RADIATION DETECTOR

摘要

In a terahertz radiation detection system, such as a terahertz camera, an array of feedhorns feeds detected radiation to diode-based mixers for mixing with a local oscillator to produce modulated intermediate frequency ("IF") signals that can be amplified and used in imaging. The mixers are accommodated on the surface of a substrate and multiple substrates can be layered up to support a two-dimensional array of feedhorns. In order to improve packing density and thus potentially the resolution of a camera, IF filters for use in extracting the modulated IF signals are accommodated in vias through the substrates. Further, stub tuners are provided which co-operate with signal-carrying sections of microstrip to improve coupling of detected radiation and local oscillator signals to the mixers. Although the stub tuners are shared with respect to both the detected radiation and the local oscillator signals in each mixer, the involvement of the microstrips means that tuning can be optimised independently with respect to the detected radiation and to the local oscillator signals.