Vivaldi antenna with improved directivity for medical applications

This paper presents a compact balanced antipodal Vivaldi antenna for medical microwave imaging applications. The antenna is supposed to operate in a matching liquid with a high dielectric permittivity. The proposed antenna covers the frequency range from 0.5 GHz to over 3 GHz. In the presented design, the substrate between the tapered radiating parts of the antenna is removed and as a result the matching liquid fills the resulting cavity. Thus higher directivity and narrower beam in the E-plane are obtained. The results of the simulation are verified with the measurement of the fabricated prototype.