An investigation of broadband antennas

Abstract

Broadband antennas are not just a novelty, but fast becoming a necessity. As more and more frequency bands are utilized for wireless communications, and ever higher date rates are demanded, broadband antennas are becoming the de facto standard. Traditionally, broadband antennas are realized using frequency independent concepts (absence of characteristic lengths and self-complementary structures). More recently, the ultra-wideband (UWB) antenna has gained popularity due to its low complexity and cost, low interference and high data rate. In this thesis, different modifications to the edges of the slot were introduced to improve the bandwidth performance of the UWB planar volcano-smoke antenna (PVSA). The modified PVSAs achieved a 40% to 60% improvement in the impedance bandwidth over the original antenna. A straightforward and fast synthesis method was also derived for PVSA. Finally a novel broadband P-shaped slot antenna is designed and implemented on LTCC substrate. It displayed excellent radiation properties and had a bandwidth of 40%. The use of the high-K dielectric loading in the slot of the P-shaped antenna was investigated. It was found that the high-K dielectric loading had the effect of lowering the operating frequency of the antenna. Therefore, high-K dielectric loading has the potential for miniaturization of the antenna.