True Time Delay System Using Phase Change Materials

By exploiting the high refractive index contrast between the two material phases (amorphous and crystalline) of a phase change material (PCM) and by incorporating the PCM inside a photonic Bragg Grating Resonator (BGR), programable on/off reflectors can be obtained around the operating wavelength. Delay lines containing several BGRs (geometrically separated by specific paths) are designed, and true time delay (TTD) is induced in optical signals in each delay line. In details, the optical delay introduced by each delay line depends on the position of the single BGR along the line that is programmed to work as reflector at the operating wavelength of similar to 1550 nm. By controlling the BGRs in each path, distinct time delays are introduced by different delay lines and used to control a phased-array antenna (PAA) able to steer a microwave beam towards specific angles. In this work design and simulations of different delay lines are presented to realize the steering of an antenna at multiple angles.