Analysis and design of a photoconductive integrated photomixer/antenna for terahertz applications

A new terahertz (THz) photoconductive photomixer/antenna device is presented. A continuous-wave THz signal is generated in a dc-biased photoconductive film by employing optical heterodyne scheme, and at the same time, the size of the film on the grounded dielectric substrate is designed to have an efficient broadside radiation. Incorporating the photoconductive film as the photomixing media and the radiation element not only eliminates source to antenna coupling problem but also makes the proposed device attractive for THz array source configurations. Analytical expressions for the photocurrent and the radiation power are derived under high dc bias condition, and the effects of the device configuration on its performance is studied. Two possible photomixer configurations, namely longitudinal and transversal, are introduced and their photomixing efficiencies and radiation power are compared. The typical nW output power is achievable by mW laser pump power for frequencies up to 10 THz.