Waveguide coupler for resonant‐tunnelling diode oscillator at 420 GHz

The authors proposed a waveguide coupler that extracts the radiation from a resonant‐tunnelling diode (RTD) oscillator at 420 GHz as the fundamental mode of a rectangular waveguide compatible to the WR‐2.2 standard. In the proposed structure, an RTD oscillator chip is embedded inside a hyper hemispherical silicon lens to reshape the radiation from the tiny chip into a collimated beam, which is subsequently converted into the waveguide mode using a linear horn. The authors estimate the transmission efficiency of the coupler to be −3 dB. Integrated in one package, this approach enables handy use of RTD oscillators as a platform for various terahertz applications.