Nonlinear EM-based Signal Processing

TL;DR

This paper explores innovative electromagnetic signal processing architectures using passive nonlinear elements to perform over-the-air processing, reducing system complexity and RF chain requirements in large antenna systems.

Contribution

It introduces novel EM domain architectures with passive nonlinear elements for multifunctional signal processing directly over-the-air, a new approach in scalable wireless systems.

Findings

Significant reduction in system complexity and RF chains.

Effective over-the-air direction-of-arrival and position estimation.

Potential for scalable, low-power wireless solutions.

Abstract

The use of high-frequency bands, combined with antenna arrays containing an extremely large number of elements (XL-MIMO), is pushing current technology to its limits in terms of hardware complexity, latency, and power consumption. A promising approach to achieving scalable and sustainable solutions is to shift part of the signal processing directly into the electromagnetic (EM) domain. In this paper, we investigate novel architectures that harness the interaction of reconfigurable passive linear and nonlinear (NL) scattering elements positioned in the reactive near field of signal sources. The objective is to enable multifunctional linear and NL EM signal processing to occur directly "over-the-air." Numerical results highlight the potential to significantly reduce both system complexity and the number of RF chains, while still achieving key performance metrics in applications such as direction-of-arrival and position estimation, without the need for additional analog or digital processing.