新型三频环形耦合器的设计  

Design of a Novel Tri-Band Rat Race Coupler

作　　者：林峰[1] 褚庆昕[1] 

机构地区：[1]华南理工大学电子与信息学院,广东广州510640

出　　处：《华南理工大学学报（自然科学版）》2011年第7期26-31,共6页Journal of South China University of Technology(Natural Science Edition)

基　　金：NSFC-广东省自然科学联合基金资助项目(U0635004);国家自然科学基金青年科学基金资助项目(60801033);广东省自然科学基金重点项目(07118061)

摘　　要：传统环形耦合器只能工作在单一基频,且具有奇数次谐波.为此,文中提出了一种新型三频环形耦合器的设计方法,利用有4种电路拓扑结构的Π型阶梯阻抗变换器(ΠSIT)替代传统环形耦合器中的1/4波长阻抗变换器,使得环形耦合器可以同时工作在任意两个频率及其中心频率.考虑到实际传输线阻抗实现的范围(20～150Ω),该环形耦合器的第3个工作频率和第1个工作频率的比值范围取为1.70～4.10和6.60～12.30.文中给出了解析的设计公式,基于不同的Π型阶梯阻抗变换器电路结构,设计并加工了分别工作在2.0/3.9/5.8GHz和0.9/3.5/6.1GHz的3dB微带三频环形耦合器.测量结果与仿真结果吻合良好,验证了文中三频环形耦合器设计方法的可行性.As the conventional rat race coupler can only operate at the fundamental frequency and may cause odd harmonics, the design method of a novel tri-band rat race coupler is presented. In this method, the quarter-wavelength impedance transformers in the conventional rat race coupler are replaced by the H-shaped stepped impedance ones （I-ISITs） with four circuit topologies, which enables the proposed coupler to operate at two arbitrary frequencies and their center frequency. Then, by taking into consideration the practical realization range of transmission line impedance （20 -150Ω）, the ratio of the third operating frequency to the first one of the proposed coupler is selected from 1.70 to 4. 10 and from 6. 60 to 12. 30. Moreover, the corresponding analytic design equations are deduced, and two microstrip 3-dB tri-band rat race couplers based on different IISIT circuit topologies, which respectively operate at 2. 0/3.9/5.8 GHz and 0. 9/3.5/6. 1 GHz, are designed and fabricated. Simulated results accord well with the measured ones, meaning that the proposed design method is feasible.

关 键 词：耦合器 三频耦合器 环形耦合器 Π型阶梯阻抗变化器 

分 类 号：TN819.1[电子电信—信息与通信工程]