Design of a dual-polarised wideband short backfire antenna with high gain

The short backfire antenna (SBA) has been widely used for mobile satellite communications, tracking, telemetry and wireless local-area network applications. A dual-polarised wideband SBA excited by a hybrid configuration of waveguide and ortho-mode transducer is described here. The bandwidth widening of the antenna is achieved by the appearance of the second resonance point, owing to the parasitic reflector suspended on the conical sub-reflector. The aperture radiation efficiency is improved according to the reshaping of primary and sub-reflector, as well as the choke device added to the primary reflector. The antenna is designed to operate within the L-band. It has a frequency bandwidth for voltage standing wave ratio <= 1.5 of about 8% and a maximum gain of 20 dB. Within the antenna bandwidth, the gain and the radiation efficiency have values more than 19.5 dB and 76%, respectively. The designed antenna has a simple and compact construction and high mechanical and electrical characteristics; hence, it is appropriate for the satellite communication application. The operating mechanism is investigated to explain why the SBA can obtain good impedance and radiation characteristics. A parametric study is conducted for the use of practical engineering design.