Commensurate-line, microstrip, band-pass filters

The commensurate-line bandpass filter topology, also known as the shunt-shorted-stub topology, is considered. Kuroda's network transformations are used to synthesize bandwidth-dependent structures. The distribution of the grounded stub impedances, which is also bandwidth-dependent, is discussed in detail for the 40-160% range. The realization of tee-junctions, and the method used to ground the stubs, are the key to this topology. Test results for N=11 filters show excellent correlation between test and simulated data. Sensitivity, phase and temperature stability, rejection of second harmonic, and microstrip models are also discussed.<>