Abstract: This article presents an analysis and design method for the arbitrary-coupling broad band lumped-element quadrature coupler. It starts from the odd-even mode impedance analysis of the irectional coupler, a solution of arbitrary-coupling directional unit coupler is btained and hen the design formulas for arbitrary-coupling broad band lumped-element uadrature coupler s derived from cascading two directional unit coupler. The simulation esults of ADS coincide ith the calculation results and the cascade coupler’s bandwidth is uch wider than the unit coupler. In order to further verify this method, a 5dB coupling with the center frequency of 445MHz is designed and fabricated. The measurement and simulation esults closely correspond o each other. This coupler has advantages of small size, large bandwidth, and so on.