Millimeter-wave Circularly Polarized Microstrip Antenna

Circularly polarized (CP) technique has wide application prospect in the fields of communication, aviation, guidance and so on, Millimeter waves (MMW) CP antenna is one of the key technologies of MMW CP electronic system, so it has great value to study MMW CP antenna. In this paper, MMW circularly polarized microstrip antenna is studied deeply, the detailed work includes:1. Based on analyzing the circularly polarization theory, a CP microstrip patch antenna has been designed using HFSS 9.2, and qualitative analyzed the influence of resect corner to resonant frequency and axial ratio. Parameters of the coaxial-feed and microstrip-feed antenna, such as S parameters and axial ratio bandwidth are gained and analyzed, which supply reference to design antenna array in MMW band;2. Based on analyzing single CP microstrip antenna, a four-unit antenna array has been designed using sequential rotation method, and the influence of patch distance is compared. The array is working at 35GHz, impedance bandwidth is 11.4%, axial ratio bandwidth is 5.7%, which is in agreement with measured result. The result supplies reference for building large antenna array.The MMW CP antenna designed in this paper has the advantages of smaller volume, less weight, compact structure and easy to be integrated with MMW forward components.