| dc.description.abstract | In the future, space solar power transmission and wireless power transmission will
play an important role in gathering clean and infinite energy from space. The rectenna,
i.e., a rectifying circuit combined with an antenna, is one of the most important
components in the wireless power transmission system. To obtain high power and high
output voltage, the use of a large rectenna array is necessary.
Many novel rectennas and rectenna arrays for microwave and millimeter-wave
wireless power transmission have been developed. Unlike the traditional rectifying
circuit using a single diode, dual diodes are used to double the DC output voltage with
the same circuit layout dimensions. The rectenna components are then combined to form
rectenna arrays using different interconnections. The rectennas and the arrays are
analyzed by using a linear circuit model. Furthermore, to precisely align the mainbeams
of the transmitter and the receiver, a retrodirective array is developed to maintain high
efficiency. The retrodirective array is able to track the incident wave and resend the
signal to where it came from without any prior known information of the source location. The ultra-wideband radio has become one of the most important communication
systems because of demand for high data-rate transmission. Hence, ultra-wideband
antennas have received much attention in mobile wireless communications. Planar
monopole ultra-wideband antennas for UHF, microwave, and millimeter-wave bands are
developed, with many advantages such as simple structure, low cost, light weight, and
ease of fabrication. Due to the planar structures, the ultra-wideband antennas can be
easily integrated with other circuits. On the other hand, with an ultra-wide bandwidth,
source power can be transmitted at different frequencies dependent on power availability.
Furthermore, the ultra-wideband antenna can potentially handle wireless power
transmission and data communications simultaneously. The technologies developed can
also be applied to dual-frequency or the multi-frequency antennas.
In this dissertation, many new rectenna arrays, retrodirective rectenna arrays, and
ultra-wideband antennas are presented for microwave and millimeter-wave applications.
The technologies are not only very useful for wireless power transmission and
communication systems, but also they could have many applications in future radar,
surveillance, and remote sensing systems. | en |
