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http://dx.doi.org/10.6109/jkiice.2011.15.2.286

Branch line directional coupler with coupled lines  

Han, Dae-Hyun (동의대학교 전자공학과)
Publication Information
Journal of the Korea Institute of Information and Communication Engineering / v.15, no.2, 2011 , pp. 286-291 More about this Journal
Abstract
Directional couplers are widely used in RF and microwave applications to distribute or monitor signals. This paper presented a new structure of microstrip branch line directional coupler with coupled lines. The loose couplings of microstrip branch line directional couplers are impractical for the high characteristic impedance values required for the shunt branches. To overcome this limitation, the parallel coupled lines with the shorts were used for the high characteristic impedance. The results of the simulations and measurements were presented for the proposed branch line directional coupler. Measurement of the 10 dB branch line directional coupler shows that the return loss is higher than 30 dB over 10 % bandwidth and the isolation is 35 dB or better over 8 % bandwidth.
Keywords
directional coupler; branch line directional coupler; coupled lines; microstrip line;
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