GB631944A - Antennas - Google Patents

Abstract

631,944. Aerials. STANDARD TELEPHONES & CABLES, Ltd. July 13, 1946, No, 21016. Convention date, Aug. 13, 1945. [Class 40 (vii)] An aerial arrangemen comprises a sheet of con ducting material providec with an aperture having a closed periphery to two spaced points on which feeder means are coupled, the aper ture being other than a single slot of uniform width. Ir one arrangement, Fig. 2 the aperture comprises twc portions ABC ; ACD, the perimeter of each portior being #/2 and the feeder transmission line 2, 3 being connected across the aperture at the points A, C. This arrangement is said to give a preponderance of radiation in the plane XY and zero radiation along the Z axis, the radiation characteristic being similar to that of a di-pole located at the centre of the portion ABC with its axis parallel to the Z axis. In a similar arrangement (Fig. 3, not shown), the aperture portion ABC of Fig. 2 has a rectangular shape, the perimeter, as with ABC being equal to #/2. In a further arrangement, Fig. 4, the perimeter of the circular aperture portion is less than #/2 and preferably not greater than #/4, the perimeter of the other aperture portion being greater than #/2 and providing a radiation characteristic similar to that from a loop aerial having the plane of the loop located in the plane of the conducting sheet. In an. arrangement for producing a characteristic equivalent to that of a folded dipole, Fig. 5, the portion ABCDE has a length equal to #/2 and the portion AFE a perimeter equal to #/2. By folding the portion ABCDE through 90 degrees about the axis of the portion AFE a characteristic similar to that of a folded V-aerial is obtained (Fig. 6, not shown). A doublet of the arrangement of Fig. 4, producing a characteristic equivalent to that of two spaced loops excited in out-of-phase relation is described with reference to Fig 7 (not shown). A further doublet of the arrangement of Fig. 2, having a characteristic equivalent to that of two spaced dipoles excited in the same phase relationship, is described with reference to Fig. 8 (not shown). In a modification of Fig. 8 the two aperture portions are of similar triangular shape and merge into each other to provide a common gap across which the transmission line is connected (Fig. 9, not shown). Fig. 10 shows an arrangement producing radiation along the major axis of the aperture in the plane of the sheet 1, the characteristic being obtained by making the end B of the portion ABC shorter than the end D of the portion ADC, so that the field due to the latter end is not completely cancelled by the field due to the former end.