In this paper we describe the system integration and the experimental demonstration of a photonically beamformed four-element receiving array antenna for radio astronomy applications. To our knowledge, the work described here is the first demonstration of the squint-free, continuously tunable beamsteering capability offered by an integrated photonic beamformer based on optical ring resonator truetime-delay units, with measured radiation patterns. The integrated beamformer is realized in a low loss, complementary metal-oxide-semiconductor (CMOS) compatible optical waveguide technology. The measurements show a wideband, continuous beamsteering operation over a steering angle of 23.5 degrees and an instantaneous bandwidth of 500 MHz limited only by the measurement setup.
Burla, M., Roeloffzen, C. G. H., Zhuang, L., Marpaung, D. A. I., Khan, M. R. H., Maat, P., ... Heideman, R. (2012). System integration and radiation pattern measurements of a phased array antenna employing an integrated photonic beamformer for radio astronomy applications. Applied Optics, 51(7), 789-802. https://doi.org/10.1364/AO.51.000789