Design of reconfigurable siot antennas with polarization diversity

• Main Authors: Yu-Yi Chu, 朱祐頤
• Other Authors: 羅鈞壎
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/98924482372079567818

碩士 === 國立彰化師範大學 === 電機工程學系 === 96 === A three-element circularly-polarized (CP) slot antenna composed of a circular wide slot, a director patch, and a metallic reflector is first studied in this thesis. The CP radiation of the slot antenna is excited by the proximity coupling of an L-shaped strip. To obtain an optimum peak gain and a broad CP bandwidth, the effects of varying the positions of the director and reflector on the antenna performances are respectively investigated. Then, the three-element CP slot antenna structure is used to design a reconfigurable antenna whose polarization can be adjusted by mechanically rotating a conducting strip. A prototype of the reconfigurable antenna was implemented and measured. Experimental results exhibit that the prototype can provide one linear polarization and dual circular polarization operations over a 10dB-return-loss impedance bandwidth of 21 %; moreover, the antenna gain is around 10 dBi for each polarization operation. Finally, a grounded ring slot antenna with CP operation is studied to reduce back radiation, and it is used as the elements of polarization reconfigurable arrays with a series-fed network. The polarization switching of the arrays is achieved by controlling the states of diodes. Details of the array designs are described. Keywords: slot antenna, broadband, high gain, polarization switching, array