Background Touchless interaction systems have grown in prevalence in recent years, including gesture-based interaction systems. Gesture recognition forms an integral part of human-computer interaction (HCI) technologies that deal with recognizing various movements of the human body, and interpreting them as commands to interact with a machine. Hand...

Heart rate and other cardiac function monitoring is conventionally performed in a healthcare setting utilizing devices such as EKGs and finger pulse oximeters. While effective, this requires physical contact with the patient and a doctor visit, making continuous or long-term monitoring difficult. Microwave radars have been used extensively for...

Background Reflective surfaces, including metasurfaces and reflectarray antennas, are comprised of several subwavelength (< λ/2) passive reflective elements and can steer the reflection of an incident electromagnetic wave in arbitrary directions. Typically, reflective surfaces use one or multiple single-pull-single-through (SPST) switches...

Background Simultaneous localization and mapping (SLAM) is the process by which a robot or system constructs a map of an undefined environment and tracks its location within it. By allowing autonomous agents to safely and independently navigate crowded settings, SLAM has found applications in virtual and augmented reality, driverless vehicles, and...

Current portable and wearable devices use fingerprint analysis for secure authentication. The fingerprint pattern systems analyze only the surface morphology of the fingerprint, making it easy for hackers to spoof and bypass authentication. RF signals can collect tissue information beyond the surface of the finger and can provide increased security...