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Substrate integrated waveguide antenna systemsSalem Hesari, Sara 29 January 2019 (has links)
Due to high demand for planar structures with low loss, a considerable amount
of research has been done to the design of substrate integrated waveguide (SIW)
components in the mm-wave and microwave range. SIW has many advantages in
comparison to conventional waveguides and microstrip lines, such as compact and
planar structure, ease of fabrication, low radiation loss, high power handling ability
and low cost which makes it a very promising technology for current and future
systems operating in K-band and above. Therefore, all the work presented in this
dissertation focuses on SIW technology. Five di erent antenna systems are proposed
to verify the advantages of using SIW technology.
First, a novel K-band end- re SIW circularly polarized (CP) antenna system on
a single layer printed-circuit board is proposed. A high gain SIW H-plane horn and a
Vivaldi antenna are developed to produce two orthogonal polarizations in the plane of
the substrate. CP antennas have become very popular because of their unique characteristics and their applications in satellites, radars and wireless communications.
Second, a K-band front-end system for tracking applications is presented. The circuit comprises an antenna array of two Vivaldi antennas, a frequency-selective power combiner, and two frequency-selective SIW crossovers, which eliminate the need for subsequent ltering. The integration of monopulse systems in planar, printed circuit
SIW technology combined with the added bene ts of ltering functions is of great importance to the antennas and propagation community.
Third, a phased array antenna system consisting of 24 radiating element is designed
as feed system for reflector antennas in radio astronomy applications. A Ku-band antipodal dipole antenna with wide bandwidth, low cross-polarization and wide beamwidth is suggested as the radiating element.
Forth, four di erent right-angled power dividers including in-phase and out-of-phase
dividers as feed systems for antenna arrays are introduced. TE10 - to - TEq0 mode transducers are used for obtaining two, three, and four output dividers with phase control ability at K- and Ka-band. This feature is practical, for instance, when designing tracking systems since they are employed to obtain controllable phase distributions over the output ports.
Fifth, a Ku-band beam steering antenna system which is applicable to use for wireless communications, radar systems, and also 5G applications is proposed. This antenna system uses variable reflection-type phase shifters which electrically steer the beam over a 50-degree scan range.
Therefore, the SIW technology's reliability and also promising behavior in the microwave frequency range is proven for di erent applications. / Graduate
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Compact-size linearly tapered slot antenna for portable ultra-wideband imaging systemsZhu, F., Gao, S., Ho, A.T.S., See, Chan H., Abd-Alhameed, Raed, Li, J., Xu, J. 10 August 2012 (has links)
No / A compact-size asymmetrical linearly tapered slot antenna required for portable ultra-wideband (UWB) imaging systems is presented. The total antenna size is reduced compared with the conventional linearly tapered slot antenna by using a triangular slot on the left-hand side of the tapered-shaped radiator, whereas introducing a corrugated pattern of cuts on the right side. The antenna operates over a wide bandwidth extending from 3.1 to 10.6 GHz with a maximum gain of 8.5 dBi. Stable radiation patterns are observed across the operational bandwidth, with cross-polarization levels below 20 dB. The realized antenna structure occupies a volume of 35 x 36 x 0.8 mm3, and possesses the essential time domain fidelity needed for UWB imaging applications. (c) 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.
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Realization of Miniaturized Multi-/Wideband Microwave Front-EndsAl Shamaileh, Khair Ayman January 2015 (has links)
No description available.
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