- Ruđera Boškovića 32
21 000 Split
Croatia
EU - +385 21 305 676
- Engineering, Electrical Engineering, Antennas & Radio Wave Propagation, Radio, Wireless Communications, Wireless networks, and 8 moreWireless Sensor Networks, Wireless Power Transmission, Wirelles, Radio Channel Modelling, Radio Communications, Nikola Tesla, Nikola Tesla Wireless Power Transmission, and Tesla Coiledit
- I'm a university professor from Split, Croatia, EU.edit
Research Interests:
Research Interests:
Research Interests:
Passive Gen2 RFID systems based on the wireless communication between readers and tags have become the enabling technology for Internet of Things (IoT) application. Such passive RFID tags are powered up by incident RF power and they... more
Passive Gen2 RFID systems based on the wireless communication between readers and tags have become the enabling technology for Internet of Things (IoT) application. Such passive RFID tags are powered up by incident RF power and they respond back to the reader by modulating the backscattering power in terms of changing the tag IC impedance. In various environments this incident power can oscillate and have a certain influence on the power of tag signal. This may have a significant influence on the data available at the reader, especially when analyzing the multiple tag responses, which may happen at the same time (usually referred to as a collision of multiple tags). This paper associates the electromagnetic problem of chip's impedance matching with the variation of tag SNR at the reader. The simulation results depict the difference of tag's backscattering for some chip impedance states. By using fully configurable Software Defined Radio (SDR), the performances of the actual system and characterize the variation of SNR at the reader was retrieved.
Research Interests:
It is well known in the research community that the throughput of dynamic frame slotted ALOHA (DFSA) in a radio frequency identification (RFID) system can be maximized when DFSA frame size is set to the number of tags. However, related... more
It is well known in the research community that the throughput of dynamic frame slotted ALOHA (DFSA) in a radio frequency identification (RFID) system can be maximized when DFSA frame size is set to the number of tags. However, related works often neglect the fact that tag responsiveness is of a stochastic nature, depending on the tag hardware performance in the wireless channel. Therefore, as number of tag responses may not be equal to the number of tags located in the interrogation area, corrections to the standard simulation models should be applied. In this letter, we provide the corrections that are based on tag read probability (TRP) metrics. At first, numerically, TRP was retrieved by the usage of fully configurable open-source software defined radio RFID reader in an indoor nonfading radio channel at the single frequency and constant output power, while considering reliable communication parameters in the environment of single and a pair of commercial Gen2 RFID tags. Then, TRP is statistically modeled, and the implications to the throughput are shown.
Research Interests:
Research Interests:
The paper deals with a simplified assessment of distribution of Specific Absorption Rate averaged over a whole body (SARWB) for the human exposure to near RFiD reader antennas. SARWB is computed for various distances between the antenna... more
The paper deals with a simplified assessment of distribution of Specific Absorption Rate averaged over a whole body (SARWB) for the human exposure to near RFiD reader antennas. SARWB is computed for various distances between the antenna and the user featuring parallelepiped model of the human body. The frequencies of interest are $f = 100$ kHz, $f = 13.56$ MHz, $f = 915$ MHz and $f = 2.4$ GHz, and the reader is assumed to radiate EIRP of 4 We.i.r.p.. The obtained results show that for distances between 1 cm and 2 m from the reader antenna SARWB values are below the allowed limit of 0.4 W/kg for workers.
Research Interests:
Ground penetrating radar as a non-invasive method is widely used in various areas. In this paper we focused on GPR wall inspection application where wideband channel properties are analyzed. The contribution is related to the... more
Ground penetrating radar as a non-invasive method is widely used in various areas. In this paper we focused on GPR wall inspection application where wideband channel properties are analyzed. The contribution is related to the characterization of indoor multipath propagation of GPR signal in order to address the possible influence on human exposure and interference with other devices. Using the commercial software for simulation model and visualization of the propagation effects, it is shown that the position of the transmitter can be crucial for exceeding the prescribed regulatory limits.
Research Interests:
Radio frequency identification (RFID) technology, based on wireless communication between a reader and tags, is the most popular technology for indoor item identification and tracking. Among competing RFID technologies, Gen2 has emerged... more
Radio frequency identification (RFID) technology, based on wireless communication between a reader and tags, is the most popular technology for indoor item identification and tracking. Among competing RFID technologies, Gen2 has emerged as the most popular one, due to the best price/performance ratio. In order to communicate with multiple tags, Gen2 RFID systems use dynamic frame slotted ALOHA (DFSA) as a medium access control (MAC) mechanism. To maximize DFSA throughput simple calculations show that the number of tags should equal the DFSA frame size. However, the number of tags in an environment is usually unknown and has to be estimated. So far, significant effort has been invested in estimating the correct number of tags. However, to the best of our knowledge, no one has explored the estimator performance in a real RFID measuring scenario. In this paper, we evaluate the throughput of a real RFID system by using the Software Defined Radio (SDR) technology. Our results show that phenomena related to radio waves propagation and reception have a significantly bigger influence on Gen2 RFID throughput than traditional approaches take into account.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
In this paper, iterative procedures based on Banach fixed-point theorem of adjusting transmitter and receiver impedances for achieving the maximum near-field power transfer performances are explored. As the background of proposed methods... more
In this paper, iterative procedures based on Banach fixed-point theorem of adjusting transmitter and receiver impedances for achieving the maximum near-field power transfer performances are explored. As the background of proposed methods for controlling frequency splitting, an important phenomenon that occurs when two antennas are coupled in near-field, the analysis of the resonant near-field coupling using spherical mode theory-antenna model is applied. Methods of recursive alternate system tuning, critical coupling, and conjugate matching are mutually compared, and selection among them is given on disposal to user to achieve aimed performances.
Research Interests:
Research Interests:
Research Interests:
Passive Gen2 RFID systems based on the wireless communication between readers and tags have become the enabling technology for Internet of Things (IoT) application. Such passive RFID tags are powered up by incident RF power and they... more
Passive Gen2 RFID systems based on the wireless communication between readers and tags have become the enabling technology for Internet of Things (IoT) application. Such passive RFID tags are powered up by incident RF power and they respond back to the reader by modulating the backscattering power in terms of changing the tag IC impedance. In various environments this incident power can oscillate and have a certain influence on the power of tag signal. This may have a significant influence on the data available at the reader, especially when analyzing the multiple tag responses, which may happen at the same time (usually referred to as a collision of multiple tags). This paper associates the electromagnetic problem of chip's impedance matching with the variation of tag SNR at the reader. The simulation results depict the difference of tag's backscattering for some chip impedance states. By using fully configurable Software Defined Radio (SDR), the performances of the actual system and characterize the variation of SNR at the reader was retrieved.
Research Interests:
In an RFID network, the signal transmitted by a reader to query tags may interfere with the communication of other surrounding readers. As a consequence, the readers are not able to detect the weak reply from tags. The reader-to-reader... more
In an RFID network, the signal transmitted by a reader to query tags may interfere with the communication of other surrounding readers. As a consequence, the readers are not able to detect the weak reply from tags. The reader-to-reader interference affects readers located within a given distance, called interference range. This phenomenon can be estimated when deploying an RFID system, because the initial positions of the readers are known. It is also possible to completely avoid it by placing the readers far enough each other. However, if the readers are mobile, the distances among readers change and the probability of reader-to-reader interference dramatically increases. A theoretical analysis is conducted in this paper in order to estimate the probability of interference among static and mobile readers. The random waypoint model, one of the most common mobility models, is adopted to describe the movements of the readers. The theoretical results are validated with simulations.
Research Interests:
In this paper, human body exposure to LF and HF electromagnetic field is analyzed. Antennas and wireless power transfer (WPT) systems are numerically modelled using commercial software FEKO. The analysis is carried out for two simplified... more
In this paper, human body exposure to LF and HF electromagnetic field is analyzed. Antennas and wireless power transfer (WPT) systems are numerically modelled using commercial software FEKO. The analysis is carried out for two simplified models of human body (parallelepiped and cylinder model) exposed to radiation in terms of power transfer efficiency (PTE) and specific absorption rate (SAR)) at frequencies of 13.56 MHz, 6.78 MHz and 100 kHz. It is shown that the SAR in simplified human body model does not exceed the reference limit values prescribed by international guidelines. Used simplified models are validated by comparison with realistic human body model results at 13.56 MHz from literature.
Research Interests:
The paper deals with a simplified assessment of distribution of Specific Absorption Rate averaged over a whole body (SARWB) for the human exposure to near RFiD reader antennas. SARWB is computed for various distances between the antenna... more
The paper deals with a simplified assessment of distribution of Specific Absorption Rate averaged over a whole body (SARWB) for the human exposure to near RFiD reader antennas. SARWB is computed for various distances between the antenna and the user featuring parallelepiped model of the human body. The frequencies of interest are $f = 100$ kHz, $f = 13.56$ MHz, $f = 915$ MHz and $f = 2.4$ GHz, and the reader is assumed to radiate EIRP of 4 We.i.r.p.. The obtained results show that for distances between 1 cm and 2 m from the reader antenna SARWB values are below the allowed limit of 0.4 W/kg for workers.
Research Interests:
RFID tags, made of IC and connected antenna represent a huge advantage in process automation. Now, it is possible to track, identify and get tagged item status in real time. However, the weaknesses of technology cause tags to be missed... more
RFID tags, made of IC and connected antenna represent a huge advantage in process automation. Now, it is possible to track, identify and get tagged item status in real time. However, the weaknesses of technology cause tags to be missed during the read process which can happen due to many different reasons. Consumers would appreciate if these performances can be given in a lean way. Although many contributions done so far to evaluate the performances, still there is certain space for improvements from different aspects ranging from cost-effectiveness of the platform to particular metrics of interest to be defined upon specific test scenario. This paper, in tutorial fashion, provides results obtained from SDR-based measurement platform. The results can be used for building custom-based performance metrics and evaluate RFID tags in particular scenario.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
It is well known in the research community that the throughput of dynamic frame slotted ALOHA (DFSA) in a radio frequency identification (RFID) system can be maximized when DFSA frame size is set to the number of tags. However, related... more
It is well known in the research community that the throughput of dynamic frame slotted ALOHA (DFSA) in a radio frequency identification (RFID) system can be maximized when DFSA frame size is set to the number of tags. However, related works often neglect the fact that tag responsiveness is of a stochastic nature, depending on the tag hardware performance in the wireless channel. Therefore, as number of tag responses may not be equal to the number of tags located in the interrogation area, corrections to the standard simulation models should be applied. In this letter, we provide the corrections that are based on tag read probability (TRP) metrics. At first, numerically, TRP was retrieved by the usage of fully configurable open-source software defined radio RFID reader in an indoor nonfading radio channel at the single frequency and constant output power, while considering reliable communication parameters in the environment of single and a pair of commercial Gen2 RFID tags. Then, TRP is statistically modeled, and the implications to the throughput are shown.
Research Interests:
Radio frequency identification (RFID) technology, based on wireless communication between a reader and tags, is the most popular technology for indoor item identification and tracking. Among competing RFID technologies, Gen2 has emerged... more
Radio frequency identification (RFID) technology, based on wireless communication between a reader and tags, is the most popular technology for indoor item identification and tracking. Among competing RFID technologies, Gen2 has emerged as the most popular one, due to the best price/performance ratio. In order to communicate with multiple tags, Gen2 RFID systems use dynamic frame slotted ALOHA (DFSA) as a medium access control (MAC) mechanism. To maximize DFSA throughput simple calculations show that the number of tags should equal the DFSA frame size. However, the number of tags in an environment is usually unknown and has to be estimated. So far, significant effort has been invested in estimating the correct number of tags. However, to the best of our knowledge, no one has explored the estimator performance in a real RFID measuring scenario. In this paper, we evaluate the throughput of a real RFID system by using the Software Defined Radio (SDR) technology. Our results show that phenomena related to radio waves propagation and reception have a significantly bigger influence on Gen2 RFID throughput than traditional approaches take into account.