GB490383A - Improvements in or relating to antennae for radio transmission and reception - Google Patents

Abstract

490,383. Aerials. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Feb. 15, 1937, No. 4444. Convention date, Feb. 15, 1936. [Class 40 (v)] Loop aerials for broadcasting or receiving horizontally polarized ultra - short waves with maximum field strength in the horizontal plane have a radius a which bears such a ratio to the wavelength A that J1(2#a/#) is a maximum or minimum; thus a may be 0À29 #, 0À85 #, 1À36 A, 1À86 # ... in correspondence with successive maxima and minima of the Bessel function. Condensers C may be inserted for partially tuning the loop and for ensuring uniform current-distribution, the segments of the loop being excited in opposite phase. There may be a single loop with radius 0À29 #, Fig. 1 (not shown), or a series of loops, Fig. 2, whose radii have the above values, may be arranged in one plane, adjacent loops being excited in opposite phase. Several loops, Fig. 3, or several sets of coplanar loops may be arranged one above the other at intervals of at least half a wavelength. The segments of a loop may be energized by separate feed lines, which may be connected near the middle of the segments, Fig. 4 (not shown), or at their ends ; or the loops may be formed with re-entrant portions 12, Fig. 5, for the purpose of giving approximately uniform and unidirectional current in the radiating sections 8, whose length must not exceed ¢ #.