GB282905A - Improvements in or relating to electrical energy transferring, transforming, coupling and the like devices - Google Patents

Abstract

282,905. Franklin, C. S., and Green, E. Oct. 2, 1926. Coupling oscillating and radiating circuits; receiving systems. - Relates to electric energy transferring, transforming, coupling, and like devices, particularly in connection with feeding multiple aerial systems for wireless signalling. A feeder cable carrying high-frequency currents is connected to a working circuit such as an aerial through a coupling device comprising shunt and series resistances designed to make the effective load on the feeder equal to its surge impedance. As shown in Fig. 1, an inductive reactance L is inserted in series and a capacitive reactance C on shunt with the line, but these impedances may be reversed in position. When output resistance is required to be stepped up, the input is applied across the terminals X, YL. If it is to be stepped down the input is applied across the points A, B. If the load on the secondary is a resistance R and a primary load of 2R is required, then the inductance L should have a reactance R ohms and the condenser C and reactance of 2R ohms at the working frequency. In Fig. 3 main feeder section M is supplied with high-frequency current at the points A, B which is attributed to two sub-feeders S1, S2 arranged in parallel at the output side. Each of the sub-feeders may again supply two further feeders similarly arranged in parallel. The coupling device may comprise a substantially uniform length of feeder an appreciable fraction of a wavelength long, inserted in series between a feeder and its load. In this case if R1 is the load resistance and R2 the required effective impedance, a quarter wavelength of feeder designed to have a surge impedance R1, R2 is inserted as the coupling device. Or the inserted length of cable may be replaced by an artificial line built up of impedance elements. The method is also applicable to the reception of wireless signals.