Waveguide Coupling of Resonant-Tunneling Diode Terahertz Oscillator

We propose a coupler which extracts the terahertz output of a resonant-tunneling diode (RTD) oscillator into a rectangular waveguide. In the proposed structure, the RTD is embedded in a hyperhemispherical silicon lens to reshape the radiation diverging from a tiny chip into a collimated beam, which is subsequently converted into a fundamental mode of a WR-2.2 standard waveguide by a linearly tapered horn. This approach allows handy use of RTD oscillators as a platform for a variety of terahertz applications without bulky quasi-optical components.