Mixed type branch line coupler designs

A mixed type branch line coupler combining T-type and pi-type equivalent circuits and keeping main lines characteristic impedance at 50Ω is reported. The new branch line coupler contains only capacitors and open stubs. Two prototypes of two and three branches are designed, simulated and measured. The size reduction reached 40% comparing with the original circuits. The simulated and experimental results show a good agreement within the frequency of interest.

[1]  Shry-Sann Liao,et al.  A novel compact-size branch-line coupler , 2005, IEEE Microwave and Wireless Components Letters.

[2]  Tae-Soon Yun,et al.  Investigation on size reduction of a branch-line power divider using shunt-stub , 2005, 2005 Asia-Pacific Microwave Conference Proceedings.

[3]  Giorgio Luzzatto.  A General 180-Degree Hybrid Ring , 1968 .

[4]  J. W. Gipprich,et al.  A new class of branch-line directional couplers , 1993, 1993 IEEE MTT-S International Microwave Symposium Digest.

[5]  Kae-Oh Sun,et al.  A compact branch-line coupler using discontinuous microstrip lines , 2005 .

[6]  Chao-Hsiung Tseng,et al.  Design of compact branch-line couplers using π-equivalent artificial transmission lines , 2012 .

[7]  Kai Chang,et al.  Compact second harmonic-suppressed bandstop and bandpass filters using open stubs , 2006, IEEE Transactions on Microwave Theory and Techniques.

[8]  J. Reed,et al.  A Method of Analysis of Symmetrical Four-Port Networks , 1956 .

[9]  I. Sakagami,et al.  A reduced branch-line coupler with eight stubs , 1997, Proceedings of 1997 Asia-Pacific Microwave Conference.

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