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Mohamed Saeed: Graphene-based Rectifier circuits

posted 18 Jul 2016, 06:28 by info admin
Mohamed Saeed*, Ahmed Hamed*, Mehrdad Shaygan**, Zhenxing Wang**, Daniel Neumaier** and Renato Negra*
*Chair of High Frequency Electronics, RWTH Aachen University, Aachen, Germany
**AMO GmbH, Aachen, Germany

Graphene is a 2D material that has excellent mechanical, thermal and electrical properties that promote it to be used in wide range of application. In addition, Graphene technology is an add-on technology that can be integrated alongside with different technologies. In this work we present  graphene based rectifier circuits using the Graphene-based diodes that was introduced in [1]. Rectifier circuit is crucial for efficient AC-DC conversion. Efficient rectifier requires low-loss diodes with high on-off currents ratio. The used diodes are Metal-Insulator-Graphene junction with 6nm TiO2 as barrier material on 500µm quartz substrate including a 3µm thick top-metal for low loss interconnects, fabricated on our in-house MMIC technology. The design is optimized for low loss applications with excellent on-off ratio. With proper matching for maximum power transfer, the devices can be used in energy harvesting applications. Besides, the low loss design improves the rectification and the cutoff of the diodes and enables if for the use in frequency multipliers. The measured diodes exhibit asymmetric behaviour with bias voltage. A large-signal model of the diode is used to simulate a full- (FWR) and a half-wave rectifier (HWR).
The prototyped diodes have been measured, characterized, and a large-signal model has been extracted based-on the measured data. This diode model was used in simulating HWR and FWR circuits. The excellent measured efficiency of the HWR circuit proves the concept.

[1] M.Shaygan, Z. Wang, M. Saeed, A. Hamed, D. Neumaier, R. Negra "Fabrication and characterization of metal-insulator-graphene diodes for microwave and THz application.", In proc. Graphene Week 2016, June 2016

Mohamed Saeed received the B.Sc. and M.Sc. in Electrical Engineering from Ain Shams University, Cairo, Egypt, in 2004 and 2011, respectively. From 2005 to 2008 he was an analog design engineer for Si-Ware Systems, Cairo, Egypt, designing ADC for video and communications applications, also he designed power management circuits and was in the team that developed the FTIR spectrometer solution that was announced in 2012.
In 2009 he built and led the layout and physical verification team in the same company as an Senior engineer. Then he was promoted to a senior stuff engineer in 2011 and developed the layout process that is used till now in the company.

Since August 2013 he is working towards the PhD degree at the Chair of High Frequency Electronics at RWTH Aachen University, Aachen, Germany. 

His research interests are development of a microwave graphene compatible MMIC process backend. Design, modelling and characterisation of graphene-based RF and microwave devices and circuits. This research is financially supported by the European Commission under the project Graphene Flagship.