| 摘要 |
806,120. Radio aerials. SYKES, B. June 7, 1957 [March 9, 1956], No. 7466/56. Class 40 (7). A wireless aerial suitable for use at frequencies of the order of 200 Mc/s. comprises a skeleton slot or closed frame section combined with a V-type section which extends in a plane at right angles to the plane of the slot, the lengths of the V-section elements and the slot or frame section elements being resonant at substantially the same frequency. The feeder is connected to the apex of the V-section which has its open ends connected to opposite sides of the slot which, in one embodiment, is square as in Fig. 1. Due to changes of reactance with frequency of the two aerial sections tending to cancel, the feed impedance at the apex of the V-section is substantially constant over a range of frequency. The aerial is directional in a direction from the apex of the V to the slot. For two band operation, say Bands I and III, two Band I dipole sections are mounted at the joins of the V-section and the slot, these sections being preferably colinear. This aerial resonates only at one frequency and is non-directive unless provided with a reflector and/or director whereas the V and slot aerial is directional and resonates satisfactorily over a wide frequency range. The aerial matches to standard lowimpedance coaxial cable. |
