Millimeter waves.

Differactional Optics of Millimetre Waves Minin, O. V. 2004 Millimeter wave radar edited by Stephen L. Johnston 1980 Millimeter wave technology in wireless PAN, LAN, and MAN Shao-Qiu Xiao, Ming-Tuo Zhou, and Yan Zhang. (editors) 2008 Millimeter-wave radar targets and clutter Kulemin, G. P. 2003 Proceedings of the Symposium on millimeter waves Polytechnic Institute of Brooklyn. Microwave Research Institute 1960