Techniques for precision high-frequency (RF to THz) characterization of electronic components, materials, and biological samples (Impact Case Study 2)
Submitting Institution
University of LeedsUnit of Assessment
Electrical and Electronic Engineering, Metallurgy and MaterialsSummary Impact Type
TechnologicalResearch Subject Area(s)
Technology: Communications Technologies
Summary of the impact
Research at the University of Leeds, in partnership with the US company
Agilent Technologies,
has directly resulted in the development of high performance vector
network analyzer
instrumentation used by electronics, aerospace and defence companies
globally to measure the
high frequency properties of electronic devices and materials. University
of Leeds research also
directly resulted in the development of two further Agilent Technologies
products — a high
frequency dielectric probe kit and a capacitance scanning probe
microscope. Agilent Technologies
confirms that the collective sales of these products are in the region of
tens of millions of dollars
annually since 2008.
Underpinning research
The University of Leeds has a long-standing collaboration with Agilent
Technologies (formerly
Hewlett Packard) dating back to 1981 when Professor Roger Pollard,
then lecturer in the School of
Electronic and Electrical Engineering, took up a consultancy position with
Agilent Technologies,
Santa Rosa, California. Pollard subsequently assumed an on-going R&D
consultancy role in the
company, visiting each summer, until 2010 when he retired from the
University and took up a
permanent, part-time, position with Agilent.
Pollard's research focussed on the study of solid-state devices and
circuits operating at microwave
frequencies, and in particular the development of techniques to measure
the high frequency
properties (from a few megahertz up to the terahertz frequency range) of
electronic devices and
materials. His research exploited vector network analyzers, which are used
to measure these high
frequency electronic properties — a high frequency signal is applied to a
device or material and the
output signal analyzed. Key characteristics, termed S-parameters, are
measured, which show
what proportion of the input radiation is absorbed and what is reflected
by the material or device-
under-test, and how this changes as a function of frequency.
A key focus of Leeds research since 1993 has been the development of new
algorithms to quantify
and extract background noise from S-parameter measurements. This research,
led by Pollard,
resulted in a theory for error correction and noise figure analysis in
1994. An algorithm was
developed using load pull measurements to establish very accurate
impedance and noise states,
working with Agilent to develop the mathematics to derive a noise figure
from these noise state
measurements [1]. These algorithms now underpin the operation of all
Agilent network analyzers,
including the PNA-X platform launched in 2008.
In 1997, Leeds researchers under Pollard reported a new way to measure
the high frequency
properties of materials without the need for the test material to have
integral electrical contacts.
Instead, an open-ended coaxial cable is placed on the surface of the test
sample [2]. Supported in
part by EPSRC award GR/K00783 (£114,320, 1994-1996), Pollard developed the
algorithms that
allow accurate extraction of the microwave frequency properties of
materials by this method
without needing to form any fixed waveguide on the material surface. The
results of this research
form the basis of Agilent's 8507E dielectric probe kit launched in 2009,
and the body of work to
date led, in part, to a major JIF/EPSRC award in 2001 (GR/M87535,
£2,188,383, 2001-2003),
which developed a 300 GHz microwave and millimeter-wave instrumentation
facility at Leeds.
In 2008, Pollard's group (now including Hunter who joined the
University from Filtronic in 1998)
developed the world's first substrate integrated waveguide sensor for
measuring microwave
properties of small volumes of liquid solvents [3]. This work (carried out
in part while Pollard's PhD
student, Saeed, was on a five month GRASS-ROOT internship at Agilent in
2008) formed the basis
for the development of Agilent's scanning capacitance probe microscope.
This is a modified
atomic force microscope, which not only produces topographical and
morphological images of a
surface — as is standard — but also provides information on the high
frequency dielectric properties
of the surface under examination, allowing doping maps of semiconductors
to be produced, for
example. The latter application has seen widespread sales of this
equipment across the
semiconductor sector, inter alia.
For his scientific and engineering contributions internationally, Pollard
was elected as an IEEE
Fellow in 1997. He served as president of the IEEE Microwave Theory and
Techniques Society
(MTT-S) in 1998, received the IEEE Third Millennium Medal in 2000, was
elected to a Fellowship
of the Royal Academy of Engineering in 2005, and received the MTT-S
Distinguished Service
Award in 2006. He was also a Fellow of the Institution of Engineering and
Technology.
Key researchers:
Roger Pollard (Senior Lecturer, 01/10/1985 - 31/07/1998; Professor,
01/08/1998 - 30/09/2010,
when he retired). Pollard also served as Head of the School of Electronic
and Electrical
Engineering (1999-2002), and inaugural Dean of the Faculty of Engineering
(2002-2010).
Ian Hunter (Senior Research Fellow, 01/08/1998-31/08/2001; Reader,
01/09/2001-31/05/2003;
and Professor, 01/06/2003-present).
References to the research
[1] C E Collins, R D Pollard, R E Miles and R
Dildine, `A new method for determination of
single sideband noise figure', IEEE Transactions on Microwave Theory
and Techniques 42,
2435-2439 (1994). DOI: 10.1109/22.339778.
[2] D V Blackham and R D Pollard, `An improved technique for
permittivity measurements using
a coaxial probe', IEEE Transactions on Instrumentation and Measurement
46, 1093-1099
(1997). DOI: 10.1109/19.676718.
[3] K Saeed, R D Pollard and I C Hunter,
`Substrate integrated waveguide cavity resonators for
complex permittivity characterization of materials', IEEE Transactions
on Microwave Theory
and Techniques 56, 2340-2347 (2008). DOI: 10.1109/TMTT.2008.2003523.
Leeds researchers in bold.
These outputs are all published in internationally leading peer-reviewed
archival journals, and are
recognised internationally in terms of originality, significance and
rigour. All three outputs underpin
the impact described in this case study.
Details of the impact
The underpinning University of Leeds research has had a direct and
substantial economic impact
during the review period through sales generated by Agilent Technologies.
Our research has also
had a broader impact through the companies within the electronics sector
that have bought the
Agilent Technologies instrumentation for the design and testing of new
products, which were
themselves released onto the market. Further impact has been generated
through the use of this
instrumentation in, for example, the metrology and standards industry.
The PNA-X platform, which is the microwave industry's highest performing
network analyzer in
terms of its noise performance and accuracy, together with portable RF
analyzers incorporating the
same technology (the FieldFox platform), are sold to the wireless,
aerospace and defence
industries and were all directly brought about by research at Leeds [A].
The results from the
research on noise measurement [1] were incorporated into the PNA-X
platform as an option from
2008. Customers include (but are not limited to) in aerospace and defence:
Northrop Grumman,
Astrium, Selex, Raytheon, multiple defence agencies; in
telecommunications: NSN, Ericsson,
Motorola; in computing: Cisco, Huawei, Intel; and, in microwave
electronics: Mini-circuits, Miteq,
and Filtronic (itself an earlier spin-out from the School). This work
contributed to Agilent becoming
a global leader in network analyzers, with a greater market share than all
other companies
combined. Owing to commercial sensitivity, Agilent is unable to provide
precise figures for sales of
its products, however, a senior Agilent executive confirms: "The
revenue from the noise figure
option to the PNA-X is in the tens of millions of dollars annually"
[A].
The algorithms described in reference [2] were incorporated into the
Agilent dielectric probe
measurement kit (model number 85070E) in 2009 [A]. The University of Leeds
related work with
Agilent on the extraction of material parameters from substrate integrated
waveguide cavity
resonators [3] led directly to the Agilent Technologies scanning probe
microscope range, with
models 5400 and 5600LS first brought to market in 2009. Specifically, this
work led to a new
modality being incorporated into this instrumentation (SMM mode), which
enables complex
impedance (resistance and reactance), calibrated capacitance, and
topography measurements
within the same instrument [A]. This microscopy modality outperforms
traditional AFM-based
scanning capacitance microscopy techniques, since it does not require any
contact between the
probe head and the sample. The instrument is now being sold routinely to
the semiconductor
industry for calibrated dopant density measurements on silicon wafers, as
well as to research
organisations worldwide [A]. Again, precise sales figures of the
dielectric probe kit and scanning
probe microscope range are not available for commercial reasons, but a
senior Agilent executive
states: "I can confirm that the key academic work on which these
developments were based was
published in two papers by Pollard and co-workers (References [2] and
[3]) ... The specific revenue
from these solutions is in the tens of millions of dollars annually"
[A]. Furthermore, "collective sales
of all these products (network analyzers, open-ended dielectric probes,
and scanning probe
microscope) have been in the region of hundreds of millions of dollars
per year" [A].
To give one example of the broader impact that University of Leeds
research has achieved through
the organizations that have bought Agilent Technologies instrumentation,
there has been
substantial impact in the metrology sector, with the network analyzers
being used by, for example,
the National Physical Laboratory (NPL) for accurate calibration of high
frequency instrumentation
[B]. Agilent's network analyzers, incorporating technologies developed at
Leeds as discussed
above, are now considered to be the industry standard for these
measurements - "we have
specifically chosen Agilent Technologies Network Analysers for the high
precision that they offer,
for their ability to offer state-of-the-art error correction routines,
and, for their ability to provide
implementations of the very latest measurement and calibration
techniques" [B]. NPL has also
confirmed that the availability of this Agilent Technologies
instrumentation has enabled them to
offer a wide range of measurement capabilities to its customers "that
have led to an income over
the period 2008-2013 of approximately £50M" [B]. The fan-out/impact
from the customer
calibration services also provides a major source of income for many
third-party laboratories
involved as links in the measurement assurance/traceability chain — for
example, one calibration
from NPL can validate tests made on many thousands of devices on many
industrial shop floors
and production lines [B].
This case study exemplifies how the School of Electronic and Electrical
Engineering at Leeds
adopts a long-term and sustainable approach towards ensuring the impact of
its research. Agilent
Technologies (and formerly Hewlett Packard) have sponsored 15 PhD students
in the School over
this on-going period of collaboration. Furthermore, the School has also
trained a number of
researchers who have taken up employment with Agilent, providing further
impact from the
research. Four current staff at the company obtained their doctoral
degrees through work
performed in collaboration with Leeds, under the supervision of Pollard.
The staff are: Mark
Pierpoint (PhD completed 1987), who is currently Vice President/General
Manager of the Software
and Modular Solutions Business section of Agilent; Loren Betts (PhD 2009),
an engineer
responsible for many of the Agilent's vector network analyzer products;
Dave Blackham (PhD
1999) who specializes in measurement uncertainties; and, Joel Dunsmore
(PhD 2004), an Agilent
Fellow developing measurement applications.
Sources to corroborate the impact
[A] Testimonial from a General Manager, Agilent Technologies, 1400
Fountaingrove Parkway,
Santa Rosa, CA 95403, 19 September 2012.
[B] Testimonial from the Lead Scientist (RF & Microwave Measurements
division), National
Physical Laboratory, Teddington, Middlesex, 9 September 2013.