Dynamic Range Considerations for Modern Digital Array Radars

Dynamic range (DR) is generally defined as the ratio between the largest and smallest identifiable signals in a radar and is often quoted as a critical metric when referring to the performance of a radar system. However, the definition of DR can vary widely depending on the context; there are a large number of cited DR definitions in the literature, many of which differ only very slightly. In the increasingly crowded wireless spectrum of today's world, a more complete definition of DR, specifically for digital phased arrays, is needed for clarity and consistency. This paper reviews several useful DR definitions and evaluates their overall ability to accurately define radar performance in light of impairments that occur, especially in recently developed digital arrays. Additionally, while digital arrays can experience DR improvements on the order of 10 $\text{log}_{10}(N)$, where $N$ is the number of transceivers, this improvement has been shown to be limited by the correlation of spurious products. Methods for removing these spurs and decorrelating any remaining nonlinear distortion are briefly mentioned to highlight their effect on the overall system DR. Ultimately, the goal of this paper is to take a system-level approach to evaluating the DR of modern digital array radar systems that leverage recent advancements in digital signal processing techniques.