GB1418805A - Coaxial and helical resonator assemblies - Google Patents

Abstract

1418805 Band-pass filters FINOMMECHANIKAI VALLALAT 8 Jan 1973 [7 Jan 1972] 916/73 Heading H1W A band-pass filter consists of at least two resonant co-axial cavities with homologous ends open (or partially open) and facing each other to effect mutual coupling, such coupling being adjustable by relative movement of the cavities. Fig. 7a shows four such cavities each consisting of a quarter-wave resonator having an internal helical conductor 3. The cavities are arranged with earthed and live ends alternately facing each other and adjustably connected by threaded or slidable sleeves 6. Halfwave cavities, either earthed at both ends or earthed at the centre, may be used. Thus, Fig. 10 shows a central half-wave cavity with open-circuited ends coupled to a pair of quarter-wave cavities. In this example, the internal conductors are straight cylinders. Input/output may be of the direct (Fig. 10) type or of the inductive type (Fig. 7a). The outer conductors may be of polygonal section. The relative movement may be axial (as shown), angular or rotational. Thus, a number of cavities may be arranged to form a rotational switch. In another embodiment (Fig. 11, not shown), a number of cavities are arranged sideby-side with homologous ends facing and open to a further cavity through which they are mutually coupled.