THz Sources and Related Topics

In this chapter, a review on various electrical methods to generate THz signals and related techniques will be presented. Traditional THz sources based on vacuum devices and diodes will be first discussed, followed by oscillator circuits with transistor technology operating at the THz band. Discussed next will be two effective ways to boost the oscillation frequency of THz signal sources, the n-push technique and frequency multiplication. This will be followed by the description of two widely used power-boosting techniques, amplification and power combining. Lastly, beamforming, which is a special case of power-combining technique that additionally enables the steering of beams with improved directivity, will be treated as a separate topic.