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The characteristics of probe-fed rectangular microstrip
antennas on a cylindrical or planar body have been studied in
this dissertation. Two different theoretical treatments of
cavity-model method and full-wave analysis are used. The
cavity- model method is based on the magnetic-wall
approximation, which is valid for thin-substrate conditions. On
the other hand, the full-wave analysis incorporating with a
moment-method calculation is more rigorous for analyzing
microstrip antennas. Various characteristics obtained using
these two methods are discussed. Besides the analysis of a
single microstrip antenna, the mutual coupling between two
microstrip antennas is also investigated. Numerical results for
the microstrip antennas covered with a lossy or lossless
dielectric superstrate are presented, and the curvature effects
on the mutual coupling are studied. With the introduction of
loss into the superstrate layer, a noticeable reduction in the
coupling level is observed. A broadband cylindrical-rectangular
microstrip antenna using two parasitic patches gap-coupled to
its radiating edges is also analyzed. Results indicate that,
with parasitic patches, the antenna bandwidth greater than two
times that of a single cylindrical- rectangular microstrip
antenna can be obtained. Finally, a planar microstrip Yagi
antenna is investigated. Both the E-plane and H-plane coupling
cases are disscussed. Numerical results show that such an array
antenna has a much wider bandwidth than a single antenna, the
array''s main-beam radiation is tilted from the broadside
direction. The dependence of the antenna bandwidth and
radiation pattern on the patch size, gap-spacing, substrate
thickness, and substrate dielectric constant is calculated and
discussed.
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