Improved the Design for Wideband Balun and High-isolation Dual-Band Power Divider using Couple Transmission Lines

• Main Authors: Chiang-Lin Yen, 顏江霖
• Other Authors: Ching-Wen Tang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/2z67ga

碩士 === 國立中正大學 === 電機工程研究所 === 102 === The thesis includes two parts. The first part is introduced in chapter 3, which investigates the compensation of microwstrip Balun. The second part is introduced in chaper 5, which focuses on the isolation improvement of dual-band power divider. In order to increase the available bandwidth of Port-1, the traditional Marchand Balun shown in chapter 3 has been compensated by cascading a forward or reverse coupled line. In the analysis of fractional bandwidth defined by greater than 10-dB return loss, the impedance and coupling of the traditional Marchand Balun are fixed at fitst, and then we alter the impedance, coupling, and electrical length of the cascaded coupled line. Finally, the traditional Marchand Balun cascaded with a section of reverse coupled line has been chosen and verified. In chapter 5, a coupled line is cascaded at the output ports of the traditional Wilkinson power divider to realize the wideband performance. In addition, two open stubs shunted at the output ports saprately can produce the dual-band perfomance and improve the isolation between these two passbands at the same time. All the circuits are simulated with full-wave electromagnetic simulator. The results are well matched between electromagnetic simulations and measurements which has been evidenced the availability of all the proposed circuits.