Large-scale array of resonant-tunneling-diode terahertz oscillators for high output power at 1 THz

We proposed and fabricated large-scale arrays of resonant tunneling diode (RTD) oscillators for high-output-power terahertz (THz) sources. The array element is composed of an RTD, a slot resonator, and a dipole array antenna on a dielectric layer stacked on the RTD. In this structure, the output power is radiated in the upward direction of the substrate without a hemispherical silicon lens. The dipole array antenna was designed so that the average output power determined by the variation in the size of the RTD in the array was maximized. The experimental output power was proportional to the element number, and its value was 0.73 mW for an 89-element array at similar to 1 THz in a pulsed mode with a repetition rate of 300 Hz and a duty ratio of 10%. Multiple peaks were observed in the oscillation spectra, because the elements were not intentionally coupled with each other. The average output power per element was 9 mu W in the array, which was lower than that of the separated single oscillators (21 mu W). Possible causes of this difference are discussed. Published under license by AIP Publishing.