Design of dual-band rat-race couplers

New designs of dual-band rat-race couplers are proposed. The desired dual-band operations are realised by adding tapped open stubs to the branches of the conventional rat-race coupler. It is found that these stubs can be implemented in two different ways to satisfy the conditions for dual-band applications, which results in two types of designs. The two different designs can be separately used to achieve low and high ratios between two operating bands, therefore providing enhanced design flexibility. The design formulas are developed using ABCD matrix and the even-odd mode analysis. On the basis of the derived design equations, a type I rat-race coupler working at 1 GHz/3.5 GHz and a type II coupler working at 2 GHz/5 GHz are devised and fabricated on Rogers's RO3006 printed circuit boards. Measurement results prove the design concepts.

[1]  Chu-Chen Yang,et al.  A novel broad-band Chebyshev-response rat-race ring coupler , 1999 .

[2]  K.-K.M. Cheng,et al.  Dual-band Rat-Race Coupler with Bandwidth Enhancement , 2006, 2006 IEEE MTT-S International Microwave Symposium Digest.

[3]  K.-K.M. Cheng,et al.  A novel approach to the design and implementation of dual-band compact planar 90/spl deg/ branch-line coupler , 2004, IEEE Transactions on Microwave Theory and Techniques.

[4]  Masahiro Muraguchi,et al.  Reduced-size branch-line and rat-race hybrids for uniplanar MMIC's , 1990 .

[5]  K. Cheng,et al.  Dual-band rat-race coupler design using tri-section branch-line , 2007 .

[6]  Peter Jung,et al.  Fast frequency hopping diversity scheme for OFDM-based UWB systems , 2007 .

[7]  Kai Chang,et al.  Broad-band uniplanar hybrid-ring and branch-line couplers , 1993 .

[8]  Yuanxun Ethan Wang,et al.  A $Ka$-Band FMCW Radar Front-End With Adaptive Leakage Cancellation , 2006, IEEE Transactions on Microwave Theory and Techniques.

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

[10]  D. Pozar.  Microwave Engineering , 1990 .

[11]  K.-K.M. Cheng,et al.  A novel rat race coupler design for dual-band applications , 2005, IEEE Microwave and Wireless Components Letters.

[12]  H. Ghali,et al.  Miniaturized fractal rat-race, branch-line, and coupled-line hybrids , 2004, IEEE Transactions on Microwave Theory and Techniques.

[13]  Kimberley W. Eccleston,et al.  Compact planar microstripline branch-line and rat-race couplers , 2003 .

[14]  T. Itoh,et al.  Arbitrary dual-band components using composite right/left-handed transmission lines , 2004, IEEE Transactions on Microwave Theory and Techniques.

[15]  V.K. Tripathi,et al.  Compact folded line rat-race hybrid couplers , 2000, IEEE Microwave and Guided Wave Letters.

[16]  K.J. Chen,et al.  A Stub Tapped Branch-Line Coupler for Dual-Band Operations , 2007, IEEE Microwave and Wireless Components Letters.

[17]  Ching-Kuang C. Tzuang,et al.  Synthetic quasi-TEM meandered transmission lines for compacted microwave integrated circuits , 2004, IEEE Transactions on Microwave Theory and Techniques.

[18]  Ming-Lin Chuang.  Miniaturized ring coupler of arbitrary reduced size , 2005 .

[19]  Kian Sen Ang,et al.  A new class of multisection 180/spl deg/ hybrids based on cascadable hybrid-ring couplers , 2002 .

[20]  T. Ho,et al.  A W-band integrated power module using MMIC MESFET power amplifiers and varactor doublers , 1993 .