Broadband quadrature couplers for microwave power amplifiers

The overview of existing constructions of broadband (>octave) quadrature 3-dB power divider\combiners (quadrature hybrids), widely used in the microwave power amplifiers, was presented. The results of experimental and theoretical investigations to improve the microstrip multi-coupled lines quadrature hybrids characteristics were presented. The quadrature hybrids applications in the broadband microwave power amplifiers were discussed.