Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178641
N. Khiabani, Yi Huang, Yao-chun Shen, S. Boyes
In designing terahertz (THz) antennas with high output power and/or high optical-THz conversion efficiency, the photoconductor property is an important consideration. According to the type of the optical excitation, THz antennas can be divided into two categories: THz photoconductive antennas in a pulsed system and THz photomixing antennas in a Continuous-Wave (CW) system. How different excitation types can affect the performance of the antenna is an important issue in THz systems. Thus, the aim of this paper is to investigate and compare THz photoconductive antennas and THz photomixing antennas from an important design parameter point of view; namely the conductance of the photoconductive material substrate which acts as the source for a PC antenna. Through numerical analyses of example systems, it is shown that source resistance of a THz antenna in a CW system is greater than those in a pulsed system. Further, an important practical system setting, the dependency of alignment of two beams in CW systems on antenna gap size is also investigated. It is illustrated that mixing efficiency for large gap antennas is more sensitive to angle between two beams.
{"title":"THz photoconductive antennas in pulsed systems and CW systems","authors":"N. Khiabani, Yi Huang, Yao-chun Shen, S. Boyes","doi":"10.1109/IWAT.2012.6178641","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178641","url":null,"abstract":"In designing terahertz (THz) antennas with high output power and/or high optical-THz conversion efficiency, the photoconductor property is an important consideration. According to the type of the optical excitation, THz antennas can be divided into two categories: THz photoconductive antennas in a pulsed system and THz photomixing antennas in a Continuous-Wave (CW) system. How different excitation types can affect the performance of the antenna is an important issue in THz systems. Thus, the aim of this paper is to investigate and compare THz photoconductive antennas and THz photomixing antennas from an important design parameter point of view; namely the conductance of the photoconductive material substrate which acts as the source for a PC antenna. Through numerical analyses of example systems, it is shown that source resistance of a THz antenna in a CW system is greater than those in a pulsed system. Further, an important practical system setting, the dependency of alignment of two beams in CW systems on antenna gap size is also investigated. It is illustrated that mixing efficiency for large gap antennas is more sensitive to angle between two beams.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"77 1","pages":"181-184"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90564822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178650
Jaehoon Choi, Uisheon Kim, Soonyong Lee, Kyeol Kwon
In this paper, an implantable planar inverted-F antenna (PIFA) for an artificial cardiac pacemaker is proposed. The antenna has a simple structure with a low profile and is placed on the top side of the pacemaker. The dimension of the pacemaker system, including the antenna element, is 42 mm × 43.6 mm × 11 mm. When the antenna is embedded in pig tissue, -10 dB impedance bandwidth of the antenna is 6 MHz (399 ~ 406 MHz). The proposed PIFA in tissue has a peak gain of -20.19 dBi and a radiation efficiency of 1.12 % at 403 MHz. When the proposed antenna is placed in a liquid flat phantom, its specific absorption ratio (SAR) value is 0.038 W/Kg (1 g tissue). Performances of the proposed PIFA is sufficient to operate at the MICS band (402 ~ 405 MHz).
{"title":"Design of an implantable antenna for WBAN applications","authors":"Jaehoon Choi, Uisheon Kim, Soonyong Lee, Kyeol Kwon","doi":"10.1109/IWAT.2012.6178650","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178650","url":null,"abstract":"In this paper, an implantable planar inverted-F antenna (PIFA) for an artificial cardiac pacemaker is proposed. The antenna has a simple structure with a low profile and is placed on the top side of the pacemaker. The dimension of the pacemaker system, including the antenna element, is 42 mm × 43.6 mm × 11 mm. When the antenna is embedded in pig tissue, -10 dB impedance bandwidth of the antenna is 6 MHz (399 ~ 406 MHz). The proposed PIFA in tissue has a peak gain of -20.19 dBi and a radiation efficiency of 1.12 % at 403 MHz. When the proposed antenna is placed in a liquid flat phantom, its specific absorption ratio (SAR) value is 0.038 W/Kg (1 g tissue). Performances of the proposed PIFA is sufficient to operate at the MICS band (402 ~ 405 MHz).","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"1 1","pages":"213-216"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76331106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.5515/JKIEES.2013.13.1.22
S. Ta, Jea Jin Han, H. Choo, I. Park
This paper describes a wideband double dipole quasi-Yagi antenna fed by a microstrip-to-slotline transition. The transition feed consists of a microstrip radial stub and a slot radial stub, each with the same angle of 90°, but with different radii to achieve wideband impedance matching. Double dipoles with different lengths are utilized as primary radiation elements to enhance bandwidth and achieve stable radiation patterns. The antenna has a bandwidth of 3.65-8.90 GHz for a -10 dB reflection coefficient, and a flat gain of 6.4-7.6 dB across the bandwidth. The proposed antenna could be widely applicable to wideband wireless communication systems due to wideband characteristics, planar structure, and stable radiation pattern.
{"title":"A wideband double dipole quasi-Yagi antenna using a microstrip-slotline transition feed","authors":"S. Ta, Jea Jin Han, H. Choo, I. Park","doi":"10.5515/JKIEES.2013.13.1.22","DOIUrl":"https://doi.org/10.5515/JKIEES.2013.13.1.22","url":null,"abstract":"This paper describes a wideband double dipole quasi-Yagi antenna fed by a microstrip-to-slotline transition. The transition feed consists of a microstrip radial stub and a slot radial stub, each with the same angle of 90°, but with different radii to achieve wideband impedance matching. Double dipoles with different lengths are utilized as primary radiation elements to enhance bandwidth and achieve stable radiation patterns. The antenna has a bandwidth of 3.65-8.90 GHz for a -10 dB reflection coefficient, and a flat gain of 6.4-7.6 dB across the bandwidth. The proposed antenna could be widely applicable to wideband wireless communication systems due to wideband characteristics, planar structure, and stable radiation pattern.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"5 1","pages":"84-87"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75205475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178685
Z. A. Pour, L. Shafai
A novel adaptive aperture antenna is presented. It can provide adaptive phase centre locations within a single aperture. It can be used to virtually make more than one antenna by controlling the excitation modes of the multimode primary feed illuminating the aperture. In this paper, the selected aperture is an offset reflector antenna fed by a dual-mode stacked microstrip. The resulting antenna has promising applications in electronically displaced phase centre antennas.
{"title":"Adaptive aperture antennas with adjustable phase centre locations","authors":"Z. A. Pour, L. Shafai","doi":"10.1109/IWAT.2012.6178685","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178685","url":null,"abstract":"A novel adaptive aperture antenna is presented. It can provide adaptive phase centre locations within a single aperture. It can be used to virtually make more than one antenna by controlling the excitation modes of the multimode primary feed illuminating the aperture. In this paper, the selected aperture is an offset reflector antenna fed by a dual-mode stacked microstrip. The resulting antenna has promising applications in electronically displaced phase centre antennas.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"125 1","pages":"355-357"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75989367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178390
N. Gvozdenovic, P. Gentner, C. Mecklenbrauker
In this paper we present channel measurements of an ultra-wideband radio frequency identification tag (UWB RFID) with on-chip antenna (OCA). The manufactured prototype with a size of 1×1.3 mm2 transmits a carrier-based UWB signal, with adjustable pulse duration and carrier frequency. The signal bandwidth is more than 1 GHz, on a carrier frequency up to 12.5 GHz. A measurement setup has been developed to emulate a relevant office scenario at very short distances, up to 30 cm. The known bit sequence, sent by the manufactured tag, allows us to estimate the near-field channel characteristics, and path loss exponent. We propose a simple near-field UWB path loss model based on our measurements.
{"title":"Near-field channel measurements for UWB RFID with on-chip antenna","authors":"N. Gvozdenovic, P. Gentner, C. Mecklenbrauker","doi":"10.1109/IWAT.2012.6178390","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178390","url":null,"abstract":"In this paper we present channel measurements of an ultra-wideband radio frequency identification tag (UWB RFID) with on-chip antenna (OCA). The manufactured prototype with a size of 1×1.3 mm2 transmits a carrier-based UWB signal, with adjustable pulse duration and carrier frequency. The signal bandwidth is more than 1 GHz, on a carrier frequency up to 12.5 GHz. A measurement setup has been developed to emulate a relevant office scenario at very short distances, up to 30 cm. The known bit sequence, sent by the manufactured tag, allows us to estimate the near-field channel characteristics, and path loss exponent. We propose a simple near-field UWB path loss model based on our measurements.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"64 1","pages":"28-31"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77510524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178416
X. Qing, Zhi Ning Chen
Near-field radio frequency identification (RFID) technology at ultra high frequency (UHF) bands is of increasingly interest because of its promising opportunities in item-level RFID applications. The conventional single solid-line loop antenna is unable to generate strong and uniform magnetic field within an electrically large interrogation zone at the UHF bands. Segmented loop antennas are promising for UHF near-field RFID applications since they are able to generate uniform and strong magnetic field in an electrically larger interrogation zone. The reported segmented loop antennas have been able to offer an interrogation zone with a perimeter of around two operating wavelengths. In this paper, the segmented loop antennas with enlarged interrogation zone are presented. Using dual or multiple segmented loop configurations, the perimeters of the interrogation zone of the antennas can be larger than three operating wavelengths at the UHF bands.
{"title":"UHF near-field segmented loop antennas with enlarged interrogation zone","authors":"X. Qing, Zhi Ning Chen","doi":"10.1109/IWAT.2012.6178416","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178416","url":null,"abstract":"Near-field radio frequency identification (RFID) technology at ultra high frequency (UHF) bands is of increasingly interest because of its promising opportunities in item-level RFID applications. The conventional single solid-line loop antenna is unable to generate strong and uniform magnetic field within an electrically large interrogation zone at the UHF bands. Segmented loop antennas are promising for UHF near-field RFID applications since they are able to generate uniform and strong magnetic field in an electrically larger interrogation zone. The reported segmented loop antennas have been able to offer an interrogation zone with a perimeter of around two operating wavelengths. In this paper, the segmented loop antennas with enlarged interrogation zone are presented. Using dual or multiple segmented loop configurations, the perimeters of the interrogation zone of the antennas can be larger than three operating wavelengths at the UHF bands.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"56 1","pages":"132-135"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86556369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178405
U. Azad, Y. Wang
Shannon theorem suggests that power coupled through and bandwidth of an inductively coupled near field communication (NFC) link must be traded off for optimal capacity. Direct Antenna Modulation (DAM) is a possible scheme to break this dilemma. With DAM technology utilized in NFC link, the power and bandwidth product limit in a high Q system can be circumvented because of non-linear/time varying operation. In this paper, a NFC link, consisting of identical transmitter and receiver coils of 5 cm radius and 24 turns with a Q value of 35, operating at 283 kHz is used. DAM is implemented on transmitter side and improvement in capacity is experimentally demonstrated for low loaded Q receiver.
{"title":"Direct Antenna Modulation scheme for enhanced capacity performance of near-field communication link","authors":"U. Azad, Y. Wang","doi":"10.1109/IWAT.2012.6178405","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178405","url":null,"abstract":"Shannon theorem suggests that power coupled through and bandwidth of an inductively coupled near field communication (NFC) link must be traded off for optimal capacity. Direct Antenna Modulation (DAM) is a possible scheme to break this dilemma. With DAM technology utilized in NFC link, the power and bandwidth product limit in a high Q system can be circumvented because of non-linear/time varying operation. In this paper, a NFC link, consisting of identical transmitter and receiver coils of 5 cm radius and 24 turns with a Q value of 35, operating at 283 kHz is used. DAM is implemented on transmitter side and improvement in capacity is experimentally demonstrated for low loaded Q receiver.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"1 1","pages":"88-91"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82729956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178675
T. Nguyen, Haewook Han, I. Park
This paper presents antenna structures suitable for terahertz photomixer designs. Two antenna structures are selected: a four-leaf-clover-shaped antenna on an extended hemispherical substrate lens and a full-wavelength dipole antenna on a thin substrate with backside excitation. The input impedance and radiation characteristics of each antenna are different, being affected by both the antenna shape and the substrate geometry. In addition, the bias line structure, which is indispensable in a THz photomixer antenna design, has a substantial effect on antenna performance, and a thorough understanding of its characteristics is necessary. Each antenna design will be presented in turn and some challenges facing antenna design will be discussed.
{"title":"Highly efficient resonant antennas for terahertz photomixers","authors":"T. Nguyen, Haewook Han, I. Park","doi":"10.1109/IWAT.2012.6178675","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178675","url":null,"abstract":"This paper presents antenna structures suitable for terahertz photomixer designs. Two antenna structures are selected: a four-leaf-clover-shaped antenna on an extended hemispherical substrate lens and a full-wavelength dipole antenna on a thin substrate with backside excitation. The input impedance and radiation characteristics of each antenna are different, being affected by both the antenna shape and the substrate geometry. In addition, the bias line structure, which is indispensable in a THz photomixer antenna design, has a substantial effect on antenna performance, and a thorough understanding of its characteristics is necessary. Each antenna design will be presented in turn and some challenges facing antenna design will be discussed.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"98 1","pages":"315-318"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87748356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178408
F. Bobor-Oyibo, S. Foti, David Smith, O. Yurduseven
Dynamic concentration of the users within a part of a cell sector has placed pressure on network operators to find ways to dynamically optimise the sector to increase capacity and quality of service while maintaining coverage. Smart antenna systems have been identified as being capable of dynamically optimising the network. Network operators need to estimate the actual performance gain that can be achieved with this smart antenna system and a comprehensive knowledge of radio propagation effects is an important factor for the development and performance evaluation of mobile telecommunication systems. This paper presents a performance evaluation of this smart antenna concept within a realistic radio environment.
{"title":"A smart antenna system with sub-sector dynamic capacity enhancement for mobile telecommunication networks","authors":"F. Bobor-Oyibo, S. Foti, David Smith, O. Yurduseven","doi":"10.1109/IWAT.2012.6178408","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178408","url":null,"abstract":"Dynamic concentration of the users within a part of a cell sector has placed pressure on network operators to find ways to dynamically optimise the sector to increase capacity and quality of service while maintaining coverage. Smart antenna systems have been identified as being capable of dynamically optimising the network. Network operators need to estimate the actual performance gain that can be achieved with this smart antenna system and a comprehensive knowledge of radio propagation effects is an important factor for the development and performance evaluation of mobile telecommunication systems. This paper presents a performance evaluation of this smart antenna concept within a realistic radio environment.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"1 1","pages":"100-103"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89556137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-05DOI: 10.1109/IWAT.2012.6178419
H. Rajagopalan, Y. Rahmat-Samii
This paper addresses two important aspects in the area of RFID technology namely, development of platform tolerant tags and RFID tags and systems in medicine. Firstly, platform tolerant tag designs are discussed. A dual patch/fat folded-dipole type tags (for human monitoring) is described and measurements are performed to validate the performance of the tag in different environments including human body and metals. Then, a medicine monitoring system is briefly discussed which can prove vital for medical compliance. The concept of the tagging of each medicine pill with RFID tag is presented and its design is discussed including proper operability within the human body.
{"title":"Platform tolerant and capsule-pill RFID antenna designs: An overview of recent developments at UCLA","authors":"H. Rajagopalan, Y. Rahmat-Samii","doi":"10.1109/IWAT.2012.6178419","DOIUrl":"https://doi.org/10.1109/IWAT.2012.6178419","url":null,"abstract":"This paper addresses two important aspects in the area of RFID technology namely, development of platform tolerant tags and RFID tags and systems in medicine. Firstly, platform tolerant tag designs are discussed. A dual patch/fat folded-dipole type tags (for human monitoring) is described and measurements are performed to validate the performance of the tag in different environments including human body and metals. Then, a medicine monitoring system is briefly discussed which can prove vital for medical compliance. The concept of the tagging of each medicine pill with RFID tag is presented and its design is discussed including proper operability within the human body.","PeriodicalId":6341,"journal":{"name":"2012 IEEE International Workshop on Antenna Technology (iWAT)","volume":"9 1","pages":"144-147"},"PeriodicalIF":0.0,"publicationDate":"2012-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87786457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：