The use of a pair of spur lines for broadband circular microstrip antenna with embedded reactive loading

This communication demonstrates the use of a pair of spur lines for a broadband circular microstrip antenna with an embedded reactive loading. With the use of the spur lines, the impedance bandwidth of the proposed design can be enhanced. The obtained bandwidth can reach up to 112.5 MHz, which is about 1.32 times that (86 MHz) of the original broadband antenna without spur lines. The variations in antenna gain within the impedance bandwidth are also less than 2 dBi. Details of the proposed design are described, and experimental results of the antenna performance are presented and discussed.