News

• IMS 2008

  Jan Verspecht attended the International Microwave Symposium 2008 in Atlanta (June 17-20). He presented "Poly-Harmonic Distortion Measurements: A Maturing Amplifier Measurement Technology" during the full day workshop "Measurements for Wireless System-Level Evaluation" (WSH) on Sunday. Jan also co-authored the paper "High-Power On-Wafer Capabilities of a Time Domain Load-pull Setup" (download pdf). The paper was presented by Fabien De Groote during the ARFTG Interactive Forum. Co-authors are F. De Groote (Verspecht-Teyssier-DeGroote s.a.s.), J-P Teyssier and J. Faraj (Xlim).

  
  

• Get introduced to Power Transistor Characterization!

  Our paper entitled "Introduction to Measurements for Power Transistor Characterization" (download pdf) was published in the June 2008 issue of the IEEE Microwave Magazine. Authors are Fabien De Groote (Verspecht-Teyssier-DeGroote s.a.s.), Jean-Pierre Teyssier (XLIM), Tony Gasseling (Amcad Engineering), Olivier Jardel (XLIM) and Jan Verspecht. The paper introduces the concepts of pulsed IV measurements, pulsed S-parameter measurements and time domain loadpull techniques.

  
  

• Time domain loadpull of GaN and GaAs transistors presented at ESA workshop

  On May 7th 2008 Jan Verspecht presented the paper "Advanced Time Domain Loadpull Technique for Characterization of Microwave Power Transistors" (download pdf) at the ESA Microwave Technology and Techniques Workshop 2008 (Noordwijk, The Netherlands). Co-authors are Fabien De Groote (Verspecht-Teyssier-DeGroote s.a.s., Brive, France) and Jean-Pierre Teyssier (Xlim, Brive, France).

  
  

• EDN puts X-parameters in the spotlight

  X-parameters and Poly-Harmonic Distortion (PHD) modeling, invented by Jan Verspecht and developed in cooperation with Agilent Technologies, gain acceptance in industry. Read what Paul Rako, technical editor at EDN, has to say about X-parameters and the PHD-model in the following paper (click below for a link to the full paper). .

  
  

• MTT-11 contest on "Creativity and Originality in Microwave Measurements"

  The IEEE MTT-11 committee has launched a contest on "Creativity and Originality in Microwave Measurements". Everyone can participate and win $1000, provided by the Technical Coordinating Committee (TCC), part of the MTT Society Administrative Committee (ADCOM). The purpose of the contest is to highlight creative and original microwave measurement setups or procedures. There is no need to use the latest or most expensive equipment, only to have a good idea that presents a creative solution to an existing measurement problem. MTT-11 members Rashaunda Henderson of The University of Texas at Dallas and Jan Verspecht are responsible for the organization. One enters the contest by emailing a 2 page PDF-file describing the microwave measurement setup or procedure to Jan Verspecht (contact@janverspecht.com) by May 15 2008. The winner is the one whose entry is, according to the MTT-11 committee, the most creative and original microwave measurement setup or procedure. The winner will be known by Friday June 20th 2008. For more information please check the MTT-11 web-site.

  
  

• IEEE Fellowships Awarded to Jose Carlos Pedro, John Wood and Jan Verspecht

  Picture courtesy of Gayle Collins

  In 2007 the Board of Directors of the IEEE awarded the prestigious grade of IEEE Fellow to 16 members of the MTT. They were recognized in Honolulu during the well attended plenary session of the IMS 2007. On the picture we recognize 3 new Fellows: Jose Carlos Pedro of the Universidad de Aveiro, (Aveiro, Portugal), John Wood of Freescale (Tempe, Arizona, USA) and Jan Verspecht (Opwijk, Belgium), all of them experts in the field of nonlinear microwave measurements and modelling. At Jan Verspecht b.v.b.a. we want to congratulate the new Fellows. We also want to express our gratitude to all of the people who supported Jan Verspecht during his challenging career as an independent consultant and as such contributed to his IEEE Fellowship.

  
  

• Aloha!

  Jan Verspecht was in Hawai`i for the International Microwave Symposium 2007. He presented the paper "Multitone, Multiport, and Dynamic Memory Enhancements to PHD Nonlinear Behavioral Models from Large-Signal Measurements and Simulations" (download pdf). This paper is co-authored by Daniel Gunyan, Jason Horn, Jianjun Xu, Alex Cognata and David Root of Agilent Technologies. Jan co-authored the paper "On-Wafer Time Domain Load-Pull Optimization of Transistor Load Cycle with the New Multi-Harmonic MPT Tuner" (download pdf), presented as a poster paper at the ARFTG Conference on Friday June 8th. Other authors are Fabien De Groote, Olivier Jardel, Jean-Pierre Teyssier of XLIM (France), Tony Gasseling of AMCAD Engineering (France), Vince Mallette and Christos Tsironis of Focus Microwaves (Canada).

  
  

• Presenting our affordable LSNA technology at the Power Amplifier Symposium

  Jan Verspecht presented two papers at the Power Amplifier Symposium in Long Beach, CA, from Sunday January 7th until Tuesday January 9th. On Sunday Jan presented a talk on "Affordable Large-Signal Network Analyzer Technology" during the workshop "WS2: RF Power Transistors and Amplifier Characterization Techniques", organized by John Wood and Basim Noori (Freescale, Tempe, USA). During the plenary session on Monday morning Jan presented an invited paper entitled "Advanced Measurements for Power Transistors" (download pdf). Both presentations are co-authored by Jean-Pierre Teyssier and Fabien De Groote (XLIM, France) and introduce our affordable LSNA technology.

  
  

• Meeting Metrologists at the Fall 2006 ARFTG Conference

  During the last week of November 2006 Jan Verspecht attended the 68th ARFTG conference in Broomfield (Colorado, USA). He co-authored a paper entitled "Load-pull measurement of transistor negative input impedance" (download pdf). The first author of the paper is Fabien De Groote, other co-authors are Jean-Pierre Teyssier and Raymond Quere of XLIM (formerly IRCOM, France). Friday afternoon all members of ARFTG were invited for a fascinating visit to the laboratories of the National Institute of Standards and Technologies (NIST) in Boulder. During the visit we had the honor of seeing the world's one and only traceable harmonic phase standard. This setup was built by Dr. Dylan Williams and is based on a photo-electric sampler. A special thanks from Jan Verspecht goes to Dylan Williams and Kate Remley for hosting me in their wonderful historical house, known as the Arnett-Fullen house (see picture).

  
  

• Our PHD Model Made the Cover of the June 2006 Issue of the IEEE Microwave Magazine!

  We proudly announce the publication of our paper on Polyharmonic Distortion Modeling as the features article in the June 2006 issue of the IEEE Microwave Magazine (download pdf). The article is authored by Jan Verspecht and David Root. The paper introduces you to the Polyharmonic Distortion Modeling technique. This so-called PHD modeling technique is a powerful black-box frequency domain behavioral modeling technique, based on the theory of the scattering functions. It is explained in the paper how nonlinear behavior may cause unhappiness. This fact is illustrated by (:-) faces that get squeezed (:-( by the conjugate a21-terms, which are only present in the case of nonlinear behavior.

  
  

• We have been to San Francisco

  Jan Verspecht was in San Francisco for the International Microwave Symposium 2006. Jan co-authored two presentations. The first was entitled "Nonlinear Behavioural Models with Memory: Formulation, Identification and Implementation". Authors are David Root (Agilent Technologies), Jan Verspecht and David Sharrit. It was presented in the workshop "WSL: Memory Effects in Power Amplifiers". The second paper was entitled "Accurate Phase Measurements of Broadband Multitone Signals using a Specific Configuration of a Large Signal Network Analyzer". Authors are M. El Yaagoubi, G. Neveux, D. Barataud, J. Nebus (University of Limoges XLIM) and Jan Verspecht (download pdf). We thank rookies Hind Bousbia of Xlim and Floria Blanchet of STMicroelectronics for providing the undistorted (:-) faces on the picture.

• Don't miss the December 2005 issue of the IEEE Microwave Magazine!

  We proudly announce the publication of our paper on Large-Signal Network Analysis as a features article in the December 2005 issue of the IEEE Microwave Magazine (download pdf). The paper introduces you to the world of Large-Signal Network Analysis (LSNA) and invites you to join the rapidly growing LSNA community.

  
  

• The 66th ARFTG conference: definitively a three-pointer!

  December 1st and 2nd Jan Verspecht attended the 66th ARFTG conference in Washington DC. There were many interesting presentations on a wide variety of topics, from nanotubes to 500 GHz network analyzers. Mohamed Sayed, technical program chair, and Greg Burns, general chair, did a great job and definitely scored a three-pointer. Jan Verspecht presented the paper "Hot S-Parameter Techniques: 6=4+2" (download pdf). Read the paper and find out what is missing with the Hot S-parameter techniques of Agilent, Anritsu and Rohde & Schwarz. Fabien De Groote of IRCOM did an excellent job in presenting the paper "Time Domain Harmonic Load-Pull of an AlGaN/GaN HEMT" (download pdf). Co-authors are Olivier Jardel, Denis Barataud, Jean-Pierre Teyssier and Raymond Quere of IRCOM and Jan Verspecht. Friday evening was NBA time: the picture on the left shows a Milwaukee Buck taking a shot at the Washington Wizards basket.

  Courtesy Fabien De Groote

  
  

• New IEEE Transactions Paper on PHD Models Published

  A new extensive paper on the Poly-Harmonic Distortion (PHD) black-box frequency domain modelling technique has been published in the November 2005 issue of the IEEE Transactions on Microwave Theory and Techniques (download pdf). Authors are David Root, David Sharrit and Alex Cognata of Agilent Technologies, John Wood of Freescale and Jan Verspecht. The paper is entitled "Broad-Band Poly-Harmonic Distortion (PHD) Behavioral Models From Fast Automated Simulations and Large-Signal Vectorial Network Measurements". Next to the theory of the PHD model, it is explained how the PHD model can be extracted based on nonlinear vector network analyzer (NVNA) measurements or harmonic balance simulations using Agilent ADS.

  
  

• The International Microwave Symposium 2005: A Vibrant Experience

  On the left David Root and Jan Verspecht prepare for presenting their joint paper "Broad-Band, Multi-Harmonic Frequency Domain Behavioral Models from Automated Large-Signal Vectorial Network Measurements" (download pdf). The paper was presented at the MTT-S poster session on Thursday June 16th. Other authors are Alex Cognata of Agilent Technologies and John Wood, now with Freescale. During the poster session a small earth quake took place, a vibrant experience. A second IMS paper was also co-authored by Jan Verspecht. The title is "An improved coupling method for time domain load-pull measurements". The work was brilliantly presented by rookie Fabien De Groote at the ARFTG conference on Friday June 17th (download pdf). Other authors are Jean-Pierre Teyssier of IRCOM (France) and Christos Tsironis of Focus Microwaves (Canada).

  Picture courtesy of Daniel Gunyan, Agilent Technologies.

  
  

• The book of Wood and Root: your number 1 survival guide

  Artech House recently published the book "Fundamentals of Nonlinear Behavioral Modeling for RF and Microwave Design" (link to Artech House). The book was edited by Dr. John Wood and Dr. David Root. The book is a revised collection of groundbreaking presentations that were made at a successful workshop during the 2003 International Microwave Symposium. The book gives an excellent overview of existing methods and is a great starting point on any large-signal microwave modelling journey. It is authored by no less then 10 renowned experts in the field of nonlinear behavioral modeling for RF and microwave: Nuno Borges Carvalho, Edouard Ngoya, Jose Carlos Pedro, David E. Root, Arnaud Soury, Nick Tufillaro, Jan Verspecht, John Wood, Jianjun Xu and Qi-jun Zhang. At "Jan Verspecht bvba" we offer you a chance to win this book. It is real easy to participate: click here and register.

  
  

• Fresh of the Press: Circles of the Olympic Games Logo Start Rolling!

  Fortunately for the athletes the press has it wrong: the coloured rings on the left have nothing to do with the next Olympics. The meaning of the rotating coloured rings is explained in detail in a new paper entitled "Linearization of Large-Signal Scattering Functions" (download pdf). The paper is the result of a fruitful collaboration between the National Institute of Standards and Technology (NIST), the Catholic University of Leuven (Belgium) and "Jan Verspecht bvba". The paper has been published in the April 2005 issue of the IEEE Transactions on Microwave Theory and Techniques. Authors are Jan Verspecht, Dylan F. Williams (NIST), Dominique Schreurs (Catholic University of Leuven), Kate A. Remley (NIST) and Michael D. McKinley (NIST).

  
  

• Tutorial on Large-Signal Network Analysis

  Jan Verspecht presented the tutorial "Large-Signal Network Analysis - 'Going beyond S-parameters'" (download pdf) during the 64th ARFTG Conference on "Digital Communication System Metrics". The conference took place from November 30 to December 3, 2004 in Orlando, Florida, USA. The tutorial was presented on Wednessday December 1st as part of the ARFTG Short Course program. More information on ARFTG is available on the ARFTG web-site (www.arftg.org).
  

• Tribute to Bill and Dave

  During one of his business trips Jan Verspecht visits the famous garage where Bill Hewlett and Dave Packard started their business in the late 30's. Considered as the "birthplace of Silicon valley" the garage is recognized as a monument by the State of California. A truly inspiring moment!
  

• Meeting cowboys in Fort Worth, Texas (:-)

  The International Microwave Symposium 2004 took place from June 6th until June 11th in Fort Worth, Texas. This offered a unique opportunity to meet with all kinds of cowboys. At the left Jan Verspecht meets with French cowboy Jean-Pierre Teyssier, just before the NVNA user forum. At the right he meets with an American cowboy at the rodeo arena. Despite their quite different looks, it was discovered that both cowboys have a lot in common. Both wear the same kind of hat and both of them are used to deal with highly nonlinear problems (power transistors for the French cowboy and raging bulls for the American cowboy) (:-).
  

• WME workshop at IMS 2004 was a hit!

  On June 7th 2004 Mr. Ruediger Follman of IMST and Jan Verspecht co-organized the fullday workshop "More efficient Circuit Design by Means of Large-Signal Models and Large-Signal Measurements". This workshop was part of the International Microwave Symposium 2004 in Fort Worth, Texas. The workshop was a real succes having about 80 attendees. As an unfortunate consequence we run out of workshop notes. I apologize to all the people who did not get their notes. A pdf-file of the workshop notes extended with additional and very informative comments for most of the speakers can be downloaded by clicking the button below.
  

     Extended WME Workshop Notes (10MByte)

• Multidimensional interpolation and curve fitting with scattered input data in Mathematica

  Multidimensional interpolation and curve fitting based on scattered input data is now possible in Mathematica thanks to the JanVerspechtMultiDim Mathematica package. This package implements multidimensional interpolation and curve fitting functions which can handle scattered input data. Adding this package to your copy of Mathematica you are no longer constrained to "regular grid" input data, as it is the case with the standard Mathematica Interpolation function. You can download your fully functional free trial version on our products page.

• It was a great 62nd ARFTG Conference!

  We attended the ARFTG Microwave Measurement Conference. The conference and the associated tutorial sessions took place from Tuesday December 2 until Friday December 5 2003 in Boulder, Colorado, USA. Jan presented the tutorial "Large-Signal Network Analysis - 'Going beyond S-parameters'" (download pdf) during the ARFTG Short Course session on Wednessday December 3. Jan also made a presentation entitled 'The Return of the Sampling Frequency Convertor' (download pdf).

  This 62nd edition of the ARFTG was definitely one of the best editions in many years. Many topics were covered in high quality presentations. A special thanks from Jan Verspecht goes to his hosts Chair Dylan Williams and Technical Program Chair Kate Remley (see picture) for organizing a truly commemorable event!
  
  
  Picture courtesy of Dr. Marc Vanden Bossche, NMDG Engineering, Belgium.

• It was a pleasure to meet at the International Microwave Symposium - 2003

  Jan Verspecht attended the International Microwave Symposium (IMS) 2003 in Philadelphia. He made a presentation entitled "Scattering Functions for Nonlinear Behavioral Modeling in the Frequency Domain" (click for pdf) in the workshop "Fundamentals of Nonlinear Behavioral Modeling: Foundations and Applications", organised by Dr. David Root and Dr. John Wood of Agilent Technologies. The symposium visit was a big hit. We were able to meet many old friends and colleagues and made many new acquintances.
  
  Too bad the Phillies baseball game on Saturday was cancelled because of the rain! But we did get a chance to see the Liberty bell. I really like the picture below: the symbol of Liberty together with Jan Verspecht, who in his own way proclaimed liberty by founding "Jan Verspecht bvba". Great!
  
  
  Picture courtesy of Dr. Dominique Schreurs, Catholic University of Leuven, Belgium.

• Good news (:-)

  "Jan Verspecht bvba" is up and running. We move fast forward with confidence. The mission is simple: to assist the many people who are developing the RF and microwave tools of the future. For Jan Verspecht it is like continuing his old job in a new company. We are looking forward to keep on interacting and cooperating with the many great people we have met in the past. And of course we are eagerly looking forward to make new acquintances. Working together we can take RF and microwave instrumentation beyond S-parameters!

• Search engine created for our database of publications

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