Dielectric duplexer with different capacitive coupling between antenna

Abstract

A compact and highly effective dielectric duplexer comprises a dielectric ceramic block and a plurality of resonators arranged in a direction in the dielectric ceramic block, a half of the resonators constituting a transmitting section T, the remaining half of the resonators constituting a receiving section R, wherein an antenna terminal pad is capacitively coupled to the innermost resonator of the transmitting section T and to the innermost resonator of the receiving section R located adjacent to the innermost resonator to eliminate the use of a wave-dividing resonator, whereby the dielectric ceramic block can be dimensionally reduced in the direction along which resonators are arranged and hence it is adapted to down-sizing. Additionally, the coupling capacitance Ct of the antenna terminal pad and the transmitting section T is made greater than the coupling capacitance Cr of the antenna terminal pad and the receiving section R, whereby a return loss is reduced in both the transmitting section T and the receiving section R to improve the signal transmitting performance and the signal receiving performance of the dielectric duplexer.