The focus of this activity is developing radio frequency (RF) and mm-wave analogue components and circuits incorporating sensors aiming at increased complexity, higher power (using wide bandgap semiconductors) and exploring future transparent and flexible electronics for high frequency. Application are mainly in near future wireless smart systems, radars and other more than Moore approaches. Within this activity smart sensors for biomarkers are also explored.


Research Topics

Electromagnetism has a profound effect on our lives since applications such as wireless and satellite communications, space, airborne or ground active array radars, cable TV, and smart automotive infrastructure all depend on it. All of them are in continuous need of components with improved performance at higher power & frequency, smaller footprint & volume, with increased functionalities and at a lower cost and enhanced reliability. Novel solutions need to be sought to enable the next-generation of products with the efforts focusing on RF front ends (transceivers TRX modules) which are the key electromagnetic component that allows emission and reception of electromagnetic waves. Currently such innovative technologies are GaN based electronic components (high power capacity, low noise, chemically and thermally robust) and RF Microelectromechanical switches (MEMS) (lower insertion loss, higher isolation, greater power handling).
MRG in collaboration with Thales SA (France) has been developing technologies for the monolithic integration of GaN based Monolithic Microwave Integrated Circuits (MMICs) with RF MEMS focusing more on what is termed “coplanar approach”. MRG has already developed GaN based coplanar high power transistors operating in the X-band exhibit performances at par with commercially available “microstrip” ones such as the UMS GH25 transistor. MRG is currently attempting to set up a pilot line for the production of such RF front end modules. 


Starting around 1970, Surface Acoustic Wave (SAW) devices were developed for pulse compression radars, oscillators, and band-pass filters for domestic TV and professional radio applications and recently for mobile or satellite communication systems. The shift of the resonance frequency of a SAW resonator, as effect of change of various physical parameters (temperature, pressure, mass loading, etc.) make these devices very useful in sensing applications. The traditional materials (quartz, langasite, langatate) used in SAW resonators manufacturing have excellent piezoelectric properties but they have also the disadvantage of their limited operating frequency, which remains normally below 2 GHz. Lately, the amount of data transmission in wireless network systems is increasing and the demand for SAW devices operating at frequencies around 5 GHz becomes important. Also in sensor applications, the sensitivity increases with the resonance frequency, being proportional with the square of the resonance frequency for mass, humidity and gas sensors. According to the wave mode there can be waves of Rayleigh, Lamb or a combination of both category. Wide bandgap (WBG) materials like GaN and AlN have very good piezoelectric properties and significantly higher acoustic velocities and are increasingly used for acoustic devices.
For over a decade, MRG has been developing SAWs, Film bulk acoustic resonators (FBARs) mainly for temperature, pressure and humidity sensing, Lamb resonators for biosensing (e.g. protein detection) and UV photodetectors. Key parameters are the developed micromachining process for extremely thin GaN membranes (below 500nm) and the electron beam lithography protocols for extremely narrow and densely packed interdigitated transducers (IDTs) as thin as 100nm with 100nm period.
This activity has resulted in more than 15 publications in established journals with citations in the range of 600 and in numerous conference presentations.

Acoustic sensors: For over a decade, MRG has been developing SAWs, Film bulk acoustic resonators (FBARs) mainly for temperature, pressure and humidity sensing, Lamb resonators for biosensing (e.g. protein detection) and UV photodetectors. Key parameters are the developed micromachining process for extremely thin GaN membranes (below 500nm) and the electron beam lithography protocols for extremely narrow and densely packed interdigitated transducers (IDTs) as thin as 100nm with 100nm period.
EEG sensors: Within the past 5 years, MRG has developed a dry microneedles based  Electroencephalogram (EEG) electrode with simple fabrication involving just a single lithography step without the use of “sacrificial” substrates. The resulting process is therefore simpler and of lower cost.
Gait sensors: MRG as part of a Greek collaborative effort, is working towards the design and manufacture of a smart, wearable insole (Smart Insole) with built-in pressure measurement sensors, other micro-electronic sensing elements and communication devices to tackle the challenge of efficient gait monitoring in real life. This wearable insole is based on unique layer that consists of a polymeric material with embedded piezoelectric flakes, an inertial measurement unit including a triaxial accelerometer, gyroscope and magnetometer to capture the gait characteristics in motion.

Future RF systems are in continuous need of components with improved performance at higher power & frequency, smaller footprint & volume, with increased functionalities and at a lower cost and enhanced reliability. Aggressive miniaturization is the key requirement for future RF Transceiver (TRX) systems. In order to achieve, there is a need to transform current TRX 2D architecture into 3D heterogeneously or sequentially integrated one.

MRG conducts research in III-nitride based MMIC, III-nitride based sensors and RF MEMS and has already demonstrated the monolithic integration of MMICs with RF MEMS.  A major advantage of III-nitride based acoustic sensors is the possibility of monolithic integration with other active and passive circuit elements, enhancing the future development of smart microsystem technological platforms on this material. In particular MRG is working on the idea of “all-in-Gallium Nitride” solution involving MMICs, RF MEMS, multimodal sensors supported by disruptive nanotechnologies such as 1D &2D materials, which will deliver a single transceiver component which will radically transform the current 2D TRX architecture into a 3D System in Package (SiP). 

Transparent and Flexible electronics are part of the Key Enabling Technologies of Nanotechnology, Advanced Materials, Photonics and Micro-Nanoelectronics. Flexible and transparent electronic devices and systems can find applications in the high growth market sectors of healthcare, smart packaging for food and pharmaceutical products security, human-machine interfacing, sensor networks, automotive electronics, the Internet of Things, flexible displays, wearable gadgets and other emerging chip markets.
The activity on flexible and transparent electronics within MRG employs low temperature PVD deposition techniques like rf sputtering and rf magnetron sputtering for fabricating n-type and p-type nanostructured oxides, nitrides and oxynitrides like ITO-N, ZnO-N-Al, Ir, NiO-Al, TaO-N, ZnSnO, CuO, etc, with controllable properties and long term stability, on flexible substrates (PET, glass, etc). By making use of innovative and low-cost fabrication-approach devices, TTFTs, photo-transistors, transparent diodes and transparent PVs are developed.

A novel wearable sensor for continues human gait analysis and evaluation
Heterogeneous 3D integration using breakthrough nanotechnologies for new generation microwave power transceivers
Pilot line production of transceiver modules of the next generation of smart RF power applications
Intelligent Reliability 4.0
A system for monitoring sleep and healthy living with low energy radio technology
Predictive Reliability for High Power RF MEMS
3D Integration Technologies of Radio for Phase Shift in Phase-Array antenna Systems
A study of high field hopping transport during discharging in SiNx films for MEMS capacitive switches
D. Birmpiliotis, M. Koutsoureli, G.Stavrinidis, G. Konstantinidis, G. Papaioannou
Microelectronics Reliability, Volume:114, Page:113878, Year:2020, DOI:doi.org/10.1016/j.microrel.2020.113878
Field emission induced damage in the actuation paths of MEMS capacitice structures
J. Theocharis, M. Koutsoureli, S. Gardelis, G. Konstantinidis, G. Papaioannou
Microelectronics Reliability , Volume:114, Page:113760, Year:2020, DOI:doi.org/10.1016/j.microrel.2020.113760
Thermally activated discharging mechanisms in SiNx films with embedded CNTs for RF MEMS capacitive switches
M. Koutsoureli, G. Stavrinidis, D. Birbiliotis, G. Konstantinidis, G. Papaioannou
Microelectronic Engineering, Volume:223, Page:111230, Year:2020, DOI:doi.org/10.1016/j.mee.2020.111230
On the discharge transport mechanisms through the dielectric film in MEMS capacitive switches
D. Birbiliotis, G. Stavrinidis, M. Koutsoureli, G. Konstantinidis, G. Papaioannou
Journal of Microelectromechanical Systems, Volume:202, Page:1-12, Year:2020, DOI:doi.org/10.1109/JMEMS.2019.2962068
Monolithic Intergrated Antenna and Schottky diode multiplier for free space millimeter wave power generation
Al. Bunea, D. Neculoiu, A. Stavrinidis, G. Konstantinidis, G. Stavrinidis, A. Kostopoulos, Z. Chatzopoulos
IEEE Microwave and Wireless Components Letters, Volume:30, Page:74-77, Year:2020, DOI:doi.org/10.1109/LMWC.2019.2954208
A comparative study of nanostructured Silicon-Nitride electrical properties for potential application in RF-MEMS capacitive switches
D. Birbiliotis, G. Stavrinidis, M. Koutsoureli, G. Konstantinidis, G. Papaioannou, A. Ziaei
Microelectronics Reliability, Volume:100-101, Page:113360, Year:2019, DOI:doi.org/10.1016/j.microrel.2019.06.052
Long-term stability of transparent n/p ZnO homojunctions grown by rf-sputtering at room-temperature
V.Kampylafka, A.Kostopoulos, M.Modreanu, M.Schmidt, E.Gagaoudakis, K.Tsagaraki, V.Kontomitrou, G.Konstantinidis, G.Deligeorgis, G.Kiriakidis, E.Aperathitis
Journal of Materiomics, Volume:5, Page:xxxx, Year:2019, DOI:https://doi.org/10.1016/j.jmat.2019.02.006
GaN Membrane Supported SAW Pressure Sensors With Embedded Temperature Sensing Capability
A. Muller, G. Konstantinidis, I. Giancu, GC. Adam, A. Stefanescu, G. Stavrinidis, A. Kostopoulos, G. Boldeiu, A. Dinescu
IEEE Sensors, Volume:17, Issue:22, Page:7383 - 7393, Year:2017, DOI:doi.org/10.1109/JSEN.2017.2757770
Technology of integrated self-aligned E/D-mode n++GaN/InAlN/AlN/GaN MOS HEMTs for mixed-signal electronics
M Blaho, D Gregušová, Š Haščík, A Seifertová, M Ťapajna, J Šoltýs, A Šatka, L Nagy, A Chvála, J Marek, J-F Carlin, N Grandjean, G Konstantinidis and J Kuzmík
Semicond. Sci. Technol., Volume:31, Issue:6, Page:065011, Year:2016, DOI:doi.org/10.1088/0268-1242/31/6/065011
A high frequency GaN Lamb-wave sensor device
A.K. Pantazis, E. Gizeli and G. Konstantinidis
Appl. Phys. Letters, Volume:96, Page:194103, Year:2010, DOI:doi.org/10.1063/1.3427484
GaN/Si based single SAW resonator temperature sensor operating in the GHz frequency range
A.Müller, G.Konstantinidis, V.Buiculescu, A.Dinescu, A.Stavrinidis, A.Stefanescu, G.Stavrinidis, I.Giangu, A.Cismaru and A.Modoveanu
Sensors and Actuators A, Volume:209, Page:115 - 123, Year:2014, DOI:doi.org/10.1016/j.sna.2014.01.028
Room Temperature p-Type NiO Nanostructure Thin Film Sensor for Hydrogen and Methane Detection
E. Gagaoudakis, G. Michail, V. Kampylafka, K. Tsagaraki, E. Aperathitis, K. Moschovis, V. Binas and G. Kiriakidis
Sensor Letters, Volume:15, Issue:8, Page:663 - 667, Year:2017, DOI:doi.org/10.1166/sl.2017.3864
Front and backside-illuminated GaN/Si based metal–semiconductor–metal ultraviolet photodetectors manufactured using micromachining and nano-lithographic technologies
A. Müller, G. Konstantinidis, M. Androulidaki, A. Dinescu, A. Stefanescu, A. Cismaru, D. Neculoiu, E. Pavelescu, A. Stavrinidis
Thin Solid Films, Volume:520, Issue:6, Page:2158 - 2161, Year:2012, DOI:doi.org/10.1016/j.tsf.2011.09.045
Monolithic integration of nitride-based transistor with Light Emitting Diode for sensing applications
F.G.Kalaitzakis, E.Iliopoulos, G.Konstantinidis and N.T.Pelekanos
Microel. Eng., Volume:90, Page:33 - 36, Year:2012, DOI:doi.org/10.1016/j.mee.2011.04.067
Transparent p/n diode device from a single zinc nitride sputtering target
V.Kambilafka, A.Kostopoulos, M.Androulidaki, K.Tsagaraki, M.Modreanu and E.Aperathitis
Thin Solid Films, Volume:520, Issue:4, Page:1202 - 1206, Year:2011, DOI:doi.org/10.1016/j.tsf.2011.06.072
Properties of n-type ZnN thin films as channel for transparent thin film transistors
E.Aperathitis, V.Kambilafka and M.Modreanu
Thin Solid Films, Volume:518, Issue:4, Page:1036 - 1039, Year:2009, DOI:doi.org/10.1016/j.tsf.2009.01.155
AlN on silicon based surface acoustic wave resonators operating at 5 GHz
D. Neculoiu, A. Müller, G. Deligeorgis, A. Dinescu, A. Stavrinidis, D. Vasilache, A.M. Cismaru, G.E. Stan and G. Konstantinidis
Electronics Letters, Volume:45, Issue:23, Page:1196 - 1197, Year:2009, DOI:doi.org/10.1049/el.2009.2520
Millimeter-wave identification: A new short-range radio system for low-power high data-rate applications
P. Pursula, T. Vähä-Heikkilä, A. Müller, D. Necoloiu, G. Konstantinidis, A. Oja, J. Tuovinen
IEEE Transactions on Microwave Theory and Techniques, Volume:56, Issue:10, Page:2221 - 2228, Year:2008, DOI:doi.org/10.1109/TMTT.2008.2004252


Dr. Konstantinidis George
Research Director
Prof. Georgakilas Alexandros
University Faculty Member
Dr. Aperathitis Elias
Principal application Scientist

Technical Staff

Ms. Kayambaki Maria
Ms. Tsagaraki Katerina
Mr. Papadakis Nikos
Mr. Stavrinidis George
Mr. Stavrinidis Antonis
Ms. Androulidaki Maria
Ms. Kontomitrou Vasiliki (Valia)
Mr. Makris Nikolaos
Technical Scientist

Research Associates

Dr. Pantazis Alexandros
PostDoctoral Fellow
Dr. Michalas Loukas
PostDoctoral Fellow


Mr. Koliakoudakis Charidimos (Harris)
Ph.D. student


Mr. Sfendourakis Michalis

Infrastructure Equipment

Molecular Beam epitaxy system by VG 80H with automated control.

  1. Capable of handling up to 3" substrates
  2. RHEED 15KeV system
  3. Mass spectrometer 1 - 300 amu
  4. K-cells for Galium (2), Aluminum (2), Arsenide, Indium, Silicon and Berilium

UHV e-beam evaporator with an 8 target turret and in situ ion beam cleaning system.


Two thermal evaporators  (Home-made) 

RF diode and RF magnetron sputtering system with 3 electrodes. 


Reactive Ion Etching system (Vacutec 1500) with in situ laser interferometry and optical emission spectroscopy end-point detection techniques (Jobin Yvon  Sofie)

Inductively Coupled Plasma Etching system (Oxford Plasma Pro 100 Cobra)

Plasma enhcanved CVD system (Plasmatherm Vision 310 PECVD) with stress control of Si3N4 achieved by using mixed-frequency deposition or low-damage He dilution.

Atomic layer deposition (Picosun R-200 Advanced) with sources for Aluminum oxide and Hafnium oxide deposition capability) + Ozonator (InUSA AC Series Ozone Generator)

Programmable 3-stage tube furnace (Carbolite)

Two programmable hot plates with vacuum (UniTemp GmbH VHP-210-160)

Two programmable spinners up to 6” (Suss MicroTec LabSpin 6BM)

Electron beam writer attachment (Raith Elphy Quantum) for the field emission SEM (Jeol 7000F)

Programmable horizontal tube (3”) furnaces up to 1200°C  (ELITE Thermal Systems Limited TMH12/75/750)

Semiconductor Characterisation System (Keithley K4200):

  • Two SMUs (max 0.1A, max 210V, 2W)
  • High power SMU (1A, 210V, 20 W)
  • DC and pulsed measurements ( 500 ns minimum pulse width)