Impedance Transforming 3-Db 90 ° Hybrids

Design techniques and performance results for impedance transforming 3-dB 90° hybrids are presented. A broadband hybrid with 50- to 20-Omega impedance transformation has been realized by tandem connection of coupled-line sections. Measured results show an amplitude balance of 3.7 +- 0.68 dB and return loss and isolation of approximately 15 dB over the 3- to 5-GHz range. Test results for a 50-Omega tandem hybrid and a 50- to 25-Omega branch-line hybrid are also presented.