Modeling a longitudinally coupled dual-mode leaky-SAW resonator filter with enhanced upper-sideband suppression.
Recently, it has been experimentally reported that enhanced upper-sideband suppression of a longitudinally coupled (first/third) dual-mode leaky SAW (LSAW) resonator filter may be obtained by incorporation of a selectively valued capacitor between input and output terminals. In this paper, coupling-of-modes (COM) and bandstop-filter modeling is applied to realize this enhanced suppression. Tradeoffs are examined between upper and lower side-band suppression levels caused by the ensuing capacitive coupling between input and output terminals. Good agreement is obtained between this theory and reported experimental results for an 800-MHz band cellular filter.
Campbell
C K
CK
Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada. colin.kydd.campbell@sympatico.ca
Edmonson
P J
PJ