Chip-Size Double-Resonant-Tunneling-Diode Patch-Antenna Oscillators and their sub-THz Application

To enable applications in the THz frequency range, chip-size room-temperature THz and sub-THz sources are required. We present here the concept and experimental results on such sources using double-resonant-tunneling-diode (RTD) patchantenna oscillators. With these sources, we could cover the frequencies up to 1.09 THz, with the output powers between 70 to 10 mu W from a single oscillator. These data demonstrate an order of magnitude improvement in terms of the output power and factor 2 improvement in terms of the fundamental operating frequency compared to the previous reports on patch-antenna RTD oscillators. Next, we show the possible direct application of these oscillators as a source for FMCW radar or optical coherent tomography working at a frequency of 680 GHz, with a bandwidth of 38 GHz (5.5 %), allowing 4 mm spatial resolution. The output power was 23 mu W.