Quasi-Reflectionless Filters Using Simple Coupled Line and T-Shaped Microstrip Structures
Quasi-Reflectionless Filters Using Simple Coupled Line and T-Shaped Microstrip Structures
复制标题
使用简单耦合线和 T 形微带结构的准无反射滤波器
DOI：
10.1109/jrfid.2021.3106664
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发表时间：
2022
影响因子：
3.1
通讯作者：
Qiang Chen
中科院分区：
文献类型：
--
作者：
K. Xu;Sen Lu;Yingjiang Guo;Qiang Chen
在本文中，两个简单的结构，耦合线和T形微带结构，用于构建四种类型的准无反射（QR）滤波器，包括单端口和双端口QR带通滤波器（BPF）和带阻滤波器（BSF）。首先，分别用两个电参数详细分析了耦合线和T形微带结构的特性。然后，利用这两种简单结构构成的FPGA结构设计了单端口QR BPF和BSF。在单端口QR滤波器结构的基础上，通过在输出端口附近增加一个吸收通道，构造了双端口QR BPF和BSF。给出了两种简单结构QR滤波器的分数带宽与3 dB分数带宽之间的关系，为QR滤波器的设计提供了指导。此外，一个简短的设计过程中提出的QR滤波器进行了总结。最后，为了验证所提出的方法的可行性，两个概念验证的微带原型的两端口QR滤波器的制造，其仿真和测量吻合良好。这项工作将有助于不同规格的QR滤波器的设计，并简化其设计过程。
In this paper, two simple structures, i.e., coupled line and T-shaped microstrip structures, are used to construct four types of quasi-reflectionless (QR) filters, including single-and two-port QR bandpass filters (BPFs) and bandstop filters (BSFs). First, the characteristics of the coupled line and T-shaped microstrip structures are analyzed in details using each two electrical parameters. Then, the single-port QR BPF and BSF are designed using duplexer architectures formed by these two simple structures. Subsequently, the two-port QR BPF and BSF are constructed through loading an additional absorption channel near the output port based on the architectures of single-port QR filters. The relations between the fractional bandwidth (FBW) of each type of QR filters and 3-dB FBWs of the two simple structures are provided, which give a guidance of the QR filter design with desired specifications. Moreover, a brief design procedure for the proposed QR filters is summarized. Finally, to validate the feasibility of the proposed approach, two proof-of-concept microstrip prototypes of the two-port QR filters are fabricated, whose simulations and measurements agree well with each other. This work will facilitate the design of QR filters with different desired specifications and simplify their design procedures.