Analysis of terahertz oscillator using negative differential resistance dual-channel transistor and integrated antenna

The terahertz (THz) band ranges from 100 GHz to 10 THz generally. For easy available of the applications, for example, an imaging system and an indoor wireless communication system using this band, an ultrahigh-frequency oscillator device as a wave source with a frequency of one or a few hundred GHz using the negative differential resistance dual-channel transistor (NDR-DCT) proposed by National Institute of Advanced Industrial Science and Technology (AIST) has been studied. The equivalent circuit model of NDR-DCT was based on the measured device properties and analogy with resonant tunnelling diodes (RTDs). It was shown that an antenna on an wafer, which consists of the electrodes of the transistor, could be realized with the slit reflector by numerical analysis. In this study, we simulated and confirmed the validity of our design of the antenna at any frequencies up to a few hundred GHz. The oscillation frequency of this device was analyzed at 150 GHz and more mainly by specifying the dependence of NDR-DCT characteristics on the gate length for the first time. Improvements in the characteristics of the oscillation device using the optimum gate length were shown.