Passive millimeter-wave imaging technology for phased array systems

Trex Enterprises has developed a passive millimeter-wave imaging system incorporating a number of new technologies. The system has a pupil-plane architecture that uses a phased array, flat panel antenna and a phase processor based upon microwave optics. The production and operation of a 232-element W-band phased array and processor poses a number of technical problems including minimizing losses in the front end and adjusting the phase lengths of the processor. The system also has 192 frequency processor cards that perform real-time Fourier analysis of W-band signals over an 18 GHz bandwidth using millimeter-wave optics. Production of a suitable phase and frequency processor in large quantities that form good beams and maintain signal strength requires the adoption of new materials and design strategies. The refinement of these technologies at W-band frequencies allowed Trex Enterprises to produce an imager that is both compact and suitable for large-scale production. In this paper, we will discuss the design and production of the millimeter-wave components unique to this system architecture. We will also present the performance of these components and how they affect the performance of the millimeter-wave imager as a whole. An integrated front end is tested to determine the accuracy of the beam-forming network in producing antenna patterns.