The design satisfies a complex set of technical and economic requirements.
A compact, high-dynamic-range, electronically tunable vector measurement system that operates in the frequency range from ≈560 to ≈635 GHz has been developed as a prototype of vector measurement systems that would be suitable for use in nearly-real- time active submillimeter-wave imaging. A judicious choice of intermediate frequencies makes it possible to utilize a significant amount of commercial off-the-shelf communication hardware in this system to keep its cost relatively low. The electronic tunability of this system has been proposed to be utilized in a yet-to-bedeveloped imaging system in which a frequency- dispersive lens would be used to steer transmitted and received beams in one dimension as a function of frequency. Then acquisition of a complete image could be effected by a combination of frequency sweeping for scanning in the aforesaid dimension and mechanical scanning in the perpendicular dimension.
As used here, “vector measurement system” signifies an instrumentation system that applies a radio-frequency (RF) excitation to an object of interest and measures the resulting amplitude and phase response, relative to either the applied excitatory signal or another reference signal related in a known way to applied excitatory signal. In the case of active submillimeter- wave imaging, the RF excitation would be a submillimeter-wavelength signal radiated from an antenna aimed at an object of interest, and the response signal would be a replica of the RF excitation as modified in amplitude and phase by reflection from or transmission through the object.