High Output Power (∼400 µW) Oscillators at around 550 GHz Using Resonant Tunneling Diodes with Graded Emitter and Thin Barriers

Abstract

We report resonant tunneling diode (RTD) oscillators with a high output power of around 400 µW at frequencies of 530–590 GHz. RTDs with a graded emitter and thin barriers were employed to obtain large negative differential conductance at high frequencies for high output power. An optimized structure of offset slot antennas was also used to maximize the radiation conductance. The highest output power obtained in this study was 420 µW at 548 GHz for an RTD with a peak current density of 24 mA/µm2; the RTD was placed 58 µm apart from the center of a 130-µm-long slot antenna.

Terahertz oscillation of resonant tunneling diodes with deep and thin quantum wells

“…2. The former composition is the same as that in the previous reports [16,18,20,21,22], which the latter is newly introduced here.…”

“…Resonant tunneling diodes (RTDs) are also a good candidate [13,14,15]. High-frequency and high-power oscillation has been achieved at room temperature [16,17,18,19,20,21].…”

Epitaxial Designs for Maximizing Efficiency in Resonant Tunneling Diode Based Terahertz Emitters

“…Tunable RTDs were achieved by integrating varactor epi-layers with the resonating element [7], opening the possibility to multi-channel, wide-band emitters. In addition to the record high frequency emission of up to 1.92 THz [8], RTDs have shown great versatility as a resonator across the spectrum, having been demonstrated with high output powers (420 µW) at a frequency of 548 GHz [9], 1 mW at 300GHz and 5 mW at 160 GHz [10]. Maximizing RTD DC-to-RF conversion efficiency not only allows the realization of high power emitters, as area scaling is presently limited by catastrophic failure, but also allows higher frequency emitters to be conceived as conduction losses limit high frequency performance [8].…”

Bow-tie antenna for terahertz resonant tunnelling diode based oscillators on high dielectric constant substrate

“…Resonant tunnelling diode (RTD) based THz oscillators in integrated circuit (IC) form have recently been shown to be the technology in which many of these applications could be implemented [4], [5]. They operate at room temperature and have the potential to produce output power of around 1 mW at these frequencies [6].…”

“…A high gain and directive antenna is preferable in order to radiate most of the RF power into specific direction and, as a consequence, offer larger coverage distance. RTD THz oscillators employing integrated slot antennas [4] and planar horn antennas [7] have been demonstrated. The slot antenna is a resonant antenna with infinity input impedance at the centre of the slot and zero at the edges.…”