Research And Testing Of 3mm Beam Detector Array

With the development of high-power millimeter-wave gyrotron power source technology, the millimeter wave system output power increases. During transmission the antenna radiation beam due to environmental reflections and multipath effect influenced more obviously, cause the abnormal beam time and spatial distribution, these affect the beam performance severely. The millimeter-wave detector test method proposed in this thesis can test the beam spatial and temporal distribution of the high-power density beam in an accurate and real-time way.This thesis is based on the 3 mm beam detector array research and testing and it adopts the method of detector test to complete beam probe array design. This thesis studies the receiving antenna in detail, then completes unit antenna selection and the layout of the antenna array, finally proposes detector array system design and some experimental results of the whole detector array system. This thesis mainly studies the following four aspects:(1) Analysis of the cell antennas. The design of 3mm microstrip antenna is completed by combining the microstrip antenna theoretical analysis. The antenna can meet the requirements of S-parameters and pattern. Use electromagnetic simulation software CST to simulate the open-aperture waveguide antenna in different opening form, length, thickness and the flange simulation, and sums up the open-aperture waveguide structure parameters on the influence law of gain.(2) Array antenna design. The coupling elements of microstrip antenna and open-aperture waveguide antenna is simulated respectively, then open-aperture waveguide antenna is selected as a unit array antenna by combining the advantages and disadvantages of two element antenna. The layout of the basic parameters is determined by simulating the opening waveguide array antenna’s gain, pattern and the received power. The layout of 1m × 1m array antenna is completed by the size of the measured beam diameter and cost-efficient.(3) Detection array system design. Firstly, the principle of the detection array system is proposed. Secondly, the parameter index of the aperture waveguide antenna, attenuator and detector is listed in reception system. Thirdly, the support structure design and assembly is completed of the system. Fourthly, the one through five switch array is designed and data acquisition is completed by switching 305-channel signal to 64-way acquisition card in five times. Finally, the design of numerical signal processing systems is completed. The system can realize real-time collect single-channel waveform, real-time display voltage value and the power value and replay 2D beam effect.(4) Complete testing experiment. Firstly, a 100 mm × 100 mm(distribution of 4 × 4) detector array is completed, which can verify the accuracy of the theory and the feasibility of the experiment. Secondly, the preliminary experiments of 3mm beam detector array(distribution of 1m × 1m 305 channel) is completed and obtain experimental results.Another kind of thinking is proposed in this thesis to study the space-time distribution of high power beam. The 3mm beam detector array system can achieve a spatial resolution of 25 mm and a sampling frequency of 200 Hz, which gives some reference to the further studies on the application of millimeter wave high-power beam.