Wide band asymmetric coupled-transmission-line magic-T and sum-difference circuit

A novel broadband 3-dB/0/spl deg//180/spl deg/ coupler and a novel sum-difference /spl Sigma/-/spl Delta/ circuit, consisting of a coupled-line multi-section asymmetric 3-dB directional coupler and a coupled-line multi-section phase compensation network, are comprehensively theoretically and experimentally reviewed. The multi-octave bandwidth of such networks can be achieved by increasing the number of coupled-line sections of both the asymmetric 3-dB coupler and the phase compensation network. An approximate computational procedure for designing such a network is proposed. Tables are given with example computational results for two and three section magic-T networks. An ultra-broadband (with bandwidth BW=10:1) magic-T has been designed manufactured and measured. The measured results are in a good agreement with the theoretical ones.