Antipodal Vivaldi Antenna with Ceramic Cone Lens for Biomedical Microwave Imaging Systems

Microwave imaging (MWI) for biomedical applications has drawn great attention in recent decades owing to its attractive features such as low cost, portability, and use of non-ionizing radiation. In the microwave imaging system, the antenna plays the most crucial role because it dictates the amount of electromagnetic power transmitted to the human body. In this contribution, an ultra-wideband antipodal Vivaldi antenna was designed for a biomedical MWI system. The antenna is immersed in a coupling medium of permittivity 23 and operates in the frequency band 0.5 - 5 GHz. The radiation of the antenna was improved by removing a piece of substrate from the aperture and replacing it with a high permittivity ceramic cone lens. Such a ceramic lens was capable to increase antenna radiation without changing the antenna impedance. This study paves the way for the assessment of a biomedical microwave imaging system.