A rectangular cavity-backed cross-loop slot antenna

For the application of antennas on high speed moving objects, such as space shuttles, airplanes and bullet trains, low-profile and flat-structured planar antennas are the most eligible. A slot antenna is one of the major interests because of its flush mounting and simple structure. We previously reported that a rectangular cavity-backed slot antenna with parasitic slots has a VSWR bandwidth of 10.6% (see Kotani, T. et al., IEEE AP-S Int. Symp. on Antennas and Propagat., July 2001). A rectangular cavity-backed cross-loop slot antenna, whose cavity size is the same as in the previous report, is proposed and the characteristics are investigated. The method of moments (MoM) is used to calculate the antenna characteristics (see Shi, S. et al., IEEE Trans. Antennas and Propagat., vol.49, p.1517-24, 2001). By introducing a short point on the slot and choosing its proper position, the VSWR bandwidth is increased from 5.2% to 17.2%.