Antenna beam steering and beam forming at mm Wave and THz frequencies
The evolution of wireless communications and the emergence of novel applications will spur the demand of higher data rates, requiring, on one hand, unallocated spectrum in the millimeter Wave (mm-Wave) and Terahertz (THz) frequency bands to be exploited. On the other hand, the high propagation loss...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/343770 |
| Acceso en línea: | https://hdl.handle.net/2117/343770 |
| Access Level: | acceso abierto |
| Palabra clave: | Wireless communication systems Antennas (Electronics) wireless communications mm-Wave Terahertz beam forming beam steering Comunicació sense fil, Sistemes de Antenes (Electrònica) Àrees temàtiques de la UPC::Enginyeria de la telecomunicació |
| Sumario: | The evolution of wireless communications and the emergence of novel applications will spur the demand of higher data rates, requiring, on one hand, unallocated spectrum in the millimeter Wave (mm-Wave) and Terahertz (THz) frequency bands to be exploited. On the other hand, the high propagation loss in the higher spectral bands will entail reduction of coverage areas, so that taking the signal in native format up to the radio interfaces leveraging existing optical fiber infrastructure will be advantageous. Along the same lines, beam steering techniques are expected to play an important role in the envisioned integrated wireless-photonic network. Photonic techniques for next generation fiber-wireless networks will be explored in this work. On one hand, a multiwavelength (MW) optical true time delay Network (OTTDN) to feed a phased array antenna (PAA) is presented. Beam steering capabilities can be demonstrated when applying MW tuning. A Dual Electrode Mach Zehnder Modulator (DE-MZM) as radio frequency (RF) external modulating stage allows to tune the operative band avoiding severe Chromatic Dispersion (CD) fading to obtain a flattened response. An experimental setup for testing the technique in the UPC labs is described and studied in detail, showing the RF multiband spectral flat response potential of the technique, as well as the network conditions needed for beam steering with free-lobe operation. On the other hand, a simulation methodology to obtain the Co-Polar and Cross-Polar components of the far fields radiated by THz lens-coupled photoconductive antennas (PCAs) is presented and validated by applying and contrasting the solution with previous publications models, with excellent agreement, as well as by comparing simulated lens-coupled PCAs with measures made in our UPC labs with a Menlo time-domain spectrometer, showing the same pattern trends. Sierpinski structures are simulated at f=0.5 THz using this method, observing that the power improvement with the fractal order, as well as the Airy pattern width depend on both the sampling aperture and the receiving antenna pattern. Finally, a simulation of an off-axis feeding example scenario shows the steering properties of the hyperhemispherical lens geometry. |
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