Metasurface-Programmable Wireless Network-on-Chip

Abstract

We introduce the concept of smart radio environments, currently extensively studied for wireless communication in metasurface-programmable meter-scaled environments (e.g., inside rooms), on the chip scale. Wired intra-chip communication for information exchange between cores increasingly becomes a computation-speed-bottleneck for modern multi-core chips. Wireless intra-chip links with millimeter waves are a candidate technology to address this challenge, but they currently face their own problems: the on-chip propagation environment can be highly reverberant due to the metallic chip enclosure but transceiver modules must be kept simple (on/off keying) such that long channel impulse responses (CIRs) slow down the communication rate. Here, we overcome this problem by endowing the on-chip propagation environment with in situ programmability, allowing us to shape the CIR at will, and to impose, for instance, a pulse-like CIR despite the strong multipath environment. Using full-wave simulations, we design a programmable metasurface suitable for integration in the on-chip environment ("on-chip reconfigurable intelligent surface"), and we demonstrate that the spatial control offered by the metasurface allows us to shape the CIR profile. We envision (i) dynamic multi-channel CIR shaping adapted to on-chip traffic patterns, (ii) analog wave-based over-the-air computing inside the chip enclosure, and (iii) the application of the explored concepts to off-chip communication inside racks, inside the chassis of personal computers, etc.

Microwave Speech Recognizer Empowered by a Programmable Metasurface

“…The reprogrammable coding metasurface is an ultrathin planar array of meta-atoms that are individually reconfigurable via electronic commands 17,31,32 . Thanks to its unique capabilities to manipulate electromagnetic wavefields in a reprogrammable manner, it has elicited many exciting physical phenomena (e.g., nonreciprocal reflection effects 33 ) and versatile functional devices, including computational imagers 18,22,26,19,27,[34][35][36][37][38][39][40] , dynamic holography 41 , wireless communications [42][43][44][45][46][47][48][49] , analog wave-based computing [50][51][52] , and dynamic cloaks 53 .…”

Controlling the Spatiotemporal Response of Transient Reverberating Sound

“…Endowing reverberant enclosures, such as indoor environments [14,17], with electromagnetic programmability has become a very active research track in the microwave domain with applications in wireless communication [17][18][19], sensing [20], analog computing [21,22], and fundamental research on scattering anomalies like perfect absorption [23]. Moreover, the purely spatial control (offered by a "space-coding" programmable metasurface [24]) is leveraged to focus reverberating microwaves in space and time [25], enabling pulselike impulse responses despite rich scattering for low-power wireless receivers [26,27]. Indeed, control over the spatial boundaries of a transient wavefield also affects the time dependence of the impulse response because it yields partial control of all the secondary sources that interfere with the primary source to constitute the impulse response.…”