Browsing by Author "Chin, KS"

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Insertion loss function synthesis of maximally flat parallel-coupled line bandpass filters
(2005-10-01)
Chin, KS
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
Insertion loss (IL) functions are derived for synthesis of microstrip parallel-coupled line bandpass filters with maximally flat responses. The derivation is performed by successively multiplying the ABCD matrices of all coupled stages. Simultaneous equations for determining linewidth and line spacing of the coupled stages are established by total Q (Q(T)) of the filter specification and comparing the IL function with the canonical form. The results are provided for filters of order N <= 6. Two filters with fractional bandwidths Delta = 30% are synthesized and demonstrated by simulation using a full-wave software package. In addition, two filters with Delta = 40% and 50% are fabricated. Tapped line inputs are employed to these two circuits since some linewidths or gaps are beyond the fabrication resolution. The measured results show very good agreement with the theoretical responses.
New formulas for synthesizing microstrip bandpass filters with relatively wide bandwidths
(2004-05-01)
Chin, KS
;
Lin, LY
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
New formulas are proposed for designing wideband parallel-coupled microstrip bandpass filters with improved prediction of bandwidth. When a fractional bandwidth Delta is required, a correction theta = (pi / 2) (1 +/- Delta / 2) is incorporated into the formulation for determining the dimensions of each coupled stage. Two filters with Delta = 50% are designed and fabricated to show the improvement. The measurement shows a very good agreement with the simulation.