GB618680A - Improvements in or relating to radio aerial systems - Google Patents

Abstract

618,680. Aerials. PHILIPS LAMPS, Ltd. Aug. 1, 1946, No. 22927. Convention date, Oct. 22, 1942. [Class 40 (vii)] An aerial system comprises a rhombic aerial terminated by an impedance formed by a dipole aerial the feeding end of which is directly connected to the terminating end of the rhombic aerial. The rhombic aerial comprised of conductors 2, 21 of lengths 4# is connected to a transmitter 4 (or receiver) and the terminating end 5, 5<1> is connected to a dipole comprised of conductors 6, 6<1> each of length A/4 and earthed at the free ends and having an input impedance equal to the surge impedance of the rhombic. The main direction of radiation from both aerials may be made to coincide (e.g. in direction of arrow 7) by correct choice of the angle between conductors 2, 6 and 21, 61. In an alternative arrangement (Fig. 2, not shown), the sides of the rhombic that are connected to the dipole are crossed so that the free ends of the dipole are brought adjacent and may be connected together without the need of an earth connection. In a further arrangement (Fig. 3, not shown), the sides of the rhombic connected to the transmitter are crossed similarly to the sides connected to the dipole. The #/2 dipole may be replaced by a dipole of other suitable length (e.g. #) or by one having conical limbs. The arrangement described, which avoids the use of a transmission line for interconnecting the aerials is stated to reduce or prevent variation of efficiency with frequency.