Reflectionless Stripline Filters

Reflectionless strapline filters designed to improve the electromagnetic compatibility of electronic equipment units are considered. To build such filters the schemes and design of frequency-selective devices based on segments of coupled strip lines (CSL) and RLC lumped circuits included in diagonal CSL ports are proposed. As a result of simulation the possibility of building one-cascade bandpass filters with an insertion losses of approximately -0.5 dB at the central frequency of the bandpass and return losses of about -20 dB at the frequencies of non-passing is shown. The three cascade bandpass filter provide a losses -1.5 dB at the central frequency of the transmission bandwidth and of not lower than -32 dB at the out of band frequencies up to 8 GHz and return losses of not more than -15 dB in frequency band. One-cascade band-stop filter was simulated which provide the frequency characteristics with a minimum level of reflection in the wide frequency band. The frequency characteristics of an experimental device of a single-stage bandpass filter with losses of -1.8 dB at the central frequency of the bandpass and providing a minimum level of return losses of -10 dB in the frequency band up to 5 GHz are presented.