High Power Terahertz Source Based on Planar Antenna Integrated Vacuum Photodiode

Abstract

Technologies and industrials in imaging, security detection, and spectroscopy applications are still in great need of much higher output power THz source. In this paper, a new fiber-coupled THz photomixer based on a THz vacuum photodiode with an integrated broadband antenna is proposed and designed to produce high-power terahertz wave. Compared with the low-temperature-grown (LTG) III-V material-based photomixer, and UTC-PD-based photomixer, the proposed photomixer could transport high-density carriers (only electrons) using a vacuum channel, and the carrier mobility is further improved. This paper also demonstrates the integrated antenna design and antenna radiation pattern. The antenna return loss is optimized below −10 dB for a wide bandwidth which is suitable for the photomixer tuning range.