IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 54, NO. 11, NOVEMBER 2006
4009
Design and Development of a Package Using LCP for
RF/Microwave MEMS Switches
Morgan Jikang Chen, Member, IEEE, Anh-Vu H. Pham, Senior Member, IEEE, Nicole Andrea Evers,
Chris Kapusta, Joseph Iannotti, William Kornrumpf, John J. Maciel, Member, IEEE, and Nafiz Karabudak
Abstract—We present the development of an ultrahigh moisture-resistant enclosure for RF microelectromechanical system
(MEMS) switches using liquid-crystal polymer (LCP). A cavity
formed in LCP has been laminated, at low temperature, onto a
silicon MEMS switch to create a package. The LCP-cap package
has an insertion loss of less than 0.2 dB at -band. E595 outgas
tests demonstrate that the LCP material is suitable for constructing reliable packages without interfering with the operation
of the MEMS switch. The package also passes Method 1014,
MIL-STD-883 gross leak, and fine leak hermeticity tests.
Index Terms—Cavities, chip-on-flex, liquid-crystal polymer
(LCP), microelectromechanical system (MEMS), microwave,
packaging.
I. INTRODUCTION
P
ACKAGING is a critical part in bringing the RF microelectromechanical system (MEMS) into application at an
affordable cost. MEMS switches are very sensitive to contamination and must be packaged with hermetic or near-hermetic
seals in inert noble gas environments. These switches require
hermetic packaging to prevent against contaminating particles
and moisture. Invasion of particles into the MEMS device can
cause the switch to be wedged open, stuck closed where the
particle aggravates stiction, or simply degrade performance by
acting as a resistive material [1].
A number of solutions are available for packaging MEMS
switches. Several techniques used by industry to package
MEMS devices include epoxy seals, glass frit, glass-to-glass
anodic bonding, and gold-to-gold bonding1 [2]–[6]. These
techniques face two main problems. First, organic materials
outgas inside the MEMS cavity during the bonding process
due to wetting compounds in the glass, gold, or epoxy layers.
Manuscript received February 23, 2006; revised July 17, 2006. This work was
supported in part by the National Science Foundation under CAREER Award
ECS 0300649 and by the University of California MICRO. This work was supported in part by Lockheed Martin Commercial Space Systems.
M. J. Chen and A.-V. H. Pham are with the Electrical and Computer Engineering Department, Microwave Microsystems Laboratory, University of California at Davis, Davis, CA 95616 USA (e-mail: mjchen@ece.ucdavis.edu).
N. A. Evers, C. Kapusta, and J. Iannotti are with General Electric Global
Research Center, Niskayuna, NY 12309 USA.
W. Kornrumpf was with the General Electric Global Research Center,
Niskayuna, NY 12309 USA. He is now with MicroKorn LLC, Schenectady,
NY 12345 USA.
J. J. Maciel is with Radant MEMS Inc., Stow, MA 01775 USA.
N. Karabudak is with Lockheed Martin Commercial Space Systems, Newtown, PA 18940 USA.
Color versions of Figs. 1–8 are available online at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TMTT.2006.884639
1[Online].
Available: http://flipchips.com
This contamination detrimentally affects the MEMS switch
reliability. Second, to achieve a good seal, most bonding
processes utilize high temperatures (300 C–400 C) that can
degrade MEMS structures [7]. Furthermore, available hermetic
packages and ceramic/glass feed-throughs have significant
parasitic losses at microwave frequencies, can be expensive,
and add significant weight to a system. Packaging MEMS
switches into an organic module, in which compact multilayer
substrates house active and passive components present even
more challenges. Although multilayer chip-on-flex modules
using Kapton films are a proven technology for high-density
packaging of microwave modules,2 3 Kapton is found to be
incompatible with RF MEMS switch packaging due to its high
moisture absorption, high out-gassing characteristics, and the
need to use high outgassing epoxies for lamination.
In this paper, we present the development of an ultrahigh moisture-resistant package for RF MEMS switches in
chip-on-flex modules using liquid-crystal polymer (LCP). We
have developed a lamination process to adhere LCP onto silicon
to form an enclosure for MEMS. Using multilayer flex and
laser-drilled vias, the first level interconnect parasitic losses are
negligible at -band. The microwave measurements demonstrate that the LCP-package has less than 0.2-dB insertion
loss and maintains the return loss of a switch to greater than
20 dB. The LCP MEMS package passes the E595 out-gassing
test and Method 1014, MIL-STD-883 gross leak, and fine leak
hermeticity tests.
Section II provides a brief review of multilayer organic modules, an introduction to LCP, and processes to create the LCP
MEMS package. Section III demonstrates the experimental
results of peeling strength tests, out-gassing tests, hermeticity
tests, and lamination process evaluation. Section IV provides
detailed analysis of the electrical performance of a package.
Section V demonstrates the electrical performance of a packaged RF MEMS switch in an LCP enclosure.
II. PACKAGE TOPOLOGY
The multilayer organic multichip module (MCM) is a potential candidate for integrating a system-in-package (SiP) at microwave and millimeter-wave frequencies. This technology has
been utilized to package high-speed memory integrated circuits
(ICs) and transceiver modules for communications [8], [9]. In
1998, Butler et al. had attempted to use this MCM technology to
package MEMS devices [10]. However, the multilayer Kapton
is not suitable for hermetic packaging of MEMS. In order to
2[Online.]
3[Online.]
Available: http://www.kapton-dupont.com
Available: http://www.gore.com/electronics
0018-9480/$20.00 © 2006 IEEE
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TABLE I
TYPICAL MATERIAL PROPERTIES [8]
Fig. 2. Diagram of a packaged RF MEMS switch in an LCP enclosure.
Fig. 1. Diagram of the lamination process of LCP on Si.
provide hermetic packaging of an RF MEMS switch, we investigate the feasibility of LCP as a multilayer interconnect layer
in place of Kapton.
LCP is an emerging low-cost dielectric material that is commercially available as single sheets or laminated substrates that
have low moisture absorption (equivalent to glass). Table I compares the basic properties of LCP with Kapton. LCP can be manufactured to have different properties including a coefficient of
K and
thermal expansion (CTE) range from 8 17 10
a glass transition temperature Tg from 280 C to well over
350 C. The use of low and high melting-point temperature
LCP allows for layer-to-layer lamination processes without the
use of adhesive materials. The main advantages of LCP compared to other organic substrate materials are low moisture absorption, low coefficient of hydroscopic expansion (CHE), excellent barrier properties, and adjustable CTE through thermal
treatment processes. Moreover, LCP shows a very low dielectric
constant and loss factor, over the frequency range of 1 GHz up to
110 GHz [11]. This unique combination of excellent electrical
characteristics, excellent mechanical properties for harsh environment operation, and economical considerations make LCP
a serious candidate for all MCM, SiP, and advanced packaging
technology.
We have developed a process to laminate LCP onto silicon to
form an enclosure for packaging an RF MEMS switch without
the use of adhesives [12]. One of the advantages of lamination is
the low-temperature processing (below 315 C), as compared
to metallic or glass bonding ( 400 C). Fig. 1 demonstrates our
Fig. 3. Prototypes of the packaged RF MEMS switch using LCP capping.
process flow for laminating LCP on silicon. The process starts
with a bare 2-mil-thick LCP that has copper on one side. The
copper serves as the roof of the cavity drilled in the LCP film.
The MEMS cavity is formed in the 2-mil-thick LCP using laser
ablation to the copper lid. The ash is removed using isopropyl
alcohol solvent. This cavity acts as a hermetic enclosure formed
by the copper lid and LCP walls. The laser ablation is a convenient method to pattern the chemically stable LCP to provide
very accurate vertical sidewalls. The single-sided copper-clad
LCP film with the laser-drilled cavity is laminated onto an exposed and released silicon switch. The commercially available
LCP films have a melting temperature from 240 C to 315 C,
which, for robustness of process, is thermally well below any
temperature that may impact the MEMS switch. Inert gas can be
injected into the cavity to help improve the switch performance
during the lamination process. Excellent lamination results have
been obtained over a large range of pressures. Through our processing, we obtain 1 m of accuracy using conventional flipchip die bonding equipment.
Once the lamination is completed, square microvias 100- m
long along each side and interconnects are formed on the LCP
layer. The fabrication of vias and metal interconnects is similar
to the process reported in [12]. Fig. 2 shows the three-dimensional (3-D) diagram of the LCP packaged RF MEMS switch,
and Fig. 3 shows the actual packaged RF MEMS switch prototypes.
CHEN et al.: DESIGN AND DEVELOPMENT OF PACKAGE USING LCP FOR RF/MICROWAVE MEMS SWITCHES
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TABLE II
TABLE OF OUT-GASSING SPECIFICATIONS AND RESULTS FOR LCP
Fig. 5. Sputtered metal adhesion strengths versus material.
Fig. 4. Peel strength test of copper being pulled from the LCP/silicon substrate.
III. PROCESS AND PACKAGE EVALUATION
In order to demonstrate that LCP may be used as a package
material, tests have been performed to address out-gassing, adhesion strengths, structural integrity, and hermeticity.
A. Out-Gassing Tests
Out-gassing is a major barrier in using polymer materials
for packaging RF MEMS. During the processing of polymer
in RF MEMS packaging, polymer materials tend to release gas
particles that would degrade the reliability of the RF MEMS
switch. The ASTM-E 595–93 (1999) tests were employed to
evaluate the out-gassing characteristics of LCP materials [13].
These tests were conducted by measuring mass changes at
125 C under vacuum for 24 h. Results are given as total mass
loss (TML), collected volatile condensable materials (CVCMs),
and water vapor regain (WVR). TML is the percent difference
of mass measured before and after the test. CVCM is the percentage of condensed mass measured on a collector plate over
the initial specimen mass. WVR is calculated by placing the
measured specimens through 50% relative humidity at 23 C
for 24 h, and the value is given as the percentage of increase
of specimen mass before and after humidity conditioning.
Historically, a TML of 1% and a CVCM of 0.1% are the maximum levels for materials used in spacecraft applications. As
seen from Table II, the experimental results demonstrate that
the LCP has passed the out-gassing tests and satisfies the requirements for spacecraft applications. More importantly, even
though LCP is a polymer material, it has negligible out-gassing
and is suitable for RF MEMS switch packaging.
B. Adhesion and Package Integrity
One of the advantages of LCP films is that they are able to adhere to other materials without the use of external adhesives in
a lamination process. This feature not only simplifies the packaging process, but also reduces the electrical loss that is associated with lossy adhesive materials. Out of reliability concerns,
adequate adhesion strengths are required because either a weak
LCP-to-silicon or a weak LCP-to-metal bond could prevent vias
from being formed and contacted correctly.
We have conducted a pulling test to evaluate the adhesion
strength of LCP on silicon using a Chatillon pull tester. Fig. 4
Fig. 6. LCP adhesion strength to silicon.
shows a cross section of the test structure and how the experiment has been conducted. The experimental results demonstrate
that the adhesion of LCP onto Si is more than 3 lbs/in. A comparison of sputter adhesion strengths is provided in Fig. 5, which
indicates that the 3-lbs/in adhesion strength is adequate to provide a reliable enclosure. A photograph of a test sample after
being subjected to a peel test is shown in Fig. 6. It is interesting
to note that even though the Cu/LCP was being separated from
Si, it was actually the Cu/LCP interface that came apart first,
which attests to the high lamination strength between LCP and
silicon.
C. Structural Integrity
From the peel testing, we discovered that optimal lamination
strength actually occurred over a temperature range around the
melting temperature ( ), as opposed to simply being above
a certain threshold value. If the lamination temperature was
too low, the lamination strength would be poor. Conversely, if
the lamination temperature was too high, then widely varying
nonuniform lamination strengths occurred along the interface
of LCP and silicon. At the extremes, nonuniform lamination at
the interface gave the appearance of good bonds speckled in regions of generally poor lamination. Under optimal conditions,
our peel tests show LCP-to-silicon lamination to be in excess of
10 lbs/in.
Fig. 7(a) shows an open rectangular hole in LCP laminated
on a silicon substrate that has interdigitated fingers. This rectangular hole is the same size as the cavity used in the MEMS
switch enclosure. Fig. 7(b) shows the cross section of the laminated LCP onto Si. As can be seen from Fig. 7(a), after the
lamination, the LCP has reflowed and altered the original shape
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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 54, NO. 11, NOVEMBER 2006
Fig. 8. Finite-element method (HFSS) simulation of: (a) an unpackaged and
(b) a packaged thru line in LCP with thickness .
H
Fig. 7. (a) Top-down photograph and cross-sectional diagram of LCP cavity on
silicon. (b) Side view of the laminated LCP on Si. (a) Photograph of laminated
LCP cavity. (b) Cross section of laminated LCP cavity.
of the sharp rectangular hole. The width of the rectangular hole
200 m. The reflow is measured to be less than 5 m at
is
the midpoint of the cavity sidewall and 25 m at the corners
(noncritical features).
D. Hermeticity Tests
It is well known that polymer materials are usually unsuitable for hermetic packaging because of their high permeabilities, which cause failure during fine leak testing. In order to establish that LCP would be viable for hermetic enclosures, hand
calculations are performed based on referred data [14]. LCP has
cm s for
been reported to have a permeability of 2.19 10
helium in LCP. This value may be compared to the hermetic
shielding material Corning 7740 glass in helium, which has a
cm s. Package hermeticity is quantileak rate of 8.5 10
tatively analyzed by using the diffusion leak rate closed-form
approximation equation [15]
Leak rate
(1)
where is the permeability, is the exposed package area,
is the pressure difference, and is the package wall thickness.
cm s for helium in
Using a permeability of 2.19 10
LCP, an exposed area of 0.22 mm , an effective wall thickness
of 300 m, and pressure as specified for testing the package with
7.5 10 mm cavity volume, the leak rate is estimated to be
atm cm s. This value is significantly below the
6.424 10
cutoff condition required by Method 1014, MIL-STD-883.
Fig. 9. Return and insertion losses of a 50- and 80-
thru line as compared to
an unpackaged 50-
line.
Gross and fine leak hermetic testing has been performed on
five LCP-packaged MEMS switches at Six Sigma.4 These parts
are fully functional with both dc and RF via connections. The
gross and fine leak tests evaluate the hermetic properties of the
LCP packages in accordance with Method 1014, MIL-STD-883
[15]–[19]. Gross leak is generally indicative of structural failure,
while fine leak more generally detects contamination pathways
by bulk diffusion mechanisms through materials. Gross-leak
testing is performed under 60 pounds per square inch guage relative to atmosphere (PSIG) of perfluorocarbon fluid for 125 min
and immediately vacuumed under 5 torr for 30 s. The parts are
then submerged in a bubble tester and visually inspected for
leaks, as indicated by the appearance of any bubbles from the
parts. Fine leak testing is performed under 125 min, 60 PSIG
helium soak, followed by a 5-torr vacuum for 1 min. The experimental results demonstrate that our packages have passed
the gross and fine leak tests in accordance with Method 1014,
MIL-STD-883. Due to the small volume size of our package
( 0.06 mm ), standard detection methods may not be capable
of measuring the species inside the cavity. Hence, it is questionable if Method 1014, MIL-STD-883, which is the current
standard test, can provide conclusive results on hermeticity for
small-volume packages [16].
IV. ELECTRICAL PACKAGE DESIGN AND SIMULATIONS
In order to evaluate the effects of the package on RF MEMS
switches, full-wave electromagnetic simulations have been
conducted using Ansoft High Frequency Structure Simulator
(HFSS) software that employs a finite-element method. The
basic structure for studying insertion loss and return loss includes a bare microstrip transmission line on silicon with a
S m. This structure is considered as an
bulk conductivity
4[Online.]
Available: http://www.sixsigmaservices.com/hermeticity.asp
CHEN et al.: DESIGN AND DEVELOPMENT OF PACKAGE USING LCP FOR RF/MICROWAVE MEMS SWITCHES
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TABLE III
RETURN AND INSERTION LOSSES AS SIMULATED WITH THE FINITE-ELEMENT METHOD (HFSS)
unpackaged device, shown in Fig. 8(a). The bare microstrip line
,
) with a 2-mil
is then packaged in LCP (
height cavity capped by a copper lid, as shown in Fig. 8(b).
Copper vias 100 m by 100 m with 5- m-thick walls form
the first-level interconnect. Each metal layer is also 5- m thick.
The chip is 3000 m by 3000 m.
Agilent’s Advanced Design System (ADS) LineCalc, which
uses close-form equations for calculating impedance and transmission-line geometry, is employed to determine the width of
microstrip lines on 254- m-thick Si. The widths of 50- and 80microstrip lines (unpackaged) are found to be 197 and 50.7 m,
respectively. In the packaged simulation, the microstrip section
feeding to the coplanar waveguide is deembedded at the port.
Fig. 9 shows the simulation results of the unpackaged and
packaged microstrip lines. When the 80- microstrip line
is packaged with a 2-mil-high metal lid, the characteristic
impedance is tuned down closer to 50 . In this case, the
return and insertion losses of the packaged 80- microstrip
lines improves from 13 to 25 dB and from 0.76 to 0.42 dB,
respectively, at 10 GHz. The insertion and return losses of the
50- microstrip line worsens from 0.581 dB unpackaged to
0.624 dB packaged and from 24.1 dB unpackaged to 20.6 dB
packaged, respectively at 10 GHz.
Table III compares simulation results of unpackaged and
packaged 50- and 80- microstrip lines in 1- and 2–mil-high
metal lids. High characteristic impedance microstrip lines are
tuned closer to 50- transmission lines when they become
striplines with 1- and 2-mil high metal lids. The capacitance per
unit length of the striplines increases, which, in turn, decreases
the characteristic impedance. This phenomena is described
by the well-known equation for characteristic impedance
.
In our research, the MEMS switch has been designed to have
a high characteristic impedance ( 80 ) without a package.
Hence, we expect that the package will improve the matching
of the device to a 50- system. For mechanical robustness, we
have chosen a 2-mil-high cavity.
An equivalent-circuit model for the microvia interconnect has
been developed from simulations using the Sonnet Software that
employs the method of moments. This model targets the -band
to understand the switch performance. The interconnect model
fF,
pH, and
is shown in Fig. 10 to have
. models the capacitance between the via to the
surrounding ground, and models the inductance associated
with the narrow via constructed through the LCP thin film from
the outer package to the metal trace on chip.
-parameters are measured from a packaged thru line. An
analytical method (ADS) is used to deembed all elements in the
path other than the interconnect using the technique shown in
[20]. Fig. 11 compares modeled and measured -parameters of
the transition. This is an agreement to 0.02 dB between model
Fig. 10. Electrical via model for LCP packaged switch with
L = 124 pH, and R = 0:05 .
C
= 120 fF,
Fig. 11. Modeled versus measured package interconnect.
and measurement insertion losses at 10 GHz, which is our frequency of interest. Model and measurement both show less than
0.07-dB insertion loss per package transition at 10 GHz. Return
loss shows agreement to less than 4-dB difference between modeled and extracted measurement. This lumped circuit strictly
models the via interconnect. When devices are packaged, the
interconnects and the additional copper over the packaged device together can cause tuning effects.
V. MEASURED RESULTS
-parameter measurements have been performed with a
Cascade probe station, an Agilent PNA E8364B network
analyzer, and Picoprobe coplanar-waveguide probes. A load-reflect-match (LRM) calibration was performed to establish the
reference planes to be at the RF probe tips. A dc probe is used
to electrostatically bias the switch on with 90 V. The measured
results of the LCP packaged switch in the closed state for
insertion loss are provided in Fig. 12 over the -band region
and plotted up to 18 GHz. Our packaged switches show a total
insertion loss of 0.45 dB at -band due to the low-loss LCP
material, microvias, and excellent shielding. This includes the
additional 0.07 dB loss per interconnection at the input and
0.3 dB being attributed to the MEMS switch
output with
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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 54, NO. 11, NOVEMBER 2006
loss of the LCP packaged switch is roughly 0.5 dB at -band
with return loss greater than 25 dB and isolation loss of 14 dB.
ACKNOWLEDGMENT
The authors wish to acknowledge the collaborative work
between the Microwave Microsystems Laboratory, University
of California at Davis, the General Electric Global Research
Center, Niskayuna, NY, Radant MEMS Inc., Stow, MA, and
Lockheed Martin Commercial Space Systems, Newtown, PA.
REFERENCES
Fig. 12. Insertion and return losses versus frequency when the switch is closed.
Fig. 13. Isolation and return losses versus frequency when the switch is open.
at -band. In addition, the measured return loss is better than
25 dB. The metal cap of the package tunes the characteristic
impedance of the switch closer to 50 . Hence, the return loss
of the packaged switch is improved to less than 25-dB return
loss.
The -parameters of the packaged MEMS switch had also
been measured in the open or off states (0 V \#\bias). Fig. 13
shows the measured -parameters of the off-state switch. The
measured isolation of the packaged switch is 15 dB, which remains relatively the same as the unpackaged switch to within
1 dB.
Since the particular switches we use had been optimized for
an 80- characteristic impedance system, rather than a 50system, the isolation is a better metric of the packaging.
VI. CONCLUSION
This paper has successfully demonstrated an ultrahigh moisture-resistant RF MEMS switch enclosure using LCP. Simulations show that the entire package introduces miniscule electrical degradation to the overall circuit performance. Insertion
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Morgan Jikang Chen (S’00–M’03) was born in Indianapolis, IN, on January 9, 1981. He received the
B.S. degree in electrical engineering and computer
science (EECS) from the University of California at
Berkeley, Berkeley, in 2003, and is currently working
toward the Ph.D. degree at the University of California at Davis.
In Summer 2000, he interned as an Engineer with
Boeing Autometric Inc., San Diego, CA. In Summer
2001, he participated in National Science Foundation
(NSF) research with Clemson University, Clemson,
SC. In Summer 2003 and 2004, he was an Intern with General Electric Global
Research, Niskayuna, NY. He is currently a Graduate Research Assistant with
the University of California at Davis. His research interests include developing
low-cost packaging implementations using LCP for RF and microwaves.
Mr. Chen is a member of Eta Kappa Nu (HKN) and the IEEE Microwave
Theory and Techniques Society (IEEE MTT-S).
Anh-Vu H. Pham (SM’03) received the B.E.E.
(with highest honors), M.S., and Ph.D. degrees from
the Georgia Institute of Technology, Atlanta, in
1995, 1997, and 1999, respectively.
In 1997, he co-founded RF Solutions, LLC, an
RFIC company that was acquired by Anadigics in
2003. He has held faculty positions with Clemson
University and the University of California at Davis,
where he is currently an Associate Professor. He is
also active as a consultant to the industry. He has
authored or coauthored over 50 technical journal and
conference papers. His research interests are in the area of RF and high-speed
packaging and signal integrity, RF integrated-circuit (RFIC) design, and
wireless sensors.
Dr. Pham is a member of the IEEE Microwave Theory and Techniques
Society (IEEE MTT-S) International Microwave Symposium (IMS) Technical
Program Committee (TPC) on Power Amplifiers and Integrated Circuits. He
has been the chair of the IEEE MTT-12 Microwave and Millimeter Wave
Packaging and Manufacturing Technical Committee of the IEEE MTT-S. He
was the recipient of the 2001 National Science Foundation (NSF) CAREER
Award on millimeter-wave organic packaging.
Nicole Andrea Evers received the Ph.D. degree in
electrical engineering from the Georgia Institute of
Technology, Atlanta, in 1998.
In Fall 1997, she joined the GE Global Research
Center, Niskayuna, NY. She was a member of the Advanced Electronics Program, where she developed,
led, and supported projects in the areas of SiC and
GaN RF and power devices, thin-film passives, and
packaging. In 1999, she joined the Electronic Power
Conversion Program, where she led the Ballast in a
Socket Project with the Department of Energy (DOE)
and GE Lighting and the Electronic Power Control Module Project with GE
4015
Appliances. In March 2001, she became the Global Research Center Edison
Engineering Representative and Advanced Courses in Engineering Supervisor
and was assigned the task of building a training program at the Global Research
Center. After successfully establishing the Edison program at the Global Research Center, she moved to the Electronic and Photonics Technologies Organization in June 2002, where she currently leads a wiring diagnostics program, providing technical support on due diligence efforts in corporate acquisitions, and providing technical consulting in the RF/microwave and opto-electronic sensors area. She has authored or coauthored over 14 technical publications. She has made numerous technical presentations. She holds three patents.
Her primary research with the Georgia Institute of Technology was in the area
of microelectronics and packaging and included modeling, design, and fabrication of InP high electron-mobility transistors (HEMTs), circuit integration
of thin-film InP-based resonant tunneling diodes (RTDs) with silicon circuits,
mixed material integration of thin-film InP HBTs on silicon, high-frequency
testing and characterization of high-speed electronic devices, and integration,
measurement, and modeling of high-frequency passive structures with active
III–V thin-film devices on silicon. Her other areas of interest have included RF
amplifier design, communications, and photovoltaics.
Chris Kapusta, photograph and biography not available at time of publication.
Joseph Iannotti, photograph and biography not available at time of publication.
William Kornrumpf, photograph and biography not available at time of publication.
John J. Maciel (M’83) was born in Stoneham,
MA, on December 7, 1960. He received the B.S.
degree in electrical engineering from Northeastern
University, Boston, MA, in 1983, and the M.S.
and Ph.D. degrees in electrical engineering from
Polytechnic University, Brooklyn, NY, in 1986 and
1990, respectively.
From 1983 to 1996, he was with Missile Systems
Division Laboratories, Raytheon Company, Tewksbury, MA, where he designed, conducted analyses
for, developed, fabricated, and tested missile seeker
radar antenna and radome systems. Since March 1996, he has been with Radant
Technologies, Stow, MA, where he is currently Manager of electromagnetics
technology. He has performed analyses for ground, shipborne, and submarine
antennas and radomes, and has also developed lightweight passive phased-array
antennas, including those that contain MEMS. In addition, since May 2002, he
serves as Vice President and Chief Operating Officer of Radant MEMS Inc.,
Stow, MA, where he directs MEMS switch and component developments.
Dr. Maciel is a member of Sigma Xi, Tau Beta Pi, Eta Kappa Nu, and Phi
Kappa Phi. He was the recipient of Second Place in the 1989 Union of Radio
Science (URSI) Student Prize Paper Contest, Boulder, CO.
Nafiz Karabudak, photograph and biography not available at time of publication.