THESIS
2012
xi, 77 p. : ill. ; 30 cm
Abstract
Wireless capsule endoscope system has been widely used for gastrointestinal monitoring,
since it can provide biological statistics in real time without causing any pain or discomfort.
Current commercial capsule endoscope system suffers from low transmission data rate which
cannot meet the requirement for high-resolution images. MIMO systems can provide high
data rate without the need for additional spectrum and transmitting power. However, the
design of MIMO antennas for capsule endoscope system is a challenging task due to the
capsule size as well as the hostile human body environment.
Cross-polarized nearly omni-directional MIMO antennas in the ISM band 433 MHz for
capsule endoscope system are proposed in this thesis. The proposed MIMO antennas consist
of a small magnetic l...[
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Wireless capsule endoscope system has been widely used for gastrointestinal monitoring,
since it can provide biological statistics in real time without causing any pain or discomfort.
Current commercial capsule endoscope system suffers from low transmission data rate which
cannot meet the requirement for high-resolution images. MIMO systems can provide high
data rate without the need for additional spectrum and transmitting power. However, the
design of MIMO antennas for capsule endoscope system is a challenging task due to the
capsule size as well as the hostile human body environment.
Cross-polarized nearly omni-directional MIMO antennas in the ISM band 433 MHz for
capsule endoscope system are proposed in this thesis. The proposed MIMO antennas consist
of a small magnetic loop antenna with horizontal polarization and a conformal meandered
dipole antenna with vertically polarization. By using polarization diversity, the antennas still
maintain good isolation even within the limited available space in the capsule. Simulation and
measurement results are in good agreement. Multipath fading characteristics of human body
channel is studied through discrete-time baseband equivalent impulse response and can be
best described by normal distribution. MIMO system model is studied with consideration of
antenna correlation and mutual coupling. The capacity gain for the proposed MIMO system is
evaluated through simulation and it is shown capacity can be nearly doubled for a 2 × 2
MIMO capsule system. Finally, external multiple-port beam switchable base station antennas
for receiving small signals transmitted from the implanted biomedical devices are introduced.
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