Broad-band directional antenna

摘要

1,066,151. Aerials; aerial amplifiers; tunnel diode amplifiers. ROHDE & SCHWARZ. June 22, 1965 [June 24, 1964], No. 26259/65. Headings H3Q, H3T and H4A. A broad-band dipole array operating on the logarithmic periodic principle in which the physical lengths of the elements is reduced in consequence of the insertion therein of loading networks S 1 to S n , Fig. 1, is further provided with phase-matching networks V 1 to V n-1 connected in series in the common feeder between consecutive dipoles, so that the spacings between the said dipoles may be reduced. The loading networks may comprise inductors 7 to 10, Fig. 2 (not shown), one being inserted between each dipole element and the appro-- priate leg of a feeder 6, and tuning capacitors 11, 12, one being connected across the feeder at each dipole. A phase-matching network may comprise a capacitor 13 connected across the feeder. Amplifiers comprising tunnel diodes D1, Figs. 3, 4 (not shown), or other active elements may be inductively coupled to the dipoles, with power supply over a separate feeder. As described, two insulating boards 33, 34, Fig. 5 (not shown), carry the halves of the dipoles, such as 35, 36, and the halves 37, 38 of an H.F. strip transmission line. Cores 39, 40 on which are wound, respectively, coils L 1 , L 2 , L 3 and L1 1 , L1 2 , L1 3 are inserted in holes in the insulating boards 33, 34. The dipole 35, 36 is coupled through the coils L 2 , L1 2 , a tuning capacitor C 2 being interposed. The H.F. strip transmission line is coupled through the coils L 1 , L1 1 and an amplifier is coupled through the coils L 3 , L1 3 . The amplifier comprises a tunnel diode D 1 shunted by a capacitor C 1 and in series with a resistor R 1 shunted by a capacitor C 3 . Direct current power supply is by twisted leads 47 which are passed through sleeves 48, made of a material which absorbs H.F. energy, and are connected across the resistor R 1 . A similar amplifier is provided for each element of the array. The array may feed several receivers, each tuned to a different frequency within its operating band. It may also be used for transmission, when the amplifiers may be the output stages of the transmitters. It is stated that adjustments may be made to . produce so-called super-gain operation of the array.