  An accurate and fast method is presented for scattering of electromagnetic
waves from an array of time-modulated graphene ribbons. We derive a time-domain
integral equation for induced surface currents under subwavelength
approximation. Using the method of harmonic balance, this equation is solved
for a sinusoidal modulation. The solution of the integral equation is then used
to obtain the transmission and reflection coefficients of time-modulated
graphene ribbon array. The accuracy of the method was verified through
comparison with results of full-wave simulations. In contrast with previously
reported analysis techniques, our method is extremely fast and can analyze
structures with a much higher modulation frequency. The proposed method also
provides interesting physical insights useful for designing novel applications
and opens up new vistas in the fast design of time-modulated graphene-based
devices.
