Design Method for Quasi-Optimal Multiband Branch-Line Couplers

• In this article, the design approach, the implementation, and experimental results of multiband branch-line couplers operating at arbitrary frequencies are presented. The conventional branch-line coupler structure is adapted to multiband operation by shunting its four ports with multiband reactive networks. The performance of the proposed multiband couplers is theoretically analyzed and optimized through the even-odd mode circuit analysis. Dual-band (2.4-3.5 GHz), triple-band (1.5-2.4-4.2 GHz), and quad-band (1.5-2.4-3.5 GHz) microstrip branch-line couplers have been realized and tested to verify the design method. The good experimental results (input return loss greater than 15 dB and amplitude imbalance lower than 0.7 dB) show excellent agreement with theoretical and simulated ones, thus validating the proposed approach.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Keyword

HYBRID

TRANSMISSION-LINES

coupler

multiband

branch-line

balanced

AMPLIFIER

passive

DUAL-BAND

Publication and Content Type

art (subject category)

ref (subject category)