Cum Laude PhD Defense Sven van Berkel

The research

In millimeter and submillimeter-wave radiometric imaging systems, a persistent goal is the increase in the speed of acquisition of the image while maintaining a high sensitivity. Typically, the highest sensitivity is achieved by cryogenically cooling the detectors, specifically in astronomical applications. However, for the purpose of low-cost imaging applications, it is desirable to operate at room temperature. Without cryogenically cooling, the electronic noise introduced by the detectors becomes dominant, making the detectors less sensitive. In this thesis focal plane architectures are proposed that maximizes the imaging speed of radiometers operating at room temperature without using any amplification circuitry. It is shown that in such scenario a practical image acquisition speed can still be achieved when a very broad portion of the THz-band is exploited. Ultimately, the imaging speed is maximized when the FPA is undersampled, implying a tradeoff in the size of the optics. The analysis is substantiated by a case study with recently developed wideband leaky lens antenna feeds operating from 200 to 600 GHz. THe entire front end has been developed, fabricated (CMOS Technology) and characterized, demonstrating the complete feasibility of passive imaging in the THz frequencies at neglibile costs. The implications for the automotive and security applications are dramatic, as detecting obstacles in fog, and spotting concealed weapons or bombs can now be done at negligible costs (tens of euros). That these systems will be in our future lives is now sure. When this will happen, as usual, will depend on the market request.

Future Dr. Sven van Berkel

Sven has already signed a contract at NASA, in California where he will start working as soon as the Covid lockdown stops.