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Design of New, Compact and Efficient Microstrip Filters for 5G Wireless CommunicationsAl-Yasir, Yasir I.A. January 2020 (has links)
The electromagnetic spectrum is becoming increasingly congested due to the
rapid development of wireless and mobile communication in recent decades.
New, compact and efficient passband filters with multi-functions and good
performance are highly demanded in current and future wireless systems. This
has also driven considerable technological advances in reconfigurable/tunable
filter and filtering antenna designs. In light of this scenario, the objectives of this
thesis are to design, fabricate and measure efficient, compact, multi-standard,
and reconfigurable/tunable microstrip resonator filters and study the integration
of the resonators with patch antennas. As a passive design, a compact dual-band
filter is implemented to cover 2.5 to 2.6 GHz and 3.4 to 3.7 GHz for 4G and 5G,
respectively. Another design is also presented with the advantages of a wide
passband of more than 1 GHz. Conversely, new and compact reconfigurable
filters are designed using varactor and PIN diodes for 4G and 5G. The proposed
filters are tunable in the range from 2.5 to 3.8 GHz. The bandwidth is adjustable
between 40 and 140 MHz with return losses between 17 to 30 dB and insertion
loss of around 1 dB. Also, the thesis investigates the design of cascaded and differentially-fed filtering antenna structures. The cascaded designs operate at
2.4 and 6.5 GHz and have a relatively wide-band bandwidth of more than 1.2
GHz and a fractional bandwidth of more than 40%. For the differentially-fed
structures, good performance is achieved at the 3.5 GHz with a high realized gain
of more than 7.5 dBi is observed. / European Union Horizon 2020 Research and Innovation Programme (Marie Skłodowska-Curie Actions) under grant agreement H2020-MSCA-ITN-2016 SECRET-722424.
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Coverage optimisation for aerial wireless networksEltanani, S., Ghafir, Ibrahim 05 April 2022 (has links)
Yes / Unmanned Aerial Vehicles (UAVs) are considered, nowadays, as a futuristic and robust paradigm for 5G wireless networks, in terms of providing Internet connectivity services onto infrastructure cellular networks. In this paper, the interference regime caused by multiple downlink aerial wireless transmission beams has been highlighted. This has been introduced by estimating the UAVs coverage area that is analytically derived in a tractable closed-form expression. The rationale of the analysed coverage approach relies on observing and adapting the joint aerial distance between the aerial base stations. This can minimize the intra-overlapped coverage and ultimately maximize the overall coverage performance for a better quality of service demands. The novelty of our approach brings useful design insights for UAVs system-level performance that technically helps in aerial coverage computations without the need of performing an aerial deployment setup. To the end, the performance effectiveness of our methodology has been tested under an urban propagation environment conditions, in which the original probabilistic channel model approximation has been taken into account. Moreover, this paper identifies the interference issue of such an aerial network as a shrinkage or distortion phenomenon.
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Investigation and Design of New, Efficient and Compact Load Modulation Amplifiers for 5G Base Stations. Design, Simulation, Implementation and Measurements of Radio Frequency Power Amplifiers Using Active Load Modulation Technique for More Compact and Efficient 5G Base Stations AmplifiersAbdulkhaleq, Ahmed M. January 2020 (has links)
High efficiency is an essential requirement for any system, where the energy
can be saved with full retention of system performance. The power amplifier in
modern mobile communications system consumes most of the supplied power
through the dissipated power and the required cooling systems. However, as
new services were added as features for the developed mobile generations, the
required data rate has increased to fulfil the new requirements. In this case, the
data should be sent with the allocated bandwidth, so complex modulation
schemes are used to utilise the available bandwidth efficiently. Nevertheless,
the modulated signal will have a Peak to Average Power Ratio (PAPR) which
increases as the modulation complexity is increasing. In this case, the power
amplifier should be backed off and designed to provide good linearity and
efficiency over high PAPR.
Among the efficiency enhancement techniques, the Doherty technique (Load
modulation technique) is the simplest one, where no additional circuity nor
signal processing is required. In this work, the theory of load modulation
amplifiers is investigated through two asymmetrical Doherty Power Amplifiers
(DPA) targeting 3.3-3.5 GHz were designed and fabricated using two transistors
(25 W and 45 W). In addition, more compact load modulation amplifiers
targeting sub 6-GHz bandwidth of 5G specifically 3.4-3.8 GHz is discussed
including the theory of implementing these amplifiers, where different amplifier
capabilities are explored. Each amplifier design was discussed in detail, in
which the input and output matching networks were designed and tested in
addition to the design of the stability circuit to make sure that the amplifier is
stable and working according to the specified requirements. The fabricated
circuits were evaluated practically using the available instrument test, whereas
Microwave Office software was used for the simulation purpose, each amplifier
was designed separately, where all the designed amplifiers were able to provide
the targeted efficiency at different back-off power points. Besides, some
additional factors that affect the designed load modulation amplifiers such as
the effect of the harmonics at the back-off and mismatching the amplifier is
discussed. / European Union’s Horizon 2020 research and innovation programme (SECRET)
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