Title :
Compact Planar Microstrip Branch-Line Couplers Using the Quasi-Lumped Elements Approach With Nonsymmetrical and Symmetrical T-Shaped Structure
Author :
Liao, Shry-Sann ; Peng, Jen-Ti
Author_Institution :
Dept. of Commun. Eng., Feng Chia Univ., Taichung
Abstract :
A class of the novel compact-size branch-line couplers using the quasi-lumped elements approach with symmetrical or nonsymmetrical T-shaped structures is proposed in this paper. The design equations have been derived, and two circuits using the quasi-lumped elements approach were realized for physical measurements. This novel design occupies only 29% of the area of the conventional approach at 2.4 GHz. In addition, a third circuit was designed by using the same formula implementing a symmetrical T-shaped structure and occupied both the internal and external area of the coupler. This coupler achieved 500-MHz bandwidth while the phase difference between S21 and S31 is within 90degplusmn1deg. Thus, the bandwidth is not only 25% wider than that of the conventional coupler, but occupies only 70% of the circuit area compared to the conventional design. All three proposed couplers can be implemented by using the standard printed-circuit-board etching processes without any implementation of lumped elements, bonding wires, and via-holes, making it very useful for wireless communication systems
Keywords :
UHF couplers; lumped parameter networks; microstrip couplers; microstrip lines; 2.4 GHz; 500 MHz; UHF; bonding wires; nonsymmetrical T-shaped structure; phase difference; planar microstrip branch-line couplers; printed-circuit-board etching; quasilumped elements; via-holes; wireless communication; Bandwidth; Bonding; Circuits; Communication standards; Couplers; Equations; Etching; Microstrip; Wireless communication; Wires; Branch-line coupler; compact size; nonsymmetrical T-shaped structure; quasi-lumped elements; symmetrical T-shaped structure;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2006.880650