Design Of Ka-band Circularly Polarization Antenna Based On SIW Technology

With the improvement and the development of electromagnetic theory, the requirements for a variety of active and passive microwave devices become more sophisticated in practical engineering applications. Applications in the microwave field are developed toward miniaturization,, lightweight and highly integrated.In the Ka-band,for most antennas and feed networks, the traditional rectangular waveguide structure has the shortcoming of complex in structure, long production cycle and high production costs, while the traditional microstrip transmission line in the Ka-band has a larger loss and smaller power capacity.In short,the development of antennas’ miniaturization and high integration is limited to the traditional transmission lines.By means of the emerging substrate integrated waveguide(SIW) technology developed in the early 21 st century, drawbacks of the conventional transmission line above-mentioned have been overcomed. Compared with conventional microstrip and rectangular waveguide,the substrate integrated waveguide has advantages of low profile, small size, ease of processing and high-power capacity etc. Substrate integrated waveguide structure can be effectively integrated in the base pieces assembled carrier system, which provides a viable solution for the antenna and feed networks.Based on substrate integrated waveguide technology, a circularly polarized antenna is designed in this paper. The antenna has a good VSWR bandwidth,the orthogonal coupling slots is used for excitating circularly polarized wave,an air layer is adopted fot broadening the AR bandwidth. The proposed antenna achieved 26.5-28.9GH 3dB axial ratio bandwidth and gain of 8.42 dBic respectively.Finally,A 4-unit circularly polarized slot antenna array is designed for achieving higher gain. The properties of the array has good broadband of 25.5-30 GHz 3dB axial ratio bandwidth and gain of 13.33 dBic.