Prof. Khaled Salama in collaboration with Dr. Ahmed Radwan and Prof. Atif Shamim obtained a US Patent (US 8762114 on fractional-order element-based matching. The invention of the fractional-order circuit elements concept has opened the doors to numerous applications with exceptional performance, which were not achievable for integer-order standard circuit elements like inductors and capacitors. In contrast to the traditional elements, a fractional element is a function of the parameter value (C or L) and the fractional-order a, which brings in immense freedom and versatility towards design and applications. The concept has already found its utility in many applications of electromagnetics, mechanics, signal processing, bioengineering, agriculture, and control.
We have found many interesting utilities of the fractional concept in the RF and microwave domain. Investigations predict a paradigm shift in fundamental concepts and techniques traditionally used for these designs. We show that for fractional-order Î± <; 1, a single parallel fractional element can match a wider range of load impedances. In comparison to the conventional integer basedL-type matching networks, fractional matching networks are much simpler and versatile. Any complex load can be matched utilizing a single series fractional element, which generally requires two elements for matching in the conventional approach. The concept is supported by design equations and impedance matching examples. This work was presented in the following papers:
- A.G. Radwan, A. Shamim and KN Salama, "Impedance Matching Through a Single Passive Fractional Element," IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting in Chicago, IL, USA, pp 1-2, July 8-13, 2012.
- A. G. Radwan, A. Shamim, K. N. Salama, "Mathematics behind the Fractional-order Smith chart," the 30th Progress in Electromagnetic Research Symposium (PIERS), pp 155-159, China, 2011.
- A. G. Radwan, A. Shamim, K. N. Salama, "Theory of Fractional Order Elements Based Impedance Matching Networks," IEEE Microwave and Wireless Components Letters, Vol. 21, No.3, pp.120-122, 2011.
- A. Shamim, A. G. Radwan, K.N. Salama, "Fractional Smith Chart Theory and Application", IEEE Microwave and Wireless Components Letters, Vol. 21, No.3, pp.117-119, 2011.
In addition, the sensors lab headed by Prof. Salama has been working on the design and fabrication of fractional elements and their application. For example, Dr. Amro Elshurafa's paper on electrostatic fractional capacitors using reduced graphene oxide percolated polymer composites was accepted at the prestigious Applied Physics Letters (impact factor of 3.844 ranking it first out of 105 in the category "Physics, Applied"). The work is in collaboration with Prof. Husam Alshareef's nanomaterials lab. The electrostatic fractional capacitors proposed are easy to fabricate and offer integration capability on electronic printed circuit boards.