Wideband Microstrip Bandpass Filters with Asymmetrically-Loaded Interdigital Coupled Lines
Asymmetrically-loaded interdigital coupled lines are proposed for innovative design of wideband microstrip bandpass filters with excellent out-of-band performanceInboth lower and upper stopbands. It is realized by properly terminating one of outer coupling lines with a two-stage open-ended stub.In this way,the lower and upper stopbands can be greatly enhanced by adjusting the stepped-impedance ratio of suchA stub. Based on the analysis for a six-port three-line network,the resultant two-port network of the proposed interdigital coupled-lines can be derived in terms of the simple impedance or admittance parameters. Taking advantage of their tightened coupling degree and self-inclusive transmission zeros,they are utilized to implement a class of compact wideband filters. Two filters with one and two half-wavelength resonators are designed,aiming at achieving a desired passbandInthe frequency range 2.8 to 5.1 GHz and good out-of-band rejectionInDC to 2.8 GHz and 5.1 to 10.0 GHz. Measured results of the two fabricated filters have evidently verified the predicted wideband filtering performance.
Sheng Sun Lei Zhu
School of Electrical & Electronic Engineering,Nanyang Technological University,Singapore
国际会议
2008 International Conference on Microwave and Millimeter Wave Technology(2008国际微波毫米波技术会议)
南京
英文
10-13
2008-04-21(万方平台首次上网日期,不代表论文的发表时间)