GB1379620A - Wideband cirection filter device - Google Patents

Abstract

1379620 Cavity resonator filters NIPPON TELEGRAPH & TELEPHONE PUBLIC CORP and HITACHI ELECTRONICS CO Ltd 20 Dec 1972 [24 Dec1971] 58923/72 Heading H1W A filter for removing selected components from a composite signal travelling along a semicircular waveguide 34 comprises two coplanar ring-shaped cavity resonators 35 and 36 which are divided into two portions coupled by holes 37, 38 spaced a quarter wavelength apart and the circumferences of the cavities are respectively integral multiples of the wavelength of two components f 1 , f 2 of the composite signal. The cavities are directionally coupled to waveguide 34 by slits 45, 46 and to two rectangular waveguides 40, 41 by slits 42, 43, the components f 1 and f 2 being taken as outputs from the rectangular waveguides. Similar filters can be disposed along the semi-circular waveguide 34 to remove other pairs of components therefrom. In Fig. 7 (not shown) the rectangular guides are disposed along the outer limbs of the ring shaped cavities. In Fig. 8 (not shown) the coupling slits are replaced by coupling guides (451, 461, 421, 431) which are arranged in a similar manner to the slits but are through a plate a quarter wavelength thick. In addition to coupling slits, further slits for impedance matching can be provided.