A novel top-sleeve monopole in two parallel plates

A novel top-sleeve monopole antenna in two parallel plates is presented, which is developed to enhance its impedance bandwidth in a significant manner. By the introduction of a sleeve into a common SMA connector with a thin dielectric jacket, a noticeably broad bandwidth on the order of up to 70% is achieved for the proposed antenna. An eigenmode expansion technique is used to simulate the impedance characteristics of the top-sleeve monopole. The effects of geometric parameters of the structure, such as the sleeve length, monopole length, and the plate spacing on its impedance characteristics, are investigated. On the basis of our theoretical studies, an experimental prototype with bandwidth of 50% is designed and its characteristics are confirmed experimentally.