The Research Of HF Surface Wave Radar Antenna Based On Joint Transmit-receive Array

HF surface wave radar is studied and concerned widely for its superiority inmaritime moving target detection beyond the horizon. However, considering thedemands for covering a large area stemming from both transmitting antenna andreceiving antenna as well as the scarcity of the land at seaside nowadays, it isdifficult to find the areas for them independently. Therefore, based on the studies ofT/R antenna with small size and simple structure, this thesis did deep research onJoint transmit-receive antenna array, aimming at arranging T/R antenna in the sameplace for the reduction in total area.Fristly, for the problem of large size of traditional Yagi antenna, this paperdiscussed small spacing antenna and carried on the design of two-folded Yagiantenna, combing with genetic algorithm. Two three-element two-folded Yagiantennas were designed and simulated by HFSS software, whose center frequencywere8MHz and5MHz respectively, and the simulation results validate thisstructure possesses an optimal impedance and radiation characteristics in case ofsmall spacing. What’more, this paper designed a lumped loading monopole as thereceiving antenna, utilizing genetic algorithm to optimize the values of lumpedelements and loading position, and consequently its characteristics of impedanceand radiation on can reach the certain requirement with frequency ranging from4MHz to9MHz.Secondly, this paper described two ways of designing Joint transmit-receiveantenna array, and analysised corresponding advantages and disadvantages.Considering the safety and practicality comprehensively, this paper proposed themethod of T/R antenna Co-location, i.e. to locate a transmitting antenna on bothside of receiving antenna array. After that, the coupling problem between thetransmitting and receiving antenna was discussed. By analysising the radiationcharacteristic of transmitting antenna and isolation between T/R antenna withdifferent distances and orientations, this paper prvoves that transmitting antennacan keep a good radiation characteristic in the proper position.The main lobe width and sidelobe level of Chebyshev-Dolph weightedreceiving array with diferent antenna spacing analysed furtherly, this paper finally designed the layout of Joint transmi-receive antenna array. Comtraposing themutual coupling problem in the receiving array elements, this thesis proposed amutual coupling calibration method, and simulations showed that the DOAalgorithm can be proceeded accurately and precisely.