Publications de Andrei Müller

Radio Frequency Temperature Transducers Based On Insulator-Metal Phase Transition In Vo2 And Ge-Doped Vo2 Ald Thin Films

Mihai Adrian Ionescu, Elison de Nazareth Matioli, Andrei Müller

The need for new accurate temperature monitoring is becoming high, especially with the proliferation of IoT monitoring and biological applications. In this work, we report the design, fabrication and electrical characterization results of a new type of res ...

IEEE2021

3D Smith chart constant quality factor semi-circles contours for positive and negative resistance circuits

Mihai Adrian Ionescu, Andrei Müller

The article firstly proves that the constant quality factor (Q) contours for passive circuits, while represented on a 2D Smith chart, form circle arcs on a coaxal circle family. Furthermore, these circle arcs represent semi-circles families in the north he ...

2020

The 3D Smith Chart: From Theory to Experimental Reality

Mihai Adrian Ionescu, Andrei Müller

The Smith chart was primarily developed, extended, and refined by Phillip Hagar Smith [1] in a series of works published [2]-[4] between 1939 and 1969. Smith was born in Lexington, Massachusetts, in 1905. He majored in electrical communications at Tufts Un ...

2020

Radio-Frequency Characteristics of Ge-doped Vanadium Dioxide Thin Films with Increased Transition Temperature

Igor Stolichnov, Mihai Adrian Ionescu, Andreas Schueler, Teodor Rosca, Anna Krammer, Riyaz Mohammed Abdul Khadar, Matteo Cavalieri, Fatemeh Qaderi Rahaqi, Andrei Müller

This work investigates and reports on the radio-frequency (RF) behavior in the frequency range of 5 – 35 GHz of germanium-doped (Ge-doped VO2) vanadium dioxide thin films, deposited on silicon substrates via sputtering and pulsed laser deposition (PLD) wit ...

2020

Temperature dependence of reconfigurable bandstop filters using vanadium dioxide switches

Mihai Adrian Ionescu, Matteo Cavalieri, Andrei Müller

In this Letter, we report and investigate the temperature dependency of various radio frequency (RF) parameters for a fabricated reconfigurable bandstop filter with vanadium dioxide (VO2) switches measured up to 55 GHz. Here, the insulator-to-metal (ITM) a ...

AIP American Institute of Physics2020

A Novel Reconfigurable CMOS Compatible Ka Band Bandstop Structure Using Split-Ring Resonators and Vanadium Dioxide (VO2) Phase Change Switches

Mihai Adrian Ionescu, Andreas Schueler, Emanuele Andrea Casu, Junrui Zhang, Anna Krammer, Riyaz Mohammed Abdul Khadar, Andrei Müller

The article presents the design, fabrication and characterization of a novel complementary metal-oxidesemiconductor (CMOS) compatible reconfigurable Ka band bandstop structure using split ring resonators (SRR) while employing the Vanadium Dioxide (VO2) pha ...

IEEE2019

Millimeter-wave-triggering of insulator-to-metal transition in Vanadium dioxide

Anja Skrivervik, Mihai Adrian Ionescu, Andreas Schueler, Anna Krammer, Fatemeh Qaderi Rahaqi, Andrei Müller

We establish insulator-to-metal transition (IMT) in Vanadium dioxide (VO2) by millimeter-wave (mm-wave) actuation, using two coupled dipole antennas: a simple one as a continuous mm-wave-source and the other one with an embedded VO2 part as an absorber. We ...

IEEE2019

3D Smith charts scattering parameters frequency-dependent orientation analysis and complex-scalar multi-parameter characterization applied to Peano reconfigurable vanadium dioxide inductors

Mihai Adrian Ionescu, Andreas Schueler, Josef Andreas Schuler, Montserrat Fernandez-Bolanos Badia, Emanuele Andrea Casu, Junrui Zhang, Anna Krammer, Matteo Cavalieri, Andrei Müller

Recently, the field of Metal-Insulator-Transition (MIT) materials has emerged as an unconventional solution for novel energy efficient electronic functions, such as steep slope subthermionic switches, neuromorphic hardware, reconfigurable radiofrequency fu ...

Nature Research2019

Tunable RF phase shifters based on Vanadium Dioxide metal insulator transition

Mihai Adrian Ionescu, Josef Andreas Schuler, Montserrat Fernandez-Bolanos Badia, Wolfgang Amadeus Vitale, Emanuele Andrea Casu, Nicolò Oliva, Anna Krammer, Alessandro Fumarola, Matteo Cavalieri, Andrei Müller

2018

Special Section Proposal Tunable Devices for Modern Communications: Materials, Integration, Modeling, and Applications

Andres Müller, Andrei Müller

2018

A Review and Mathematical Treatment of Infinity on the Smith Chart, 3D Smith Chart and Hyperbolic Smith Chart

Mihai Adrian Ionescu, Andrei Müller

This work describes the geometry behind the Smith chart, recent 3D Smith chart tool and previously reported conceptual Hyperbolic Smith chart. We present the geometrical properties of the transformations used in creating them by means of inversive geometry ...

MDPI2018

A Reconfigurable Inductor Based on Vanadium Dioxide Insulator-to-Metal Transition

Mihai Adrian Ionescu, Montserrat Fernandez-Bolanos Badia, Emanuele Andrea Casu, Alessandro Fumarola, Matteo Cavalieri, Andrei Müller

This letter introduces a reconfigurable planar square-coil-shaped inductor exploiting as the tuning mechanism the insulator-to-metal transition (IMT) of a vanadium dioxide (VO2) switch placed in the interwinding space in an unprecedented manner. The VO2 th ...

2018

Advanced Sensor Systems by Low-Temperature Heterogeneous 3D Integration Processes

Montserrat Fernandez-Bolanos Badia, Andrei Müller, Josef Weber

A few application demonstrators of heterogeneous 3D integrated systems including innovative nanosensors for gas detection and biofludic applications have been successfully implemented showing efficient low-temperature heterogeneous integration processes, m ...

IEEE2018

Vanadium Oxide Bandstop Tunable Filter for Ka Frequency Bands Based on a Novel Reconfigurable Spiral Shape Defected Ground Plane CPW

Mihai Adrian Ionescu, Josef Andreas Schuler, Montserrat Fernandez-Bolanos Badia, Emanuele Andrea Casu, Anna Krammer, Alessandro Fumarola, Andrei Müller

2018