M.S THESIS DEFENSE
INVESTIGATIONS ON CAVITY BACKED MICROSTRIP PATCH
ANTENNAS WITH ENHANCED PERFORMANCE FOR WIRELESS
COMMUNICATION APPLICATIONS
By
Shiv K. Varanasi
Master of Science in Electrical Engineering
San Diego State University, 2010
Advisor: Dr. Satish K. Sharma
Where: E 203E (The Dean’s Conference Room)
When: Friday, September 24th, 2010 at 1:00 P.M.
ABSTRACT
Since their inception, microstrip patch antennas (MPA) have been widely implemented in
wireless communication applications owing to their compact size, light weight, ease of design and
fabrication. Narrow impedance bandwidth and relative larger size in microwave frequency ranges have
often been a limitation to the performance characteristics of the microstrip patch antennas. The wireless
communication industry applications demand for smaller and compact antennas which can provide wide
impedance bandwidth and good radiation performance occupying less space when installed.
This thesis initially presents remedies for problems encountered with a novel full Ψ-shape MPA
which include adding layer on top and also designing metallic strips onto the layer. Then a reduced size
(almost 50% than original patch size) half Ψ-shape MPA with optimized design dimensions is presented
which provides a wide impedance bandwidth but at the cost of increased cross-polarization. Next, a cavity
backed half Ψ-shape MPA is presented which consists of a copper cavity placed behind the patch antenna
mainly to increase the co-polarization gain and reduce the cross-polarization level but proved futile in
reducing the cross-polarization levels. Finally an optimized cavity backed half Ψ-shape MPA employing
defects in the ground plane is presented which has been effective in increasing the co-polarization gain
along with reduced cross-polarization while maintaining almost similar antenna performance as the earlier
design.
-------------- All are Welcome ---------------