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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 60, NO. 11, NOVEMBER 2011
3669
Thick-Film Ceramic Strain Sensors
for Structural Health Monitoring
Saad A. A. Jabir and Naren K. Gupta, Senior Member, IEEE
Abstract—Structural Health Monitoring represents one of the
primary field applications for new sensor technologies. Different
kinds of sensors to monitor stability anomalies of civil structures
are deployed on different kinds of building materials. Observation
of stability must be durable and reliable for the lifetime of a structure. This paper is part of a research to investigate the possibility
of application of thick-film (TF) piezoresistive sensors on building
materials for the scope of monitoring structure’s stability and
conditions of load. As a first approach toward this objective, TF
piezoresistive sensors will be used like metal-foil strain gauges on
two different building materials, namely brick (clay) and concrete.
A boosted Wheatstone bridge interface circuitry will be proposed
and simulated with a Saber simulator. Thick film ceramic sensors
(TFCS) will be applied on red brick and concrete to investigate TF
response proportionality and linearity when applied on these two
kinds of building materials.
Index Terms—Hybrids, piezoresistive, Saber, sensors, simulation, strain, stress, Structural Health Monitoring (SHM), thick
film (TF).
I. I NTRODUCTION
I
N ORDER to monitor the health of large structures such as
highways, bridges, buildings, and dams, the outputs from
various kinds of sensors, which are positioned at different
places of structures, should be collected simultaneously and/or
sequentially [1]. Sensors could be of different nature and for
measuring different physical entities. The most relevant entity
to observe when monitoring the health of a structure is the strain
due to material deformation. Strain indicates the load or load
variation at the points where these sensors are located.
The common way of measuring strains on structures is by
applying foil film strain gauges [2], widely known as strain
gauges. A myriad of shapes and configurations of such foil
strain sensors suitable for force and torsion measurements
on various structure geometries are commercially available
[Fig. 1(a)]. On the other hand, the application of thick-film
(TF) sensors (TFSs) is a well-consolidated technology that has
been used for many years to build pressure transducers, as in
Fig. 1(b). Certain TF pastes placed on a ceramic substrate with
Manuscript received November 22, 2010; revised March 15, 2011; accepted
March 16, 2011. Date of publication June 2, 2011; date of current version
November 9, 2011. The Associate Editor coordinating the review process for
this paper was Dr. Jesús Ureña.
S. A. A. Jabir is with Synopsys GmbH, D-85609 Munich, Germany (e-mail:
[email protected]).
N. K. Gupta is with the School of Engineering and the Built Environment,
Edinburgh Napier University, EH10 5DT Edinburgh, U.K.
Color versions of one or more of the figures in this paper are available online
at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TIM.2011.2138310
a conventional silkscreen technique have a piezoresistive effect,
i.e., will change in resistor value with strain developed on the
ceramic substrate.
The TF technology is the same technology used to build
hybrid circuits. It was developed during the fifties and was
considered as a replacement of printed circuit technology to
provide mechanical assembly support for electronic circuits.
A TF circuit comprises of layers of special inks or pastes
deposited and fired onto an insulating substrate. The ink is
composed of various metals, oxides, and ceramic and glass
powders suspended in an organic vehicle. TF components make
conductive, resistive, capacitive, and dielectric film patterns
on a substrate surface. Deposition of the ink on the substrate
surface is by screen printing through stainless-steel masks.
The deposited inks are then fired in a kiln with predefined
temperature profile. The steps to produce TF piezoresistive
sensors are the same as those to produce hybrid circuits [3].
In the 1960s and with the advent of resistors built with this
technology using certain pastes, the piezoresistive effect was
observed and used to build TF stress sensors.
Table I highlights the main characteristics of TF strain
sensors with respect to metal-foil and silicon strain gauge
sensors. The combination of relatively high gauge factor (GF)
and good temperature stability in addition to mass production
capability and low cost are the major factors that justify the
implementation of this technology to build reliable force and
pressure sensors in general.
TFS technology for measuring force related to deformation
is applicable in automotive, industrial, medical, and sport apparatus fields. Long-term stable TF pressure transducers are
commercially available. TF materials are known for their survival, longevity, and reliability in harsh environments, extreme
temperatures, and high mechanical stresses, such as those
present in automotive applications [4]. This fact makes TF
technology a good candidate for civil engineering applications.
TF hybrid technology responds to the needs of civil and industrial structures of different kinds of sensors to measure various
physical and environmental entities relevant to building security
monitoring like temperature measurement [5]–[7] and chemical biosensors [8]. An important topic in Structural Health
Monitoring is the power supply for the intelligent sensors. The
supply is necessary to drive electronics and the networking
to monitor a structure during its life, which might last for
tens of years. It is well known that cadmium sulfide can be
screen printed and sintered to form films that display photosensitivity. Photoconductive sensors based on screen-printed
cadmium sulfide and cadmium selenide thick films printed
over standard silver–palladium conductors are feasible. Simple
0018-9456/$26.00 © 2011 IEEE
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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 60, NO. 11, NOVEMBER 2011
Fig. 1. Examples of (a) metal film strain gage and (b) Ceramic pressure membranes.
The linearity and proportionality of response with material
modulus of elasticity, for the first deployment method, will be
discussed and experimented in this paper.
IV. BASICS OF S TRAIN G AUGE C ONCEPTS
AND R ELATIONSHIPS
For the first deployment method, like foil-metal strain
gauges, TFCS obeys
R = ρ (L/A).
(1)
Fig. 2. Single piezoresistive TFS.
photoconductive arrays and a potentiometric position sensor
have been fabricated with TF technology [9]–[11].
Substrates made of ceramic material or steel have outstanding mechanical and thermal properties, which make them adequate to have stable electronic circuits on the one hand and to
withstand harsh environmental conditions on the other.
II. S AMPLE P REPARATION
For the purpose of the investigation for the deployment of
TFSs on building materials, a single TF resistor was developed
on 0.3-mm-thick 96% alumina substrate (AL2 O3 ), as shown in
Fig. 2.
The piezoresistor aspect ratio, W : L, was 1.3. The paste
used was DP2041 with a GF of 10. This paste is widely used
for TFSs. Sheet resistance was 10 kΩ/. The resistance value
obtained was in the range of 7.2–8 kΩ with a medium value of
7.5 kΩ.
In general, if the effect of all variables on the resistor is
considered
ΔR
Δρ ΔA ΔL
=
−
+
.
(2)
R
ρ
A
L
In this context, ΔL/L is the strain and ΔA/A = −2νε in
an isotropic material stressed within its elastic behavior and
characterized by a Poisson’s ratio ν [12].
Accordingly, the following relationship is obtained:
ΔR
Δρ
GF =
=
+ 1 + 2ν.
(3)
RC
ρC
The GF is dependent on two terms, one is due to change in
resistivity with strain and the other is for geometrical alteration.
Solids may have a Poisson’s ratio ν of 0.2–0.45. Hence, even
if the term dependent on resistivity of the material is nil, the
geometrical contribution will give rise to a GF of 1.5–1.9.
The GF for TF piezoresistive sensors ranges from 2 to 35, as
indicated in Table I.
V. C ONSIDERATION OF THE E LECTRONIC I NTERFACE
III. D EPLOYMENT M ETHODS
The sample sensor was deployed on structures in three ways.
1) Glued on the material surface like a common foil strain
gauge. The force in this case acts parallel to the sensor
surface, as in Fig. 3(a).
2) Similar to 1) with force perpendicular on sensor surface
[Fig. 3(b)].
3) Embedded in the material, as in Fig. 3(c), where the
sensor is mounted on a printed circuit board or ceramic
substrate in surface mount technology (SMT).
For each of these methods of deployment, the TFS exhibits a
different GF.
The quarter Wheatstone bridge of Fig. 4 has one TF resistor,
R + ΔR, changing with strain. After balancing the bridge i.e.
Vo = VAB = 0, the applied stress on the TF sensor will change
VAB as in (4) below: Vo is
ΔR
V
×
.
(4)
Vo =
4
R
From (3), the change in resistance to axial strain is ΔR/R =
GF C; hence
V · C · GF
(5)
Vo =
4
1
4Vo
C=
×
.
(6)
V
GF
JABIR AND GUPTA: THICK-FILM CERAMIC STRAIN SENSORS FOR STRUCTURAL HEALTH MONITORING
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TABLE I
COMPARATIVE CHARACTERISTICS OF STRAIN GAGE TYPES [12]
Fig. 5. Operational amplifier as current source.
strain. The TF (R_TF) sensor is placed as a feedback resistor
of the operational amplifier.
The current through R_current is
I=
Fig. 3. TF force sensor deployment methods. (a) On material surface.
(b) Direct load application on sensor surface. (c) Embedded in building
material.
V ref
.
R_current
(7)
The change in R_TF will be a change in the voltage across
it, and consequently, the op-amp output voltage Vo will change
following
ΔVo = I × ΔR_TF.
(8)
Equation (9) results from dividing both sides of (8) by R_TF
ΔR_TF
ΔVo
=
.
I × R_TF
R_TF
(9)
To be able to compare (5) with (9), I ∗R_TF is replaced by the
excitation voltage V , i.e., the maximum output voltage swing
Vo
ΔR
=
.
V
R
(10)
ΔR
V.
R
(11)
Hence
Vo =
Fig. 4.
Wheatstone bridge circuit.
This equation relates mechanical strain measurement to the
bridge unbalance voltage (Vo ). Excitation voltage (V ) and
gauge factor (GF ) are considered constants.
Alternatively, the simple inverting operational amplifier in
Fig. 5 can be used to increase output voltage variation with
The higher is the current, the more is the voltage variation
with strain. However, the current must be as high as that allowed
by the amplifier dynamic range; thus, I ∗R_TF is almost the
excitation voltage V . Output voltage swing is a function of the
op-amp technology. Certain CMOS op amps have rail-to-rail
output swing capability.
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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 60, NO. 11, NOVEMBER 2011
Fig. 6. Wheatstone bridge voltage amplified by an instrumentation amp.
Fig. 7. Vout versus TF Rt1 change. ΔY should be divided by ten.
From (3)
Vo = V · GF · C.
(12)
This equation relates mechanical strain measurement to the
op-amp output voltage (Vo ). Excitation voltage (V ) and gauge
factor (GF ) are considered constants.
Comparing (5) with (12), it is obvious that for the piezoresistive change with strain of one single sensor resistor, the output
voltage swing in the op-amp configuration is four times bigger
than the common quarter Wheatstone bridge setup at the same
excitation voltage.
A. Verification by Simulation
To verify the derived mathematical conclusion before deploying the op-amp solution in real measurements, the two
solutions were simulated with Saber simulator. The convention
used in the circuitry is by having TFS resistances in compression denoted by Rc while those in tension are denoted by Rt .
The full Wheatstone bridge of Fig. 6 shows four mechanically excited TF resistors. Resistors in the bridge are marked
Rt for resistors in tension and Rc for resistors in compression.
Those resistors must be positioned on the structure under test
in a way to be excited mechanically in an opposite sense to
enhance the signal output product.
To verify the quarter bridge as in (4), only resistor Rt1
will be varied. The TF typical initial value resistance will be
assumed 7500 Ω similar to the manufactured sample’s typical
value. A GF of ten for a maximum strain of 1000 μstrain, which
is approximately the maximum allowed strain for alumina [13],
will produce maximum amount of piezoresistance change of
1%, i.e., 75 Ω. Counting for overload and tolerances, the circuit
was simulated with Saber simulator, assuming a change of dr
from 0 to 100 Ω in steps of ten.
The instrumentation amplifier has a fixed gain of ten. During
simulation cycles, the instrumentation amplifier (LT1101) gives
an immediate reading of the voltage difference across the bridge
and it is actually of the type that was used in the experiments.
Fig. 8.
TFS resistor in op-amp LMC6482 configuration.
Transient analysis simulation of the circuit was setup for
100 μs.
Fig. 7 shows the output voltage on the waveform viewer of
Saber named cosmoscope. In the plot, there is one waveform
for each value of Rt1 .
The maximum obtainable voltage, ΔY can be seen from the
measurement on the waveform to be = 0.397/10 = 0.0397 V.
The division by ten is for the LT1101 amplifier fixed gain
of ten.
The same single TF resistor is made to change in a rail-torail operational amplifier configuration, as shown in Fig. 8. The
amplifier is of type LMC6482 (CMOS rail-to-rail op amp). A
current of (11 V/7500 Ω) A flows through the TF feedback
resistor. With the change of R_TF by ΔR, the output remains
in the allowed linear amplifier dynamic range.
Simulation for 100-μs result with Rt1 changing in steps of
10 Ω is shown in Fig. 9. The measured voltage change ΔY =
0.14666 V.
The ratio of the op-amp configuration to the quarter bridge
configuration is thus
0.14666
V (op − amp)
=
= 3.69.
V (bridge)
0.039
(13)
JABIR AND GUPTA: THICK-FILM CERAMIC STRAIN SENSORS FOR STRUCTURAL HEALTH MONITORING
Fig. 9.
Output of op-amp with Rt1 stepping by 10 Ω.
Fig. 10. Op-amp-driven Wheatstone bridge.
This is almost four times the Wheatstone bridge interface
circuit. The result is similar to the mathematical derivation.
However, a higher value can be achieved by increasing the
current as long as the maximum allowed output voltage swing
of the chosen op-amp type is not exceeded.
In Fig. 9, the small output voltage change is offset by 11 V
from zero, while the waveform in Fig. 7 swings to almost 0.4 V
from zero.
One of the advantages of Wheatstone bridge is its elimination
of the offset by having two branches or two voltage dividers
that when subtracted, the difference is almost at zero level.
This differential mode of functionality eliminates all nondesired
common signals like noise and dc voltage. In addition, by using
similar elements on opposite sides of the bridge, temperature
drift of the sensors can be significantly reduced.
To collect the advantages of both solutions, the circuit in
Fig. 10 was simulated with a Saber simulator to examine the
output voltage maximum swing with 1000 μstrain applied on
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Fig. 11. Op-amp-driven Wheatstone bridge max output voltage swing.
all four bridge resistors Rt1 , Rt2 , Rc1 , and Rc2 . Rt1 and Rt2
are supposed to be under tension, hence increasing, and Rc1
and Rc2 are supposed to be contemporarily under compression,
hence decreasing. ΔR changes in steps of 10 Ω.
A maximum voltage change of 5.3 V can be observed at the
instrumentation amplifier output, as shown in the waveform
of Fig. 11. The differential amplifier removes the dc offset
voltages at op-amp outputs; thus, its output swing starts from 0
to 5.3 V. The noise and temperature drift of the sensors will be
also canceled by the differential final stage. This way, besides
signal mitigation by using op amps, the advantage of having a
differential output is maintained.
The transfer function of the circuit in Fig. 10 after letting the
(ΔR/R)2 term to zero is
ΔR
(14)
Vo = 4Vr G ×
R
where
Vr input reference voltage (10 V in the figure);
G instrumentation amplifier gain (set to ten);
R nominal TF resistance value;
ΔR change in resistance due to strain.
It should be noticed here that the final output is a multiplication of a dc reference voltage and instrumentation amplifier
gain (i.e., Vr × G).
VI. A PPLICATION OF TFS ON B UILDING M ATERIALS
In the circuit in Fig. 10, even if sensors are under the same
mechanical excitation, they could be placed appropriately in
the right place in the circuit to sum the effect at the output.
In other words, it is possible to use the two resistor sensors in
compression only while the sensors in tension are replaced with
fixed resistances.
The circuit in Fig. 12 is the same previous circuit with minor
practical modifications.
One important addition is the offset balance input amplifier.
TFSs are usually of different resistance values so the voltage
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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 60, NO. 11, NOVEMBER 2011
Fig. 12. Differential amplifier with offset balance.
output would be always out of zero. By varying V _DAC, the
instrumentation amplifier output could be reset to zero before
starting the test. The balance amplifier will alter the current in
Rc2 to make V2 equal to V1 .
This circuit was connected to LABVIEW on a personal computer through an interface POD named DAQPad-1200. This
later has eight A/D converter inputs and two DAC outputs, one
of which was used to zero the instrumentation amplifier output.
The instrumentation amplifier LT1101 offers the possibility to
set the gain externally, either to 10 or to 100. The analog
switch DG201 was used to eventually increase the gain to
100. The analog switch control is from LABVIEW through
DAQPod1200 the Gain_control digital output pin.
To verify applicability of TFSs on different building materials and to evaluate their response as a function of the different
materials, a test was done on the sample brick of dimensions
12.4 × 16.7 × 34.7 mm [Fig. 13(a)] and sample concrete of
dimensions 23.3 × 22.3 × 50 mm [Fig. 13(b)].
The aim of the test was to verify the following:
1) the applicability and functionality of TFSs on concrete
and bricks like foil-metal strain gauges;
2) to test the circuit and examine the possibility of adding
the effect of two adjacent sensors glued on the same
side of a structure and that the linearity is maintained,
i.e., if Y1 = f (x1 ) and Y2 = f (x2 ), then Y1 + Y2 =
f (x1 + x2 );
3) the output entity and the proportionality of response of
TFSs as a function of the material modulus of elasticity
when applied to different materials like, in the specific
case, red brick and concrete.
The two TFSs were glued to the two samples with a twocomponent epoxy adhesive and were put in the locations
indicated by Rc1 and Rc2 on the schematic. The other resistors
Rt1 and Rt2 were replaced with a fixed resistor, as shown in
Fig. 12.
The transfer function equation of the circuit is
Rc1
Rt2
−
×G
(15)
V out = Vr
Rt1
Rc2
where Vr = 10 V and Rt1 = Rt2 = 7500 Ω.
Fig. 13.
block.
(a) Sample brick of 12.4 × 16.7 × 34.7 mm. (b) Sample concrete
Fig. 14.
Concrete block sample stressed on a linear scale.
VII. E XPERIMENTAL R ESULTS
A. Experiment Overview
The brick and concrete samples were put one at a time under
pressure against an electronic linear scale in a bench vice, as
shown in Fig. 14. The load was increased step by step up to a
100 kg load.
Here, are the experimental steps.
1) The response of one single sensor at a time was considered first on the red brick sample.
2) The response of both sensors in compression at the same
time on the red brick was then registered.
3) The mathematical sum of the two sensors compressed
singularly was compared with the experimental result of
both sensors compressed contemporarily.
JABIR AND GUPTA: THICK-FILM CERAMIC STRAIN SENSORS FOR STRUCTURAL HEALTH MONITORING
3675
Fig. 18. S3 and S4 responses versus compressive force on concrete.
Fig. 15. S1 response versus compressive force.
Fig. 19. TFSs response on red brick and concrete.
Fig. 16. S2 response versus compressive force.
Fig. 17. S1 and S2 responses versus compressive force on brick.
4) The response of both sensors in compression at the same
time on the concrete sample was then registered.
5) A comparison of the TF response of the two sensors on
both samples was then considered based on the difference
in the two materials elasticity modulus.
B. Linearity of Response
Step 1: Fig. 15 shows S1 response with S2 replaced by a
fixed resistor of 7500 Ω.
Fig. 16 shows S2 response with S1 replaced by a
fixed resistor of 7500 Ω.
Step 2: Fig. 17 shows the response of both S1 and S2 under
mechanical compressive stress at the same time.
Step 3: From the linear equations of the responses of S1
and S2 , it is clear that the sum of the two equations
will produce the equation of the experimental sum in
Fig. 17, i.e., 0.4005x + 0.5538x = 0.9543 x.
C. Proportionality of Response
Step 4: Fig. 18 shows the responses of other TFSs S3 and S4
on concrete block.
Step 5: Fig. 19 shows the response of TFSs on the brick
and concrete blocks put on the same graph for
comparison.
The sensor used to measure strain on material should have a
response consistent with different materials under test. Following is the proof from the measurement curves of Fig. 19.
If we consider Hook’s law E = σ/C and apply this on the
two samples, red brick and concrete, where c = concrete and
b = brick
σ
Ec =
(16)
∈c
σ
Eb = .
(17)
∈b
By dividing (16) by (17) and considering the application of
the same force change on both samples
Ec
=
Eb
ΔF
Ac ×∈c
ΔF
Ab ×∈b
=
Ab × ∈b
.
Ac × ∈c
(18)
Since the output voltage is linearly proportional to strain and
the applied ΔF for the two samples is the same
Ec
Ab × ΔVb
=
.
Eb
Ac × ΔVc
(19)
Considering the coefficients in the generated equations from
the curves in Fig. 19 for the same 100 kg force change and
substituting the values for the different sample areas, i.e., Ab =
205 mm2 and Ac = 545 mm2
Ec
205 × 0.9476
= 1.4524.
=
Eb
545 × 0.2454
(20)
To evaluate the left side of (20), the elastic moduli of brick
and concrete need to be substituted. From [7], the concrete
elastic modulus depends on the ratio of sand to aggregate (S/A)
and it varies from 22 to 25 k · N/mm2 . The sample under test
has almost no aggregate, and hence, the modulus is around
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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 60, NO. 11, NOVEMBER 2011
22–23 k · N/mm2 ([7, p. 11, Fig. 5]). The experimental modulus
of elasticity of red brick is around 15 k · N/mm2 [14]. Hence
Ec
22 000
= 1.466.
(21)
=
Eb
15 000
The reason for the small difference is due to a) the different
sensors which have been chosen randomly from a production
lot. b) Exact modulus of elasticity of the samples, which could
be different from the values considered in the calculation. However, result shows that response is consistent and proportional
with material elastic modulus.
VIII. S UMMARY AND D ISCUSSION
This paper has examined the applicability of TF piezoresistive sensors on building material. For this purpose, a generic
TFCS has been manufactured and used to investigate the possibility of its application on building materials. The designed
sensor suits different deployment methods: 1) glued on the
material with force parallel to the sensor surface; 2) glued on
the material with force perpendicular on the sensor surface; and
3) mounted in surface mounting technology (SMT) on PCB to
be embedded in the material.
The paper has examined the linearity and proportionality of
the sensor response for the first deployment method. As interface circuitry, an op-amp-boosted Wheatstone bridge has been
verified to give better output response. Simulations proved the
mathematical conclusion. This interface circuit has then been
used to verify linearity and proportionality of response of TF
piezoresistors on two kinds of building materials, namely, red
brick and concrete. The measured response of the TF piezoresistive sensor has been shown to be, first, linear, i.e., if Y1 =
f (x1 ) and Y2 = f (x2 ), then Y1 +Y2 = f (x1 +x2 ), and second,
proportional to the modulus of elasticity of these two materials.
To reach a practical deployment, besides linearity and proportionality, many other aspects need to be considered, studied,
and experimented. Reliability of readings in time as a function
of glue and structure deterioration, humidity and temperature
effects, networking, and supply are part of the many considerations to qualify this technology. In addition, other kinds of
substrates like LTCC and fiberglass have to be considered in
light of exceeding the 1000-μstrain limitation of alumina and
to have major integration.
Different kinds of glue were experimented, and the most
reliable was a hard two-component epoxy. However, there was
no systematic scientific approach for which comparative results
can be given at this stage.
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Saad Abdul Ameer Jabir received the B.Sc. degree
in electrical engineering from Baghdad University,
Baghdad, Iraq, and Ph.D. degree from Edinburgh
Napier University, Edinburgh, UK.
He is an Application Engineer Consultant for system and mixed-signal analysis software with Synopsys GmbH, Munich, Germany. He has worked as
an Electronic System Designer in several industrial
fields including nuclear medicine, orthopaedics, automatic test equipment, consumer electronics, and
sensor design before joining Synopsys GmbH in
2002. He has over 30 successful industrial electronic projects. He is also the
holder of patents in sports and orthopaedics apparatus and sensor elements.
Naren K. Gupta (SM’87) received the B.Sc. degree
in electrical engineering from Ranchi University,
Ranchi, India, in 1969, the Postgraduate Diploma
in technical science from the Institute of Science
and Technology, The University of Manchester,
Manchester, U.K., in 1972, the M.Sc. degree from
Brunel University, Uxbridge, U.K., in 1976, the
Ph.D. degree from the Institute of Science and Technology, The University of Manchester, in 1986, and
the MBA degree from Edinburgh Napier University,
Edinburgh, U.K., in 1996.
He is a Professor in Electrical Engineering, a Teaching Fellow, and the
Director of Quality in the School of Engineering and the Built Environment,
Edinburgh Napier University, Edinburgh, U.K. He is an active Researcher
and has published over 110 papers in international journals and conference
proceedings. He has refereed papers for several journals, 545 in all, including
those of IEEE and the Institution of Civil Engineers, U.K. He is currently
a Consulting Editor for the journals EngineerIT and Energize. His current
research involvement is in neural networks, measurements, and tests, including
nondestructive testing, railway technology, and sensors and materials. He is also
interested in pedagogical research.
Dr. Gupta is a Chartered Engineer. He has been a fellow of the Institution of
Engineering and Technology since 2001, a member of the Institution of Railway
Signal Engineers, U.K., since 1982, and a fellow of the Higher Education
Academy since 2000.