| 摘要 |
1532237 Log periodic arrays AERIALITE AERIALS Ltd 16 July 1976 [22 July 1975] 30626/75 Heading H4A An aerial comprises a first log periodic end-fire set of dipoles for operatiion in one frequency band, and a second log periodic end fire set for operation in a second frequency band, at least some of the dipole elements of one set being collinear with those of the other set to produce a compact aerial. As shown, the first set includes dipole elements 20A-24A mounted on boom 12 and elements 20B-24B on boom 13; the second set includes elements 25A-33A on boom 12 and elements 25B-33B on boom 13. The parallel booms 12 and 13 constitute a transmission line impedancematched to a coaxial cable which is connected to them at their forward end and led through boom 13 to a rearward termination 35, thence to a downhead. Dipole elements which are collinear, e.g. 20A and 29A, may be made as a single rod. Booms 12 and 13 are connected electrically together at their rearward end. |
