GB1507674A - Aerials - Google Patents

Abstract

1507674 Aerials C & S ANTENNAS Ltd 23 May 1975 [7 June 1974] 25472/74 Heading H4A A loop antenna for vertically polarized, HF signals, has a termination 1 and a resistive impedance 2, on the opposite side of the loop. The size of the impedance determines the shape of the radiation pattern by attenuating zero and even order Fourier components of the current in the loop, so that a cardioid or circular pattern is formed in preference to the common "figure of eight". The loop may comprise two conductive strips 3, 4 joined by cross pieces 5 so that it has large effective width but reduced series inductance and shunt capacitance. The resistor may be soldered in a break in the strips. A low-noise amplifier, housed in box 6, may be provided at the termination of the loop for an improved signal to noise ratio. Arrays of such loop antennas having phase diferences between adjacent loops may provide further enhanced directivity (Figs. 12-14, not shown).