Design of Planar Six-Port Crossover With Two Cascoded Rings and Defected Ground Structure Dual-Band Bandpass Filter

• Main Authors: Wei-Min Chuang, 莊偉閔
• Other Authors: Ching-Wen Tang
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/9fj7wk

碩士 === 國立中正大學 === 電機工程研究所 === 103 === In the first study, A six-port crossover have been proposed in this thesis. Analytical equations of the circuit are derived by using the even-odd mode and the sixfold symmetry methods. By the approach of cascoding two rings with quarter-wavelenth branches, the six-port crossover can be implemented greatly. Moreover, based on the derived formulas, the software ADS is used to calculate the performance for selecting line impedance, investigated on the predetermined operational bandwidth. For experimental verification, the presented crossover has a bandwidth of 13.5% for 15dB return loss. Compared with the other previously reported, it has feature for wide operational bandwidth and compact size. The second part is design the dual-band bandpass filters with DGS(Defected Ground Structure) resonators. Combining the two DGS resonators, the results of dual passbands can be obtained. In addition, the use of tapped input/output and adjust the gap between two DGS resonators can achieve the simultaneously matching among the designated passbands. This filter is simulated with full-wave electromagnetic simulator HFSS, and the prototype of the bandpass filters are fabricated and measured. Comparing with simulated results and experimental data, we can find that the measured results can match well with the EM simulation