A Compact Wideband 180o Hybrid Coupler and Its Applications to Wideband Coupler and Bandpass Filter Designs

• Main Author: 紀鈞翔
• Other Authors: 張志揚
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/74452306160137140777

博士 === 國立交通大學 === 電信工程系所 === 97 === This dissertation presents the research and application of the compact wideband 180 degrees hybrid coupler. In the first part, a stepped-impedance wideband 180 degrees hybrid ring coupler with a novel wideband 180 degrees phase-shifter implemented by the hybrid CPS/interdigital CPS structure is introduced. Due to the combination of the stepped-impedance structure and a wideband phase inverter, the proposed hybrid coupler achieves size reduction, wide bandwidth, and excellent phase and amplitude performances. In the second part, wideband multi-section 180 degrees hybrid couplers using the vertically installed planar (VIP) coupler are proposed. On the basis of the reconfigured ideal single-section 180 degrees hybrid coupler (the 180 degrees hybrid coupler with an ideal phase inverter), the multi-section 180 degrees hybrid rings can be realized by properly cascading of the single-section 180 degrees hybrid coupler. Compared to the conventional 3/2 wavelength 180 degrees hybrid ring, the two-section hybrid rings exhibit wide bandwidth, size reduction, and easily achievable high power-division ratios. Finally, a wideband bandpass filter with wide upper stopband is presented by cascading two stepped-impedance 180 degrees hybrid couplers. Analysis procedures of above-mentioned circuits are described in detail. Also, design equations and design curves are presented. Therefore, we can systematically design these circuits.