Single-feed dual-frequency rectangular microstrip antenna with a -shaped slot

Abstract

A novel slotted rectangular microstrip antenna for dual-frequency operation is proposed. The microstrip antenna is fed by a single probe feed and has a π-shaped slot embedded close to the patch's radiating edge. The two operating frequencies have the same polarisation planes and similar broadside radiation characteristics. By varying the lengths and the spacing of the two arms of the π-shaped slot, the proposed antenna can have a tunable frequency ratio ranging from about 1.12 to 1.64. Simple semi-empirical formulas of the two operating frequencies have also been obtained. Details of the antenna design and experimental results are presented and discussed.