A compact Balanced Antipodal Vivaldi Antenna with improved phase center stability for imaging and ultrawideband localization applications

This paper introduces a phase center stability improved Balanced Antipodal Vivaldi Antenna (BAVA) loaded with ‘I’ shaped non-resonant director array. The proposed antenna operates from 6 GHz to 18 GHz with S11 less than −10 dB and addresses the issue of phase reversal. The rectification of phase reversal produces enhanced phase center stability. Standard deviation is used to find least dispersed set of the phase center span calculated by varying design parameters of the director through a parametric study. By effective circumventing of phase reversal through improved coupling between the signal and ground planes, the proposed antenna achieves a maximum of 65.31% of improvement of phase center stability when compared to the reported Vivaldi antennas. In addition, further fine tuning of H-plane phase center stability for phi-components of about 6.5% at higher frequencies of operation is also attained using a meander-line section in the feed. With a size of 3.2λ0 ×1.6λ0 ×0.02032λ0 mm3, the proposed antenna exhibits sustained radiation patterns. Where λ0 is free space wavelength at 12 GHz. Full wave simulation of the design using CST microwave studio and experimental validation with a fabricated prototype are carried out.