Long-range Millimeter Wave Passive Tags

This SBIR develops novel long-range passive Electromagnetic (EM) tag based on millimeter waves (mmW). EM mm waves can go through fabrics, plastics, wood, and other occlusions for addressing covert target tracking. The mmW spectrum offers an attractive middle ground between radio and optical wavelengths, having unique advantages for long range (> 1 km) RFID-like tags. The mmW bands have many of the best features of the radio and the optical wavelengths, such as the ability to create focused beams of mmW energy to span long distances, potentially many kilometers. In contrast to IR or visible wavelengths, mmW signals offer an all-weather capability due to their penetration of rain, fog, and sandstorms. mmW signals are eye-safe and safe for operation near humans, unlike high power laser energy. Finally, the FCC has allocated several mmW bands for license- free industrial, scientific, and medical (ISM) use, including 250 MHz of bandwidth at 24 GHz, which is very promising for small, RFID-like, battery-free tags. The mmW band offers the ease of design with well-established integrated circuit technology on low-cost silicon, Silicon-germanium (SiGe) and Gallium-arsenide (GaAs) processes. To enable battery-free tags, energy harvesting efficiency in the mmW bands is much higher than photovoltaic (solar) cells, with reported harvester efficiency of over 54% at mmW bands. Low power data uplink via modulated backscatter is straightforward using single FET or PIN diode switches driven from low-power digital logic. From the reader/interrogator perspective, transmitters in the mmW band are much less expensive than equivalent-power lasers in the IR or visible wavelengths. Phase I will focus on simulation and analysis, laboratory hardware development, including assessment, optimization, and testing. In Phase II, DSI will have the capability to manufacture and test on real field environments. In Phase III, DSI’s EM mmW tags will be mass manufactured and made available to the government for operational use. Initial applications will focus on developing custom mmW tag solutions for selected NNSA and DOE applications. We will then broaden into DoD and other US government applications to be identified and prioritized by Phase II. Following that, it is expected there will be numerous commercial application possibilities including aerospace, industrial facilities, and possibly medical.