Abstract:A general method is presented for synthesis of quasi-elliptic filter with source-load coupling. The equivalent circuit of the low-pass prototype of a lossless coupled resonator filter is proposed, as well as its transfer function t (s ).The expressions of MSL, MSiand MiL in the coupling matrix M are obtained based on two-port admittance matrix [ YN ]. Finally, a novel quasi-elliptic two pole microstrip filter composed of two hexagonal open-loop resonators is designed. The numerical results are verified with the simulation, The measured and simulated data are in good agreement.