SIW Multi-polarized Cavity Antenna Based on Polarization Synthesis of Multi-slots

SIW multi-polarized cavity antennas have been widely concerned because of their simple structure. Main mode (TE10 mode) is mostly used in this type of antenna at present, however, the number of slots on cavity surface is limited, which leads to low gain of the cavity. Based on SIW transmission mode, multi-inputs with inverse phase is used to excite high-order mode. According to the field distribution in cavity, the direction and phase of the radiation electric field of each slot on the cavity surface are analyzed, and a method of polarization direction synthesis is analyzed theoretically. A SIW multi-polarized antenna based on TE
220
mode is designed by this method, and the slot number of radiation cell is confirmed by discussing the influence of the number on the dispersion characteristics, transmission and radiation performances of the cavity. What’s more, the antenna gain is promoted by forming a 2×2 array. The measured results show that this array has good radiation performance with relative bandwidth of 10%, gain of 11.7dBi at 9.7GHz, and cross polarization ratio greater than 10dB, which verifies the effectiveness of the polarization synthesis method.