Abstract In this paper, parallel coupled meander lines (PCML) composite right/left-handed transmission line (CRLH-TL) based symmetrical quasi-0 dB coupled-line coupler is presented. Proposed coupler shows measured backward wave coupling level of 0.81 dB at frequency of 6.17 GHz with 3 dB fractional bandwidth (FBW) of 12.64%. Throughout the 3 dB frequency range (5.78–6.56 GHz), isolation and insertion loss of the coupler is better than 24 dB. Overall size of the proposed coupler is 19.6 × 12.1 mm. An equivalent lumped LC circuit model of the coupler is demonstrated. Measured results of the coupler show good agreement with the electromagnetic (EM) simulated and lumped LC circuit model simulated results, which validates proposed coupler design and its performance.

中文翻译：

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基于对称准 0 dB 耦合器的紧凑型平行耦合曲折线形复合左手/右手传输线 (CRLH-TL)

摘要 本文提出了一种基于平行耦合曲折线（PCML）复合左右手传输线（CRLH-TL）的对称准0 dB耦合线耦合器。建议的耦合器显示在 6.17 GHz 频率下测得的反向波耦合电平为 0.81 dB，3 dB 分数带宽 (FBW) 为 12.64%。在整个 3 dB 频率范围 (5.78–6.56 GHz) 中，耦合器的隔离和插入损耗均优于 24 dB。建议耦合器的总尺寸为 19.6 × 12.1 mm。演示了耦合器的等效集总 LC 电路模型。耦合器的测量结果与电磁 (EM) 仿真和集总 LC 电路模型仿真结果非常吻合，这验证了所提出的耦合器设计及其性能。