GB1348620A - Aerials - Google Patents

Abstract

1348620 Aerials SOC LANNIONNAISE D'ELECTRONIQUE SLE-CITEREL 22 Dec 1972 [22 Dec 1971] 59502/72 Heading H4A In an aerial arrangement, two parallel arms 1, 2, Fig. 1a, extend for equal distances from a ground plane 3, and pass through respective holes 7, 8 in a plane metallic member 6. The arm 1 is connected at its end 5 to the ground plane 3, and the arm 2 is connected by a bushing 4, placed below said ground plane, to a coaxial cable 4<SP>1</SP>. Two parallel conductors 9, 10 of equal lengths are spaced above the member 6, and are respectively joined at their ends P, Q to the arms 1, 2, to which they are transverse. The conductors 9, 10 are connected at their other ends to the member 6, by means of short vertical conductors 11, 12. The length of each arm, 1, 2 may be one-twelfth of the wavelength at the mean operating frequency, and the impedance at the feed point 4 may be matched to that of the coaxial cable 4<SP>1</SP> (e.g., 50 ohms). In another embodiment, equivalents to the conductors 9, 10 and to the conductive member 6 are provided by metallic deposits on the upper and lower faces of an insulating plate 21, Fig. 4a, which is secured horizontally inside the top of a radome 30. Radiating arms 1, 2, which are slightly inclined to the vertical, extend from a coaxial bushing 35 in the centre of a metallic closure plate 32 at the bottom of the radome 30. The assembly may be installed upon the sheetmetal roof 36 of a vehicle.