Circular array providing fast 360° electronic beam rotation

The paper describes an experimental 16-element circular array and associated receiving system which is capable of forming a fan-beam directional pattern and electronically rotating this pattern through 360°. The receiver operates at a frequency of 427 MHz and a beam rotation rate of 400kHz. The system is designed to study the possible application of this technique to a 360° within-pulse scanning radar. Studies are made of the phase- and frequency-stability requirements of parts of the receiving system necessary to avoid distortion of the rotating directional pattern. Satisfactory results are obtained from the experimental receiver which employs a directional pattern in the form of a J0(x) function having an 8 dB sidelobe level; proposals are discussed for extending the system to handle patterns with lower sidelobe levels.