GB578617A - Improvements in or relating to systems for transmitting guided electromagnetic waves - Google Patents

Abstract

578,617. Wave guides. WESTERN ELECTRIC CO., Inc. Nov. 5, 1943, No. 22914/45. Convention date, July 30, 1942. Divided out of 578,597. [Classes 40 (iii) and 40 (v)] Impedance elements for wave guides comprise a slotted transverse obstruction, the height and width of the slots being proportioned to provide resonance. For a rectangular guide 1, Fig. 4, the slot may have height V in the direction of the electric vector E and width W perpendicular thereto. All slots giving parallel resonance have their corners along a curved line 13, and the effective resistance shunted across the guide decreases as the height V decreases. If the resistance is made equal to the characteristic impedance of the guide, the element 11 serves as a reflectionless termination of the guide when followed by a solid partition 15 placed a quarter-wavelength behind the element 11. For a circular guide, Fig. 5, the element may have a rectangular slot into which project screwed studs 17 fitted with adjustable flanged discs 19. For series resonance, the discs are closely adjacent, while for parallel resonance, the spacing is greater and the flanges may be omitted. In Fig. 7, the slot is divided by inward projections 21, 22 which are provided with flanges facing each other. The projections 21, 22 may be fitted with deformable overlapping flaps (Fig. 6, not shown). In Fig. 8, a wave-guide 60 is matched to a wave-guide 61, by an intermediate section 62 of length N equal to a quarter-wave, or an odd multiple thereof. The height of the section 62 is the geometric mean of the heights of the two guides, and the width may be the same for all three. The junction 63 is constricted by the insertion of slats 65, 66 and the junction 64 by slats 67, 68 of such dimensions that each junction functions as a parallel-resonant shunt reactance.