Design of Wideband Rotman Lens Microstrip Phased Array Antenna

Abstract

Beam formers are well known in modern radars and antenna-based systems applications. Since the demand of wide angular coverage, adaptive beam power, and operate over a wide range of frequencies increased, the development of beam formers are rapidly increasing. Microwave is a wide area that supports wideband, and true time delay device. Rotman Lens (RL) antenna is a type of microwave device. This device consists of beam ports that transmit signal to array port which radiate the energy to antenna array elements. The main objective of this thesis is to design and implement an improved Rotman lens design with optimum performance in the wide bandwidth of 2-6 GHz with scanning range of ± 50º. This take the form of wider angular, lower phase error, lower cost, and more compact. This is achieved by electronically controlling the phase of the individual array elements. The RL was specifically designed for 11 input beam ports and 8 output array ports including 16 dummy ports to absorb the reflections. To design the RL, Genetic algorithm was implemented in the Matlab. A lot of iterations were made in the algorithm to attain the optimum performance. The parameters taken from Matlab were used in CAD-Feko software to check the performance. The performance of the RL was analyzed in terms of scattering-parameters and array factor. Another software REMCOM was also used to simulate the lens, and then both simulation results were compared. The RL was then fabricated, and measured. The fabricated lens was verified and validated by comparing the measurement results with FEKO simulation results. The measurement results have reflection co-efficient of less than -10 dB in the complete bandwidth and transmission co-efficient within the limits of 5 dB variation. The project was executed using specialized antenna softwares which are FEKO and REMCOM.

Date of Award	Apr 2018
Original language	American English
Supervisor	Baker Mohammad (Supervisor)