SIB62 HF Circuits
Publishable JRP Summary Report for SIB62 HF Circuits
Metrology for new electrical measurement quantities
in high-frequency circuits
Background
The lack of traceability for newly developed instrumentation in the radio frequency (RF), microwave and
millimetre-wave areas of technology is a barrier to the development and trading of equipment in high value,
high impact fields - for example, medical, security, consumer electronics and environmental monitoring uses.
This project will develop the state-of-the-art in the measurement of waveguides, coaxial lines and printed circuit
boards (PCBs) that are critical components in these high-frequency systems and will use dissemination
techniques to deliver National Measurement Institute (NMI)-levels of traceability directly to the end-users. This
will be achieved by forming a Europe-wide consortium of NMIs from the JRP-Partners in this project.
Need for the project
Existing requirements coming from cutting-edge high-frequency industrial electronics applications have driven
test equipment manufacturers to develop new types of instrumentation. These new classes of instruments now
offer new types of measurement quantities and/or existing quantities that fall beyond the scope currently
supported by European (and other) NMIs and as a result end-user requirements for calibration and traceability
to the International System of units (SI) cannot be met.
New, applied, metrology is needed, to enable exploitation of these new instrumentation capabilities by
industrial end-users where lack of traceability has an impact on trading and the supply chain (e.g. in medical,
security, consumer electronics and environmental monitoring). The outcomes from this project will benefit all
sectors of the electrical and electronics industries involved in high-frequency devices and systems.
Many of these issues impact the progress indicated by the International Technology Roadmap for
Semiconductors (ITRS) and the roadmap compiled by the EURAMET Technical Committee on Electricity and
Magnetism (TC-EM). The JRP also aligns with broader European visions, as outlined in the Europe 2020
Strategy and echoed in the EURAMET 2020 Strategy, e.g. relating to flagship European initiatives such as “A
Digital Agenda for Europe”.
Scientific and technical objectives
New advanced techniques will be developed for implementing and disseminating measurement traceability to
users of metrology services – i.e. other NMIs, accredited laboratories, instrumentation manufacturers and endusers (in industry and academia). The project will achieve this by addressing the following key scientific and
technical objectives:
1. Traceability and verification techniques to support millimetre-wave and submillimetre-wave electronics
and electromagnetics in coaxial line (to 110 GHz) and waveguide (to 1.1 THz)
2. Traceability and verification techniques to support multi-port device configurations including the use of
electronic calibration units for Vector Network Analysers (VNA)
3. Traceability and verification techniques to support high-speed digital PCBs for Signal Integrity
applications, including differential transmission lines
4. Traceability and verification techniques to support large-signal / non-linear device characterisation
(e.g. high-power transistors and power amplifiers) and nano-scale devices (e.g. carbon-nano-tubes,
graphene-related electronics and organic macromolecules)
Report Status: PU
Public
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SIB62 HF Circuits
5. Input to the following European and International industry-level documentation:

a revised version of “EURAMET Guidelines on the Evaluation of Vector Network Analysers”, Guide
cg-12;

the development of IEEE standard P1785 for millimetre- and submillimetre-wave waveguides;

the revision of IEEE standard P287 for precision coaxial connectors at RF, microwave and
millimetre-wave frequencies;

input to an IEEE Special Interest Group that is reviewing documentary standardisation needs in
the area of defining nonlinear measurement quantities.
Expected results and potential impact
The primary outcome from this JRP will be the public availability of an extensive range of traceability services
for end-users that match the current capabilities of state-of-the-art measurement instrumentation, such as
VNAs. These services will enable all end-users to demonstrate traceability to SI for their measurements and
tests. This will enable end-users to be able to justify performance indicators (such as product specifications)
used in both scientific and commercial arenas. Progress to date on each of the scientific and technical
objectives in the JRP is summarised below:
1. Millimetre-wave and Submillimetre-wave Electronics and Electromagnetics
Significant extensions to the metrological traceability capabilities of several NMIs have been achieved.
Specifically, in coaxial line, traceability in the 1.85 mm connector type (that operates at frequencies up to at
least 65 GHz) has been achieved by PTB, NPL and LNE, and, traceability in the 1 mm connector type (that
operates at frequencies up to at least 110 GHz) has been achieved by PTB and METAS. In rectangular
waveguide, LNE and PTB have performed traceable measurements in WR-06 waveguide (110 GHz to 170
GHz); NPL, PTB and REG(ULE) have performed traceable measurements in WR-05 waveguide (140 GHz to
220 GHz); PTB have performed traceable measurements in WR-03 waveguide (220 GHz to 325 GHz) and
NPL and REG(ULE) have performed similar traceable measurements in WR-01 waveguide (750 GHz to 1100
GHz).
In both coaxial line and waveguide, the measurements have been of one- and two-port devices, providing
reflection coefficients (for the one-port devices) and all four S-parameters (forward and reverse reflection and
transmission) for the two-port devices. In all cases – coaxial line to 110 GHz; waveguides from 110 GHz to
325 GHz, and, from 750 GHz to 1100 GHz – these are state-of-the-art capabilities that put Europe at the
forefront of millimetre- and submillimetre-wave metrology. In addition, five papers describing most of this work
have been written and submitted in recent months.
2. Multiport Devices and Electronic Calibration Units (ECUs) for Vector Network Analysers
For the work on multi-port VNA calibration techniques, NPL has undertaken a series of comparisons between:
(i) full 4-port calibrations and multiple 2-port calibrations; and (ii) full 4-port calibrations and so-called ‘quick’
calibrations (such as Q-SOLT). A paper describing the outcomes from these comparison exercises will be
submitted for publication shortly.
Candidate methods for monitoring the operational status of ECUs have been developed by SP and NPL. In
addition, large amounts of data have been gathered by METAS, SP and PTB concerning the stability of these
ECUs over short time periods (of minutes and hours), and, over long time periods (of months and years). The
outputs from both these activities are contributing substantially to the overall knowledge base relating to the
operational performance of these devices. These ECUs are being used extensively by many European
calibration and test facilities and so this new knowledge should make a significant impact on this end-user
community for many years to come.
3. High-speed Digital Printed Circuit Boards (PCBs) for Signal Integrity Applications
Designs for both balanced and unbalanced calibration standards on PCBs have been developed by LNE, CMI
and NPL. An investigation has been made by PTB into the effect of asymmetries in the conductor lines of
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SIB62 HF Circuits
differential transmission lines on S-parameter measurements. A report has been issued describing the
outcomes from this investigation. In a separate (but related) activity, the design of a reference PCB has been
completed. The reference PCB has now been fabricated based on this design. The design includes knowledge
and research input from many of the project partners: NPL, LNE, CMI, PTB, R&S, REG(FVB) and REG(CTU),
as well as a visiting researcher to NPL from KRISS (the South Korean National Metrology Institute). The work
that was contributed by REG(CTU) (on radiation effects from interconnects) has since been published and
presented at a recent IEEE/ARFTG Microwave Measurement conference (in Phoenix, Arizona, USA, in May
2015).
4. Large-signal / Non-linear Devices and Nano-scale Devices
In the work relating to large-signal devices, two stages of prototype reference device design have been
completed. These devices are intended to be used for verifying the performance of Large Signal Network
Analysers (LSNA) and Nonlinear Vector Network Analysers (NVNA). To date, two devices have been
designed, fabricated and tested by REG(KU Leuven), with assistance from NPL and Keysight Technologies,
Belgium. The 2nd generation device outperforms the earlier design as it is insensitive to harmonics at the input
and mismatches at the output, occurring at the same time. Long term tests, by NPL, demonstrated good
stability for the device to nonlinear waveforms over significant time periods.
In the work relating to nano-scale devices, REG(CTU) and CMI have designed, fabricated and characterised
a range of extreme impedance standards (suitable for both calibration and verification). These standards can
be used to calibrate a measurement system (such as a VNA) so that it is optimised for performing
measurements of devices with intrinsic impedance values much greater than the usual system reference
impedance of 50 ohms. This is particularly relevant to carbon-based devices (e.g. devices comprising CNTs
and/or graphene) that can be used in high-frequency electronics applications. The extreme impedance
standards are now being tested at NPL using conventional VNA measurement techniques. This is helping to
demonstrate the versatility of these devices under a wide range of operating conditions (i.e. both conventional
and extreme impedance scenarios).
5. European and International Industry-level Documentation
Formats for representing sets of multiple complex-valued S-parameter data have been established, by PTB
and METAS, and these have been used, by LNE and NPL, to develop a procedure for propagating data through
measurement equations during the evaluation of the measurement uncertainty. In addition, work has been
undertaken on developing verification schemes for S-parameter measurements at frequencies up to 110 GHz.
Much of this work has been undertaken by METAS, with support from NPL, PTB and VSL. Artefacts for
verifying measurements of high dynamic range devices have also been tested in waveguide to 220 GHz by
PTB, NPL and the University of Leeds.
A report (written by METAS, PTB and VSL) has been submitted to the IEEE P287 standard Working Group,
summarising the investigations undertaken in the JRP into performance characteristics of precision coaxial
connectors. These investigations were based on a mechanical parameterisation of all connector families and
subsequent electromagnetic modelling. The findings and conclusions from these investigations will be
incorporated into the revision that is taking place of the IEEE P287 standard (which is the global ‘industry’
reference for connectors of this type). Similarly, a document (based on a recent conference paper) has been
submitted to the IEEE P1785 standard Working Group providing performance indications for waveguide
devices operating to 1100 GHz. The information in this document is likely to impact two of the new IEEE
standards that this Working Group is currently developing: 1785.2 “Waveguide Interfaces” and 1785.3
“Uncertainty Specifications”. In addition, a draft continues to be developed of a revision to the “EURAMET
Guidelines on the Evaluation of Vector Network Analysers (VNA)”, Guide cg-12. This draft should be available
for public review and comment early in 2016.
Creating Impact
Links to the end-user community have been maintained and strengthened by:
(i)
Regular six-monthly teleconferences, throughout the JRP lifetime, with the project’s Stakeholder
Advisory Group (SAG). This Group consists of 6 international experts in the scientific areas being
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SIB62 HF Circuits
addressed in this project. These teleconferences are used to bring in expertise from the SAG to
help inform discussions that take place amongst the project partners (e.g. on how best to achieve
the technical deliverables in the JRP).
(ii)
Maintaining a JRP web-site (www.hfcircuits.org), a LinkedIn Discussion Group and a list of
attendees at the JRP public events (i.e. training courses, workshops and European ANAMET
technical seminars – see below).
(iii)
Running two training courses, for external clients, on: (i) “Good Practice with VNAs”, which was
given at VSL, The Netherlands, in June 2014; and (ii) “Multiport VNA Measurements”, which was
given at METAS, Switzerland, in June 2015. Both courses involved several of the JRP participants
as instructors and were attended, on both occasions, by approximately 40 participants.
(iv)
Delivering three workshops, for external clients, on: (i) “Electronic Calibration Units”, which was
given at SP, Sweden, in December 2013; (ii) “Plans and Considerations for the Upcoming Revision
of the EURAMET VNA Calibration Guide”, which was given at PTB, Germany, in December 2014;
and, (iii) “Uncertainties for VNA Measurements”, which was given at LNE, Paris, France, in
December 2015. All three workshops included presentations given by several of the JRP
participants and were attended, on each occasion, by approximately 40 participants.
(v)
Organising five European ANAMET technical seminars featuring presentations describing the
technical outputs from the JRP. These seminars were run on the same dates and at the same
venues as the above training courses and workshops.
(vi)
Participating in standards development meetings. In particular, the IEEE P287 ‘coaxial connector’
working group meetings and the IEEE P1785 ‘waveguide’ working group meetings. These
meetings have taken place at various locations in the USA in November 2013, May 2014,
November 2014, May 2015 and November 2015. In addition, there has been participation by the
project partners in two new IEEE standards-making activities: P370 “Electrical Characterization of
Printed Circuit Board and Related Interconnects at Frequencies up to 50 GHz”; P1770
“Recommended Practice for the Usage of Terms Commonly Employed in the Field of Large-Signal
Vector Network Analysis”.
(vii)
Publishing scientific papers. To date, there have been 40 submitted publications in the scientific
literature resulting from the work achieved in this JRP.
JRP start date and duration:
June 2013, 3 years
JRP-Coordinator: Nick M. Ridler, NPL, UK
Tel: +44 208 983 7116
JRP website address: http://projects.npl.co.uk/hf-circuits/
E-mail: [email protected]
JRP-Partners:
JRP-Partner 1 NPL, UK
JRP-Partner 2 CMI, Czech Republic
JRP-Partner 3 EJPD, Switzerland
JRP-Partner 4 LNE, France
JRP-Partner 5 PTB, Germany
JRP-Partner 6 SP, Sweden
JRP-Partner 7 VSL, Netherlands
JRP-Partner 8 AGILENT, Denmark
JRP-Partner 9 R&S, Germany
REG-Researcher 1:
(associated Home Organisation):
Karel Hoffmann
CTU, Czech Republic
REG-Researcher 2:
(associated Home Organisation):
Dominique Schreurs
KU Leuven, Belgium
REG-Researcher 3:
(associated Home Organisation):
Roland Clarke
ULE, UK
REG-Researcher 4:
(associated Home Organisation):
Franz Josef Schmückle
FVB, Germany
The EMRP is jointly funded by the EMRP participating countries within EURAMET and the
European Union
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