A DEVELOPMENT OF COHN''S THEORY ON DIRECTLY COUPLED RESONATOR FILTERS
对Cohn直耦滤波器理论的推广

In this paper Cohn's theory on directly coupled resonator filters is extended to one-quarter-wavelength coupled filters, thus theoretically unifying the two different types of microwave filters. The frequency response transformation from a lowpass to a band pass filter is given, the change of the filter susceptance with frequency being taken into account. Experimental results show that, using formulas derived in this paper for filter designing, the expected bandwidth and stop-band attenuation are in better agreement with practice. Finally, a method for eliminating asymmetry in frequency characteristics is discussed.