Module integration and amplifier design optimization for optically enabled passive millimeter-wave imaging

ABSTRACT This paper will discuss the development of a millimeter-wave (mm-wave) receiver module used in a sparse array passive imaging system. Using liquid crystal polymer (LCP) technology and low power InP low noise amplifiers (LNA), enables the integration of the digital circuitry along with the RF components onto a single substrate significantly improves the size, weight, power, and cost (SWaP-C) of the mm-wave receiver module compared to previous iterations of the module. Also comparing with previous generation modules, the operating frequency has been pushed from 77 GHz to 95 GHz in order to improve the resolution of the captured image from the sparse array imaging system. Keywords: passive millimeter wave imaging, brownout mitigation, distributed aperture imaging, optical upconversion, SiGe amplifier, liquid crystal polymer (LCP) 1. INTRODUCTION For the past several years, Phase Sensitive Innovations (PSI) Inc. have been using millimeter wave (mm-wave) technology to develop state-of-the-art real time imaging systems capable of peering through degraded visual environments (DVE) such as dust, smoke, and fog. Along with DVE imaging, the system is capable of peering through fabric material, wood panels, and other such non-conductive materials. This technology is capable of achieving this ability is due to the phenomenon of the atmospheric attenuation as a function of frequency. As shown in Figure 1 is a plot of the atmospheric attenuation for different levels of humidity and fog from 10 GHz to 1 THz. In specific portions of the spectrum, the attenuation is low, thus allowing the radiation to propagate through DVE. Such an example of mm-wave imaging is shown in Figure 1 of a building on a clear day, then on a foggy day, and as well as a mm-wave image of the building in the same foggy environment.