GB529290A - Improvements in or relating to ultra high frequency electro-magnetic wave transmission - Google Patents

Abstract

529,290. Dielectric guides for displacement waves. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. May 26, 1939, No. 15704. Convention date, May 28, 1938. [Class 40 (iii)] Relates to means for matching the impedances of a transmission line and a wave guide, comprising a coupling formed by a tapered extension of the inner line conductor extending within the guide and terminated in a tapered element of dielectric material whereby conduction currents in the line are gradually transferred into displacement currents in the guide. In the Fig. the outer conductor 3 of the coaxial line 1 is of the same diameter as the pipe 31 forming the wave guide 9, the inner conductor 5 having a tapered end 6 to which is attached a tapered extension 15 of insulating material more than one wavelength long. The value of the dielectric constant of the extension 15 may be arranged to decrease towards the tapered end where it approaches the value for the guide medium; the non-uniform dielectric constant may be effected by embedding particles in the dielectric material. When a two-wire transmission line is used, the two conductors are terminated in a similar manner to the inner conductor 5 of the coaxial line.