Compact Microstrip Dual-Band Quadrature Coupler Based on Coupled-Resonator Technique

A compact dual-band coupled-resonator quadrature (90°) coupler with flexible passband allocation has been presented. By introducing the dual coupling paths between input and output ports, the design flexibility is increased, and thus, a dual-band response can be realized. For demonstration, a dual-band 90° coupler operating at 1.6 and 2.1 GHz has been designed and fabricated with microstrip technology. The 90° coupler is formed by only four dual-mode stub-loaded resonators, leading to a compact size, i.e., about 0.27 λg by 0.27 λg. A good agreement is achieved between simulation and measurement.

[1]  Y. Konishi,et al.  Bandpass Directional Couplers with Electromagnetically-Coupled Resonators , 2006, 2006 IEEE MTT-S International Microwave Symposium Digest.

[2]  Byungje Lee,et al.  Dual-Band Branch-Line Coupler With Port Extensions , 2010, IEEE Transactions on Microwave Theory and Techniques.

[3]  Qing-Xin Chu,et al.  Design of Dual-band Filtering Quadrature Coupler Using λ/2 and λ/4 Resonators , 2012 .

[4]  Feng Lin,et al.  Design of Dual-Band Filtering Quadrature Coupler Using $\lambda /2$ and $\lambda /4$ Resonators , 2012, IEEE Microwave and Wireless Components Letters.

[5]  Kuo-Sheng Chin,et al.  Compact Dual-Band Branch-Line and Rat-Race Couplers With Stepped-Impedance-Stub Lines , 2010, IEEE Transactions on Microwave Theory and Techniques.

[6]  Ruey-Beei Wu,et al.  Miniaturized rat-race coupler with bandpass response and good stopband rejection , 2009, 2009 IEEE MTT-S International Microwave Symposium Digest.

[7]  L. Yeung,et al.  A Compact Dual-Band 90° Coupler With Coupled-Line Sections , 2011, IEEE Transactions on Microwave Theory and Techniques.

[8]  Byungje Lee,et al.  Dual-band, cross coupled branch line coupler , 2005 .

[9]  Myun-Joo Park.  Dual-Band, Unequal Length Branch-Line Coupler With Center-Tapped Stubs , 2009, IEEE Microwave and Wireless Components Letters.