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- 实验方案
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High-Performance Tunable Narrowband SIW Cavity-Based Quadrature Hybrid Coupler
摘要： This letter presents, for the first time, a tunable narrowband substrate integrated waveguide (SIW) cavity-based quadrature hybrid coupler. Four high-quality factor (Q) SIW evanescent-mode cavity resonators are employed in the design and tuned using piezoelectric actuators. This allows the proposed coupler to have wide spurious-free range (SFR), low-power consumption, and high-power handling capability compared to other tunable planar couplers. The coupler can be tuned starting from 1.32 to 2.22 GHz with a measured insertion loss range from 1.29 to 0.7 dB. Over the full range, the measured 3-dB fractional bandwidth ranges from 5% to 18% while the phase error (∠S21 ? ∠S31) absolute bandwidth measured ±5° ranges from 40 to 82 MHz with an amplitude imbalance range between 1 and 0.3 dB. The measured reflection and isolation are better than 12 and 17 dB, respectively. Moreover, the coupler has a measured SFR of 5.1–3 fo (lowest–highest frequency).
关键词： tunable quadrature hybrid coupler,Evanescent-mode (EVA) cavity,tunable resonators
更新于2025-09-23 15:22:29
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Ultra-Compact Tunable Filtering Rat-Race Coupler Based on Half-Mode SIW Evanescent-Mode Cavity Resonators
摘要： In this paper, for the first time, an ultra-compact frequency-tunable filtering rat-race coupler based on half-mode evanescent-mode (EVA) cavity resonators is presented. Employing EVA cavity resonators in the coupler design yields attractive characteristics, such as a wide tuning range and a wide spurious-free range, while also adding filtering functionality to the device. The presented coupler is synthesized as a two pole bandpass filter using the coupling matrix method. Then, the coupling coefficients are mapped to a coupler topology. Design, simulations, and experimental validation are presented. The implemented rat-race coupler has a very compact size [0.14λg × 0.14λg (λg at 885 MHz)] achieving a 92% miniaturization in the structure footprint compared to the conventional planar one. The coupler has an 86% tuning range ranging between 0.885–1.65 GHz. Throughout the tuning range, the coupler shows an equal power splitting ratio and filtering profile with a measured insertion loss and 3-dB fractional bandwidth between 5 and 4.2 dB and 6.8% and 8%, respectively. The measured isolation is better than 30 dB. In addition, the coupler has a measured spurious-free range of 10.2 fo (at the lowest frequency) to 5.45 fo (at the highest frequency).
关键词： rat-race coupler,tunable resonators,Evanescent-mode (EVA) cavity,tunable coupler,half-mode
更新于2025-09-11 14:15:04