On the Bandpass/Lowpass Microwave/RF Filter

M. Zaradny (Wrocław Univ. of Science and Techn., Poland)

This paper presents a practical possibility of realization of a filter with simultaneous band-pass and low-pass characteristics within one simple, microstrip mixed circuit with lumped components. In particular, it was important to obtain an arbitrary, narrow-band microwave filter - BPF - with a fractional bandwidth of 10%, and a low-pass filter with favourable RF characteristics up to several hundred-MHz. The proposed simplified design method and transformations provide good theoretical and experimental results. One model of the distributed/lumped filter which confirms the theory as to the realization of the filter was designed and experimentally made.