Mahdi Moosazadeh

A Compact High-Gain and Front-to-Back Ratio Elliptically Tapered Antipodal Vivaldi Antenna With Trapezoid-Shaped Dielectric Lens

A modified compact antipodal Vivaldi antenna is proposed with good performance for different applications including microwave and millimeter wave imaging. A step-by-step procedure is applied in this design including conventional antipodal Vivaldi antenna (AVA), AVA with a periodic slit edge, and AVA with a trapezoid-shaped dielectric lens to feature performances including wide bandwidth, small size, high gain, front-to-back ratio and directivity, modification on E-plane beam tilt, and small sidelobe levels. By adding periodic slit edge at the outer brim of the antenna radiators, lower-end limitation of the conventional AVA extended twice without changing the overall dimensions of the antenna. The optimized antenna is fabricated and tested, and the results show that S11 <; -10 dB frequency band is from 3.4 to 40 GHz, and it is in good agreement with simulation one. Gain of the antenna has been elevated by the periodic slit edge and the trapezoid dielectric lens at lower frequencies up to 8 dB and at higher frequencies up to 15 dB, respectively. The E-plane beam tilts and sidelobe levels are reduced by the lens.

UWB elliptically-tapered antipodal Vivaldi antenna for microwave imaging applications

An elliptically-tapered antipodal Vivaldi antenna with operating frequency range from 1.65 GHz - 18 GHz designed for microwave imaging applications is presented. It includes comb-shaped slits and opening elliptical rate of top and bottom radiators to lower frequency band limitation of conventional antipodal Vivaldi antenna. It is shown that the antenna gain has been increased by comb-shaped slits at lower frequencies up to 9.5 dBi at 2 GHz and at higher frequencies up to 14.2 dBi at 18 GHz. Feasibility of the proposed antenna for the use in microwave imaging technique is also demonstrated.