Șerban Mihalache

Lecturer, Researcher, PhD,
Department of Electronic Devices, Circuits, and Architectures (DCAE),
Faculty of Electronics, Telecommunications, and Information Technology (ETTI),
National University of Science and Technology POLITEHNICA Bucharest (UNSTPB)

Email: serban.mihalache@upb.ro
Office: B030, Leu Campus – 1-3, Blvd. Iuliu Maniu, Bucharest, 061071, Romania
Tel.: +40 21 402 46 88

 

Last updated: February 2024
  • Scientific activity
    • National research projects
    • Member in organizing committees
    • Reviewer for international journals
    • Reviewer for international conferences
    • Invited speaker
    • Awards
    • Scientific community affiliation
  • List of publications
    • Textbooks, chapters, handbooks
    • Journal articles
    • Conference papers
    • Theses: PhD, MSEE, BSEE

Research and teaching interests

  • Artificial Intelligence, Machine Learning, Deep Learning;
  • Audio Signal Analysis, Processing, and Synthesis;
  • Speech Emotion Recognition;
  • Speech under Stress Detection;
  • Deceptive Speech Detection;
  • Analog Integrated Circuits and Analog System Design.

Degrees and professional experience

Degrees

  • Doctorate (PhD) in Speech Signal Analysis and Processing Techniques for Automatic Recognition of Paralinguistic Elements, with Applications in Forensic Speech (2017 – 2023); Doctoral School of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest.
  • Master of Science in Electronic Engineering (MSEE); Microsystems program (2015 – 2017); Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest.
  • Bachelor of Science in Electronic Engineering (BSEE); major in Electronic Engineering, Telecommunications, and Information Technologies, specialization in Microelectronics (2011 – 2015); Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest.
  • Baccalaureate Degree (2007 – 2011); “Saint Sava” National College, Bucharest.

Professional experience

  • Lecturer (26 Feb. 2024 – present) at the Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania.
  • Teaching Assistant (2 Oct. 2017 – 26 Feb. 2024) at the Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania.
  • Researcher (5 Oct. 2015 – present) at the Speech and Dialogue Research Laboratory, National University of Science and Technology POLITEHNICA Bucharest, Romania. Research on speech emotion recognition (SER), speech stress detection (SSD), and deceptive speech detection (DSD) using machine learning and deep learning models and techniques, with emphasis on forensic applications.
  • Researcher (1 Jan. 2022 – present) at the Research Institute for Artificial Intelligence “Mihai Drăgănescu”, Romanian Academy, Bucharest, Romania. Research on speech technology.
  • Analog Design Engineer (1 Oct. 2015 – 1 Sep. 2017) at Microchip Technology Inc., Bucharest, Romania. Analog circuit and system design and simulation for High-Voltage Power Management ICs (DC-DC asynchronous step-down converters), layout development and verification, IC testing and validation.
  • Analog Design Intern (18 Feb. 2013 – 1 Oct. 2015) at Microchip Technology Inc., Bucharest, Romania. Analog circuit and system design and simulation for High-Voltage Power Management ICs (DC-DC asynchronous step-down converters), layout development and verification, IC testing and validation.

Academic activity

All my teaching activity takes place at the Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest.

Postgraduate curricula

  • Artificial Intelligence Applied in Speech Forensics, BIOSINF Master’s program, 1st year course, lectures and project (2024 – present); supervisor: Prof. Dragoș Burileanu.
  • Artificial Intelligence I: Classical Machine Learning Systems, BIOSINF Master’s program, 1st year course, lectures and labs (2023 – present); supervisor: Prof. Dragoș Burileanu.
  • Biometric Technologies. Speech and Biological Signals Analysis, BIOSINF Master’s program, 1st year lectures and labs (2023 – present); supervisor: Prof. Dragoș Burileanu.
  • Research and Documentation Project, BIOSINF Master’s program, 1st year project (2023 – present); supervisor: Prof. Dragoș Burileanu.

Undergraduate curricula

  • Analog Integrated Circuits, 3rd year course, lectures and tutorials (2022 – present), English class.
  • Analog Integrated Circuits, 3rd year tutorials (2016 – present) and labs (2016 – 2017); supervisor: Prof. Claudius Dan.
  • Advanced Techniques in Digital Signal Processing, 4th year project (2021 – present) and labs (2015 – present); supervisor: Prof. Dragoș Burileanu.
  • Digital Signal Processing, 3rd year labs (2016 – present); supervisor: Prof. Dragoș Burileanu.
  • Microcontrollers, 3rd year labs (2017 – 2021); supervisor: Prof. Corneliu Burileanu.
  • Microprocessor Architectures, 2nd year labs (2017 – 2021); supervisor: Prof. Corneliu Burileanu.

Graduate student supervision

2023 – 2024

  • Irina-Georgia Mutică, “Synthetic speech detection using deep learning techniques”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2022 – 2023

  • Mirela-Iuliana Gheorghe, “Machine learning techniques for detecting depression from speech”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2019 – 2020

  • Ioan-Alexandru Ivanov, “Separating speech segments from audio recordings using neural network models”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

Undergraduate student supervision

2023 – 2024

  • Ioan-Alexandru Baciu, “Machine learning techniques for audio watermark recognition”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Alexandru-Gabriel Banu, “Design and validation of a deadtime circuit for driving high-power transistors with applications in half-bridge control”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Cătălina Costache, “Design and implementation of an electric guitar effect pedal using mixed analog-digital signal processing”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2022 – 2023

  • Alexandru Busuioc, “Speech enhancement techniques for aerospace communication”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Adrian-Cătălin Iamandache, “Applied study on layout design for analog and digital integrated circuits using multiobjective optimization”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Cristian-Teodor Neamțu, “Speech liveness detection”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Andrei-Cristian Negrea, “High PSRR LDO voltage regulator for low noise applications”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Andrei-Cătălin Luca, “Wi-Fi network security methods”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2021 – 2022

  • Andreea Ionescu, “Machine learning techniques for deceptive speech detection”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Anca-Ștefania Joița, “Fully differential amplifier with increased common-mode rejection ratio”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Priscila-Dana Marin, “Analysis and design of a high-power charge pump circuit”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Irina-Georgia Mutică, “Automatic gender and age recognition from speech using neural network models”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2019 – 2020

  • Ștefania Dicu, “Automatic speaker gender identification”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Alexandru-Cristian Gorunescu, “Speech emotion recognition using machine learning techniques”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Narcisa-Ionela Guran, “Neural network models for stress detection from speech”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2018 – 2019

  • Georgiana-Elena Botezatu, “Multi-effect digital pedal for electric guitar”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Tudor-Nicolae Datcu, “Intelligent system for multimodal data acquisition and household system control”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Alexandru-Nicușor Firuți, “Software for daily physical activity recognition using movement sensors”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2017 – 2018

  • Andrei Iulian Gîrd, “Real-time automatic identification and reconstruction techniques of musical content from audio signals”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.
  • Cosmin-Valeriu Retegan, “Software for the automatic transcription of musical content from audio recordings”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Academic co-supervisor: Prof. Dragoș Burileanu.

2016 – 2017

  • Andreea Maria Florea, “3D Scanner with Infrared Optical Sensing”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Primary academic supervisor: Prof. Dragoș Burileanu.
  • Claudia Andreea Nedelcu, “Digital processing techniques for automatic music track separation”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, Romania. Primary academic supervisor: Prof. Dragoș Burileanu.

Scientific activity

National research projects

  • 2017 – 2020: Research Assistant, project PN-III-P2-2.1-SOL-2016-02-0002, agreement 2SOL/2017, funded by the Romanian Government through UEFISCDI: Intelligent Systems for Video and Audio Analysis – Technologies and Innovative Video Systems for Person Re-identification and Analysis of Dissimulated Behavior (SPIA-VA). [LINK]

Member in organizing committees

  • SpeD 2023 – The 12th International Conference on Speech Technology and Human-Computer Dialogue, Bucharest, Romania, 25-27 Oct. 2023.
  • SpeD 2021 – The 11th International Conference on Speech Technology and Human-Computer Dialogue, Bucharest, Romania, 13-15 Oct. 2021.
  • SpeD 2019 – The 10th International Conference on Speech Technology and Human-Computer Dialogue, Timişoara, Romania, 10-12 Oct. 2019.

Reviewer for international journals

  • 2024 – present: Peer reviewer for Psychology Research and Behavior Management, Dove Medical Press, Taylor & Francis Group, Oxfordshire, United Kingdom, ISSN: 1179-1578.
  • 2023 – present: Peer reviewer for Computer Science & Language, Elsevier, Amsterdam, The Netherlands, ISSN: 0885-2308.
  • 2022 – present: Peer reviewer for Romanian Journal of Information Science and Technology, Publishing House of the Romanian Academy, Bucharest, Romania, ISSN: 1453-8245.
  • 2019 – present: Peer reviewer for UPB Scientific Bulletin, Series C – Electrical Engineering and Computer Science, Politehnica Press, Bucharest, Romania, ISSN: 2286-3540.

Reviewer for international conferences

  • SpeD 2023 – The 12th International Conference on Speech Technology and Human-Computer Dialogue, Bucharest, Romania, 25-27 Oct. 2023.
  • SpeD 2021 – The 11th International Conference on Speech Technology and Human-Computer Dialogue, Bucharest, Romania, 13-15 Oct. 2021.
  • SpeD 2019 – The 10th International Conference on Speech Technology and Human-Computer Dialogue, Timişoara, Romania, 10-12 Oct. 2019.

Invited speaker

  • 26 Feb. 2024, Academy of Romanian Scientists: “Romanian research developments for the automatic recognition of paralinguistic elements of speech (emotions, stress, deception)”.

Awards

2016

  • Third Prize, in the IEEE Region 8 Student Paper Contest, Limassol, Cyprus, paper: Current-mode Capacitance Multiplier with Reduced Parasitic Elements.

2015

  • Best Student Paper Award, at the IEEE Romania 25th Anniversary Symposium, paper: Current-mode Capacitance Multiplier with Reduced Parasitic Elements.
  • First Prize, in the “Tudor Tănăsescu“ National Electronics Competition (Analog Integrated Circuits section), Bucharest, Romania.
  • Best Student Paper Award, at the 38th International Semiconductor Conference (CAS), Sinaia, Romania, paper: Automated Cooling Control System through Peltier Effect and High Efficiency Control using a DC-DC Buck Converter.

2014

  • First Prize, in the National stage of the “Robochallenge” National Robotics Competition, Bucharest, Romania, Academic section, project: COX (Line Follower Robot).

2013

  • First Prize, in the Local stage of the “Robochallenge” National Robotics Competition, Bucharest, Romania, Microsumo section, project: Abbas.

Scientific community affiliation

  • 2015 – present: Member of the Speech and Dialogue Research Laboratory (SpeeD).
  • 2013 – present: Member of the Institute of Electrical and Electronic Engineers (IEEE).

List of publications

Textbooks, chapters, handbooks (1)

2022

  • D. Burileanu, Ș. Mihalache, Prelucrarea digitală a semnalelor: concepte fundamentale, tehnici avansate, aplicații (Digital signal processing: fundamental concepts, advanced techniques, applications), MATRIX ROM Publishing House, Bucharest, Romania, 2022. ISBN: 978-606-25-0767-1

Journal articles (6)

2023

  • Ș. Mihalache, D. Burileanu, “Speech Emotion Recognition Using Deep Neural Networks, Transfer Learning, and Ensemble Classification Techniques,”Romanian Journal of Information Science and Technology, vol. 26, iss. 3-4, pp. 375-387, Sep. 2023. ISSN: 1453-8245. DOI: 10.59277/ROMJIST.2023.3-4.10. ISI WOS: 001083522800010 (Q2, IF: 3.5)

2022

  • Ș. Mihalache, D. Burileanu, E. Franti, M. Dascalu, C.A. Bratan, “Lasting emotions – An investigation of short- and long-term affective content remanence in speech,” Romanian Journal of Information Science and Technology, vol. 25, iss. 1, pp. 20-35, Mar. 2022. ISSN: 1453-8245. ISI WOS: 000775912300002 (Q2, IF: 3.5)
  • Ș. Mihalache, D. Burileanu, “Using Voice Activity Detection and Deep Neural Networks with Hybrid Speech Feature Extraction for Deceptive Speech Detection,” Sensors, vol. 22, iss. 3, art. no. 1228, Feb. 2022. ISSN: 1424-8220. DOI: 10.3390/s22031228. ISI WOS: 000759983300001 (Q1, IF: 3.576)

2021

  • Ș. Mihalache, D. Burileanu, “Dimensional Models for Continuous-to-Discrete Affect Mapping in Speech Emotion Recognition,” University Politehnica of Bucharest Scientific Bulletin, Series C – Electrical Engineering and Computer Science, vol. 83, iss. 4, pp. 137-148, Dec. 2021. ISSN: 2286-3540. ISI WOS: 000741473700013 (Q4, IF: 0.3)

2018

  • G. Pop, D. Burileanu, Ș. Mihalache, “An Evaluative ENF-Based Framework for Forensic Authentication of Digital Audio Recordings,” Proceedings of the Romanian Academy Series A – Mathematics, Physics, Technical Sciences, Information Science, Publishing House of the Romanian Academy, vol. 19, iss. 4, pp. 605-612, Dec. 2018. ISSN: 1454-9069. ISI WOS: 000454140900012 (Q2, IF: 1.752)

2017

  • Ș. Mihalache, F.S. Dumitru, A. Florescu, S.V. Pasca, “Dithering Options for Integrated Relaxation Oscillators,” Revue Roumaine des Sciences Techniques – Serie Electrotechnique et Energetique, vol. 62, iss. 1, pp. 61-67, Mar. 2017. ISSN 0035-4066. ISI WOS: 000399629400011 (Q3, IF: 1.114)

Conference papers (12)

2023

  • C.T. Neamtu, Ș. Mihalache, D. Burileanu, “Liveness Detection – Automatic Classification of Spontaneous and Pre-recorded Speech for Biometric Applications,” Proceedings of the 12th International Conference on Speech Technology and Human-Computer Dialogue (SpeD), Bucharest, Romania, pp. 1-5, 25-27 Oct. 2023. ISBN: 979-8-3503-2797-7. DOI: 10.1109/SpeD59241.2023.10314940
  • M. Gheorghe, Ș. Mihalache, D. Burileanu, “Using Deep Neural Networks for Detecting Depression from Speech,” Proceedings of the 31st European Signal Processing Conference (EUSIPCO), Helsinki, Finland, pp. 411-415, 4-8 Sep. 2023. ISBN: 978-9-4645-9360-0. DOI: 10.23919/EUSIPCO58844.2023.10289973

2021

  • Ș. Mihalache, D. Burileanu, C. Burileanu, “Detecting Psychological Stress from Speech using Deep Neural Networks and Ensemble Classifiers,” Proceedings of the 11th International Conference on Speech Technology and Human-Computer Dialogue (SpeD), Bucharest, Romania, pp. 74-79, 13-15 Oct. 2021. ISBN: 978-1-6654-2786-9. DOI: 10.1109/SpeD53181.2021.9587430. ISI WOS: 000786794700014
  • Ș. Mihalache, I.A. Ivanov, D. Burileanu, “Deep Neural Networks for Voice Activity Detection,” Proceedings of the 44th International Conference on Telecommunications and Signal Processing (TSP), Brno, Czech Republic, pp. 191-194, 26-28 Jul. 2021. ISBN: 978-1-6654-2933-7. DOI: 10.1109/TSP52935.2021.9522670. ISI WOS: 000701604600041

2019

  • Ș. Mihalache, G. Pop, D. Burileanu, “Introducing the RODeCAR Database for Deceptive Speech Detection,” Proceedings of the 10th International Conference on Speech Technology and Human-Computer Dialogue (SpeD), Timișoara, Romania, pp. 1-6, 10-12 Oct. 2019. ISBN: 978-1-7281-0983-1. DOI: 10.1109/SPED.2019.8906542. ISI WOS: 000571718700006
  • Ș. Mihalache, D. Burileanu, G. Pop, C. Burileanu, “Modulation-based Speech Emotion Recognition with Reconstruction Error Feature Expansion,” Proceedings of the 10th International Conference on Speech Technology and Human-Computer Dialogue (SpeD), Timișoara, Romania, pp. 1-6, 10-12 Oct. 2019. ISBN: 978-1-7281-0983-1. DOI: 10.1109/SPED.2019.8906537. ISI WOS: 000571718700004
  • G. Pop, Ș. Mihalache, D. Burileanu, “Forensic Recognition of Narrowband AMR Signals,” Proceedings of the 10th International Conference on Speech Technology and Human-Computer Dialogue (SpeD), Romania, pp. 1-6, 10-12 Oct. 2019. ISBN: 978-1-7281-0983-1. DOI: 10.1109/SPED.2019.8906279. ISI WOS: 000571718700002

2018

  • G. Pop, Ș. Mihalache, D. Burileanu, “Forensic Speaker Identification Using Speech Quality Data,” Proceedings of the 12th International Conference on Communications (COMM), Bucharest, Romania, pp. 509-512, 14-16 Jun. 2018. ISBN: 978-1-5386-2350-3. DOI: 10.1109/ICComm.2018.8484766. ISI WOS: 000449526000096

2017

  • F.S. Dumitru, Ș. Mihalache, M. Enachescu, “OPAMP’s finite gain and slew rate impact on a 16-bit ΣΔ ADC performance: A case study,” Proceedings of the 40th International Semiconductor Conference (CAS), Sinaia, Romania, pp. 161-164, Oct. 11-14 2017. ISBN 978-1-5090-3985-2. DOI: 10.1109/SMICND.2017.8101187. ISI WOS: 000425844500034

2016

  • Ș. Mihalache, F.S. Dumitru, “Current-Mode Capacitance Multiplier with Reduced Parasitic Elements,” Proceedings of the 18th Mediterranean Electrotechnical Conference (MELECON), Limassol, Cyprus, pp. 1-6, 18-20 Apr. 2016. ISBN 978-1-5090-0058-6. DOI: 10.1109/MELCON.2016.7495302. ISI WOS: 000390719500001

2015

  • F.S. Dumitru, Ș. Mihalache, G. Brezeanu, “A CMOS Resistorless Bandgap Reference with Minimized Current Consumption,” Proceedings of the 38th International Semiconductor Conference (CAS), Sinaia, Romania, pp. 289-292, 12-14 Oct. 2015. ISBN 978-1-4799-8863-1. DOI: 10.1109/SMICND.2015.7355235. ISI WOS: 000380566400058
  • Ș. Mihalache, I. Flamaropol, F.S. Dumitru, L. Dobrescu, D. Dobrescu, “Automated Cooling Control System through Peltier Effect and High Efficiency Control using a DC-DC Buck Converter,” Proceedings of the 38th International Semiconductor Conference (CAS), Sinaia, Romania, pp. 281-284, 12-14 Oct. 2015. ISBN 978-1-4799-8863-1. DOI: 10.1109/SMICND.2015.7355233. ISI WOS: 000380566400056

PhD thesis

Ș. Mihalache, “Speech Signal Analysis and Processing Techniques for Automatic Recognition of Paralinguistic Elements, with Applications in Forensic Speech”, Doctoral School of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, defended 8 Sep. 2023 (academic supervisor: Prof. Dragoș Burileanu).

MSEE thesis

Ș. Mihalache, “Tunnel Diode Based Bi-tangent Oscillator”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, defended 28 Jun. 2017 (academic supervisors: Prof. Gheorghe Brezeanu, Dr. Marius Budăeș).

BSEE thesis

Ș. Mihalache, “Current-mode Capacitance Multiplier with Reduced Parasitic Elements”, Faculty of Electronics, Telecommunications, and Information Technology, National University of Science and Technology POLITEHNICA Bucharest, defended 11 Jul. 2015 (academic supervisors: Prof. Gheorghe Brezeanu, Dr. Marius Budăeș).