Nowadays, there has been an increasing interest in Terahertz (THz) radiation for application across scientific disciplines including atmospheric sensing, medical diagnosis, security screening and explosive detection. The limitation of THz generators and detectors has gained interest from scientists and engineers to explore the development of both sources and detectors. With the advantages of low cost, low power consumption, high reliability and potential for large-scale integration, sub-THz generator and detector can be developed using CMOS process technology. In this thesis, an IMPATT diode acts as a sub-THz generator, HEMTs and MOSFETs act as sub-THz detectors, which are developed in AMS 0.35 μm CMOS technology and UMC, 0.18 μm CMOS technology. The size of the IMPATT diode was 120 μm x 50 μm with the target resonant frequency at 30 GHz. The experiment results show that the operating frequency of the IMPATT diode was between 12 GHz up to 14 GHz. Then by using HEMTs with 0.2 μm gate length and 200 μm gate widths, sub-THz radiation detection has been demonstrated. Experimental results show that the photoresponse depends on the drain current and the gate to source voltage VGS. In addition, photoresponse also depends on varying frequencies up to 220 GHz and fixed the drain current. Furthermore, the HEMT also give an indication of response by varying the input power of microwave extender. MOSFETs from two types of CMOS technology; AMS 0.35μm and UMC 0.18 μm technology with different gate length ranging from 180 nm up 350 nm were demonstrated. These results provide evidence that the photoresponse increases with the drain current and the RF input power, but inversely to the frequencies. These results also provide evidence that the MOSFETs are able to work as low cost and sensitive sub-THz detector.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:580246 |
| Date | January 2013 |
| Creators | Othman, Mohd Azlishah |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/13375/ |
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