BrainMap

Mr. Liviu Nedelcu

PhD

- INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA

Researcher

Web of Science ResearcherID: B-9882-2011

Expertise & keywords

Investigations on advanced dielectric materials and structures in Terahertz and millimeter waves Call name: Exploratory Research Projects - PCE-2012 call
PN-II-ID-PCE-2012-4-0654 2013 - 2016

Role in this project: Key expert

Coordinating institution: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA

Project partners: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO)

Affiliation: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO)

Project website: http://www.infim.ro/node/4190

Abstract:

At the present, terahertz technology is certainly one of the most dynamic research fields with wide variety of applications: terabit wireless communication, spectroscopy, biology, medical sciences, food control, security systems, etc. The project aims to investigate advanced conventional as well as structured materials in Terahertz and millimeter wave range. On one hand, highly accurate characterization methods of complex perovskite dielectrics (bulk and thin films) with high values of the product between the quality factor and the frequency will be developed for millimeter wave and Terahertz range. The application of development methods to measure ferroelectric perovskites in Terahertz range is very important for such applications as tunable photonic crystal filters. On the other hand, numerical and experimental investigations on structured materials will allow the study of the Terahertz spoof surface plasmon-polaritons in new complex geometries. The electromagnetic simulation, fabrication and characterization of the proposed materials and structures will benefit of recent acquisitioned state-of-the-art equipment in the host institution. The final outcome of the project will consist in solution for an improved controlled of the electromagnetic radiation in millimeter wave and Terahertz range.

Terahertz Spectroscopy of Low-Loss Microwave Dielectrics Call name: Postdoctoral Research Projects - PD-2011 call
PN-II-RU-PD-2011-3-0237 2011 - 2013

Role in this project: Project coordinator

Coordinating institution: Institutul National de Cercetare-Dezvoltare pentru Fizica Materialelor

Project partners: Institutul National de Cercetare-Dezvoltare pentru Fizica Materialelor (RO)

Affiliation: Institutul National de Cercetare-Dezvoltare pentru Fizica Materialelor (RO)

Project website: http://www.infim.ro/projects/terahertz-spectroscopy-low-loss-microwave-dielectrics

Abstract:

The aim of the present project proposal is to investigate the intrinsic and extrinsic sources and the mechanisms of the dielectric loss in advanced microwave dielectric ceramics. This proposal approach a new research domain in Romania, which international has a rapid increase in the last years. The project proposal is focused on the synthesis, characterization, and optimization of some dielectrics materials, which exhibit high permittivity and low dielectric loss in the microwave domain. The investigations will begin with studies of the phenomenological correlations between the dielectric loss and the composition, the microstructure, the grain–boundary conditions, the crystal structure, etc. The project proposal will cover the entire research cycle, starting with the material preparation, continuing with the investigation of the physical properties, and ending with model for potential applications. In order to achieve the desired objectives the obtained materials will be examined by means of various techniques including X-ray diffraction (XRD) analysis, electron microscopy, and broad-band dielectric spectroscopy(1 GHz-7 THz). The results obtained should result in an identification of the key elements and factors that control the microwave and millimeter wave dielectric properties, especially the dielectric loss.

Compact and integrated agile antennas based on tunable ferroelectric materials Call name: Joint Research Projects Romania-France - IDROFR-2012 call
PN-II-ID-JRP-RO-FR-2012-0160 2012 -

Role in this project: Partner team leader

Coordinating institution: National Institute of Materials Physics

Project partners: National Institute of Materials Physics (RO); XLIM UMR 7252 CNRS/ Université de Limoges (FR)

Affiliation: National Institute of Materials Physics (RO)

Project website:

Abstract:

The project will create an integrated compact and low power consumption reconfigurable antennas exploiting the agility of ferroelectric materials.

Indeed, the main property of such a material is to change their dielectric permittivity depending on an external electric field through a non-linear dielectric effect. To reach both low power consumption and the best trade-off between miniaturization and efficiency, wireless communication devices have to reach a 3D integration (move toward on-chip reconfigurable antennas).

Compact antennas are limited by fundamental physical limits (in terms of bandwidth and radiation performances), are disturbed by antennas' surrounding and so totally dependent on their using context. Developing an antenna integrating tunable elements allows to change:

-The antenna operating frequency band: it is the ideal alternative to compensate various housings and environments.

-The angle of the radiation boresight: that means an optimization of the link budget and thus an enhancement of the quality and the reliability of wireless links.

The reconfigurable antennas state-of-the-art presents varactor diodes, MicroEiectroMechanical systems (MEMS), Positive Intrinsic Negative (PIN) diodes, Field Effect Transistor (FET) and tunable ferroelectric materials to tune antenna's matching bands or to steer the radiating beam. PIN diodes have only two states and thus do not allow the antenna to be tuned over a wide frequency band. FETs have too high power consumption and the range of the variable capacitance based on MEMS is limited when its top membrane collapses onto the bottom plate. Varactor diodes are the most widely referenced and used for reconfigurable antennas. However, their characterization according to antenna designer criteria reveals a very low power handling capability. Thus, antennas integrating such components can be only used for reception devices. For future generation of low-powered wireless sensors or cognitive radio, devices have to be connected. Antennas using varactor diodes will no longer be integrated in new generation devices.

This is in the framework of these technical barriers that ferroelectric materials present a great alternative. Indeed, the agility of ferroelectric materials allows developing tunable antennas and the films depositions technology is particularly interesting when tunable capacitors and antenna need to be integrated both together.

This project requires multiple competences in different areas: Materials, electromagnetic simulation and devices characterizations. It needs to link the various complementary competences of the three partners:

• The Xlim laboratory to develop new modeling methods to simulate thin films within an antenna and also for the ferroelectric materials characterization from RF to millimeter frequency bands. Two teams from the laboratory (OSA and MINACOM) will be associated to this project

• The SPCTS laboratory for its maturity on materials development and thin films deposition by Pulsed Laser Deposition of numerous materials for electronic and optic applications. These 2 Labs are already associated in the 'excellence Laboratory'

Sigma-LIM.

• The NIMP (National Institute of Materials Physics) for the expertise in preparation and characterization of bulk, thin and thick film materials, as well in devices, which use advanced materials.

FILE DESCRIPTION	DOCUMENT
List of research grants as project coordinator or partner team leader
Significant R&D projects for enterprises, as project manager
R&D activities in enterprises
Peer-review activity for international programs/projects