A Microstrip Antenna with 180 Degree Out-of-Phase Power Divider Function and Its Application to Array Antenna Design

• Main Authors: Su, Yu-Ting, 蘇育廷
• Other Authors: Chung, Shyh-Jong
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/44042293162311559071

碩士 === 國立交通大學 === 電信工程研究所 === 101 === In this thesis, a microstrip antenna with 180 degree out-of-phase power divider function and its application to array antenna design are proposed. This three-port microstrip antenna composed of two substrates and three metal layers is fed by a microstrip line at bottom layer and double metal vias between top and bottom layers, whose diameters are different. Two high-impedance microstrip lines at top layer are connected to the microstrip antenna to feed the subarray at the two sides. By changing the size, spacing and offset of the double metal vias and the length of the opening stub at the end of bottom microstrip line, we can exactly control the power division ratio and phase difference of the two ports at top layer. The rules of designing this antenna are generalized and applied to the synthesis of array antenna of 77 GHz vehicle collision-warning radar system in this thesis. In order to minimize the size of the system, antenna and RF circuit have to be placed at different layers, therefore, signals need to transfer from bottom to top layer to feed antenna. Besides, in case the feeding structure do not need to placed at the center of antenna array, the degrees of freedom of designing RF circuit layout at bottom layer would increase. The three-port microstrip antenna we introduced has this two characteristics: layer-transfer function and ability to synthesize offset-feed antenna array.