Some recent developments in the design of centimetric aerial systems

The development of microwave radar systems was started in 1940 largely because microwave aerial systems offered, particularly for airborne use, the definite advantages of narrow beams and high power-gains from practical aerial apertures. The principle was well known that to achieve these things it is necessary to spread out the power being radiated over as large an aperture as possible. One of the simplest forms of microwave aerial used to achieve this was the simple paraboloid. As radar in the centimetric field developed the characteristics demanded from the aerials systems increased in complexity. The paper starts with a very brief survey of some of the main features of paraboloid aerials and then outlines in rather more detail some of the work which has been done in recent years upon more complex microwave aerials to meet the new requirements.