Experimental investigation of frequency characteristics of bandpass microwave filters on waveguide slots membranes with angular geometry of slots

In this paper we present the results of an experimental study of the amplitude-frequency characteristics (AFC) of four one-stage bandpass filters made on waveguide-slotted membranes (WSM). The slot metal membranes of each filter are inserted transversely to the direction of propagation of electromagnetic waves in the waveguide and clamped between the flanges of the input and output coaxial-waveguide transitions (CWT). The membranes have slots (slits) located close to one of the angles of the cross-section waveguide 35×15 mm. The filters differ from each other by the width of that of the sides of the angular gap that lies along the wide wall of the waveguide. The results of the experiments show the resonance-type AFC in such structures, as well as the significant changes in the frequency response of the filters, depending on the geometric dimensions of the slots (slits) in the metal membranes both across the width of the passband and the resonance frequency of the filters of the AFC filters. Selectivity of filters reaches 25 dB in the range of 5.5 ... 8.5 GHz, which shows the possibility of using filters of this type as selective systems of centimeter wavelength band of microwave, even with a small number of cascades of such filters and small dimensions of the filtering systems.