Low-loss polynomial White cell optical true-time delay engine for wideband radio frequency array beam steering

An optical true-time delay (OTTD) engine based on a polynomial White cell (quadratic) is designed and simulated with commercially available components with a time delay increment of at least 25 ps for wideband beam steering in the frequency range of 2-18 GHz. The simulated quantification of aberration losses show for the first time that aberration losses in the null cell are about 5.0 dB. However, for the longer delay arms, there is an additional loss of about 3.2 dB/delay each time a beam travels an arm with a lens train used as a delay element compared with the same delay generated without a lens train. We present a design and simulation of a low-loss delay arms quartic cell without a lens train by using a separate field lens for each delay arm for efficient wideband beam steering.