volume | PIER Journals

Abstract

In RF front-end circuits, the miniaturization and high-performance integration of duplexer remain critical challenges for 5G communication and IoT devices. A microstrip duplexer design scheme is proposed based on electric and magnetic coupling path separation and dual-mode characteristics. Through the collaborative design of second-order uniform impedance resonators and dual-mode T-shaped resonators, the design achieves signal separation for dual frequency bands at 2.4 GHz and 3.6 GHz. The design forms the electric coupling path via edge-gap coupling of rectangular split-ring resonators, and realizes magnetic coupling path through vias. By independently regulating electric and magnetic coupling strengths, eight transmission zeros are introduced on both sides of the dual passbands, significantly enhancing out-of-band suppression and port isolation. The simulation results show that the passband insertion loss is less than or equal to 1.9 dB. Due to machining tolerances, the measured center frequencies shift to 2.04 and 3.48 GHz, while the out-of-band rejection remains better than 39 dB, validating the engineering adaptability of the design. This scheme achieves high-performance integration of RF front-ends in a compact architecture through the coordinated regulation of multiple transmission zeros and coupling path separation technology, providing a solution for wireless communication devices.

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Dr. Mingxin Liu

Dr. Jialin Zhang

Dr. Yan Zhang

Dr. Qunjie Zhang

Dr. Lin Fu