficient, self-adaptive matching of the directional diagram mode and array beam pointing is achieved, the sidelobe level of the array antenna is lowered, and the gain of the array antenna is improved.

The invention provides a a multi-channel SAR (Synthetic Aperture Radar) antenna performance detection method based on wireless single Transmitter and Receiver calibration. The objective of the invention is to verify the influence of a satellite SAR antenna on the performance change of a multi-channel SAR antenna before and after long-distance transportation and vibration tests. According to the method, the satellite transition test cost and the technical risk possibly caused by folding and unfolding of the antenna are greatly reduced, the SAR antenna performance after transportation and vibration tests is simply and quickly detected; meanwhile, compared with a traditional directional diagram repeated detection method, a novel multi-channel SAR antenna detection method is provided, and thedetection efficiency is improved.

The invention discloses an anti-interference zero setting system, and belongs to the technical field of signal processing. The system comprises an antenna radiation unit, a receiving link, a digital array module and an adaptive beam forming module, wherein a spatial incoming wave signal is received by the antenna radiation unit, amplified and filtered by the receiving link and then sent to the digital array module to complete primary digital beam forming of multiple signals in a subarray, and finally, the adaptive beam forming module forms a zero setting beam and a static beam. According to the invention, through the dimension reduction two-stage beam forming architecture, the calculation amount of beam forming and the adaptive zero setting requirement are both considered. Besides, the optimized non-uniform subarray and layout arrangement are used, so that the sidelobe performance of a directional diagram is improved, and the grating lobe influence of zero-setting beam forming is reduced. The method can be realized on the basis of FPGA and SoC pipeline iterative loop architecture, so that the calculation amount of adaptive zero setting can be further reduced, and the real-time performance of interference signal detection is improved.

The invention belongs to the technical field of a broad-angle scanning phased-array antenna, and discloses a broad-angle scanning phased-array antenna adopting a special directional diagram array element, and a design method. A low-profile phased array adopts sub arrays with special directional diagrams as the array element to enable a low-profile phased-array antenna to realize stable gain withina broad scanning angle range or to satisfy the requirement of higher gain with a large scanning angle; the maximum gain directions of the special directional diagram are symmetrically distributed between the normal direction of the array plane and the maximum scanning angle direction close to the maximum scanning angle direction so as to form the characteristic of a concave center of the directional diagram; the central concave depth of the array element directional diagram is designed according to the array group requirement; and the array factor directivity is stronger, the central concaveis deeper. Stable gain of the low-profile phased-array antenna in the broad scanning angel range can be realized or the requirement of higher gain with a large scanning angle can be satisfied under the premise of not changing the phased array factors.

The invention discloses a novel broadband three-dimensional imaging sonar sparse arraying method. The method comprises the steps of initializing preset parameters of a three-dimensional imaging sonar system array; calculating a Fermat spiral array arrangement constant according to the preset parameters; calculating the position of a transducer in a Fermat spiral array structure according to the preset parameters and the Fermat spiral array arrangement constant; replacing a transducer positioned in the inner circle of the three-dimensional imaging sonar Fermat spiral structure with a sound signal emission source transducer; resetting the preset parameters and determining a Fermat spiral ring surface sparse matrix according to the reset preset parameters; and converting the Fermat spiral ring surface sparse matrix into a Cartesian coordinate system. By using the method, the beam forming directivity diagram of the three-dimensional imaging sonar system is ensured to meet the use requirements, and the problems of high hardware consumption and large real-time calculation amount of the existing three-dimensional imaging sonar system are effectively solved. As a novel broadband three-dimensional imaging sonar sparse arraying method, the method can be applied to the technical field of underwater three-dimensional imaging sonar.

The invention discloses a broadband planar array antenna, which comprises a polarization layer, a radiation layer and a feed layer which are sequentially stacked from top to bottom. The feed layer isused for converting a single TE10 mode into multiple TE10 mode signals with the same power and the same phase, and transmitting the multiple TE10 mode signals to the radiation layer; the radiation layer is used for radiating the multiple TE10 mode signals from the feed layer to a free space; and the polarization layer is used for enabling the electric field polarization direction generated by theradiation layer to rotate, so that side lobes of an E-plane directional diagram and an H-plane directional diagram are reduced. The antenna has the advantages of high gain and efficiency and low processing cost on the basis of low sidelobe.

Disclosed are a metasurface-based random waveform generator and a setting method. A metasurface unit with simultaneous amplitude and phase regulation capability is set, wherein the amplitude regulation depends on adjustment of the rotation angle of a unit, while the phase modulation depends on change of the size of the unit; the phase and amplitude distribution of the metasurface is optimized through a genetic algorithm, so that a target directional diagram is formed in a far field; a Vivaldi antenna is used for irradiating the metasurface, and the amplitude and phase distribution interceptedon the surface are combined, and the amplitude and phase distribution required to be compensated for generating the target far-field directional diagram are calculated; and according to the above steps, a sector-shaped wave generator is arranged. The analysis result shows that a display device can form a very high sector-shaped far-field directional diagram in the range of 9.5 to 10.5GHz.