Perfect pulse filtering under simultaneous incidence at the same frequencies with waveform-selective metasurfaces

Abstract

We present a new concept of metasurface filters to preferentially extract pulsed waveforms at a constant frequency from a complex superimposed input signal. This filtering capability is realized using circuit-based metasurfaces, denoted waveform-selective metasurfaces, that behave according to the pulse duration of the incident wave. Importantly, our metasurface filters overcome a long-lasting issue of eliminating unnecessary pulses under simultaneous incidence without relying on variables that are commonly used for modulation schemes, e.g., frequency, time, and spatial variation (angular dependence). Such simultaneous filtering is made possible by integrating several types of waveform-selective metasurface unit cells with delay lines and successive interference cancellation processes. Moreover, we show that our concept can be extended to incorporating broadband signals, additional pulses, and variables used for existing modulation schemes. Our study therefore provides a higher degree of freedom to control electromagnetic waves and phenomena with possible applications including wireless power transfer and communications.