Sample Designs of Microwave Passive Circuits Using Suspended Striplines

• Main Authors: Xian-Jie Liao, 廖顯傑
• Other Authors: Min-Hua Ho
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/20872449786601260747

碩士 === 國立彰化師範大學 === 電信工程研究所 === 98 === In this thesis, quasi-lumped design of filters using the suspended stripline (SSL) is demonstrated. The proposed SSL filters have achieved the benefits of size compactness, extremely low insertion losses, low dispersion, high operation frequency, and sometimes the wide stopband bandwidth. The SSL filters include the low-pass filters (LPFs), the high-pass filters (HPFs), the bandstop filter (BSF), and the bandpass filters (BPFs). The BPFs are implemented by a cascade of an LPF and an HPF, and demonstrates the performance in a UWB application that covering a frequency range from 3.1 to 10.6 GHz. Two UWB BPFs are built to exhibit benefits of compactness, low losses, steep band-edge slops, and wide stopband BW. A novel design of a suspended stripline using stepped impedance suspended stripline (SISSL) in building the diplexer. The diplexer’s characteristics are analyzed by a lumped-element circuit model of the SISSL. In the last, we demonstrate the design of the directional coupler , the proposed belt line of suspension (Suspended stripline, SSL) using the SSL structure. Two meander SSL lines deposited above and below directional coupler is the substrate, respectively, compose the directional coupler. The overlapping length of the SSL lines control the coupling strength between them to achieve the 3-dB coupling effect. The length of the SSL is set to λ/4 of the mid-band frequency of the target band. All mentioned microwave circuit’s behaviors are analyzed by their developed equivalent circuit models based on lumped elements. Calculated data from the lumped elements circuit models and those from the commercial electromagnetic software vs. the dimensions of the SSL are given in the figures. Experiments are conducted to verify the passive circuits design.