Achieving More with Less: Time-Modulated Multi-Beam Arrays for MIMO Communication and Sensing

Multi-beam MIMO systems can deliver higher capacity for the communication network or support multi-target tracking in situation-aware radars. However, conventional analog or hybrid beamforming array architectures often require substantial complexity and overhead to support multi-beam operation. Digital beamforming arrays can intrinsically support concurrent multi-beam operation, but they require a full transceiver chain with ADC/DAC for each element, which is impractical for resource constrained mobile platforms, such as drones or robots. This tutorial focuses on the Time-Modulated Arrays (TMA) concept, which was originally proposed in the antenna community and is now gaining popularity in the circuits and microwave communities. The TMAs utilize time as a new degree-of-freedom to modulate the array and realize Linear Periodically Time-Varying (LPTV) performance at the array level. Several recent examples of TMAs with IC implementations will be presented, such as multi-beam MIMO receiver/transmitter systems, relays, radars, fine beam steering, and TX backoff efficiency enhancement.