Active Broad X-Band Circular Patch Antenna

This letter presents the results of experimental study of omnidirectional circular patch antenna operating in the $ TM_010$ mode. Antenna geometrical parameters have been selected on the basis of theoretical calculations. It has been shown that the antenna of this kind with $ VSWRle 2$ and bandwidth of 18% has a conical radiation pattern with maximum oriented 36 $^circ$ to the zenith. The antenna has a side radiation level of $- 15~ dB$ and a cross-component level of less than $- 25~ dB$. The experimental results are in good agreement with the theoretical calculations. Employment of the one-stage HEMT amplifier makes it possible to obtain the total gain of an active antenna of no less than 10 dB. This antenna can be successfully used for mobile systems, wireless indoor communications, as well as for array applications.