GB770940A - Coupling arrangement for slot antennas - Google Patents

Abstract

770,940. Aerials. BENDIX AVIATION. CORPORATION. May 16, 1955 [June 1, 1954], No. 14117/55. Class 40(7) . An aerial consisting of an elongated slot 11 in a conductive wall member 10 is fed from an unbalanced feeder such as the co-axial line 13 by means of an L- shaped coupling conductor 17. This conductor is attached at one end of its longer arm 18 to the inner conductor 16 of the line 13 and the said longer arm 18 extends parallel to the slot walls and closer to one wall than the other. Its shorter arm 19 joins the end of the arm 18 across the larger gap to the opposite slot wall. The outer conductor of the line 13 is coupled to the wall member 10 by means of the clamp 15. The coupling conductor may be supported in material 22 having a higher dielectric constant than air and extending between it and the nearer slot wall or between it and both slot walls. Preferably the conductor is in strip form arranged as shown in Fig. 2a. The slot is either made half a wavelength long or of some shorter length and tuned by a condenser connected between the mid-points of its sides. The coupling acts as a voltage transformer and the length of the arm 18 is not critical above a certain minimum length but may in practice be one eighth of the short length.