Browsing by Author "Liao, CK"

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Design of microstrip quadruplet filters with source-load coupling
(2005-07-01)
Liao, CK
;
Chang, CY
;
電信工程研究所
;
Institute of Communications Engineering
Quadruplet microstrip filters with source-load coupling are proposed to achieve similar skirt selectivity and/or in-band flat group delay as that of a sixth-order canonical form or an extracted pole microstrip filter. The diagnosis method of unwanted effects such as asynchronous resonant frequencies and unwanted couplings, which often occurs in the microstrip's open environment, is described in detail. A systematic design flow to implement a quadruplet microstrip source-load coupled filter with proper filter response is also provided. Two trial filters exhibited quasi-elliptical and flat group-delay response are designed and fabricated. Both theoretical and experimental results are presented.
Modified parallel-coupled filter with two independently controllable upper stopband transmission zeros
(2005-12-01)
Liao, CK
;
Chang, CY
;
電信工程研究所
;
Institute of Communications Engineering
A microstrip cross-coupled filter with two independently controllable transmission zeros on upper stopband is presented. The initial filter structure is a conventional Chebyshev-response parallel-coupled filter that can be easily realized by the analytical method. The newly proposed coupling/shielding lines can effectively control the cross and main couplings without changing the original filter layout. This approach allows a designer to eliminate the tedious segmentation method, which is usually used to establish the relation between the coupling coefficient and physical distance between resonators. A three-order filter is designed and fabricated for demonstration.