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Electromagnetic Compatibility Studies
by : Brian M.Harris
Advisor : Dr. Prasad N.Shastry
May 2000
ABSTRACT
This project focuses on electromagnetic compatibility, by
developing emission and susceptibility testing procedures and presenting
applicable limits in the United States and Europe. The testing procedures are
put into practice with actual lab measurements on various electrical and
electronic devices, and the test results are compared to applicable
emission/susceptibility limits. Observations and conclusions on frequency versus
emission and susceptibility characteristics for the various devices are
presented.
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A Novel Proximity Coupled Active Integrated Antenna
by : Sasidhar Vajha
Advisor : Dr. Prasad N.Shastry
May 2000
ABSTRACT
In this project, a novel design approach and measured results of a compact proximity coupled
active integrated antenna (PCAIA) are presented. A new type of antenna feed structure is proposed.
A single self-biased (through the RF port), two-stage low noise amplifier has been integrated with
a proximity coupled patch antenna having a new feed structure. The proposed approach is useful in the design
of compact PCAIA with good radiation characteristics for applications in microwave wireless systems.
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A CDMA Wireless Receiver Front-End
by : Sameer Naik
Advisor : Dr. Prasad Shastry & Dr. In Soo Ahn
August 1999
ABSTRACT
With cellular networks in the 800-900MHz band reaching capacity limits, PCS(1800-1900MHz) is proving
to be the best alternative for cellular operators. Spread Spectrum, CDMA (Code Division Multiple Access) enables one to incorporate
many users within a relatively wide bandwidth. The intent of the Phase I of the project was to design, construct and test the subsystems
for CDMA Receiver Front-End in the PCS band. The goal of the project was to transmit a CDMA signal from a transmitter (base station)
and retrieve the information at the receiver. Another goal for this project was to design a duplexer as a part of the subsystem,
fabricate and test the duplexer for its performance in the PCS band.
The CDMA signal was transmitted at 1.93 GHz from a transmitter, and received at the receiver end. The
signal was then passed through a duplexer, and a low noise amplifier. The CDMA signal was then downconverted to an IF frequency
of 210 MHz. Further, the signal was amplified (with an automatic gain control) and demodulated to a baseband signal. The design
and performance characteristics of the receiver front-end are presented in this report.
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Electronically Tunable Distributed Active Filter
by : Yongqiang He
Advisor : Dr. Prasad N.Shastry
December 1998
ABSTRACT
A design methodology for a novel, electronically tunable
bandpass active filter, based on distributed amplifier topology, at microwave
frequency, is presented. Edge-coupled microstrip line filter sections have been
blended into the conventional distributed amplifier configuration. Interstage
matching network has been used between cascaded transistors in each
amplification cell. Varactor tuning scheme has been adopted for variable
center-frequencies. The center frequency of the filter can be tuned in the range
1.7 to 2.3 GHz, which covers the PCS band. The filter has a minimum gain of
8.5dB, input and output return losses less than -6dB, in the tuning band. The
filter consumes 120 mw. The guidelines for the design of the filter, as well as
simulation and measured results are presented. The filter can be implemented in
MMIC form, and has potential for applications in wireless communication systems.
Yong He at Work
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Ali Imran working on his project
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A 2.4 GHz CDMA Wireless Communication System
by : Ali Imran Z.B.
Advisor : Dr. Prasad N.Shastry
August 1998
ABSTRACT
The field of wireless communications is rapidly growing
with the emergence of personal pagers, cellular mobile radio systems, vehicle
tracking, and commercial use of GPS. Multipath and interference from other users
are the two basic problems the designer must face. Spread spectrum, Code
Division Multiple Access (CDMA), is proving to be a viable technique for modern
wireless communications due to its ability to effectively incorporate many users
within a relatively wide bandwidth.
The intent of the project was to design, construct, and
test a network for Wireless Communication using Spread Spectrum technique. The
goal was to make a network capable of transmitting information from a portable
user unit to a receiving base station. Another goal for this project was to
design the code generator and the data buffer using XILINX-FPGA, and provide an
interface between the digital hardware and the RF system. Finally, an attempt
was made to use Omnisys (and verify of HP EEsof Series IV Version 6.1) to
investigate and verify the system's signal to noise ratio at various points in
the system.
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A 2.4 GHz GaAs FET Oscillator
by :
Advisor : Dr. Prasad N.Shastry
In Progress
ABSTRACT
Coming soon...
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Optimal Design of Low Crosstalk, Wideband, Bidirectional, Distributed Amplifier
by : Z. M. Li
Advisor : Dr. Prasad N.Shastry
May 1996
ABSTRACT
In this project, an optimal approach to the design of low crosstalk, wideband,
bidirectional, distributed amplifiers is proposed. The new technique based on Chebyshev scaling of device
transconductances, gives considerably greater directivity bandwidth than the previously published approach using
binomial scaling, for specified number of devices, and minimum directivity. The theory and design guidelines, as
well as simulated and measured results are presented.
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MMIC Technology: Processing, Layout Design and Packaging
by : G.Brubaker
Advisor : Dr. Prasad Shastry
August 1993
ABSTRACT
In this special topics course, the student is expected to learn GaAs MMIC layout design skills
using EEsof CAE tools as well as obtain the knowledge on GaAs MMIC processing and packaging techniques by reading
published material on the subject.
Learning the layout design skills will involve working on selected MMIC layout design projects.
Exposure to GaAs MMIC processing and packaging techniques will involve studies of published books and papers on the
subject matter. The student is expected to keep a good record of his work. The student is expected to confer with the instructor
at least once a week and report on the progress being made until the course in completed. The student is expected to:
Give 3 seminar talks one each, on layout design, processing and packaging at the end of the course. Submit a report at the
end of the course encompassing the topics covered by the course.
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GaAs FET Class-B Power Amplifier Study
by : Surendra Makam
Advisor : Dr. Prasad N.Shastry
May 1993
ABSTRACT
Nonlinear characteristics of FET's cause harmonic
distortion in power amplifiers and reduce the efficiency. In a Class-B
amplifier, the efficiency can be increased by trapping the harmonics present in
the amplified signal; this is achieved by using a quarterwave shorted microstrip
line at the output. A Class-B amplifier was designed and analyzed with and
without the harmonic trapping circuit. The results of the analyses are
presented.
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Microwave Transistors and Circuit Applications
by : G.Brubaker
Advisor : Dr. Prasad Shastry
December 1993
ABSTRACT
This paper presents linear and non-linear device
models used to simulate the behaviour of MESFETs, HEMTs, and HBTs. Applications
of the models are shown for amplifier design. Other microwave circuits
are shown where models are used to simulate their behaviour.
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A Large Signal Model for GaAs FETs
by : Lalitha G. Saraswathula
Advisor : Dr. Prasad N.Shastry
August 1992
ABSTRACT
In this report an attempt is made to develop a
large-signal model for GaAs FETs. Starting from measured DC-IV characteristics
and small signal S-parameters of GaAs FETs the model developed is the one
proposed by Curtice.W. The modelling procedures are illustrated by means of an
example. The tuning and optimization of the model using EEsof CAE tools and the
results obtained are discussed.
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Wideband Microwave Distributed Circuits
by : G. Brubaker
Advisor : Dr. Prasad Shastry
May 1992
ABSTRACT
This paper presents distributed paraphase amplifier, oscillator circuit based on distributed topology,
distributed mixer circuit, circulator/transmit-receive module based on distributed topology, noise considerations in distributed amplifiers,
power and efficiency considerations in distributed amplifiers, cascode distributed amplifiers, band-pass distributed amplifiers,
dual-gate distributed amplifiers and wideband power dividers and combiners.
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Band-Pass Distributed Amplifier Design Guidelines
by : Ashok Kumar Kajjam
Advisor : Dr. Prasad N.Shastry
May 1991
ABSTRACT
In this project, GaAs FET Band-Pass Distributed Amplifier
design guidelines are presented. The report focuses on fundamental design
considerations. The design approach presented enables one to examine the
trade-offs between variables and arrive at the appropriate design for a
specified gain and bandwidth. The analysis enables the designer to predict the
gain of the amplifier from the design curves for a given number of devices. The
3-dB bandwidth of the amplifier can be determined from the Normalized Frequency
response curve.
Publications : 1) Prasad N.Shastry, A.Kajjam and Z.M.Li, "
Band-Pass Distributed
Amplifier Design Guidelines",
Microwave and Optical Technology Letters, Vol.10, No.4, November 1995, pp
215-218.
2) S.Reddy and A.Kajjam, "A 2-26 GHz Distributed Power Amplifier",
submitted to Northrop
Grumman Corp., August 1992.
3) Prasad N.Shastry , A.Kajjam, S.Makam & S.Reddy, "Wireless LANs --
A Technology status Report"
submitted to Northrop Grumman Corp., August 1992.
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Design Considerations For Achieving Optimum Gate Voltages in Distributed Amplifiers
by : Srinivas Reddy Ponnala
Advisor : Dr. Prasad N.Shastry
May 1992
ABSTRACT
This paper presents a report on the design considerations
for achieving optimum gate voltages in Distributed Amplifiers. The analysis
is carried out for an exponential distribution of series capacitors in
the gate-line. This results in an increased gate voltage excitation till
the last device as compared to an uniform distribution of series capacitors.
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