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A well-known problem with microstrip patch antennas have for a long time been the low, 1-5 %, bandwidth. Extensive research to overcome this problem has been carried out during the last 10-15 years. As a result of this research several techniques to enhance the bandwidth have been proposed. These techniques have shown that it is indeed possible to increase the bandwidth considerably. The latest addition to the wideband patch antennas is the U-slotted patch antenna. Which, basically, is an ordinary patch antenna but with the difference that a U-shaped slot is etched in the patch. The U-shaped slot introduce an additional resonance frequency and thereby enhance the bandwidth. This thesis presents a parameter study of an aperture-coupled U-slotted microstrip patch antenna. Numerical calculations show that a high bandwidth, 47 % at SWR < 2, is achievable for the single element. The program used for the simulations where Ensemble 5.1, which is a 2.5-D program that uses a mixed potential integral equation formulation in conjunction with the method of moments to analyze microwave/millimeter-wave integrated circuits and printed circuit antennas. Furthermore numerical calculations of an infinite array consisting of aperture-coupled microstrip patch antennas where performed and the results are presented. Results shows that the array has a bandwidth of above 30 % (SWR < 2) at broadside. Ansoft HFSS 6.0, where used for the simulations of the infinite array. HFSS is a 3D simulation-software that uses the finite element method to make computations of full-wave and radiating effects for passive high-frequency structures.


	PARAMETER STUDY OF BROADBAND U-SLOTTED APERTURE COUPLED MICROSTRIP PATCH ANTENNAS Abstract
	A well-known problem with microstrip patch antennas have for a long time been the low, 1-5 %, bandwidth. Extensive research to overcome this problem has been carried out during the last 10-15 years. As a result of this research several techniques to enhance the bandwidth have been proposed. These techniques have shown that it is indeed possible to increase the bandwidth considerably. The latest addition to the wideband patch antennas is the U-slotted patch antenna. Which, basically, is an ordinary patch antenna but with the difference that a U-shaped slot is etched in the patch. The U-shaped slot introduce an additional resonance frequency and thereby enhance the bandwidth. This thesis presents a parameter study of an aperture-coupled U-slotted microstrip patch antenna. Numerical calculations show that a high bandwidth, 47 % at SWR < 2, is achievable for the single element. The program used for the simulations where Ensemble 5.1, which is a 2.5-D program that uses a mixed potential integral equation formulation in conjunction with the method of moments to analyze microwave/millimeter-wave integrated circuits and printed circuit antennas. Furthermore numerical calculations of an infinite array consisting of aperture-coupled microstrip patch antennas where performed and the results are presented. Results shows that the array has a bandwidth of above 30 % (SWR < 2) at broadside. Ansoft HFSS 6.0, where used for the simulations of the infinite array. HFSS is a 3D simulation-software that uses the finite element method to make computations of full-wave and radiating effects for passive high-frequency structures.