GB817740A - Improvements relating to high frequency electrical circuit arrangements - Google Patents

Abstract

817,740. Aerials; R.F. couplings. COMPAGNIE FRANCAISE THOMSON-HOUSTON. March 22, 1956 [March 22, 1955], No. 8985/56. Class 40 (7). [Also in Group XL (b)] A high-frequency circuit for distributing energy between two antennµ 10, 11 comprises a hybrid ring 1 having output terminals 6, 7 connected to the antennµ 10, 11 and input terminals 8, 9 connected to a common source 18 in such a manner that the relative phase of the portions of energy reaching the input terminals is variable. The input terminals are connected together by a coaxial line 20 of characteristic impedance Z having a slotted portion 15 which accommodates a variable tap 16. The hybrid ring shown has four branches each one quarter wavelength long at the operating frequency, the branches 2, 4 having a characteristic impedance Z and the branches 3, 5 a characteristic impedance Z/#2, where Z is the impedance presented by the antennµ 10, 11. The tap 16 is connected by a line 17 of impedance Z/2 to the source 18 whose impedance has the value Z/2. The position of the tap 16 determines the relative phase of the input energies at terminals 8, 9 and hence the relative amplitude of the energies distributed to the antennµ 10, 11. Two or more such circuits may be connected in cascade, one of the output terminals 6, 7 being connected directly to the variable tap of the next circuit and so on. The circuit may be used for reception in which case the variable taps are used to select the contribution of each receiving antennae to the total input signal applied to a receiver 18.