Spatial-Spectral Mapping Beamspace MIMO Receiver Enabled by a Programmable Space-Time-Modulated Metamaterial Antenna

This paper leverages a space-time-modulated metamaterial (ST-MTM) antenna as a beamspace multiple-input multiple-output (MIMO) receiver, which facilitates the retrieval of information from multiple users transmitting distinct data on the same carrier frequency. In this scenario, the information received from each user, located in a specific direction, is mapped to a distinct harmonic frequency component within the received spectrum. The phase constant
$(\beta)$
of each tunable composite right/left-handed (CRLH) unit cell in a leaky wave antenna (LWA) is periodically modulated in the time domain, generating harmonic frequencies around the carrier frequency of the received signal. By applying a proper time-modulated sequence to each unit cell, the power levels of the harmonics, extracted from one port of the receiver, reach their maximum values at different directions, enabling spatial-spectral mapping. The measured bit-error-rate (BER) results, obtained using a fabricated prototype as the receiver, confirm the successful retrieval of data concurrently sent by multiple users.