Q-Band Millimeter Wave Imaging in the Far-Field Enabled by Optical Upconversion Methodology

摘要

Millimeter-wave (mmW) imaging has evolved to the point where it offersdistinctive remote sensing capabilities in many application scenarios, such as port andharbor security, search and rescue, and navigational aids, due to its unique ability topenetrate atmospheric obscurants. Some of the applications being considered requirepassive imaging, imposing challenging sensitivity requirements to detect the low powerlevels in this spectral region. One metric used in this regard is the noise equivalent power(NEP), which quantifies the sensitivity of a detector. By utilizing a unique detectortechnology based on optical upconversion a low NEP value is achieved as compared toother RF methods, without the use of cryogenic cooling or low noise amplification. Inaddition, the overall size and weight may be reduced as compared to other imagingmethodologies. As such, the construction and development of a passive mmW imagingsystem utilizing optical upconversion was undertaken, operating in the Q-Band to collectradiation between 33 and 50 GHz. Herein, we describe the passive mmW imagerarchitecture and operation. Also presented are imaging results obtained using this approachas well as key imager metrics that have been experimentally validated.