Multiport multidirectional amplifiers using operational amplifiers

The paper describes a design method of constructing matched multiport circuits of arbitrary gain by converting scattering matrix into admittance matrix and presents design examples of 3-port circuits of arbitrary matched impedance and arbitrary gain. In general, n-port circuits of arbitrary gain are difficult to construct but can be realized under some constraints. Design examples are given on matched multiport multidirectional amplifiers of equal gain and matched multiport circulators of arbitrary gain. The validity of theory is confirmed by the experiment at low frequencies.