Phased-Array Antenna Patterns (Part 4)—Grating Lobes (.PDF Download)

In the first three parts of this series, we introduced the phased-array steering concept and looked at the influencers on array gain. In the next two parts, we’ll discuss grating lobes and beam squint. Grating lobes can be hard to visualize, so we’ll draw on their similarity with signal aliasing in digital converters, then use that to think of a grating lobe as a spatial alias.

In the upcoming Part 5, we’ll explore the issue of beam squint. Beam squint is an unfocusing of the antenna across frequency when we use phase shift, instead of a true time delay, to steer the beam. We’ll also discuss the tradeoff between these two steering methods and understand the impact of beam squint on typical systems.