VOR (navigation aérienne) | EPFL Graph Search

thumb|Deux azimuts relatifs à une balise VOR Le VOR (abréviation de VHF omnidirectional range) ou radiophare omnidirectionnel VHF est un système de positionnement radioélectrique utilisé en navigation aérienne et fonctionnant avec les fréquences VHF (ou UHF pour les militaires). Un récepteur VOR permet de déterminer un relèvement magnétique par rapport à une station au sol (balise émetteur VOR dont la position est connue), et donc le radial sur lequel le récepteur (donc l'avion) est situé. Par déduction, il permet de suivre n'importe quelle route passant par la station (en rapprochement ou en éloignement de celle-ci), ou même de déterminer la position exacte de l'avion en utilisant deux balises VOR (intersection de radiaux) ou un DME (intersection d'un radial et d'un arc DME). Rappelons que la route magnétique est l'angle orienté du Nord magnétique vers la trajectoire que suit l'avion. Par exemple, la route d'un avion se déplaçant vers l'est est égale à 90°. Description L

A portable picocell antenna for 5G

Danelys Rodríguez Avila

Deployable emergency communication systems are a backbone solution for replacing damaged network infrastructures and/or providing high-end services in case of an emergency event. It is important that such systems are up-to-date with the latest mobile network technology, for enabling connectivity to users and profiting from its enhanced capabilities. The advent of 5G promises higher data rates, lower latencies and improved quality of services when compared to previous generations. To achieve that, mm-Waves have been identified as a key element due to the wide available spectrum. The implementation of deployable emergency communication systems compatible with 5G mm-Waves technologies, thus benefiting from its prospective advantages, is of great interest. This thesis focuses on 5G mm-Waves antenna design for this kind of applications. The high network capacity demand, the unfavourable channel conditions at mm-Waves and the still underdeveloped related radio frequency (RF) technology define a group of challenging requirements on the antenna design. While directive antennas are required to mitigate the attenuation with distance at these bands, omnidirectional coverage still needs to be provided. In addition, wide bandwidth operation, high efficiency, and low cost and power consumption are desired. In this context, antennas with multibeam forming capabilities have been widely acknowledged as a key enabling technology to support 5G wireless communications, representing an attractive solution to provide omnidirectional coverage while supporting Multiple Input Multiple Output (MIMO) techniques. In this thesis, the design and implementation of a broadband efficient multibeam antenna for a portable picocell station are investigated. The picocell scenario in the context of emergency communications is studied and the antenna link budget is calculated considering mm-Waves propagation properties and available information on the upcoming standard. This leads to the definition of the design requirements and a preliminary antenna architecture that consists of an MxN antenna fed by a hybrid beamforming network (HBFN). This architecture is a promising approach for making multibeam antennas cost- and energy-efficient according to the latest research. The synthesis of the HBFN was realized considering the design constraints in elevation and azimuth such that the subarray, fed by an analog beamforming network, provides a csc2 pattern shape in elevation while M subarrays are controlled by a digital beamforming network to generate multiple orthogonal beams in azimuth. The antenna subarray was designed, fabricated and measured. Based on this, a study of the antenna array beamsteering capabilities in azimuth was carried out. After investigating the main parameters involved in improving its performance, the subarray design was optimized accordingly. The proposed antenna consists in a 12x6 array that works at 26 GHz with an impedance bandwidth higher than 12%. The radiation pattern shape in elevation is preserved over 7.3% of bandwidth. The antenna gain is superior to 10 dBi along the band of interest with a maximum value of 15 dBi. Simulated and measured results were compared, and the antenna beamsteering performance was tested for different sets of constraints indicating promising capabilities for a wide range of deployment scenarios. The proposed and validated design meets the requirements of the targeted applications on a practical low-profile implementation.

EPFL2021

Stacked patch antenna and hybrid beamforming network for 5G picocell applications

Danelys Rodríguez Avila, Anja Skrivervik Favre

This paper addresses the design of an antenna array for a portable picocell station with omnidirectional coverage. The proposed solution includes a stacked patch antenna as a single radiating element of the antenna array and a hybrid beamforming network. The antenna element works at 26 GHz with a bandwidth of 20% and a gain of approximately 8.5 dB along the operational bandwidth. The antenna is fed by a suspended stripline transitioned from a waveguide. This antenna element is used to compute a 5x12-element antenna array fed by the hybrid beamforming network. Results are analytically obtained for a fixed analog beamforming network that generates a csc squared pattern shape in elevation. Additionally, a digital beamforming network is computed to perform beamsteering for a desired set of constraints in the azimuth plane. Simulated results of the complete system yield promising insights on the capacity of the proposed design to provide omnidirectional coverage.

IEEE2019

Ultra-Wide Band Diversity Antenna for Omnidirectional Coverage

Tatjana Asenov, Anja Skrivervik Favre, Maxime Volery

In this paper, a 41 x 42.2 mm2 ultra-wide band (UWB) diversity antenna is designed to operate in the frequency band 5.45- 7.45 GHz with the isolation better than 15dB. To achieve omnidirectional coverage pattern diversity is applied. The proposed design is suitable for UWB applications requiring reliable radio link and coverage.

The European Association on Antennas and Propagation (EurAAP)2018

A portable picocell antenna for 5G

Danelys Rodríguez Avila

EPFL2021