The Design of Broadband Microstrip Antenna

• Main Authors: Wen Chen-Lai, 賴文正
• Other Authors: Ming Cheng-Liang
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/epk5rm

碩士 === 義守大學 === 電子工程學系 === 89 === Broadband and circular polarization(cp) is essential in many microwave application .The reason why we note is that it gets the ability of increasing the transmission speed and reducing the multipath reflection and several kind of interference. So the microstrip patch antennas that own the advantages are widely utility in Communication .In this article ,we propose a new simple design to conquer the narrow impedance and polarization bandwidth that is produced by single patch , single feed on the same layer. Moreover, we construct the double-layer structure, upper is circular radiating patch and lower is wilkinson power divider.The power divider has a 90。shift difference(1/4λlength difference) between its two outputs. But the bandwidth is limitted by the inductance introduced by the long conductor feeds . In this new design ,we load branch capacitance on power divider 70.7Ω branch parallelly the isolation resistance 100Ωto cancel out the inductance. By controlling the branch-capacitance and the height of air layer ,the 49% impedance bandwidth and 20% cp bandwidth are obtained.