Design of Planar Electromagnetic Lens and Frequency Selective Surfaces

• Main Authors: CHIN, JUI-CHING, 靳睿晟
• Other Authors: CHANG, CHIA-CHAN
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/e5zx59

碩士 === 國立中正大學 === 電機工程研究所 === 106 === In this thesis, three electromagnetic lens with different functionalities are proposed, including the Frequency Selective Surfaces (FSSs), focusing/steering Fresnel lens, and focusing electromagnetic lens. FSS uses double circular loops to realize dual stop-band resonators. The overall dimensions of FSS are 200×200 mm and the pass-band is from 8 GHz to 12 GHz. Fresnel lens is designed based on the single-slit diffraction theory. The purpose of this lens is to collect power for antenna gain enhancement, leading to beam-shaping and beam-scanning functionalities. Measurement results show that using the lens can increase the lens can increase the peak gain of 5 dB, and consequently the 3-dB beamwidth is reduced from 39∘to 15∘in E-plane patterns and form 43∘to 13∘ in H-plane patterns. By positioning the antenna and lens with a offset from the center axis, the radiation beam direction can be steered from -27∘to +27∘with offset range from -60 mm to +60 mm. Furthermore, this proposed Fresnel lens is also made with flexible substrate for potential use in the communication system. The third lens is using a mapping equation to transform the original coordinate to another coordinate with distortion. It can be equivalent to a convex lens with beam focusing property. The testing results show that this lens can also significantly enhance antenna gain.