A Miniaturized Antipodal Vivaldi Antenna with Flat Gain for RF Energy Harvesting

A miniaturized Antipodal Vivaldi Antenna (AVA) with flat gain is proposed in this paper for UWB applications. This antenna is implemented by loading a pair of open stubs, comb-shaped slot array, and semi-elliptical patches on a traditional AVA. The miniaturization property is obtained as a result of the introduction of comb-shaped slits which increases the surface current path. The function of the pair of open stubs is to improve the gain in the lower frequency band, while the effect of the pair of semi-elliptical patches is to maintain the gain in the higher frequency band. In order to verify this design concept, a prototype of the proposed AVA is fabricated and measured. The measured results show that VSWR <; 2 in the frequency band of 3 - 11GHz and the average gain in is 8.9 dBi in the end-fire direction. Besides the gain fluctuation is ± 1.1dB within this impedance bandwidth, achieving a relatively flat gain.