Millimeter waves refer to electromagnetic waves that have wavelengths ranging from 1 to 10 millimeters. This frequency range falls between the microwave and infrared regions of the electromagnetic spectrum. Millimeter waves have various applications in communications, radar systems, imaging, and security screening. They are also being studied for their potential use in next-generation wireless networks, such as 5G and beyond. Research in millimeter waves focuses on improving the efficiency and performance of these technologies, as well as exploring new applications and capabilities.