Patent GB-591855-A (GB)
Title: Antenna arrays
IPC: H01Q21/22
Filed: 1944-05-05
Abstract: 591,855. Directive radio systems. STANDARD TELEPHONES & CABLES, Ltd. , May 5, 1944, No. 8597. Convention date, March 10, 1942. [Class 40 (v)] An electric antenna system comprises an array of at least four antenna elements spaced in a line and corresponding to the combination of opposite elements of at least one hypothetical pair of staggered binomial antenna systems, the elements being connected to a single energizing circuit by individual circuits such that the currents applied to elements of the system are derived as the resultant or vector addition of the currents fed to opposite elements of the hypothetical binomial systems when the said systems of a pair are respectively supplied with current in phase opposition. A clover-leaf radiation pattern as shown at 21, Fig. 5, is produced by an array of antenna elements 13 ... 18 such as that shown in Fig. 2 which is derived from the vectorial combination of two binomial arrays as shown in Figs. I (a) and 1 (b) fed with currents in opposite phase, the individual arrays giving rise to a dumb-bell characteristic as indicated at 11. To improve the directivity, the array ,13 ... 18 of Fig. 2 is combined with a further binomial array 22 ... 26, Fig. 4A, fed with energy 90 degrees out of phase with that supplied to the array of Fig. 2 giving a built-up array, Fig. 4B, in which the elements 27 ... 36 are fed with energy corresponding to the vectorial addition of the energy supplied to the elements of the arrays, Fig. 2 and Fig. 4A. The production of a double lobe is effected by reversing the phase of the energy supplied to the elements of the array of Fig. 2 with resulting phase change in the supply of energy to the elements of the actual array in Fig. 4B. A feeding arrangement for such an array is shown in Fig. 7 in which energy from a source 37 is fed over four channels 38 ... 41 to amplitude controls 42 ... 45 and phase adjustment means 46 ... 49. Simultaneously operated switch members 50, 51, 52 effect the phase changes of the supply to the elements 27 ... 36 corresponding to the reversal of currents fed to the elements of the array in Fig. 2, the lengths of line between the contacts and the elements of the array being chosen to correspond to the appropriate phase displacements. In a further arrangement to provide high directivity with the elimination of minor lobes the actual array of antenna elements 90 ... 100 shown at Fig. 8 (e) is constituted by an array 8 (a) similar to the array of Fig. 2, a binomial array phase at 90 degrees, Fig. 8 (b), a two unit array, Fig. 8 (c), formed from two binomial arrays and a single radiating unit Fig. 8 (d), the energy supplied to the composite array Fig. 8 (e) being the vectorial addition of the energy supplied to the corresponding units of the constituent arrays. The elements 90 ... 100 may be fed with energy corresponding to a phase shift of 180 degrees in the supply to the elements of the array Fig. 8 (a) in order to obtain a directive pattern on each side of the normal axis of directivity. Fig. 10 shows a feeding arrangement for an array 60 ... 64 formed by two staggered binomial arrays fed in opposite phase combined with a binomial array of three elements fed at 90 degrees out of phase. Carrier current from a source 65 is modulated to produce signals F1, F2, which are applied to a conjugate network 71 including a phase reversal element 72 in one arm so that that channels 69, 70 are fed with the difference and sum of the modulated signals F1, F2. The side band difference is fed to the elements 60, 64 over a line including amplitude control means 74 and phase reversal means 73. The carrier and side bands are passed through a 90 degree phase shifter 76 and amplitude controller 75 to the central element 62. Since the energy to be supplied to the elements 61, 63 is in effect the combination of multiples of the energy to be supplied to the central element 62 and to the outer elements 60, 64, energy from the line 69 is applied through amplitude control means 83 to two conjugate bridges 77, 78 and to the elements 61, 63, the operative arm of the network 78 including a phase reversing means 82. The energy from line 70 is passed through an amplitude controller 84 and over the arms of the bridges 77, 78 to the elements 61, 63 without any phase shift. Balancing networks 85, 86, 87 are connected to the unused terminals of networks 66, 77 and 78 and a trimming network 88 is connected to the conjugate network 71. The array shown in Fig. 10 is arranged to modulate two lobes on either side of a course with different frequencies and to radiate a carrier wave on both sides of the course in a phase which is in quadrature with the phase of the carrier waves corresponding to the two lobes to provide an arrangement similar to that described in Specification 563,007. Specification 591,853 also is referred to.