Planare Richtkoppler in integrierten Mikrowellenschaltungen - Grundlagen

The theoretical basics for the design and optimal dimensioning of directional couplers in integrated microwave circuits are addressed. The theory of coupled lines is used to derive the scattering parameters of a general nonideal directional coupler arrangement. Conditions for optimal directional coupler behavior are given for both codirectional and contradirectional couplers. The effects of deviations from these conditions, or optimization goals, are discussed in detail. A numerical computation program for calculating planar and quasi-planar directional coupler arrangements is presented. It can be used to compute nearly all such arrangements relevant to integrated microwave circuits.