Ultra-Wideband Antennas for Medical Imaging and Communication Applications

Abstract

<p> The allocation of 7.5 GHz of bandwidth by the Federal Communication Commission (FCC) for ultra-wideband (UWB) applications has provided an exciting and a challenging opportunity to design short range wireless communication and microwave imaging systems. To fully realize the potential of the UWB, communication and microwave imaging systems are required to operate over the entire UWB frequency band. The combination of the wide bandwidth requirement and the target application of the UWB systems have led to a surge of interest in designing of novel integrated circuits and antennas for the UWB applications. In any wireless communication and microwave imaging system, the antenna has a fundamental effect on the overall performance of the system, and as a result, it has attracted considerable research interest.</p> <p> This thesis focuses on the design of UWB antennas that are suitable for UWB cancer detection and wireless communication systems. Two planar antennas, one a printed monopole antenna, and the other, a printed slot antenna fed with a coplanar waveguide, are presented in this work. First, the antennas have been designed to operate in air, making them suitable for the UWB wireless short range communication applications. Measurement and simulation results indicate that both antennas achieve input impedance matching in a bandwidth of more than 7.5 GHz. The effect on the input matching of the antennas due to the variation in their geometrical parameters has been studied and both antennas have been fully characterized in air. Next, the two antennas have been redesigned to operate in a coupling medium for medical imaging applications. Both antennas achieve return loss of less than -10 dB over the entire UWB spectrum. Also, the antennas have been fully characterized while operating in the coupling medium and in proximity to a human body model. Finally, a two-element antenna array, based on the printed monopole antenna and the printed slot antenna, in co- and cross-polarized array formation, has been designed. The tumor detection capabilities of all antenna arrays for different scenarios have been studied through electromagnetic simulation and measurements.</p>