Patent GB-591625-A (GB)
Title: Improvements in or relating to ultra high frequency antenna apparatus for directionally radiating and/or receiving electromagnetic waves
IPC: H01Q3/32
Filed: 1943-03-29
Abstract: 591,625. Wave guides. SPERRY GYROSCOPE CO.. Inc. March 29, 1943, No. 5075. Convention date, March 31, 1942. [Class 40 (v)] A wave guide has a longitudinal slot along one surface for the purpose of emitting a beam of radiation substantially along the axis of the guide, Fig. 39, or in a hollow cone having the guide as axis, Fig. 37, and the radiating guide is wholly or partially filled with dielectric material enabling the depth of the guide to be considerably reduced. The partial filling may comprise slabs of dielectric material secured to the vertical or in other positions, as shown in 12 and 14 for example. The vertical dimension of the guide should be a substantial number of wavelengths, if the angle # of the cone is to be .kept small.. The vertical walls of the guide .may be bulged inwards (Fig. 6, not shown). The radiating section 12 of the guide may be connected to the feeder guide 9 by a tapered horn 11 of increasing depth, the radiating slot 14 extending back into the horn section, Fig. 9. The flange members 3, 31 may be curved upwards in parabolic form. Fig. 17 shows a tubular guide with flanges 37, 37<1> extending on either side of the slot, and with a partial filling 38 of dielectric material. In Fig. 19 the radiating guide 64 is fed from a section 65 across which extends the inner conductor 72 of a coaxial feed line 71. The conductor 72 extends 'to a conducting plug 74, adjustable within a cylinder 71<1> for matching purposes. The feed line 71 and its supporting plates 69 are slidable along the guide and are adjusted so that conductor 72 is a .quarter wave length from the end plug 75. The character of the polar diagram may be varied from that shown in Fig. 37, by placing slabs of dielectric material 79, Fig. 21, along the face of the guide 77 opposite to the slot 76, which slab may be tapered linearly or exponentially or stepped. The slab may alternatively slope upwards towards the end of the guide, Fig. 23, or may extend horizontally half-way up the guide (Fig. 27, not shown). The slotted portion of the guide may be tilted out of line with the feed portion. (Figs. 28, 29, not shown). The slot may widen towards the free end of the guide (Figs. 30 and 31, not shown). By supplying waves 'of slightly different frequency to the guide two. stationary conical; lobes 92, 93 may be produced in the polar diagram;, Fig. 41, and by supplying frequency-modulated waves, to the guide, the beam may be arranged to scan a beam is of the form shown in Fig. 39, frequency modulation results in intermittent pulses being , radiated, between which the.radiation.is-cut off Rotation or reciprocation of.rods or slabs of dielectric material within .the guide imposes a periodic variation of the phase velocity and a corresponding variation in the polar diagram. For example, a slab 96, Fig. 34, extending along the guide may be reciprocated by a mechanism 98, 99. Wave energy reaching the free end of the guide may be absorbed by the combination of a reflecting conducting plug 102, Fig. 36, and a resistant wall 103 a quarter wavelength therefrom. The radiating guide may be coupledwith a feed guide by an impedance tansformer of the kind described in Specification 591,667..