Ph.D research project

Superconductors are amazing materials which, when cooled below a certain temperature, exhibit a zero intrinsic resistance to direct current (d.c.) flow. The temperature at which the intrinsic resistance undergoes an abrupt change is referred to as the critical temperature or transition temperature. For alternating current (a.c.) flow, the resistance does not go to zero below the critical temperature, but increases with increasing frequency. However, at typical RF/microwave frequencies (in the cellular band, for example), the resistance of a superconductor is perhaps one thousandth of that in the best ordinary conductor. It is certainly low enough to make significant improvement on performances of RF/microwave subsystems implemented with  superconducting devices.

Although superconductors were first discovered in 1911, for almost 75 years after the discovery, all known superconductors require a very low transition temperature, say 30 Kelvin (K) or lower, this limited the applications of these early superconductors. A revolution in the field of superconductivity occurred in 1986 with the discovery of the superconductors with transition temperature greater than 77 K, the boiling point of liquid nitrogen. These superconductors are therefore referred to as the high-temperature superconductors (HTS). The discovery of the HTS made world headlines since it made many practical applications of superconductivity possible. Since then, the development of microwave applications has proceeded vary rapidly.

Now, high temperature superconductivity  is at the forefront of today’s technology and is changing the way we design communication systems, electronic systems, medical instrumentation, and military microwave systems. Superconducting devices play an important role in many applications. This research will be focused on the development of novel HTS devices including filters for future communication systems. The outcome of research will be certainly of interest to industry, and can lead to licensed devices for market exploitations.  

                                                        Dr. Jia-Sheng Hong

                                                        Department of Computing and Electrical Engineering

                                                        Heriot-Watt University, Edinburgh, EH14 4AS

                                                        Email: J.Hong@hw.ac.uk

                                                        Tel: 0131 451 3339

                                                        Fax: 0131 451 3327