Design of Ultra-Wideband Antipodal Vivaldi Antenna with Square Dielectric Lens for Microwave Imaging Applications

The design of ultra-wideband (UWB) antipodal Vivaldi antenna with a simple square dielectric lens is presented for microwave imaging applications. The cosine curvature on the ground plane effectively controls the impedance matching at low frequencies. Moreover, adding the rectangular dielectric lens in front of the antenna can enhance antenna gain at high frequencies without additional complex structure. The increase of length of rectangular dielectric lens leads to the higher gain and depends on the gain requirement for practical application. The prototype of the proposed antipodal Vivaldi antenna with square dielectric lens is fabricated and test. The proposed antenna can operate in the frequency range of 1.8 GHz to more than 12 GHz. The proposed antenna has a peak gain greater than 10 dBi over the working frequency band and has a maximum gain of 13.01 dBi at 7 GHz.