Ceramic monoblock filter with inductive direct-coupling and quadruplet cross-coupling

摘要

A ceramic monoblock filter including a direct signal path defined by at least four spaced-apart through-hole resonators in combination with ground bars extending between the through-hole resonators and a separate quadruplet cross-coupling alternate signal path defined by two conductive pads located adjacent the first and fourth ones of the through-hole resonators respectively and a separate external bridge member which interconnects and couples the two pads. The bridge member is preferably made of a material having a lower dielectric constant than the block of the filter. In one embodiment, the filter is a monoblock duplexer filter comprising respective transmit and receive sections each including at least four of the through-hole resonators, the ground bars, the two pads, and the bridge member. In the duplexer embodiment, additional through-hole resonators may define shunt zeros.