Creating and sharing knowledge for telecommunications
... João Manuel Torres Caldinhas Simões Vaz

Senior Researcher

João Vaz

Academic position: Assistant Professor
Joining date: 04-10-2002
Roles in IT: Senior Researcher
Scientific Area: Wireless Communications
Group: Wireless Circuits – Lx

Email: Send Email
Address: IT – Lisboa
Instituto Superior Técnico - Torre Norte - Piso 10
Av. Rovisco Pais, 1
1049 - 001 Lisboa
Tel: +351 21 841 84 54
Fax: +351 21 841 84 72


Scientific Achievements

  • PhD, Instituto Superior Técnico, 23-07-1998
  • MSc, Instituto Superior Técnico, 01-03-1991
  • Licenciatura, Instituto Superior Técnico, 30-09-1987
  • CMOS high-efficiency power amplifiers
  • CMOS frequency analog and digital synthesizers
  • CMOS and SiGe transceivers design
  • Ultra Low Power Design
  • CMOS Wireless Sensors for IoT
  • Monolhitic passive components design and characterization
  • Instituto Superior Técnico, 28-07-1998, Assistant Professor
  • IEEE - Institute of Electrical and Electronics Engineers, 01-12-1996, Senior Member
  • Ordem dos Engenheiros, 01-12-1987, Sócio
Supervision of theses
  • An Ultra-Low Power Transceiver for Bluetooth-LE Applications, PhD Student, Marco António da Mota Carvalho Silva Pereira, 04-2018
  • Integrated Power Management for IoT Wireless Node Chip, MSc Student, Pedro Filipe Francisco Marques, 06-2018
  • Fully Integrated Magnetic Sensor for IoT Wireless Node, MSc Student, Bruno José Camacho Vieira Abreu, 05-2018
  • Sintetizador de frequência CMOS para Sensores de Redes sem Fios BLE, MSc Student, Jessica Micaela Rodrigues Caldas, 05-2018
  • Low power temperature sensor for wireless sensors networks, MSc Student, José Manuel Ferreira Soares de Oliveira, 11-2017
  • Analysis and Modeling of Thermal Influence Between Two Adjacents RF Power Amplifiers, MSc Student, Emanuel José Campina Alves Baptista, 05-2017
  • Conversor Analógico Digital CMOS para Sensores de Redes sem Fios BLE, MSc Student, Guilherme Branco Teixeira, 05-2017
Co-Supervision of theses
  • P. M. Santos, L. Mendes, J. Vaz, HJQ Quaresma, Chapter 8: Layout strategies for substrate crosstalk reduction in low cost CMOS processes, Chapter in, Noise Coupling in System-on-Chip, Thomas Noulis, CRC-Taylor & Francis Group, Boca Raton, 2017
  • M. Pereira, J. T. Sousa, J. Costa Freire, J. Vaz, A 1.7-mW -92-dBm Sensitivity Low-IF Receiver in 0.13-μm CMOS for Bluetooth LE Applications, IEEE Trans. on Microwave Theory and Tech., Vol. 67, No. 1, pp. 332 - 346, January, 2019 | BibTex
  • M. Pereira, J. Vaz, Power optimisation of both a high-speed counter and a retiming element for 2.4 GHz digital PLLs, Electronics Letters, Vol. 54, No. 4, pp. 284 - 285, March, 2018,
    | Abstract
    | BibTex
  • M. Pereira, J. Vaz, A Single-Ended Modified Class-E PA With HD2 Rejection for Low-Power RF Applications, IEEE Solid-State Circuits Letters, Vol. 1, No. 1, pp. 22 - 25, January, 2018,
    | Abstract
    | BibTex
  • M. Pereira, J. Vaz, C.A. Leme, J. Costa Freire, Gain Compression Improvement on Low-Power Cascaded Current Reuse LNAs, International Journal of Circuit Theory and Applications, Vol. 44, No. 10, pp. 1767 - 1779, October, 2016,
    | Abstract
    | BibTex
  • M. Pereira, J. Vaz, C.A. Leme, J. T. Sousa, J. Costa Freire, A 170-μA All-Digital GFSK Demodulator with Rejection of Low SNR Packets for Bluetooth-LE, IEEE Microwave Wireless and Components Letters, Vol. 26, No. 6, pp. 452 - 454, June, 2016,
    | Abstract
    | BibTex
  • L. Mendes, P. M. Santos, J. Vaz, Substrate noise isolation improvement in a single-well standard CMOS process, Integration, The VLSI Journal, Vol. 52, No. -, pp. 122 - 128, January, 2016,
    | Abstract
    | BibTex
  • L. Mendes, E. S. Pires Pires, J. Vaz, M. Rosário, P. B. Oliveira, J. A. Machado, Automated Design of Microwave Discrete Tuning Differential Capacitance Circuits in Si Integrated Technologies, Microwave and Optical Tech. Letters, Vol. 52, No. 3, pp. 629 - 634, March, 2010 | BibTex
  • E. S. Pires Pires, L. Mendes, P. B. Oliveira, J. A. Machado, J. Vaz, M. Rosário, Design of Radio-Frequency Integrated CMOS Discrete Tuning Varactors Using the Particle Swarm Optimization Algorithm, Lectures Notes in Computer Science, Vol. --, No. 5518, pp. 1231 - 1239, June, 2009 | BibTex
  • L. Mendes, E. S. Pires Pires, P. B. Oliveira, J. A. Machado, N. M. Ferreira, J. Vaz, M. Rosário, Design Optimization of Radio Frequency Discrete Tuning Varactors, Lectures Notes in Computer Science, Vol. --, No. 5484, pp. 343 - 352, April, 2009 | BibTex
  • J. Vaz, J. Costa Freire, Millimeter-Wave Monolithic Power Amplifier for Mobile Broadband System, IEEE Trans. on Microwave Theory and Tech., Vol. 49, No. 6, pp. 1211 - 1215, June, 2001 | BibTex
  • K. K. Tan, G.M. Marques, J. Vaz, J. Costa Freire, MMIC Lumped and Transversal Filter with LC Tuned Amplifiers, Microwave Engineering Europe, Vol. 1, No. 11, pp. 57 - 61, November, 1999 | BibTex
  • EJB Baptista, K. Buisman, J. Vaz, C. Fager, Analysis of Thermal Coupling Effects in Integrated MIMO Transmitters, IEEE International Microwave Symposium IMS2017, Honolulu, United States, Vol., pp. -, June, 2017 | BibTex
  • M. Pereira, J. C. Costa, M. Santos, J. Vaz, An 1µA Voltage Reference Circuit With High PSRR and Temperature Compensation, Conference on Design of Circuits and Integrated Systems DCIS, Lisbon, Portugal, Vol. 1, pp. 1 - 1, November, 2015 | BibTex
  • M. Pereira, J. Vaz, C.A. Leme, J. T. Sousa, J. Costa Freire, An Ultra-Low Power Low-IF GFSK Demodulator for Bluetooth-LE applications, IEEE International Symp. on Circuits and Systems - ISCAS, Lisbon, Portugal, Vol. 1, pp. 1226 - 1229, May, 2015,
    | Abstract
    | BibTex
  • P.G. Pereira, M. Pereira, R.M.F. Alves, A.M.C. Costa, J. Vaz, C.A. Leme, All-Digital Phase Locked Loop for Bluetooth Low Energy Transmitters, Conf. on Design of Circuits and Integrated Systems, San Sebastian, Spain, Vol. 1, pp. 1 - 1, November, 2013,
    | Abstract
    | BibTex
  • M. Pereira, J. Vaz, A 20 dBm Fully Integrated Single Stage CMOS Power Amplifier with 40 dB Power Gain, Conf. on Telecommunications - ConfTele, Castelo Branco, Portugal, Vol. 1, pp. 175 - 178, May, 2013,
    | Abstract
    | BibTex
  • V. Canosa, M. Pereira, P. Gomes, J. Vaz, J. Costa Freire, Fully Integrated Switched Dual-Band CMOS LNA for 802.11b/g WLAN and WiMAX applications, European Microwave Integrated Circuits - EuMIC, Amsterdam, Netherlands, Vol., pp. 397 - 400, October, 2012,
    | Abstract
    | BibTex
  • V. Canosa, M. Pereira, P. Gomes, J. Vaz, J. Costa Freire, Fully integrated switched dual-band CMOS LNA for 802.11b/g WLAN and WiMAX applications, European Microwave Integrated Circuits - EuMIC, Amsterdam, Netherlands, Vol., pp. 397 - 400, October, 2012 | BibTex
  • V. Canosa, J. Vaz, M. Pereira, Switched Dual-band CMOS LNA for 802.11b/g WLAN and WiMAX Applications, Conf. on Design of Circuits and Integrated Systems, Albufeira, Portugal, Vol., pp. 235 - 240, November, 2011 | BibTex
  • M. Pereira, J. Vaz, V. Canosa, A 2.45 GHz 30 dBm Differential 0.18 μm CMOS Class-E Power Amplifier with 42% PAE, Conf. on Design of Circuits and Integrated Systems, Albufeira, Portugal, Vol., pp. 381 - 385, November, 2011 | BibTex
  • R. F. Ribeiro Ribeiro, L. Mendes, J. Vaz, M. Rosário, J. Costa Freire, A 130 nm CMOS LNA for 30 GHz Applications, EUROCON and CONFTELE 2011, Lisbon, Portugal, Vol. --, pp. -- - --, April, 2011 | BibTex
  • E. S. Pires Pires, L. Mendes, P. B. Oliveira, J. A. Machado, J. Vaz, M. Rosário, Maximin Spreading Algorithm, IEEE World Congress on Computational Intelligence - WCCI, Barcelona, Spain, Vol., pp. -- - --, July, 2010 | BibTex
  • F. Azevedo, L. Mendes, V. Fialho, J. Vaz, F. Fortes, M. Rosário, A 1.8V/5GHz CMOS WLAN Low Noise Amplifier Integrated with Active BALUN, Conf. on Telecommunications - ConfTele, Santa Maria da Feira, Portugal, Vol. n, pp. n - n, May, 2009,
    | Abstract
    | BibTex
  • J. Vaz, V. Fialho, A 2.4GHz CMOS Integer-N Phase-Locked Loop, Conf. on Telecommunications - ConfTele, Santa Maria da Feira, Portugal, Vol. 0, pp. 0 - 0, May, 2009 | BibTex
  • F. Azevedo, L. Mendes, J. Vaz, F. Fortes, M. Rosário, A 5GHz/1.8V Low Power CMOS Low-Noise Amplifier, Asia Pacific Microwave Conf. - APMC, Hong Kong, China, Vol. 000, pp. 000 - 000, December, 2008,
    | Abstract
    | BibTex
  • F. Azevedo, L. Mendes, J. Vaz, F. Fortes, M. Rosário, A 5GHz/1.8V CMOS Active Balun Integrated With LNA, Asia Pacific Microwave Conf. - APMC, Hong Kong, China, Vol. na, pp. na - na, December, 2008,
    | Abstract
    | BibTex
  • L. Mendes, J. Vaz, M. Rosário, A Low Power Low Phase Noise Wide Switched Tuned Band LC VCO for S Band Applications, Asia Pacific Microwave Conf. - APMC, Hong Kong – Macau, Hong Kong, Vol. --, pp. -- - --, December, 2008 | BibTex
  • L. Mendes, E. S. Pires Pires, J. Vaz, M. Rosário, P. B. Oliveira, Automated Synthesis Procedure of RF Discrete Tuning Differential Capacitance Circuits, Asia Pacific Microwave Conf. - APMC, Hong Kong – Macau, Hong Kong, Vol. --, pp. -- - --, December, 2008 | BibTex
  • F. Azevedo, L. Mendes, J. Vaz, F. Fortes, M. Rosário, A Low Power 1.8V/5GHz Monolithic Low-Noise Amplifier, Jornadas de Engenharia de Electrónica e Telecomunicações e de Computadores do ISEL, Lisbon, Portugal, Vol. na, pp. na - na, November, 2008,
    | Abstract
    | BibTex
  • E. S. Pires Pires, L. Mendes, P. B. Oliveira, J. Vaz, M. Rosário, Single-Objective Pareto Front Optimization: Application to RF Circuit Design, Genetic and Evolutionary Computation Conf. - GECCO, Atlanta, United States, Vol. --, pp. -- - --, July, 2008 | BibTex
  • L. Mendes, E. S. Pires Pires, J. Vaz, M. Rosário, A High-Performance Digitally Controlled LC Oscillator for Ku-Band Applications, IEEE International Conf. on Electronics, Circuits and Systems, Marrakech, Morocco, Vol. --, pp. -- - --, December, 2007 | BibTex
  • L. Mendes, E. S. Pires Pires, J. Vaz, M. Rosário, An Evolutionary Synthesis Algorithm to Design Optimum Performance CMOS RFSSCAs, IEEE International Conf. on Electronics, Circuits and Systems, Marrakech, Morocco, Vol. --, pp. -- - --, December, 2007 | BibTex
  • J. Torres, J. Vaz, J. Costa Freire, 30GHz Amplifiers with 0.25ƒÝm SiGe BiCMOS, IEEE International Conf. on Electronics, Circuits and Systems, marrakesh, Morocco, Vol. I, pp. 0 - 0, December, 2007 | BibTex
  • F. Azevedo, F. Fortes, J. Vaz, M. Rosário, A Wideband CMOS LNA Integrated with Balun and Linear Digital Gain Control, IEEE International Conf. on Electronics, Circuits and Integrated Systems - ICECS, Marrakesh, Morocco, Vol. na, pp. na - na, December, 2007 | BibTex
  • E. S. Pires Pires, L. Mendes, P. B. Oliveira, J. A. Machado, N. M. Ferreira, J. Vaz, M. Rosário, Single-Objective MaxMin Sorting Scheme: Application to Radio Frequency Circuit Design, International Conf. on Electrical Engineering, Coimbra, Portugal, Vol. --, pp. -- - --, November, 2007 | BibTex
  • F. Azevedo, F. Fortes, J. Vaz, M. Rosário, A 1.7V Wideband CMOS Low Noise Amplifier with Linear Digital Gain Control, International Microwave and Optics Conf., Salvador BA, Brazil, Vol. na, pp. na - na, October, 2007 | BibTex
  • L. Mendes, E. S. Pires Pires, J. Vaz, M. Rosário, Automated Design of Radio-Frequency Single-Ended Switched Capacitor Arrays using Genetic Algorithms, Midwest Symp. on Circuits and Systems, Montréal, Canada, Vol. --, pp. -- - --, August, 2007 | BibTex
  • L. Mendes, J. Vaz, M. Rosário, Wide Tuning Band Low Phase Noise LC Voltage Controlled Oscillators Designed in Low Cost CMOS Technologies, Conf. on Telecommunications - ConfTele, Peniche, Portugal, Vol. --, pp. -- - --, May, 2007 | BibTex
  • G. St´Aubyn, J. Vaz, J. Costa Freire, Voltage Controlled Phase Shifters on CMOS Technology, Asia Pacific Microwave Conf. - APMC, Yokohama, Japan, Vol. 1, pp. 1 - 1, December, 2006 | BibTex
  • L. Mendes, J. Vaz, M. Rosário, Performance of Si-Integrated Wide-Band Single-Ended Switched Capacitor Arrays, IEEE International Conf. on Electronics, Circuits and Systems, Nice, France, Vol. --, pp. -- - --, December, 2006 | BibTex
  • J.O. Oliveira, J. Vaz, A CAD Oriented Method for Monolithic LC VCO Design, Conf. on Design of Circuits and Integrated Systems, Barcelona, Spain, Vol. 1, pp. 1 - 1, November, 2006 | BibTex
  • L. Mendes, J. Vaz, M. Rosário, Modeling of CMOS or BiCMOS Ultra-Wide-Band Single-Ended Switched Capacitor Arrays, Conf. on Design of Circuits and Integrated Systems, Barcelona, Spain, Vol. --, pp. -- - --, November, 2006 | BibTex
  • L. Mendes, J. Vaz, M. Rosário, A Closed-Form Input Admittance Solution for RF and Microwave Switched Capacitor Arrays, IEEE International Symp. on Circuits and Systems - ISCAS, San Juan, Puerto Rico, Vol. --, pp. -- - --, August, 2006 | BibTex
  • L. Mendes, J. Vaz, M. Rosário, Fully Integrated CMOS LC Voltage Controlled Oscillator for IEEE802.11a and HiperLAN2 WLAN Transceivers, International Conf. on Electrical Engineering, Coimbra, Portugal, Vol. na, pp. na - na, October, 2005 | BibTex
  • J. Bernardino, J. Vaz, High Q MMIC GaAs Active Filter for K Band Subsystems, Conf. on Telecommunications - ConfTele, Tomar, Portugal, Vol. na, pp. na - na, April, 2005 | BibTex
  • J. Vaz, M. Rosário, J. Costa Freire, Low Cost Si MMIC Design for RF Front Ends, Asia Pacific Microwave Conf. - APMC, New Delhi, India, Vol., pp. 1 - 2, December, 2004 | BibTex
  • J.O. Oliveira, J. Vaz, Oscilador Sinusoidal LC em Tecnologia BiCMOS para 2.4GHz, Workshop de Investigação e Desenvolvimento em Engenharia Electrotécnica e das Telecomunicações, Castelo Branco, Portugal, Vol. 1, pp. 1 - 1, February, 2004 | BibTex
  • M. Rosário, F. Le-Strat, P. Alleaume, J. Vaz, J. Schrotg, T. Mueller, J. Costa Freire, Low Cost LTCC Filters for a 30GHz Satellite System, European Microwave Conf. - EMC, Munique, Germany, Vol. 1, pp. 817 - 820, October, 2003 | BibTex
  • J.O. Oliveira, J. Vaz, A 2.4GHz LC-tuned VCO in BiCMOS technology, Conf. on Telecommunications - ConfTele, Aveiro, Portugal, Vol. 1, pp. 531 - 533, June, 2003 | BibTex

Currently running projects2

Acronym Name Funding Agency Start date Ending date
uFlexBat Batteryless energy supply system based on flexible organic photovoltaic cells IT/LA 01-12-2016 30-06-2019
WSN_EM Wireless Sensor Network for Environmental Monitoring FCT 01-09-2018 31-08-2021

Closed Projects11

Acronym Name Funding Agency Start date Ending date
ACTFIL Active filters IT/LA 01-01-2004 31-12-2005
AME Advanced Microelectronics Engineering ICEP 01-10-2002 22-10-2003
COMMET A COmplete analog front-end for 3G MultiMEdia Terminals ADI 01-11-2002 31-10-2005
Digital_PAs Digital_PAs - Digital RF Power Amplifiers for Wireless Applications FCT/PTDC 01-01-2009 01-06-2012
GALACTIC Innovative GaAs MMICs and Avanced LTCC packaging technologies for multicomponents Ka Band subsystems EU 01-01-2002 31-12-2004
IRFDCMOS Integration of high-frequency dc-dc converters in RF CMOS SoC IT/LA 01-09-2005 01-06-2008
LDMOSCA Low Distortion RF MOS Circuits Advances FCT/POCTI 01-01-2001 31-12-2002
NLRFCMOS Desenvolvimento de modelos não lineares de dispositivos para microondas e integração monolítica de circuitos não lineares em silício para telecomunicações CRUP 01-01-2003 31-12-2004
SiGeM Silicon Germanium MMICs for RF Front End Transceivers IT/LA 01-10-2005 01-07-2008
SWIPA Switching Mode Power Amplifiers for Wireless Communications IT/LA 01-11-2008 01-11-2010
WiFiRx Double-Band Multi_standard Frequency Front-End for WLAN aplications FCT/PTDC 01-09-2007 01-04-2010
  • J. Vaz, Docente Excelente, Considerado docente excelente relativamente à disciplina de Electrónica 1 leccionada no 2º semestre do ano lectivo 2010/11 no Mestrado Integrado em Engenharia Electrotécnica e Computadores., 01-01-2012
  • J. Costa Freire, G.M. Marques, W. Tam, J. Vaz, MMIC Lumped and Transversal Filter with LC Tuned Amplifiers, Best Poster at GAAS'99 (, 05-10-1999
  • J. Vaz, EMERGENT TECHNOLOGIES FOR FUTURE WIRELESS SYSTEMS, Portugal, Aveiro, 09-2012
  • J. Vaz, Introdução às Telecomunicações” (Ciência Viva no Laboratório – Ocupação Científica de Jovens nas Férias), Portugal, Lisboa, 07-2012
  • J. Vaz, High-Efficiency Radiofrequency Power Amplifiers, Macau, Macau, 07-2011
  • J. Vaz, M. Pereira, J. T. Sousa, Bluetooth Low Energy CMOS radio
  • Invited to chair Session 7b of XX Conference on Design of Circuits and Integrated Systems, Lisboa, Portugal, Outubro 2005., Sessions Chairman, 2005
  • ETRI Journal
    2013, 1 review(s); 2005, 1 review(s);
  • IEEE Microwave Magazine
    2016, 1 review(s); 2012, 1 review(s); 2011, 1 review(s);
  • Integration, The VLSI Journal
    2016, 1 review(s);
  • IEEE Trans. on Circuits and Systems - II: Express Briefs
    2017, 1 review(s); 2016, 3 review(s);
  • IEEE Trans. on Microwave Theory and Tech.
    2014, 1 review(s); 2013, 1 review(s); 2010, 2 review(s); 2009, 1 review(s); 2008, 2 review(s); 2006, 1 review(s);
  • Wireless Personal Communications
    2011, 1 review(s);
  • IEEE International Symp. on Circuits and Systems - ISCAS
    2015, 1 review(s); 2014, 1 review(s); 2013, 1 review(s); 2012, 1 review(s); 2011, 1 review(s); 2009, 1 review(s);
  • Conf. on Design of Circuits and Integrated Systems
    2012, 1 review(s); 2009, 1 review(s); 2006, 1 review(s); 2005, 1 review(s); 2004, 1 review(s); 2003, 1 review(s); 2002, 1 review(s); 2000, 1 review(s); 1999, 1 review(s);
  • Conf. on Telecommunications - ConfTele
    2009, 1 review(s); 2005, 1 review(s); 2003, 1 review(s); 2001, 1 review(s);
  • International Conf. on Telecommunications - ICT
    2006, 1 review(s);