GB1116348A - Improvements relating to electrical waveguide arrangements - Google Patents

Abstract

1,116,348. Waveguide coupling arrangements. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. 22 July, 1966 [23 July, 1964], No. 29678/64. Heading H1W. [Also in Division H4] In a duplexer arrangement for a radar system, two waveguides A and B, having their corresponding ends coupled by hybrid couplers H 1 and H 2 , and having a transmitter and a receiver at the two ends of the first waveguide and an aerial and a dummy load respectively at the corresponding ends of the second waveguide are further coupled, intermediate the hybrid couplers, by a first tuned coupling G2 ionizable to become a reflector, e.g. a T-R cell, and by a second tuned coupling G3, positioned on that side of the first coupling remote from the transmitter, tuned to the same frequency as the first coupling, and spaced from that coupling by a distance such that reflection from the two couplings cancel at a second frequency within the signal frequency band. The Q-factor of the coupling devices is chosen to provide small reflection in the range between the two reflectionless frequencies, whereby the pass band for signals passed from the aerial to the receiver is increased. The second tuned coupling G3 may be a tuned aperture, or a second T-R cell designed to ionize at a lower power than G2, to increase the isolation between the transmitter and the receiver.