Papers by Agostinho Linhares
Journal of Microwaves, Optoelectronics and Electromagnetic Applications, 2013
IEEE Communications Magazine
2017 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC), 2017
This paper presents an open source simulation tool called SHARC. This software is designed to sup... more This paper presents an open source simulation tool called SHARC. This software is designed to support sharing and compatibility studies between IMT systems (including 5G) and other radiocommunication systems according to the framework proposed by Recommendation ITU-R M.2101. In order to show some of the simulator capabilities, this paper also presents a preliminary sharing study between 5G systems and Fixed Satellite Service (FSS) that operate in the same frequency band.
2017 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC), 2017
This paper presents in-situ evaluations comparing the EMF exposure associated with a BTS installe... more This paper presents in-situ evaluations comparing the EMF exposure associated with a BTS installed in the vicinity of an apartment, WLAN device and baby monitor in a typical scenario. The results show that under certain circumstances the exposure in the latter cases can be higher than the former.
2021 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC)
The objective of this paper is to present the international regulations of the main sources cited... more The objective of this paper is to present the international regulations of the main sources cited in documents of the World Health Organization (WHO) dealing with the human exposure to electromagnetic fields in the radio frequency range, such as ICNIRP , ITU , IEEE and IEC, also presenting WHO's position on the accumulated scientific knowledge to date and what is being done by these entities with respect to, as well as the measures that have been taken in Brazil. The methodology used was based on literature, revisiting the documents issued by WHO , the Rules and Recommendations approved by the other mentioned entities as well as working papers and presentations at congresses held by these entities.
2019 IEEE 89th Vehicular Technology Conference (VTC2019-Spring), 2019
High-Altitude Platform Systems (HAPS) are being studied as a viable, easy to deploy and to mainta... more High-Altitude Platform Systems (HAPS) are being studied as a viable, easy to deploy and to maintain technology to provide isolated areas with connectivity. They can be integrated to existing cellular networks and have a wide coverage area, presenting a lower cost than satellite systems. The deployment of HAPS, however, demands that country administrations allocate and release spectrum for the system. That is why ITU is studying the possibility of identifying the 24.25- 27.5 GHz and 38-39.5GHz bands for HAPS. Even though these bands are already allocated to the Fixed-Satellite Service (FSS), the bands could be shared, as long as the HAPS stations do not cause harmful interference to the existing and future FSS stations. This paper presents a sharing study between these two systems, to assess the amount of interference the deployment of the HAPS in these bands would cause to the FSS. We conclude that, with some basic coordination, the two systems can share the same frequency band with...
In Brazil the 698-806 MHz frequency band was refarmed and it will be used by mobile operators for... more In Brazil the 698-806 MHz frequency band was refarmed and it will be used by mobile operators for the deployment of fourth generation IMT systems after the analog switch-off. That brings the possibility of interference on TV receivers introduced by the incoming system. Therefore, it is important to study the coexistence between both systems. In this paper we show the result of a field trial on the effect of the downlink of an LTE system with 10 MHz bandwidth (763-773 MHz) in an ISDB-T receivers on channel 51 (692-698 MHz). The results show that, for the trial scenario, interference can be identified only in critical cases and can be easily mitigated using filters between the antenna and the ISDB-T receiver.
2021 15th European Conference on Antennas and Propagation (EuCAP)
This work proposes a technological solution for allowing a peaceful coexistence between 5G New Ra... more This work proposes a technological solution for allowing a peaceful coexistence between 5G New Radio (5G NR) and satellite Television Receive Only (TVRO) services in C-band. A detailed analysis and an efficient redesign of a typical low-noise block converter feeder (LNBF), used by TVRO home users, is conducted aiming to reduce the 5G NR interference, which is going to operate at TVRO adjacent channels in some countries. Basically, we exploit two enhancements on the LNBF topology, namely: increasing the 1 dB compress point (P1dB) (input) level of its low noise amplifiers (LNAs), in both first and second stages; incorporating a low-cost and high-performance passband RF filter. As the main contribution, it is demonstrated the protection distance - calculated in accordance to the International Telecommunication Union (ITU) recommendations- might be significantly reduced from 20.85 km to only 22 m, by using the proposed high-performance LNBF.
2021 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC)
IEEE Antennas and Propagation Magazine
2017 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC)
Anais de XXXVIII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais
Journal of Communication and Information Systems
Telecommunication Systems, 2017
Microwave and Optical Technology Letters, 2015
ABSTRACT When evaluating the compliance of a radiocommunication station with the limits of exposu... more ABSTRACT When evaluating the compliance of a radiocommunication station with the limits of exposure to radiofrequency electromagnetic fields (RF EMF), the technical staff should measure the field at some points near the radiocommunication station. This procedure is usually done using the intuition of the staff. To overcome this fact, this letter shows how to calculate the region of maximum exposure to RF EMF due to a radiocommunication station. The method was tested using measurements made in Brasília/Brazil and in Aarhus/Denmark.
International Journal of Antennas and Propagation, 2014
A base station (BS) antenna operates in accordance with the established exposure limits if the va... more A base station (BS) antenna operates in accordance with the established exposure limits if the values of electromagnetic fields (EMF) measured in points of maximum exposure are below these limits. In the case of BS in open areas, the maximum exposure to EMF probably occurs in the antenna’s boresight direction, from a few tens to a few hundred meters away. This is not a typical scenery for urban environments. However, in the line of sight (LOS) situation, the region of maximum exposure can still be analytically estimated with good results. This paper presents a methodology for the choice of measurement points in urban areas in order to assess compliance with the limits for exposure to EMF.
2013 SBMO/IEEE MTT-S International Microwave & Optoelectronics Conference (IMOC), 2013
ABSTRACT Maximum human exposure to electromagnetic field associated to a base station is, usually... more ABSTRACT Maximum human exposure to electromagnetic field associated to a base station is, usually, due to the main lobe of the antenna and is located in the range of some tens to a few hundred meters from its mast. In this paper, we discuss practical situations in which the side lobes of the antenna is responsible for the maximum exposure in distances closer to the base station, even transporting less energy than the main lobe. It will also be presented guidelines to estimate what portions of the pattern of the antenna contributes to the highest field strength. This guidance may be used when few radiating system information is available, like gain, height, tilt and vertical half-power angle, and side lobe level.
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Papers by Agostinho Linhares