GB929289A - Improvements relating to electrical duplexers - Google Patents

Abstract

929,289. Waveguide duplexers. COMPAGNIE FRANCAISE THOMSON-HOUSTON. Feb. 29, 1960 [Feb. 27, 1959], No. 7022/60. Addition to 843,634. Class 40 (8). A duplexer for transmit-receive operation comprises four waveguides viz. a transmitter guide 6 connected between a transmitter E and a matched resistance 10, an antenna guide 7 connected between an antenna A and a matched resistance 11, a reception guide 8 connected between a receiver R and a matched resistance 12 containing a resonant gas TR tube 15, and an absorption guide 9 connected between matched resistances 13, 14 containing a resonant gas TR tube 16, the waveguides being coupled through (a) two 3 dB. directional couplers 17, 18 between transmitter and antenna guides, (b) two total couplers 19, 20 of the type described in the parent Specification between transmitter and reception guides and between antenna and absorption guides, and (c) a 3 dB. coupler 23 between reception and absorption guides on the sides of the TR tubes remote from the total couplers. The total couplers are arranged in the common narrow walls of the coupled waveguides and are provided with gas discharge tubes 21, 22 extending in the direction of the electric fields. During transmission, these tubes and the TR tubes 15, 16 fire and substantially the whole of the energy from the transmitter E is directed to the antenna A. Most of the energy leaking past the tubes 15, 16, 19, 20 is absorbed by the resistances 12, 13, 14. During reception none of the gas tubes is fired and the received energy passes almost entirely to the receiver R. A convenient way of arranging the waveguides is shown in Fig. 5. In this arrangement, one set of discharge tubes 42 may be used for both total couplers 19 and 20.