Compact ultra-wideband double-ridged horn antennas for medical imaging

This paper presents novel designs, analyses, and simulations of two miniaturised pyramidal double-ridged horn (PDRH) microwave antennas for medical imaging systems. The PDRH antennas have been optimised to operate within a ceramic material filling with permittivity of 41 (which approximately is the permittivity of the human skin in the intended frequency range), in order to make the compact antennas, and also to minimise the first bulky reflection due to the large contrast of the pulse from the free-space to the human skin surface, which cause the difficulty to process the overall reflected pulse. The proposed antennas can operate in conjunction with each other to cover the whole radio frequency (RF) range of 1.25 to 2.47 GHz, where the high-gain and directivity for medical imaging systems are the main factors. Both RF antennas have the bandwidth larger than 500-MHz that would qualify them as ultra-wideband (UWB) antennas. The optimised designed microwave antennas are numerically verified based on the electromagnetic (EM) method of finite integration technique (FIT), using the CST Microwave Studio (CST-MWS) software.