Système d'antennes

摘要

1,024,804. Aerials; radio navigation. RATHEON CO. Nov. 1, 1963 [Dec. 12, 1962], No. 43308/63. Headings H4A and H4V An antenna system comprises a plurality of flat beam antennµ, Fig. 4, at least one of which produces a beam whose intercept CP1G1, Fig. 3 (not shown), with a sphere centred on the system is an arc of a small circle of the sphere. The system as described produces an inverted V-beam and may be used to enable the pilot of an aircraft 7, Fig. 2 (not shown), to compute his elevation and land along a predetermined path, or, to produce the height dimension in a 3-dimensional radar display, Fig. 9 (not shown). In the first application the ground equipment 1 comprises a transmitter 2 feeding two antennµ 4 and 5 via a power divider 3. Antenna 5 produces a vertical fan beam intercepting the said sphere in a great circle CPG, Fig. 3 (not shown). Antenna 4 produces a beam having the shape of a section of a hollow cone, having an axis Y1 inclined at an angle C to the horizontal, and intercepting the said sphere in the small circle CP1G1. The two antennµ are rotated together around a vertical axis such that the two beams intercept the aircraft 7 at times spaced by an amount dependent on the elevation of the aircraft. The airborne equipment comprises a receiving antennµ 8 feeding a timer 10, angle of descent computer 11 and display 12. In the second application, Fig. 9 (not shown), the same antennµ are used, but the receiving equipment 52 and 58 receiving echos from aircraft 56 is provided at the ground station together with the computer 61. The vertical antennµ 5, Fig. 4, and Figs. 5, 6, 7 and 8 (all not shown) comprises a waveguide feed 25 having 63 radiating slots in the side facing the reflector 24, spaced either side of the centre line of said side to produce a beam having a width in azimuth of 1À5 degrees, and a distorted parabolic reflector 24 producing a vertical fan beam extending in elevation from 6 degrees to 75 degrees. The slant antenna 4 is rotated from the horizontal by an angle of 20 degrees, representing angle C, and through a clockwise horizontal angle of 10 degrees from antenna 5 (looking down in plan view) and comprises a waveguide feed 23 having 110 radiating slots, and a distorted parabolic reflector 22. The distribution of the slots in feed 23 is such as to cause the curvature of the beam cross-section, and produce a beam width in azimuth of 1À5 degrees. Tables are provided giving the slot distribution in each waveguide and the profile of each antenna reflector. Three shaped slant beams may be used together with one vertical flat beam to provide additional information. Electronic scanning may be used for the rotation in azimuth.