A synthesis procedure for allpass-networks in a T-configuration with an odd excitation

A new synthesis procedure for RC-allpass-circuits in a planar realizable T-configuration driven by two antiphase sources is presented. This circuit shows some excellent advantages in comparison to well known bridge-allpass-circuits. Furthermore a synthesis procedure for RC all-pass-circuits in an unsymmetrical bridge-configuration is developed. A GaAs-FET is used as a broadband phase splitting network to feed these RC-allpass-circuits. A broadband phase shifter was realized with two suitably designed, switched RC-allpasses in T-configurations. A phase shift difference of 90° ± 20° was obtained in a bandwidth of 12 octaves from IMHz to 4000MHz. The amplitude characteristic is ¿3dB± l.5dB.