Compact microstrip diplexer using triple-mode stub loaded resonators

摘要

This paper presents the design of compact microstrip diplexer using triple-mode resonators. This diplexer consists of two triple-mode stub loaded resonators which have the same size but dissimilar resonance frequencies for combining the diplexer. The proposed diplexer features compact size and can be tuned to be functioned as together two resonators such that the pair of even-mode resonant frequencies can be flexibly controlled while the odd-mode resonant frequency is reserved at the fundamental frequency. The diplexer operating at 1.75/1.95 GHz, and exhibits sharp attenuations near its passband is implemented and the area of the circuit is only 0.35λg × 0.40λg. An experiment was done for this diplexer, and the measurement results are in good agreement with the simulation predictions.