DESIGN AND INVESTIGATION OF A DUAL-BAND ANNULAR RING SLOT ANTENNA FOR AIRCRAFT APPLICATIONS

A novel dual-band annular ring slot antenna is investigated. The antenna consists of a center-fed circular microstrip patch antenna with a coupled annular ring. And it is shorted concentrically with a set of conductive vias. By adjusting the parameters of the antenna, the dual resonant frequencies for two modes ([TM.sub.01] and [TM.sub.02] modes) are achieved. The antenna is fabricated and tested. Results show that the proposed antenna with height of 0.0217[λ.sub.0] can provide gains of 3.01 dBi at 2.6 GHz (the receiving frequency) and 5.74dBi at 2.95 GHz (the transmitting frequency). Good agreement between the measurement and simulation for the return loss and radiation patterns is achieved. The proposed antenna has dual-band characteristics, simple structure, low profile, and omni-directional azimuth radiation pattern. It is suitable for aircraft both receiving and transmitting signals and frequency division duplex (FDD) applications.