the mtt-11 web page: a multitude of information resources ... · august 2007 107 last, but...

The MTT-11 Web Page: A Multitude of Information Resources on Microwave Measurements■ Nuno Borges Carvalho, Kate A. Remley, and Dominique Schreurs

106 August 2007

The Microwave MeasurementsTechnical Committee of the MTT-S (MTT-11) promotes activities

related to microwave measurement tech-nology and science. One of its main vehi-cles of information dissemination forgeneral IEEE Members is its Web pageinterface (http://www.mtt.org/com-mittees/mtt-11/index.html), which is avaluable tool for any microwave engi-neer who needs to be informed aboutmeasurements of radio, high-speed elec-trical, and microwave quantities.

The Web page contains severalimportant types of information forthe IEEE community; for instance, amilestone paper Web page foundhere allows the reader to navigatethrough several important IEEEpapers that are fundamental researchworks in the field and have revolu-tionized their area.

Most of the referred papers have adirect link to IEEE Xplore (http://ieeexplore.ieee.org), so that the readercan immediately download the paperfrom the net if he or she is an IEEEMember. This manner of presenting keytechnical material could reduce the time

needed for research if the engineer issearching for a quick introduction to agiven area.

The Web page also has an area dedi-cated to the members of the committee.There it is possible to find contact infor-mation for the members, each of whomis considered an expert in his or herarea. Thus, the reader can quickly findsomeone who could help with specificmeasurement issues on a given topic.

This is further complemented by apage dedicated to our Speakers Bureaulist, where the interested reader canlearn about our appointed speakersand the talks they are presenting. At thetime of this writing, MTT-11 has threespeakers appointed: Dr. Jan Verspecht[Jan Verspecht bvba] and Prof. AndreaFerrero [Politecnico di Torino], who are

presenting a talk devoted to “NonlinearMicrowave Measurements: FromPower Meters to Large-Signal NetworkAnalyzers,” and Dr. Michael Janezic[NIST], whose talk is devoted to “High-Frequency Measurements of DielectricSubstrate Materials.”

It is also possible to see and hear thetalk of MTT Distinguished MicrowaveLecturer [2004–2006] Doug Rytting relat-ed to “Calibration and Error CorrectionTechniques for Network Analysis.” Thistalk is now available to all net surfers invideo streaming format.

Other pages on the Web site lead usto the most important conferencesworldwide devoted to microwavemeasurements, and we also have linksdevoted to international institutionsrelated to measurements.

Nuno Borges Carvalho is withthe Universidade de Aveiro, Portugal.

The MTT home page

Digital Object Identifier 10.1109/MMM.2007.899892

Authorized licensed use limited to: UNIVERSIDADE DE AVEIRO. Downloaded on July 1, 2009 at 12:26 from IEEE Xplore. Restrictions apply.

August 2007 107

Last, but definitely not least, themost important feature and benefit ofthe MTT-11 Web page exclusively forIEEE Members is the online forum Webpages. MTT-11 members establishonline forum Web pages, which aredivided into the following five areas:

1) “General” Measurements2) On-Wafer S- and Noise-Parameter

Measurements 3) Signal Integrity and Multiport

Measurements 4) Nonlinear and Loadpull Measure-

ments 5) Coaxial VNA Measurements. These forums provide a way to dis-

cuss measurement themes with topresearchers in the area worldwide.IEEE Members simply sign up and arethen given access to past and futureposts of questions on measurement-related issues for some of the key top-ics of the day. At the moment, wehave an average of 82 members perforum group and an average of 150messages per area.

Table 1 presents a brief overview offorum statistics as of January 2007.

As an example, one post thatreceived a significant amount of onlinediscussion was related to “two-tier cali-bration.” This was posted in the “On-Wafer S- and Noise-Parameter Measure-ments” forum and was initiated as aquestion on how to de-embed theprobes and test fixtures on a probing sta-tion measurement.

Another post that generated a highvolume of online discussion trafficwas the one about “ACPR estimationwith multisines,” in this case in the“Nonlinear and Loadpull Measure-ments” forum. This topic was devotedto a discussion on how to measureadjacent channel power ratio (ACPR)in a nonlinear power amplifier whenthe input signal is a multi-sine, andthen how to infer that figure of meritfor WCDMA signals.

Another discussion example fromthe “Coaxial VNA Measurements”forum was related to “TRL with 3-portsymmetric devices,” where the calibra-tion of a two-port network analyzer formeasuring a three-port circulator wasdiscussed. In the “Signal Integrity andMultiport Measurements” forum, the

moderator started a discussion on mul-tiport topics such as calibration, accura-cy verification, and on-wafer problems.

The “General” Measurements for-um is mainly dedicated to providinggeneral microwave measurementdiscussions. It deals with measure-ments of the microwave characteris-tics (e.g., S-parameters) of micro-wave and lightwave components andwith the application of photonictechniques to microwave and mil-limeter-wave measurements. More-over, it focuses on the metrology and

measurement techniques for char-acterizing the broadband electricalproperties of materials.

Other interesting discussions havecentered around the name to adopt forthe so-called “large-signal measurementinstrument,” which has had many dif-ferent names depending on the manu-facturer and the research institute wereit is used. This discussion continuestoday in the “Nonlinear and LoadpullMeasurements” forum. In the future, anew forum is to be available devoted to“Uncertainty in Measurements.”

The MTT-11 Speakers Bureau list.

A snapshot of the “On-Wafer S- and Noise-Parameter Measurements” forum.

Table 1. Forum Statistics as of January 2007.

Forum Name # of Members # of Posts Date of First Post

“General” Measurements 55 14 1 Feb. 2002

On-Wafer S- and Noise-Parameter 164 603 4 Dec. 2002Measurements

Signal Integrity and Multiport Measurements 45 24 2 Sept. 2004

Nonlinear and Loadpull Measurements 81 72 28 Feb. 2003

Coaxial VNA Measurements 61 35 20 Jan. 2003


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Some of the future projectsinclude the start of a wiki pagedevoted to measurements, wheresome definitions will be open to theengineering public in general.MTT-11 intends to continue to

enhance the microwave measure-ments Web page, improving andincreasing the benefits to all IEEEMembers. Another project is devot-ed to building an archive of all thesponsored MTT-11 workshops

where most of the talks will beavailable to IEEE readers.

If you have suggestions for the Webpage or Web-based forums, please con-tact the webmaster, Nuno BorgesCarvalho, at [email protected].

Who or what is ARFTG? This isa question that I receive quitefrequently, even from people

who have been working in the field formany years. The ARFTG appears to beone of those all too well-kept secrets but,for many, it should not be.

ARFTG is an acronym for theAutomatic Radio Frequency Techni-ques Group. The ARFTG is a technical

organization formed in 1972 which isinterested in all aspects of RF andmicrowave test and measurement.Like the IEEE Microwave Theory andTechniques Society (MTT-S), theARFTG is a community which bringstogether colleagues, experts, and ven-dors with a particular focus on RF andmicrowave test and measurement.The ARFTG is not a part of the IEEE,but an independent, international,nonprofit technical organization. Likethe MTT-S, the ARFTG is a volunteer-run organization, operated exclusive-ly for scientific and educational pur-poses. The ARFTG membershipincludes a broad, if eclectic, mix ofgovernment metrologists, academic

researchers, and industrial practition-ers. Like the MTT-S, the ARFTG pro-vides a forum for the development ofnew technologies, methodologies, andinstrumentation. The ARFTG orga-nizes two conferences each year, bothof which are technically cosponsoredwith the MTT-S. The ARFTG SpringConference is held on the Friday of theInternational Microwave Symposium(IMS) week. (See Table 1.) A separateFall Conference is scheduled at vari-ous locations the week followingThanksgiving (see Table 2). Like theMTT-S, the ARFTG supports and nur-tures its student members, provideseducational opportunities for its moresenior members, and offers technicalservices specifically to the RF andmicrowave test and measurementcommunity. Our members are alwayshappy to discuss their latest researchtechniques and developments.

The most stimulating part of theARFTG experience is the opportunityto interact one-on-one with col-

leagues, experts, and vendors in theRF and microwave test and measure-ment community. Whether your inter-ests include high-throughput produc-tion or one-of-a-kind metrology mea-surements, complex systems or simplecircuit modeling, small-signal S-para-meter or large-signal nonlinear mea-surements, phase noise or noise fig-ure, from dc to lightwave, you willfind within the ARFTG a kindred spir-it or maybe even an expert. There isalways ample opportunity at everyARFTG conference for detailed techni-cal discussions with others facing sim-ilar test and measurement challenges.The members of the ARFTG often findthat these interactions are their bestsource of ideas and information fortheir current projects. So come andjoin us at our next conference, shortcourse, or workshop. You’ll find thatthe atmosphere is informal and quitefriendly. For more information aboutthe ARFTG, please visit our Web siteat www.arftg.org.

Benefits of ARFTG Membership■ Charles Wilker

The ARFTG logo.

The ARFTG Web site.Charles Wilker is with DuPont in Wilmington,

Delaware, [email protected].


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ARFTG HistoryThe ARFTG was founded in 1972 to cre-ate a more cohesive voice for the RF andmicrowave test and measurement com-munity to solicit support from the man-ufacturers of test instrumentation. Theprimary focus of the first few meetingswas on the automation and calibrationof network analyzers. In the early years,the ARFTG was more like a users’group than the professional measure-ment society the ARFTG wouldbecome. In fact, the early meetings werenot a pleasant place for the representa-tives of the instrumentation manufac-turers. The magic of these early test sys-tems was embedded and hidden fromthe user in the software, which was thennot available in source form. TheARFTG was formed to “help” the man-ufacturers realize and appreciate theneeds of the users.

Why was there a need for automatednetwork (and/or spectrum) measure-ments? When Hewlitt-Packard (HP) firstintroduced the 8410/8411 network ana-lyzer test instrument and its RF test sets,RF components were typically octavebandwidth limited. They were not wellmatched, particularly above 12 GHz.There was no repeatable phase refer-ence. There was no way to record thedata short of scope photos and analog

pen plotters. Sweeper band crossingswere not pretty or repeatable. One wasnever sure which harmonic the instru-ment would choose. This made repeat-able calibrations and phase stability anightmare. And once those measure-ments were taken, the real task of refer-encing them to some known standardbegan. Finally, engineers would muchrather a machine did these mundanebookkeeping tasks. All these problemswere eventually solved with the help ofthe ARFTG. For an entertaining reviewof the early history of the ARFTG andthe people involved, see [1].

Soon, however, issues such as mea-surement metrology, connector repeata-bility, noise and/or power measure-ments, and computer-aided design(CAD) became common topics at everyARFTG conference. The interests of theARFTG have continued to expand withthe interests of the RF and microwavetest and measurement community andnow include such diverse topics as:nonlinear measurements, productiontesting, temporal measurements, high-frequency fixturing, four- and six-portnetwork analysis, and load pull mea-surements. Indeed, the broad range ofARFTG interests is reflected in thediverse nature of our membership andof the topics of our recent conferences.

For the last 30 years, the ARFTG hasbeen at the leading edge of the develop-ment of new RF and microwave test andmeasurement techniques and instru-mentation. In 1987, the ARFTG becameaffiliated with the MTT-S and in 2000formalized the relationship with amemorandum of understanding (MOU)which governs the coordinationbetween the two organizations, espe-cially between the IMS steering commit-tee and the ARFTG Spring Conference.

In 2001, the ARFTG became incorpo-rated as a nonprofit corporation. TheARFTG is an incorporated organizationwhose purposes are limited to educa-tion, scientific research, and publicationof member research on a nonprofitbasis as limited by Section 501(c)(3) ofthe Internal Revenue Code, in the fieldof automated RF network design andmeasurement. Our areas of involve-ment are: 1) to obtain and distributeinformation on how automatic RF mea-surement systems are being used, thetypes of measurements being per-formed, and the types of items tested;2) to provide a forum for discussionand education on the interfacing of testequipment and on CAD techniques;and 3) to establish a mechanism toencourage sharing of software pro-grams, ideas, and techniques. This is

TABLE 1. ARFTG Spring conference schedule.

Date Location Topic

69th June 2007 Honolulu Addressing Metrology Needs for Future High-Speed Information and Communication Systems

67th June 2006 San Francisco Design and Measurements of High Power Devices and Applications

65th June 2005 Long Beach Measurements for Millimeter-Wave Applications

63rd June 2004 Fort Worth On-wafer Characterization

61st June 2003 Philadelphia Measurement Accuracy

The last five ARFTG Spring Conferences have been colocated with and held on the Friday of MTT-S IMS Week. The main conference theme has covered a wide variety of topics.

TABLE 2. ARFTG Fall conference schedule.

Date Location Topic

68th December 2006 Boulder Measurement for Emerging Technologies

66th December 2005 Washington, DC Measurements of High Performance Devices and Applications

64th December 2004 Orlando Digital Communication System Metrics

62nd December 2003 Boulder Differential Measurements

The last four ARFTG Fall Conferences have been scheduled the week following Thanksgiving and include the ARFTG/NIST Measurement Short Course. The main conference theme has covered a widevariety of topics.


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very similar to the nonprofitstatus of the IEEE.

ARFTG MembershipThe ARFTG membership is abroad but eclectic mix of gov-ernment metrologists, acade-mic researchers, and indus-trial practitioners. There arecurrently over 600 membersof the ARFTG; about half aretechnical participants andhalf are exhibitor participantseven though many of themhave significant technicalexpertise. The ARFTG is aninternational organizationwith over one-third of itstechnical members from out-side the United States. Most internation-al members attend their first ARFTGconference as part of IMS week, butmany soon find the ARFTG experienceto be of significant value to their pro-jects. Annual ARFTG membership duesare only US$25 per year, and applica-tions are printed on every conferenceregistration form or can be found on theWeb site at www.arftg.org.

ARFTG MicrowaveMeasurement ConferenceThe ARFTG sponsors two conferenceseach year. These conferences are theprincipal and most important enter-prise of the organization and serve as

the focal point of the society’s activities.They bring together the membership,both technical participants and ven-dors, to discuss their common prob-lems, requirements, interests, needs,desires, and hopefully, solutions. Thesetechnical interactions occur during theformal oral presentations, as part of theinteractive forum, in discussions withthe vendors, and during informal dis-cussions over coffee and/or a meal.Conferences are conducted in a single-track workshop style with papers ontopical subjects both theoretical and/orpractical, instrument user and/or man-ufacturer, modeling and/or measure-ment. A formal digest consisting of all

of the conference papers ispublished and, since 2001,the ARFTG ConferenceDigest is also availablethrough IEEE Xplore. All ofthe conference digests fromthe 19th through the 58thconference are also availableon a single compilation CD-ROM, and all of the digestsare in the process of beingimported into IEEE Xplore.

The ARFTG Spring Con-ference is a single-day confer-ence cosponsored with theMTT-S and held on theFriday following the IMS.The conference starts with acontinental breakfast where

the attendees mingle with one anotheras well as with the vendors. The techni-cal presentations are conducted in a sin-gle-track workshop style, with amplebreaks to rehash the technical presenta-tions with the authors, to discuss testand measurement issues with col-leagues, to view the interactive forumpresentations, and to catch up on thelatest from the vendors. Lunch is also anawards banquet where the best paper,best poster, and best vendor from theprevious conference are acknowledged.

The ARFTG Fall Conference is techni-cally cosponsored with the MTT-S andheld during the week following theThanksgiving holiday. The activities

Oral technical sessions at ARFTG conferences are conducted in asingle-track workshop style with papers on topical subjects boththeoretical and/or practical, user and/or manufacturer, modelingand/or measurement. Shown here is the 61st conference inPhiladelphia in June 2003.

ARFTG international membership. Over one-third of ARFTG’s technical members are from outside of the United States.

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begin on Tuesday morning with theARFTG/NIST Measurement ShortCourse. This popular two-day course isan educational opportunity offered bythe ARFTG in cooperation with theNational Institute of Standards andTechnology. This course is taught in aseminar style and provides both anexcellent grounding in the fundamentalsas well as exposure to the latest in RF andmicrowave test and measurement tech-niques taught by the experts. Basic mea-surements are covered on the first day,including: a microwave measurementoverview, circuit theory, vector networkanalysis, test fixtures, on-wafer measure-ments, power, and noise. Additional in-depth topics are covered on the secondday, including: phase noise, load-pull,digital modulation, and time domaintechniques. Several tutorialsspecifically related to theconference theme are alsocovered on the second dayand change from conferenceto conference. This course isnot only for young engi-neers just starting out butalso for experienced engi-neers who want to refresh orbroaden their expertise. Theconference itself starts witha continental breakfast onThursday (and Friday)mornings, where the atten-dees mingle with one anoth-er as well as with the ven-dors. The technical presen-tations are conducted in asingle-track workshop style,with ample breaks to rehashthe technical presentationswith the authors, to discusstest and measurementissues with colleagues, toview the interactive forum,and to catch up on the latestfrom the vendors. Dinner onThursday evening is theawards banquet where thebest paper, best poster, andbest vendor from the previ-ous conference are acknowl-edged and the society’smajor awards—the ARFTGCareer Award, ARFTGTechnology Award, and/or

ARFTG Distinguished Ser-vice Award—are presented.

ARFTG BoardI would also like to takethis opportunity to ack-nowledge the volunteerswhose efforts and dedica-tion make the ARFTG pos-sible. (See Table 3.) Often,they perform thanklesstasks that take countlesshours, and their onlyreward is the satisfaction ofgiving back to an organiza-tion that helped themsometime in the past. Theboard of directors of theARFTG consists of 15 vol-unteers, each of whom iselected to a three-yearterm. The primary functionof the board is to organizethe two technical confer-ences, the ARTG/ NISTshort course, and work-shops and to publish theARFTG Digest. Note thatthe composition of the cur-rent board reflects theeclectic mix of the member-ship as five members aregovernment metrologists,three members are academ-ic researchers, and sevenmembers are industrialpractitioners.

Dylan Williams (left) receives his Best Poster Award and Kate Remely (center) receivesher Best Paper Award from Charles Wilker (right) for their presentations at the 61stARFTG Conference in Philadelphia in June 2003. The awards were presented in Boulderat the 62nd ARFTG Conference Awards Banquet.

TABLE 3. The ARFTG board.

President Greg BurnsNorthrop Grumman

Vice-President and Publicity Leonard HaydenCascade Microtech

Secretary Nick RidlerNational Physical Laboratory

Treasurer Ken WongAgilent

Exhibits Joe TauritzUniversiteit Twente

Education Dave WalkerNIST

Publications Brian PughQuorum Systems

Nominations Mo Sayed (retired)Agilent

Standards Bill EisenstadtUniversity of Florida

Electronic Communications Ron GinleyNIST

Membership Ray Tucker (retired)United States Air Force Research Laboratory

Technical Coordinator Tom RuttanIntel

Workshops Dominique SchreursKatholieke Universiteit Leuven

Awards Uwe ArzPhysikalisch-Technische Bundesanstalt

MTT-S Liaison Chip WilkerDuPont

The ARFTG board of directors is composed of 15 volunteers, elected by the ARFTG membership, eachof whom is elected to a three-year term.


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ARFTG and Technical InnovationsThe ARFTG has often served as a forumto bring together people from industry,academia, and government laboratorieswho share common test and measure-ment problems. The following are just afew of the many examples of RF andmicrowave test and measurement tech-nical developments in which theARFTG has played a pivotal role.

1) Vector Network Analysis:Vector network analyzer (VNA)-based measurement systems, theirautomation, their calibration, andtheir measurement theory havebeen a major focus of the ARFTGtest and measurement communityfrom the society’s inception in1972. At almost every conference,at least one technical session hasbeen dedicated to this topic. In1993, the ARFTG began offeringthe ARFTG/NIST MeasurementShort Course, which rapidlybecame the industry standard foran introduction to S-parameterand VNA measurements. Manynew RF and microwave test andmeasurement engineers are ex-posed to the ARFTG for the firsttime just for this reason, learn thevalue of the ARFTG experience,and become regular participants.Doug Rytting, who many considerthe father of the modern networkanalyzer, has taught this part ofthe workshop for many years andwas awarded the ARFTG Career

Award in 1998 for his many tech-nical (and service) contributions tothe ARFTG. The author found thecourse an excellent refresher andhis numerous conversations withDoug valuable to his own work.

2) Time Domain:Time domain measurements—forexample, TDR, TDT, and time gat-ing—have also been a major focusof the ARFTG test and measure-ment community from the veryearly days. These techniques areimportant to those working in themicrowave and/or high-speed

digital world. They allow for theisolation of discontinuities andremoval of adapter, cable, fixture,and test port match problems sothat one can focus on the actualdevice under test. There have beenmany time-domain papers atARFTG conferences and thus in thedigest archives. Harold Stinehelfer,who many consider the father oftime-domain transform measure-ments, holds the record for mostpapers presented at ARFTG confer-ences and was awarded theARFTG Career Award in 1989. Healso published MAMA’s Notes thatdescribed many techniques formaking better measurements usingthe time domain. Most of thesetechniques pioneered by Haroldare now incorporated into the soft-ware of most modern VNAs. Theauthor found MAMA’s Notes andhis numerous conversations withHarold valuable to his own work.For a photograph of Harold, seethe excellent article on the earlyhistory of ARFTG [1].

3) Microwave Probing:Microwave on-wafer probing, de-embedding, calibrations, andvalidity assurance of on-wafermeasurements have been anothermajor focus of the ARFTG test andmeasurement community. Most ofthe key developments for on-wafer measurements and on-wafer calibration standards werediscussed and published in theARFTG conference digests duringthe GaAs MMIC Defense Ad-vanced Research Projects Agency(DARPA)-sponsored era. Thecommercial wireless marketplaceas we know it today formed itsroots in this key industry pro-gram, and the IC measurementand calibration methodology usedtoday had its genesis in this earlyARFTG work. Today, much of themicrowave probing work has itsfocus in on-board probing forpackage and PCB characteriza-tion. Eric Strid, instrumental indeveloping practical and readilyavailable microwave probes andprobing techniques, has presented

The most stimulating part of the ARFTG experience is the opportunity to interact one-on-one with colleagues, experts, and vendors in the RF and microwave test and measure-ment community, here shown during the interactive forum at the 68th ARFTGConference in Boulder in December 2006.

Doug Rytting, father of the modern net-work analyzer and recipient of an ARFTGCareer Award in 1998, lectures about vec-tor network analysis and the trade-offsbetween the 8-, 12-, and 16-term error cor-rection models, at the ARFTG/NISTMeasurement Short Course. Doug educat-ed a generation of ATFTG test and mea-surement engineers about the proper oper-ation and idiosyncrasies of vector networkanalysis and calibration.


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many papers at the ARFTGthrough the years and was award-ed the ARFTG Technology Awardin 1987. Today, the ARFTG is in themiddle of the action with manypapers presented at recent confer-ences addressing on-board cali-bration techniques, measurementof packaged or PCB-mounteddevices, and modeling techniques.

4) Thru-Reflect-Line Calibration:Thru-reflect-line (TRL) calibra-tions have become the acceptedstandard for accuracy to which allother calibration techniques arecompared. The fundamental theo-retical work and methodologydeveloped by the NIST, universi-ty, and industry contributors hasbeen presented over the years atARFTG conferences, and many ofthe key reference papers arefound in the ARFTG digests.Roger Marks and Dylan Williams,who were awarded the ARFTGTechnology Award in 1994, andAndrea Fererro, who was award-ed the ARFTG Technology Awardin 2006, have made many techni-cal contributions on this topic tothe ARFTG through the years. Theauthor found access to the expertsessential to his work of calibratinghis cryogenic wafer probe station.

5) Large-Signal Network Analyzer:Large-signal network analyzers(LSNAs) are becoming an indis-pensable tool used to character-ize and understand the complex-

ities of the nonlinear behavior ofmodern microwave devices.This understanding is essentialto the efficient and effectivedesign of devices with improvedhigh-frequency performanceespecially at higher powers, e.g.,high power added efficiency(PAE) amplifiers. These devicesare an integral part of the explo-sion of the microwave and wire-less market and its myriad ofapplications. Much of the origi-nal work on the development ofthe instrument, the interpreta-tion of the measurement results,the development of calibrationtechniques, and the use of themeasurement data to createhigh-frequency nonlinear mod-els have been an integral part ofevery ARFTG conference for atleast the past decade. JanVerspecht, Marc VandenBossche, and Frans Verbeyst—the team that developed theLSNA—have presented much oftheir work at ARFTG confer-ences and were awarded theARFTG Technology Award in2002. In addition, the ARFTGhosts the NVNA (nonlinear vec-tor network analyzers) user ’sgroup. This informal discussiongroup is devoted to sharinginformation and issues related toinstrumentation utilized in theanalysis of microwave circuitsand systems that contain nonlin-

ear elements. Topics includelarge-signal measurements uti-lizing NVNAs—e.g., microwavetransition analyzers (MTAs) andLSNAs—as well as these mea-surements in conjunction withloadpull, sampling oscilloscopes,vector signal analyzers, andother test equipment used to per-form large-signal measurements.

ARFTG Microwave MeasurementStudent FellowshipAn important aspect of the mission of theARFTG is to promote and encourageyoung engineers to discover, explore, andultimately choose the field of RF andmicrowave test and measurement. TheARFTG Microwave MeasurementStudent Fellowship provides financialassistance to graduate students who showpromise and interest in pursuing researchrelated to the improvement of RF andmicrowave test and measurement tech-niques. Applicants must be enrolled asfull-time students at a suitably qualifiedinstitution of higher education and mustbe carrying out research as part of a degreeprogram rather than just performingcourse work. The proposed research pro-ject must clearly involve RF and/ormicrowave test and/or measurementtechniques and be supervised by a full-time faculty member. The faculty supervi-sor must be a member of the ARFTG, oralternatively, a member of the ARFTGmust cosponsor the proposal. One or moreawards of up to US$5,000 may be grantedeach year, based on available funding and

Eric Strid (right) receives his TechnologyAward from Ray Tucker (left) for hisadvancement of the state of the art inmicrowave device wafer probing at the29th ARFTG Conference in Las Vegas inJune 1987.

Greg Burns presents the TechnologyAward to Andrea Fererro for the develop-ment and implementation of VNA calibra-tion algorithms and nonlinear measure-ment techniques. The award was presentedat the 68th ARFTG Conference in Boulderin December 2006.

Dylan Williams presents the TechnologyAward to Jan Verspecht for the developmentof the LSNA at the 60th ARFTGConference in Washington, DC inDecember 2002. Jan shared this award withMarc Vanden Bossche and Frans Verbeyst.


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on the number and quality of applicationsreceived. For more information on theseawards, including how to apply for anaward, please visit the ARFTG Web site,www.arftg.org. ARFTG MicrowaveMeasurement Student Fellowshipawardees are strongly encouraged toattend an ARFTG conference to presenttheir work. One goal of the fellowship is toexpose students and their faculty advisorsto the ARFTG community in the hopesthat our enthusiasm encourages them andthat they might become active members ofthe society in the future.

ARFTG S-ParameterMeasurementComparison ProgramA common problem of any RFand microwave test and mea-surement laboratory is to assessthe certainty (or, just as impor-tantly, the uncertainty) of itsmeasurements. After calibratingyour VNA, have you ever won-dered if your calibration wasvalid? Have you ever been asked“How does one know that themeasured results are correct?” Itwould be nice if there were aneasy way to have confidence inyour measurements. As the com-plexity of a modern VNA systemincreases, the number of calibra-tion methods, the number ofconnector types, the number ofmeasurement points, and thenumber of applications such ason-wafer probing continues togrow. It is possible that one cor-rectly follows all of the proce-dures but still makes a bad mea-surement. Users need a way toverify that their VNA system,their calibration, and the mea-surement they have just madeare good and thus have confi-dence in their overall measure-ment processes. The most com-mon way that this is done is toprovide traceability of the mea-surement system back to a com-mon source, for example, anational laboratory. A better wayto do this might be to use theARFTG Measurement Com-parison Program.

Every metrology laboratory has theircollection of “gold” standard microwaveartifacts or devices that are used for cali-bration. Supposedly, the S-parameters(and the uncertainty of the S-parameters)of these devices are accurately known.Transferring these known values toanother calibration standard relies upon aproperly functioning VNA, a valid cali-bration, and a good measurement. Inpractice, one set of standards is used tocalibrate the instrument, which is thenused to measure the S-parameters of thenew set. This is how transfer standardsare created. Uncertainties in the “gold”

standards, malfunctions in the VNAhard-ware, errors in the calibration procedure,or poor or damaged microwave connec-tors can all yield nonrepeatable, nonvalid,and/or inaccurate measurements. Sohow can a metrology lab assess the “true”S-parameters of a microwave artifact ordevice? If the same artifact was measuredby numerous labs and the results com-pared, then one has the ARFTGMeasurement Comparison Program.

Making good, repeatable, accurate,and valid measurements on a modernVNA can be a daunting task. The ARFTGMeasurement Comparison Program is

designed to give a “snapshot”of your measurement capabili-ty. It is a free service offered bythe ARFTG which allows par-ticipating laboratories to com-pare their network analyzermeasurements to those ob-tained from other laboratories.Laboratory confidentiality isstrictly maintained. There aremany places to make mistakesor to take an inappropriateprocess step. The ARFTG MCPallows each metrology labora-tory to use its own equipment,calibration, and measurementmethods and offers participantsa chance to compare the perfor-mance of their measurementprocess to those of other partic-ipants. The only cost to a partic-ipant is the time spent makingthe measurements and the costof shipping the kit to the nextparticipant. Given the increas-ing emphasis on measurementassurance, this program pro-vides a valuable, cost-effectivemethod for validating the par-ticipant’s measurement capabil-ity. And so, now there is a wayto know! For more information,please see [2] or go to www.arftg.org.

References[1] R. Tucker, “The history of theAutomatic RF Techniques Group,”IEEE Microwave Mag., vol. 8, no. 4, pp.68–74, Aug. 2007.[2] R.A. Ginley, “Confidence in VNAMeasurements,” IEEE Microwave Mag.,vol. 4, no. 3, pp. 54–58, Aug. 2007.

Uwe Arz receives his Best Poster Award from the author forthe work he performed as the recipient of the first ARFTGStudent Fellowship. This award was presented at the 59thARFTG Conference in Seattle in June 2002. Uwe is now amember of the ARFTG board.

Bob Judish and Greg Burns receive their ARFTGTechnology Award for the development of the ARFTGMeasurement Comparison Program at the 62nd ARFTGConference in Boulder in December 2003. Bob received agolf club from the ARFTG in honor of his second careeras a golf bum, which he started shortly after his impend-ing retirement from the NIST.


the mtt-11 web page: a multitude of information resources ... · august 2007 107 last, but...

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