2023 Volume 16 Pages E22-006-1-E22-006-8
In order to realize a planar quadruplexer, we analyzed a dual-mode resonator based on a hairpin resonator, focusing on the resonant frequency and transmission zero. Using the analyzed resonator, four types of bandpass filters (BPFs) with different center frequencies were designed for use in a quadruplexer applying a microstrip line structure. The target passbands of each BPF are approximately 1.9 to 2.2 GHz, 2.3 to 2.6 GHz, 2.7 to 3.0 GHz, and 3.1 to 3.5 GHz, which are very close together. A matching circuit to connect the four BPFs was designed in order to realize a quadruplexer, and the circuit was analyzed using a circuit simulator and an electromagnetic simulator. The analytical results are in good agreement with the experimental results based on the microstrip line structure.
