Low Insertion-Loss MMIC Bandpass Filter Using Lumped-Distributed Parameters for 5G Millimeter-Wave Application

Millimeter-wave (mm-wave) monolithic-microwave-integrated-circuit (MMIC) bandpass filters (BPFs) usually feature high insertion loss (IL). To this concern, an analytical method for low-loss MMIC BPFs is presented by using lumped-distributed parameters in this article. To reduce the IL, the enhanced-quality-factor resonator and low-loss coupling topology are both investigated. First, the proposed resonator and filter are realized by combining quasi-lumped elements and distributed mutual coupling. Both compact size and multiple transmission zeroes are accordingly realized. Second, a low-loss coupling topology is further introduced for MMIC filter by using mixed electric and magnetic couplings. For theoretical analysis, the lossy equivalent circuit modeling for mm-wave MMIC BPF is investigated, as well as an analytical parameter extraction. Based on the circuit analysis, a fast synthesis of low-loss mm-wave MMIC filter is presented. For demonstration, two compact MMIC BPFs are designed by using the gallium arsenide (GaAs) process. Low IL of only 0.95 dB, sharp rejection skirt of passband, and wide stopband are simultaneously obtained. The features of the proposed MMIC BPFs indicate promising applications in the fifth-generation (5G) mm-wave systems.