Broadband Antenna-Integrated, Edge-Coupled Photomixers for Tuneable Terahertz Sources

We present design and experimental results on novel antenna-integrated edge-coupled photodiodes, examining particularly their suitability as photomixers for broadband terahertz sources. We show that a simple “stub” detector positioned at the edge of the chip can yield promising overall performance when integrated with a number of different planar antennas specifically designed for this configuration. Using a slot-horn antenna connected via a coplanar line, we measure terahertz emission figures of 100 μW over the range 100-500 GHz, with 50 μW available at 750 GHz. We also present a novel planar double-horn antenna and show that with suitable use of terahertz “optics” this offers broadband through-substrate emission from 200 GHz to over 1 THz, with 10 μW terahertz power emitted at 1.004 THz.