High-frequency RFID tags: an analytical and numerical approach for determining the induced currents and scattered fields

2006 ◽  
Author(s):  
B.D. Braaten ◽  
Yuxin Feng ◽  
R.M. Nelson
Keyword(s):  
High Frequency ◽  
Numerical Approach ◽  
Rfid Tags ◽  
Induced Currents ◽  
Scattered Fields

scholarly journals Design of Nested H slot Passive UHF RFID Tag

2020 ◽  
Vol 10 (1) ◽  
pp. 346-349
Keyword(s):  
High Frequency ◽  
Microstrip Antenna ◽  
Rfid Tags ◽  
Uhf Rfid ◽  
Antenna Structure ◽  
Rfid Tag ◽  
Passive Uhf Rfid ◽  
Related Information ◽  
Distance Communication ◽  
Passive Rfid

RFID is a short distance communication system which comprises of a RFID tag, a RFID reader and a personal computer with desired software that can maintain the related information. These RFID tags can be of active or passive types. This paper focuses on design, simulation and fabrication of passive ultra-high frequency RFID tag (microchip and an antenna) which resonates at the frequency 866 MHz in the Industrial Scientific Medical Band. The nested H-slot inverted-F microstrip antenna structure is used for the design of passive RFID tag. It examines the specific tag geometry and its characteristics to optimize the PIFA antenna and in turn RFID tag’s performance.

scholarly journals THE MULTILEVEL FAST PHYSICAL OPTICS METHOD FOR CALCULATING HIGH FREQUENCY SCATTERED FIELDS

2020 ◽  
Vol 169 ◽  
pp. 1-15
Author(s):  
Zhiyang Xue ◽  
Yu Mao Wu ◽  
Weng Cho Chew ◽  
Ya-Qiu Jin ◽  
Amir Boag
Keyword(s):  
High Frequency ◽  
Physical Optics ◽  
Scattered Fields

High-Frequency Analyses for Scattered Fields by a Cylindrically Curved Conducting Surface

2009 ◽  
Vol E92-C (1) ◽  
pp. 25-32 ◽  
Author(s):  
Keiji GOTO ◽  
Toru KAWANO ◽  
Toyohiko ISHIHARA
Keyword(s):  
High Frequency ◽  
Conducting Surface ◽  
Scattered Fields

A new concept for design of the shape ship stern

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Beazit Ali ◽  
Levent Ali
Keyword(s):  
High Frequency ◽  
Mathematical Problem ◽  
Free Water ◽  
Numerical Approach ◽  
Ship Wake ◽  
Marquardt Algorithm ◽  
Cavitation Tunnel ◽  
Key Factor ◽  
The One ◽  
The Given

The paper presents an original stern shapes design which obtaining a good distribution of the ship wake able to reduce the drag. The paper begins to present the problems directly and reversely, physical mathematical shaping and the numerical implementation (including the precision of numerical approach). For this purpose, the imagining of a current tube is suggested, with increasing variable cylindrical sections, which starts from the disk in front of the propeller, extends towards the prow, very close to the cylindrical area and which includes the entire stern section of a classic hull having practiced cross corrugated sections). Certainly, the dynamics of a cavity propeller depends on the work environment system. The flow field around a propeller mounted on the ship is very different to the one that a propeller develops when tested in free water or in a section of a cavitation tunnel. A propeller with a very performance in free water may not be right for a stern shape of a hull of the given ship. For this reason, the ship wake distribution in the propeller disk plan represents a key factor for a ship design. The study tries to draw attention and briefly focuses on ships hull’s stern flows in the light of two absolutely strict original ideas (concepts) in ship hydrodynamics, belonging to the author: 1.a new stern hydrodynamic concept (NSHC), with radial crenellated-corrugated sections 2. using of an inverse piezoelectric effect [(electric current→high-frequency power generator→ piezoelectric driver made of certain ceramic material, which induces an elliptical vibratory movement (high frequency over 20 kHz), into the elastic side plates (15 mm thickness) in the streamlines direction (of the external flowing water)], able to reduce the total forward resistance. Resuming, it can be concluded that the new concept of stern shape proposed as well as the reverse mathematical problem presented above for its optimization, based on the Levenberg-Marquardt algorithm seem to be reasonable. Finally, the most important, until now, proved result, is the reducing of propeller cavitation (working in the simulated nominal wake of the hull using the new shape stern.Keywords: vessel wake, propeller cavitation, drag, stern shape, cavitation tunnel, ultrasonic vibrator.

scholarly journals High-frequency asymptotic solution for scattered fields by a junction of planar impedance surfaces

2010 ◽  
Vol 7 (14) ◽  
pp. 1072-1078 ◽  
Author(s):  
Toru Kawano ◽  
Keiji Goto ◽  
Toyohiko Ishihara
Keyword(s):  
Asymptotic Solution ◽  
High Frequency ◽  
Scattered Fields

scholarly journals Geomagnetically induced currents in the New Zealand power system

2021 ◽  
Author(s):  
Kamran Mukhtar
Keyword(s):  
New Zealand ◽  
High Frequency ◽  
Low Frequency ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Period Range ◽  
The North ◽  
Single Station ◽  
Frequency Components ◽  
Induced Currents

<p><b>This thesis focuses on the use of magnetotelluric (MT) data from both the North Island and South Island of New Zealand to model Geomagnetically Induced Currents (GIC) in the New Zealand power network. The model results have been compared with those from a previously used thin-sheet (TS) conductance model and with measured GIC. </b></p> <p>Initially, a single station modelling approach using a uniform conductivity Earth model is used to model the measured GIC in a transformer at Islington (ISL). This model is further improved by separately modelling low and high frequency components of GIC and then combining these to give full GIC. The model reproduces most of the GIC variations and the correlation coefficient is >70% for major magnetic storms from 2002-2015. As the model reproduces an average response of the network towards geoelectric fields it underestimates the most of extreme GIC. The analysis of GIC from other substations suggests that measured GIC depend on local geoelectric fields and the substation configuration within the network which cannot be captured using a single station approach. These limitations of single station model are addressed using more realistic geoelectric fields based on magnetotelluric data and consideration of the full network. </p> <p>To compute geoelectric fields in the whole network the gaps between MT sites are filled using a Nearest Neighbor interpolation technique. As the northern part of the North Island has no MT data an equivalent circuit approach is followed to model GIC for only the lower part of the network. The MT model GIC are in the period range of 2-30 minutes, based on the available MT data period range. Both the MT and TS techniques are used to compute geoelectric fields and to model GIC for the St. Patrick’s Day storm of 2015 and a 20 November 2003 magnetic storm. Both the MT and TS methods show the same transformers as experiencing large GIC during both storms. The primary difference between the models is that amplitudes of high frequency components of the TS model are significantly smaller than for the MT model. In particular they do not produce large GIC during the sudden storm commencement (SSC) of the St. Patrick’s Day magnetic storm. For the 20 November 2003 storm the TS model effectively reproduces the low frequency components and extreme GIC. The model results show that the North Island power network could be at risk during adverse space weather conditions.</p> <p>Although the South Island has sparser MT data the same technique is used to model SI GIC during both the St. Patrick’s Day and 2003 magnetic storms. Results are compared with measured data from ISL, South Dunedin (SDN) and Halfway Bush (HWB) transformers. The MT model effectively reproduces the measured GIC variations particularly during SSC during the St. Patrick’s Day storm. The TS model gives a very small GIC magnitude during the SSC. During the 20 November 2003 storm both the MT and TS models reproduce strong amplitudes of low frequency components seen in the ISL measured data. </p> <p>Both the MT and TS models show a substantial scale difference between measured and model GIC both for ISL and HWB transformers that needs to be further explored either in terms of better geoelectric interpolation or power network parameters. Overall, the MT model appears much more promising for future GIC modelling, particularly during a sudden storm commencement and for abrupt GIC variations.</p>

scholarly journals Geomagnetically induced currents in the New Zealand power system

2021 ◽  
Author(s):  
Kamran Mukhtar
Keyword(s):  
New Zealand ◽  
High Frequency ◽  
Low Frequency ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Period Range ◽  
The North ◽  
Single Station ◽  
Frequency Components ◽  
Induced Currents

<p><b>This thesis focuses on the use of magnetotelluric (MT) data from both the North Island and South Island of New Zealand to model Geomagnetically Induced Currents (GIC) in the New Zealand power network. The model results have been compared with those from a previously used thin-sheet (TS) conductance model and with measured GIC. </b></p> <p>Initially, a single station modelling approach using a uniform conductivity Earth model is used to model the measured GIC in a transformer at Islington (ISL). This model is further improved by separately modelling low and high frequency components of GIC and then combining these to give full GIC. The model reproduces most of the GIC variations and the correlation coefficient is >70% for major magnetic storms from 2002-2015. As the model reproduces an average response of the network towards geoelectric fields it underestimates the most of extreme GIC. The analysis of GIC from other substations suggests that measured GIC depend on local geoelectric fields and the substation configuration within the network which cannot be captured using a single station approach. These limitations of single station model are addressed using more realistic geoelectric fields based on magnetotelluric data and consideration of the full network. </p> <p>To compute geoelectric fields in the whole network the gaps between MT sites are filled using a Nearest Neighbor interpolation technique. As the northern part of the North Island has no MT data an equivalent circuit approach is followed to model GIC for only the lower part of the network. The MT model GIC are in the period range of 2-30 minutes, based on the available MT data period range. Both the MT and TS techniques are used to compute geoelectric fields and to model GIC for the St. Patrick’s Day storm of 2015 and a 20 November 2003 magnetic storm. Both the MT and TS methods show the same transformers as experiencing large GIC during both storms. The primary difference between the models is that amplitudes of high frequency components of the TS model are significantly smaller than for the MT model. In particular they do not produce large GIC during the sudden storm commencement (SSC) of the St. Patrick’s Day magnetic storm. For the 20 November 2003 storm the TS model effectively reproduces the low frequency components and extreme GIC. The model results show that the North Island power network could be at risk during adverse space weather conditions.</p> <p>Although the South Island has sparser MT data the same technique is used to model SI GIC during both the St. Patrick’s Day and 2003 magnetic storms. Results are compared with measured data from ISL, South Dunedin (SDN) and Halfway Bush (HWB) transformers. The MT model effectively reproduces the measured GIC variations particularly during SSC during the St. Patrick’s Day storm. The TS model gives a very small GIC magnitude during the SSC. During the 20 November 2003 storm both the MT and TS models reproduce strong amplitudes of low frequency components seen in the ISL measured data. </p> <p>Both the MT and TS models show a substantial scale difference between measured and model GIC both for ISL and HWB transformers that needs to be further explored either in terms of better geoelectric interpolation or power network parameters. Overall, the MT model appears much more promising for future GIC modelling, particularly during a sudden storm commencement and for abrupt GIC variations.</p>

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