The Miniaturization Design of C/S Band LTCC Low Loss Duplexer

This paper presents a miniaturized low-loss duplexer based on low temperature co-fired ceramic (LTCC) technology. The duplexer adopts LC structure composed of an S-band low pass filter (LPF) and a C-band band-pass filter (BPF). Serial and parallel resonators are used to achieve transmission zero in the two different filters, so as to improve suppression of the two pass-bands. By electromagnetic simulation and optimization,the measured result agrees well with the simulated one. The LPF's insertion loss is less than 0.35 dB, the BPF's loss is less than 0.6 dB, and good suppression is achieved within the desired frequency band. This miniaturized LTCC duplexer has been applied in some WLAN modules.