DOI:10.1049/ji-3a-1.1946.0002

出版商:IEE    

年代:1946

数据来源: IET

DOI:10.1049/ji-3a-1.1946.0003

出版商:IEE    

年代:1946

数据来源: IET

摘要:

The paper presents a survey of those principles in aerial design which have come to the fore during-the war in the development of aerials for radar equipments. It is intended to serve as a co-ordinating introduction to specialist papers which willfollow. It is assumed that the reader is familiar with pre-war theory and practice in relation to aerials.On metre wavelengths the aerials are divided into those working on the “flood-lighting” and those working on the “beam” principle. The beaming in the vertical plane is seldom sufficiently sharp to avoid effects from ground reflections, which therefore play a predominant role in methods of elevation-finding.In radar direction-finding from aircraft with metre waves, use is made of overlapping “polar diagrams” provided either by self-directive aerials, or by aerials so positioned that the metal body of the aircraft causes them to have the required directive properties.With centimetre waves it is possible to produce beams so sharp that complications due to reflections from the ground can, to a large extent, be avoided. It is explained how the principles of optical diffraction theory are applied to the design of linear arrays fed from wave guides, so as to produce “fan-beams” of radiation narrow in one plane and sharp in the perpendicular one. The production of “pencil-beams,” sharp in two planes at right angles, is also discussed.Some account is given of new developments in the use of slots as aerials, in the design of wide-band aerials, and in the theory and design of end-fire arrays of the Yagi type.

DOI:10.1049/ji-3a-1.1946.0004

出版商:IEE    

年代:1946

数据来源: IET

摘要:

Wave guides, though known in principle for many years, became of practical importance only with the advent of centimetre wavelengths, and are now, because of their low attenuation and high power-handling capacity, the standard feeders for these wavelengths. They only transmit energy freely above a critical frequency. Energy may then be propagated in one or more modes, and single-mode propagation is desirable for practical purposes; this is achieved by the use of wave guides of rectangular cross-section. Transmission-line theory can usefully be applied to wave guides.The use of wave guides involves a number of auxiliary components such as couplings, bends, corners, branches, switches, rotating joints, etc., whose design involves specialized techniques. The use of a single aerial and wave guide for both transmission and reception has led to close integration of wave-guide technique with transmitter and receiver design; there is similarly a close integration of wave guide and aerial techniques.

DOI:10.1049/ji-3a-1.1946.0005

出版商:IEE    

年代:1946

数据来源: IET

DOI:10.1049/ji-3a-1.1946.0006

出版商:IEE    

年代:1946

数据来源: IET

DOI:10.1049/ji-3a-1.1946.0007

出版商:IEE    

年代:1946

数据来源: IET

DOI:10.1049/ji-3a-1.1946.0008

出版商:IEE    

年代:1946

数据来源: IET

DOI:10.1049/ji-3a-1.1946.0009

出版商:IEE    

年代:1946

数据来源: IET

DOI:10.1049/ji-3a-1.1946.0010

出版商:IEE    

年代:1946

数据来源: IET

DOI:10.1049/ji-3a-1.1946.0011

出版商:IEE    

年代:1946

数据来源: IET