Proceedings Article | 19 May 2006
KEYWORDS: Terahertz radiation, Antennas, Chemical elements, Metals, Metamaterials, Microwave radiation, Optical lithography, Sol-gels, Terahertz sources, Electronics
Developments in terahertz sources include compacted electron beam systems, optical mixing techniques, and
multiplication of microwave frequencies. Although significant advances in THz science have been achieved, efforts
continue to obtain source technologies that are more mobile and suitable for field deployment. Strategies in source
development have approached generation from either end of the THz spectrum, from up-conversion of high-frequency
microwave to down-conversion of optical frequencies. In this paper, we present the design of a THz source which
employs an up-conversion method in an assembly that integrates power supply, electronics, and radiative component into
a man-portable unit for situations in which a lab system is not feasible. This unit will ultimately evolve into a
ruggedized package suitable for use in extreme conditions, e.g. temporary security check points or emergency response
teams, in conditions where THz diagnostics are needed with minimal planning or logistical support. In order to meet
design goals of reduced size and complexity, the inner workings of the unit ideally would be condensed into a monolithic
active element, with ancillary systems, e.g. user interface and power, coupled to the element. To attain these goals, the
fundamental component of our design is a THz source and lens array that may be fabricated with either printed circuit
board or wafer substrate. To reduce the volume occupied by the source array, the design employs a metamaterial
composed of a periodic lattice of resonant elements. Each resonant element is an LC oscillator, or tank circuit, with
inductance, capacitance, and center frequency determined by dimensioning and material parameters. The source array
and supporting electronics are designed so that the radiative elements are driven in-phase to yield THz radiation with a
high degree of partial coherence. Simulation indicates that the spectral width of operation may be controlled by detuning
of critical dimensions. We discuss simulation results and frequency response for a single element and the source array,
and the component density necessary to achieve target output intensities. After obtaining the primary objective of a
designing a compact fieldable THz source, the secondary goal is developing a fabrication recipe which draws upon
existing methods in PCB/integrated circuit manufacturing to obtain a device that may be produced at volume with high
yield.
