Receive Arrays for Polar Over-the-Horizon Radar

Receive array design for Polar Over-the-Horizon Radar is driven primarily by the need to mitigate auroral radar clutter that appears at all azimuth angles. Arrays must be adequate to enable the detection and location of targets in the presence of this clutter. While it is feasible to deploy a maximum-performance large two-dimensional antenna grid at half-wavelength element spacing, thinning of the array can reduce cost. Based on an analytic clutter model, it is shown that the element density could potentially be halved without significant decrease in performance. Thinning to one-quarter density starts to incur noticeable perfomance impacts.