Two Methods for Miniaturization of Stub Quadrature Couplers

Resumo

Two circuit-topological methods for reducing the overall dimensions of stub quadrature coupler (SQCs) are considered. The essence of the presented methods lies in replacing quarter-wave stubs with low-pass filters and artificial transmission lines (ATLs). It is shown that, using these methods, it is possible to reduce dimensions of two-stub and five-stub coupler by 71.9%. The design and experimental characteristics are presented; it is found out that the band of operating frequencies of compact SQCs is 1.4 times less than the bandwidth of conventional coupler and the imbalance of the power division coefficient increases.