Antenne de petites dimensions

• Main Author: LUNDBURG FRANK JOEL
• Format: Patent
• Language: French
• Published: 15.05.1953
• Subjects: ANTENNAS, i.e. RADIO AERIALS; BASIC ELECTRIC ELEMENTS; ELECTRICITY; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE; WAVEGUIDES

677,860. Aerials. STANDARD TELEPHONES & CABLES, Ltd. July 28, 1950 [Nov. 19, 1949], No. 18895/50. Class 40 (vii). A radio antenna assembly comprises a radiating antenna of small length relative to half a wavelength at the operating frequency enclosed within a structure which although surrounding the antenna allows the passage of radiation in one plane. The antenna may comprise a dipole of the order of a tenth of a wavelength long which is easy to rotate at high speeds owing to its small physical size but which will, by itself, have a very low radiation resistance. The enclosing structure increases the effective radiation resistance of the antenna, enabling it to be matched to its feeder. It may consist of an open wire cage made of rods 6 perpendicular to the plane of polarization of the dipole 2 secured at the top and bottom to plane conductive discs 5 and 4. The rods are spaced closely enough to form a polarization grating to filter the vertically polarized components and pass the horizontally polarized energy. Matching is only completely achieved at one frequency but the assembly is effective over a relatively wide band-width. In an example, where the dipole was of 30 degrees electrical length at 800 Mc/s. the spacing between the plates and diameter of the plates was made half a wavelength and twenty uniformly spaced rods were used.