Dual-Band Ring Coupler Based on the Composite Right/Left-Handed Folded Substrate-Integrated Waveguide

In this letter, a dual-band ring coupler based on the folded substrate-integrated waveguide (FSIW) is proposed. The artificial structure, the composite right/left-handed (CRLH) transmission lines were implemented in the FSIW by loading the interdigital capacitors in the middle metallic layer to generate a left-handed passband region below the cutoff frequency of the ordinary waveguide TE10 mode for coupler miniaturization. The FSIW is the folded counterpart of the substrate-integrated waveguide (SIW) and thus can prevent the CRLH transmission lines from radiation loss by shielding the interdigital capacitors in the waveguide. Besides, the FSIW-based coupler is able to eliminate the electromagnetic interference (noise) with adjacent objects and lend itself to multilayer circuit integration. A ring coupler that operates at 4.3 and 7.6 GHz was developed and experimentally verified. To the best of the authors' knowledge, it is the first time that a dual-band rat-race was implemented and reported based on the CRLH-FSIW structure.

[1]  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.

[2]  Wei Hong,et al.  Folded Half Mode Substrate Integrated Waveguide 3 dB Coupler , 2008, IEEE Microwave and Wireless Components Letters.

[3]  Y. Chow,et al.  Analysis and Experiments of Compact Folded Substrate-Integrated Waveguide , 2008, IEEE Transactions on Microwave Theory and Techniques.

[4]  L. Perregrini,et al.  Dispersion characteristics of substrate integrated rectangular waveguide , 2002, IEEE Microwave and Wireless Components Letters.

[5]  Tatsuo Itoh,et al.  Application of composite right/left-handed half-mode substrate integrated waveguide to the design of a dual-band rat-race coupler , 2010, 2010 IEEE MTT-S International Microwave Symposium.

[6]  Ferran Martin,et al.  Dual-band rat race hybrid coupler implemented through artificial lines based on complementary split ring resonators , 2009, 2009 IEEE MTT-S International Microwave Symposium Digest.

[7]  Jen-Tsai Kuo,et al.  Miniaturized Dual-Band Hybrid Couplers With Arbitrary Power Division Ratios , 2009, IEEE Transactions on Microwave Theory and Techniques.

[8]  K. Wu,et al.  Integrated microstrip and rectangular waveguide in planar form , 2001, IEEE Microwave and Wireless Components Letters.

[9]  Tatsuo Itoh,et al.  Miniaturized Dual-Band Directional Couplers Using Composite Right/Left-Handed Transmission Structures and Their Applications in Beam Pattern Diversity Systems , 2009, IEEE Transactions on Microwave Theory and Techniques.

[10]  B. Sanz-Izquierdo,et al.  Substrate integrated folded waveguides (SIFW) and filters , 2005, IEEE Microwave and Wireless Components Letters.

[11]  Tao Yang,et al.  Folded Substrate Integrated Waveguide Based Composite Right/Left-Handed Transmission Line and Its Application to Partial $H$ -Plane Filters , 2013, IEEE Transactions on Microwave Theory and Techniques.

[12]  Ke Wu,et al.  Ridge Substrate Integrated Waveguide (RSIW) Dual-Band Hybrid Ring Coupler , 2012, IEEE Microwave and Wireless Components Letters.