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Abstract:
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In recent years, there is a visible trend for products/services which
demand seamless integration of cellular networks, WLANs and WPANs. This
is a strong indication for the inclusion of high speed short range wireless
technology in future applications. In this context UWB radio has a significant
role to play as an extension/complement to existing cellular/access technology.
In the present work, three major types of ultra wide band planar antennas are
investigated: Monopole and Slot. Three novel compact UWB antennas, suitable for
poratble applications, are designed and characterized, namely
1) Ground modified monopole
2) Serrated monopole
3) Triangular slot
The performance of these designs have been studied using standard simulation
tools used in industry/academia and they have been experimentally verified. Antenna
design guidelines are also deduced by accounting the resonances in each structure.
In addition to having compact sized, high efficiency and broad bandwidth
antennas, one of the major criterion in the design of impulse-UWB systems
have been the transmission of narrow band pulses with minimum distortion.
The key challenge is not only to design a broad band antenna with constant and
stable gain but to maintain a flat group delay or linear phase response in the
frequency domain or excellent transient response in time domain. One of the
major contributions of the thesis lies in the analysis of the frequency and timedomain
response of the designed UWB antennas to confirm their suitability for
portable pulsed-UWB systems. Techniques to avoid narrowband interference by
engraving narrow slot resonators on the antenna is also proposed and their
effect on a nano-second pulse have been investigated |