Compact Antenna for Microwave Imaging Systems

A planar antenna with ultra wideband directive performance is presented. It is aimed to be part of a microwave imaging system for breast cancer detection. The antenna is designed to operate efficiently across the ultra wideband frequency (3.1 GHz to 10.6 GHz). It has a very compact size with overall dimensions of 0.9 cmtimes1 cm. The antenna is assumed to be immersed in a liquid of a high dielectric constant to improve the matching with the breast tissues, and thus to increase the dynamic range of the system. The time domain performance of the antenna shows negligible distortion, which makes it suitable for the medical imaging systems utilizing a short pulse for its operation. The effect of the multilayer breast tissues on performance of the antenna is also investigated by calculating the fidelity factor across all layers of the breast. It is shown that due to multiple reflection/scattering, the fidelity factor decreases as the signal propagates inside the breast. However, the fidelity factor is always larger than 80% revealing the possibility of using the proposed antenna in the microwave imaging systems.