Method for extracting the equivalent admittance from time-varying metasurfaces and its application to self-tuned spatiotemporal wave manipulation

Abstract

With their self-tuned time-varying responses, waveform-selective metasurfaces embedded with nonlinear electronics have shown fascinating applications, including distinguishing different electromagnetic waves depending on the pulse width. However, thus far they have only been realized with a spatially homogeneous scattering profile. Here, by modeling a metasurface as time-varying admittance sheets, we provide an analytical calculation method to predict the metasurface time-domain responses. This allows derivation of design specifications in the form of equivalent sheet admittance, which is useful in synthesizing a metasurface with spatiotemporal control, such as to realize a metasurface with prescribed time-dependent diffraction characteristics. As an example, based on the proposed equivalent admittance sheet modeling, we synthesize a waveform-selective Fresnel zone plate with variable focal length depending on the incoming pulse width. The proposed synthesis method of pulse-width-dependent metasurfaces may be extended to designing metasurfaces with more complex spatiotemporal wave manipulation, benefiting applications such as sensing, wireless communications and signal processing.

Improved Numerical Estimation Method for Surface Wave Attenuation on Metasurfaces

“…Metasurfaces (MSs) have become a crucial area for electromagnetic wave manipulation and control in recent years. [ 1 ] These artificially engineered materials are tunable and readily exploited in a wide range of applications, such as antennas, [ 2 ] absorbers, [ 3–6 ] sensors, [ 7 ] cloaking devices, [ 8 ] beam steering systems, [ 9,10 ] and wireless communication systems. [ 11–13 ] Surface waves, known as waves confined to a surface, exhibit exponential decay with increasing distance from the surface plane.…”

Improved Numerical Estimation Method for Surface Wave Attenuation on Metasurfaces

“…Metasurfaces (MSs) have become a crucial area for electromagnetic wave manipulation and control in recent years. [1] These artificially engineered materials are tunable and readily exploited in a wide range of applications, such as antennas, [2] absorbers, [3][4][5][6] sensors, [7] cloaking devices, [8] beam steering systems, [9,10] and wireless communication systems. [11][12][13] Surface waves, known as waves confined to a surface, exhibit exponential decay with increasing distance from the surface plane.…”

Design and analysis for the SPICE parameters of waveform-selective metasurfaces varying with the incident pulse width at a constant oscillation frequency

“…Moreover, a series of recent studies demonstrated that metasurfaces composed of Schottky diodes were capable of sensing different waves even at the same frequency in response to the incoming waveform, or more specifically the pulse width 41 – 44 . This waveform selectivity provides a new degree of freedom to control electromagnetic waves at a single frequency, which has thus far been exploited to mitigate electromagnetic interference 44 , design antennas 45 – 47 and related microwave devices 48 , 49 and control communication signals 43 , 50 , 51 . Although the electromagnetic response related to the conducting geometry is well known to be improved by existing methods, including the use of equivalent circuit models 52 , 53 and Jones matrices 54 , 55 , the relationship between the waveform-selective performance and SPICE parameters of diodes remains unclear, which is important for the design of waveform-selective metasurfaces.…”