Asynchronous Circuits as an Enabler of Scalable and Programmable Metasurfaces

Abstract

Metamaterials and metasurfaces have given possibilities for manipulating electromagnetic (EM) waves that in the past would have seemed impossible. The majority of metasurface designs are suitable for a particular frequency and angle of incidence. One long-sought objective is the design of programmable metasurfaces to dynamically manipulate a variety of incoming EM frequencies and angles. In order to do this, a large-scale mesh of networked chips are required below the metasurface, which apart from adapting electrical impedance properties, also communicate with each other, thus relaying information about meta-atom settings, as well as forwarding possible distributed measurements taken. This paper describes why an asynchronous mixed-signal ASIC is advantageous for the control of scalable, EM absorbing, metasurfaces.

The first family of application-specific integrated circuits for programmable metasurfaces

“…The ASICs utilize an asynchronous methodology for the control circuit to reduce noise and increase speed, while simultaneously consuming less power 29 , when compared to traditional clocked systems. The digital-to-analog converters' eight-bit resolution provides ne adjustment of the low-power complex impedance loading elements 3 .…”

“…The control circuit uses asynchronous circuits and communicates via handshake. Synchronous digital circuits are by far predominant in control circuit designs, however to maximize the ASIC usability for various metasurface designs and to avoid all issues associated with the clock tree synthesis of synchronous digital systems, we opted to go the asynchronous route 29 . A synchronous digital system would require a clock tree with scalability adjustments and would have to satisfy the requirements of exible metasurfaces and walls of irregular shapes.…”

Toward the Realization of a Programmable Metasurface Absorber Enabled by Custom Integrated Circuit Technology

“…In order to reduce the overall current consumption, each metasurface loading element should be implemented with a negligible current draw, and since each unit cell is locally controlled, the digital and analog part should also be designed with minimum power requirements. In [34], the importance of using asynchronous control circuits for enabling programmable and scalable metasurfaces is argued. Asynchronous circuits offer a low power consumption for controllers that are idling most of the time, as in the case of controllable metasurfaces.…”

Fault Adaptive Routing in Metasurface Controller Networks

“…A first HSF prototype is targeted in this work [5]. Towards the development of this prototype a three layer PCB structure has been considered where the top layer consists of the metal patches, the second layer consists of the ground plane and the bottom layer consists of an array of applications specific integrated circuit (ASIC) in which the controller functionality is embedded.…”