Study On Transmiting Beamforming At Subarray Level For Phased Array

Phased array radar is one of the main developing direction of modern radar, t he transmitting beamforming technique is becoming more and more popular in engineering applications, and has important research value. The MIMO-phased array radar is combination with the advantages of MIMO radar and phased array radar, and has a better target detection performance, high target resolution, and an important significance.In order to suppress the sidelobe of the transmitting pattern, we usually adopt the amplitude weighting method. Conventional amplitude weighting method adopt element attenuator, but it requires a large number of microwave devices to increase the cost of the hardware. To solve these engineering application problems, this paper studies the following several kinds of phased array radar transmitting beamforming method.Firstly, we study a transmitting beamforming method that is baesd on the phase-only weight, which use the genetic algorithms to optimize the phase weight of the phase shifter to suppress the sidelobe. This method dispenses with the element attenuator, reduces the hardware cost, and provides some reference value for engineering applications.Secondly, we study the transmitting beamforming method that based on the subarray weight replacing the array weight, which optimize the subarray weight to suppress sidelobe through the analytical method of weighting vector and radiation pattern approximation. For the thousands of array elements, this method dispense with the simulant attenuator, decrease the hardware cost and complexity of the system.Thirdly, we put forward the transmitting beamforming algorithm that is based on the robust subarray. While meeting the constraint condition of the sidelobe level, this method minimizes the subarray weighting vector norm of the transmitting beamforming, and constrains the stransmitting beam main lobe expansion in a range. This method reduce the dynamic range of the subarray weight to decrease the requirement of the transmitting power.Finally, for the MIMO-phased array radar, we put forward the transmitting beamforming method that is based on the subarray signal. We present the MIMO-Phased array mode, subarray signal and transmitting pattern expression. We present the simulation results in three different radar working mode, which are subarray beam pointing to the same and transmitting orthogonal signal between subarray; subarray beam pointing to the same and transmitting related signal between subarray;subarray beam pointing to different and transmitting orthogonal signal between subarray.