Modern satellite, wireless communication, and radar systems often demand
wideband performance for multi-channel operation and the ability to steer multiple
beams for multiple moving targets. This dissertation covers a variety of topics to design
low-cost and wideband antenna systems. The main areas of study are microwave devices
controlled piezoelectric transducers (PETs) and wideband baluns and balanced
microwave circuits using parallel-strip lines. Some focus has also been given to the
design of Rotman lens for multiple beam generation and Vivaldi antenna arrays for
wideband two-dimensional scanning.
The dielectric perturbation technique controlled by PET is introduced to design a
wideband phase shifter and a QPSK modulator, and to tune the resonant frequency of a
slot dipole. The designed PET-controlled phase shifters are used for beam steering in a
dual beam phased array using a bidirectional feeding scheme and a five-beam phased
array using a microstrip Rotman lens.
Vivaldi-type antennas are commonly used to achieve wideband performance. Very
wideband performance can be achieved using an antipodal tapered slot antenna because
of its inherent simple wideband transition from microstrip line to parallel-strip line. An
antipodal tapered slot antenna and a phased array are designed to span 10 to 35 GHz. In
addition, a 4??4 two-dimensional antenna array is designed using wideband antipodal
tapered slot antennas, and two sets of PET-controlled phase shifters for E- and H-plane
scanning are fabricated to steer the beam. As a microwave system using wideband
antenna array, a new low-cost and wideband phased array radar is developed using a
modulated pulse over 8 to 20 GHz band.
The double-sided parallel-strip line as a balanced line is presented. The parallelstrip
line offers much flexibility for microwave circuit designs. This transmission line
makes it possible to realize a low impedance line and allows the design of a compact
wideband balun and junction. Wideband transitions (or baluns) from parallel-strip line to
microstrip line, a typical unbalanced transmission line, are realized to cover several
octave bandwidth. Balanced microwave filters and a hybrid coupler are developed using
the parallel-strip line.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2335 |
| Date | 29 August 2005 |
| Creators | Kim, Sang Gyu |
| Contributors | Chang, Kai |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 2542522 bytes, electronic, application/pdf, born digital |
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