This paper presents a switched beam antenna suitable for localization systems operating on 2.4–2.... more This paper presents a switched beam antenna suitable for localization systems operating on 2.4–2.5 GHz ISM band. The antenna is used in a system based on a wireless sensor network, and will be used for implementing Angle of Arrival (AoA) techniques combined with RF fingerprinting solutions. The proposed antenna, called Hive 5, is based on a sectorised design integrated with patch-excited horn antennas carefully designed to provide an improved radiation pattern and Axial Ratio (AR) in order to improve the system performance. This antenna provides a low cost solution for localization systems in indoor environments with gain improvement, reduced coupling between neighbor antennas and increased multipath rejection.
Indoor location systems is nowadays a huge area of interest not only at academic but also at indu... more Indoor location systems is nowadays a huge area of interest not only at academic but also at industry and commercial level. The correct location of these systems is strongly influenced by antennas performance which can provide gain, bandwidth, polarization and radiation pattern diversity due to large variety of antennas types and formats. The improvement of antennas performance can be greatly improved by the use of Electromagnetic Band-Gap (EBG) metamaterials and Micro Electro Mechanical Systems (MEMS) switching technology. This paper presents the state of art of antennas used nowadays in diverse indoor location systems. It is described the importance of choosing an appropriate antenna according to systems requirements, a brief explanation of common antennas types used for location, metamaterials advantages, smart antennas and MEMS technology.
2013 7th European Conference on Antennas and Propagation, 2013
A low-profile planar microstrip antenna array with elliptical elements is proposed, fabricated, a... more A low-profile planar microstrip antenna array with elliptical elements is proposed, fabricated, and measured. The operating bandwidth of the antenna is about 1 GHz (5.3-6.4 GHz). The impedance matching, radiation pattern and polarization are analyzed numerically and compared to measurements. This antenna provides a two main directive radiation components (front and back), and circular polarization (CP). Each elliptical element has an inner counter-elliptical slot which provides a way to easier match the antenna in impedance and polarization. The number of elliptical elements can be scaled to increase or decrease the antenna gain and the three parameters of the inner slot of the elliptical elements (radius, ratio and rotation) can be scaled for impedance and polarization matching over the band of interest.
Abstract Outdoor location/navigation systems are a useful support for our daily life. The majorit... more Abstract Outdoor location/navigation systems are a useful support for our daily life. The majority of these systems are based on Global Navigation Satellite Systems (GNSS), which include for example, Global Positioning System (GPS) and Galileo. For indoor location ...
Abstract Typical ZigBee location applications consume significant amounts of power when end devic... more Abstract Typical ZigBee location applications consume significant amounts of power when end devices receive messages for configuration and synchronization. These intervals often consume more power than the transmission process reducing significantly the devices ...
International Journal of Antennas and Propagation, 2012
This paper provides a review of antennas applied for indoor positioning or localization systems. ... more This paper provides a review of antennas applied for indoor positioning or localization systems. The desired requirements of those antennas when integrated in anchor nodes (reference nodes) are discussed, according to different localization techniques and their performance. The described antennas will be subdivided into the following sections according to the nature of measurements: received signal strength (RSS), time of flight (ToF), and direction of arrival (DoA). This paper intends to provide a useful guide for antenna designers who are interested in developing suitable antennas for indoor localization systems.
Abstract This paper presents a switched beam antenna suitable for localization systems operating ... more Abstract This paper presents a switched beam antenna suitable for localization systems operating on 2.4–2.5 GHz ISM band. The antenna is used in a system based on a wireless sensor network, and will be used for implementing Angle of Arrival (AoA) techniques ...
2015 1st URSI Atlantic Radio Science Conference (URSI AT-RASC), 2015
With the tremendous growth and relevance of Internet of Things (IoT) is last years it became a de... more With the tremendous growth and relevance of Internet of Things (IoT) is last years it became a demand to identify, communicate and transfer energy to all objects. These technologies are often desired to be hidden (or transparent) to the human eyes, not only by its aesthetic reasons but also by its reusability of the space which is often crucial. This reasons led to a significant grow in research of transparent conductors and antennas.
This paper presents a switched beam antenna suitable for localization systems operating on 2.4–2.... more This paper presents a switched beam antenna suitable for localization systems operating on 2.4–2.5 GHz ISM band. The antenna is used in a system based on a wireless sensor network, and will be used for implementing Angle of Arrival (AoA) techniques combined with RF fingerprinting solutions. The proposed antenna, called Hive 5, is based on a sectorised design integrated with patch-excited horn antennas carefully designed to provide an improved radiation pattern and Axial Ratio (AR) in order to improve the system performance. This antenna provides a low cost solution for localization systems in indoor environments with gain improvement, reduced coupling between neighbor antennas and increased multipath rejection.
Indoor location systems is nowadays a huge area of interest not only at academic but also at indu... more Indoor location systems is nowadays a huge area of interest not only at academic but also at industry and commercial level. The correct location of these systems is strongly influenced by antennas performance which can provide gain, bandwidth, polarization and radiation pattern diversity due to large variety of antennas types and formats. The improvement of antennas performance can be greatly improved by the use of Electromagnetic Band-Gap (EBG) metamaterials and Micro Electro Mechanical Systems (MEMS) switching technology. This paper presents the state of art of antennas used nowadays in diverse indoor location systems. It is described the importance of choosing an appropriate antenna according to systems requirements, a brief explanation of common antennas types used for location, metamaterials advantages, smart antennas and MEMS technology.
2013 7th European Conference on Antennas and Propagation, 2013
A low-profile planar microstrip antenna array with elliptical elements is proposed, fabricated, a... more A low-profile planar microstrip antenna array with elliptical elements is proposed, fabricated, and measured. The operating bandwidth of the antenna is about 1 GHz (5.3-6.4 GHz). The impedance matching, radiation pattern and polarization are analyzed numerically and compared to measurements. This antenna provides a two main directive radiation components (front and back), and circular polarization (CP). Each elliptical element has an inner counter-elliptical slot which provides a way to easier match the antenna in impedance and polarization. The number of elliptical elements can be scaled to increase or decrease the antenna gain and the three parameters of the inner slot of the elliptical elements (radius, ratio and rotation) can be scaled for impedance and polarization matching over the band of interest.
Abstract Outdoor location/navigation systems are a useful support for our daily life. The majorit... more Abstract Outdoor location/navigation systems are a useful support for our daily life. The majority of these systems are based on Global Navigation Satellite Systems (GNSS), which include for example, Global Positioning System (GPS) and Galileo. For indoor location ...
Abstract Typical ZigBee location applications consume significant amounts of power when end devic... more Abstract Typical ZigBee location applications consume significant amounts of power when end devices receive messages for configuration and synchronization. These intervals often consume more power than the transmission process reducing significantly the devices ...
International Journal of Antennas and Propagation, 2012
This paper provides a review of antennas applied for indoor positioning or localization systems. ... more This paper provides a review of antennas applied for indoor positioning or localization systems. The desired requirements of those antennas when integrated in anchor nodes (reference nodes) are discussed, according to different localization techniques and their performance. The described antennas will be subdivided into the following sections according to the nature of measurements: received signal strength (RSS), time of flight (ToF), and direction of arrival (DoA). This paper intends to provide a useful guide for antenna designers who are interested in developing suitable antennas for indoor localization systems.
Abstract This paper presents a switched beam antenna suitable for localization systems operating ... more Abstract This paper presents a switched beam antenna suitable for localization systems operating on 2.4–2.5 GHz ISM band. The antenna is used in a system based on a wireless sensor network, and will be used for implementing Angle of Arrival (AoA) techniques ...
2015 1st URSI Atlantic Radio Science Conference (URSI AT-RASC), 2015
With the tremendous growth and relevance of Internet of Things (IoT) is last years it became a de... more With the tremendous growth and relevance of Internet of Things (IoT) is last years it became a demand to identify, communicate and transfer energy to all objects. These technologies are often desired to be hidden (or transparent) to the human eyes, not only by its aesthetic reasons but also by its reusability of the space which is often crucial. This reasons led to a significant grow in research of transparent conductors and antennas.
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Papers by Luis Bras