A compact crossover using NRI-TL metamaterial lines

A compact NRI-TL metamaterial branch-line crossover is presented that has an area of λ/36 × λ/12, and is a factor of 81 times smaller than its analogous transmission-line counterpart. Circuit simulations reveal that it exhibits a 34% -10 dB |S11| bandwidth, good isolation below -10 dB over a 22% bandwidth, and less than 0.5 dB insertion loss over a 15% bandwidth. Furthermore, the bandwidth of the device can be increased by incorporating additional branch-line sections into the structure.

[1]  R. Islam,et al.  Compact Negative-Refractive-Index Transmission-Line (NRI-TL) coupler, filter and diplexer , 2007, 2007 IEEE Antennas and Propagation Society International Symposium.

[2]  G.V. Eleftheriades,et al.  Phase-agile branch-line couplers using metamaterial lines , 2004, IEEE Microwave and Wireless Components Letters.

[3]  Tzyy-Sheng Homg.  A Rigorous Study of Microstrip Crossovers and their Possible Improvements , 1994 .

[4]  Irina Vendik,et al.  Wideband 0-dB branch-line directional couplers , 2000, 2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017).

[5]  G.V. Eleftheriades,et al.  Compact linear lead/lag metamaterial phase shifters for broadband applications , 2003, IEEE Antennas and Wireless Propagation Letters.

[6]  Swee Ping Yeo,et al.  Microstrip Branch-Line Couplers for Crossover Application , 2011, IEEE Transactions on Microwave Theory and Techniques.