A linear phased array design with pattern reconfigurable elements

Date

2023-12-1

Author

Berberoğlu, Ali

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In a beam steering array, if elements with broadside radiation pattern are used, the gain of the array decreases due to the element pattern, as the scan angle gets further away from the broadside direction. To prevent this loss, pattern reconfigurable antennas that can direct its main radiation direction towards the array scanning direction, can be utilized. In this thesis a pattern reconfigurable antenna suitable for beam scanning array applications is designed. 5G small cell base station antenna is chosen as the application area with an operating frequency of 26 GHz. A circular microstrip patch in the center, surrounded by a microstrip ring antenna is used to generate different radiation patterns by utilizing different radiation modes of each resonator and the antenna is designed to have two feeds to excite these modes. Conical and broadside beam patterns are obtained when the antenna ports are fed in-phase and out-of-phase, respectively. In addition to that, the direction of the main beam can be tilted from broadside for different amounts of phase difference between ports. Furthermore, by feeding the ports with different amplitudes, the radiation at the opposite side of the beam tilt can be suppressed. The performance of the antenna is examined in an array environment by building an 8-element linear array. Simulation results of the array demonstrate that a 1.2 dB increase in the gain of the array is obtained with pattern reconfigurable elements, compared to the array with broadside radiating elements, when the array is scanned to 40°. The antenna and the 8-element array are manufactured at METU MEMS Center by using micromachining processes. Only the S-parameter measurements of the antenna are performed with a probe station. The measured results show that the resonance frequency shifts towards lower frequencies, which might be due to production tolerances of the manufacturing process.

Subject Keywords

Pattern reconfigurable antennas, Array antennas, Patch antennas

URI

https://hdl.handle.net/11511/107679

Collections

Graduate School of Natural and Applied Sciences, Thesis