| 摘要 |
1,090,790. Waveguide junctions. STANDARD TELEPHONES & CABLES Ltd. May 27, 1966, No. 23912/66. Heading H1W. [Also in Division H4] A waveguide arrangement for transmission of up to four signals in multiplex comprises an inner circular waveguide 1 for transmission of two orthogonally polarized H 11 waves at frequencies within an upper band, and a surrounding coaxial waveguide 2 for transmission of two further orthogonally polarized H 11 waves at frequencies within a lower band. The signals are fed towards a horn 11, 12. The lower-band signals are fed to the coaxial guide through two rectangular waveguides 4, 5 arranged on orthogonal axes and coupled to the coaxial guide by tuned irises 6. In order to prevent backward propagation, pairs of conductive fins 7, 9 (one only of each pair visible) are arranged immediately behind the irises in planes parallel to the electric vector of the waves they are intended to reflect. Any energy propagated in the backward direction is absorbed by a termination 3. Upper-band signals are fed to the inner guide 1 by any known means. In order to isolate the two bands when the apparatus is used for reception, the diameter of the inner guide is such that only the upper frequency band will propagate in it. In addition, the coaxial guide is provided with a filter 13 to reject signals in the upper band. This consists of dielectric annuli spaced apart by a distance #/2 at the desired rejection frequency. The annuli also provide an impedance match between the waveguide and the horn. In order to correct irregularities in the polarization of the waves, each waveguide is provided with an annular clamp (Fig. 4, not shown) designed to produce a local deformation of the waveguide. |
