Pub Date : 2004-11-08DOI: 10.1109/EDMO.2004.1412396
J. Calado, J. Figueiredo, C. Ironside
The optoelectronic effect integrating a double barrier resonant tunnelling diode within a unipolar optical waveguide is analysed. Due to the non-linearities introduced by the double barrier resonant tunnelling diode (RTD) the unipolar optical waveguide (OW) can be employed both as an optical modulator and as an optical detector. The RTD also provides electrical gain over a wide bandwidth. The RTD-OW modelling results confirm preliminary experimental results, foreseeing modulation depths up to 23 dB and negative chirp in the wavelength range analysed (1500 nm to 1600 nm).
{"title":"Modelling of a modulator based on resonant tunnelling diode switching","authors":"J. Calado, J. Figueiredo, C. Ironside","doi":"10.1109/EDMO.2004.1412396","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412396","url":null,"abstract":"The optoelectronic effect integrating a double barrier resonant tunnelling diode within a unipolar optical waveguide is analysed. Due to the non-linearities introduced by the double barrier resonant tunnelling diode (RTD) the unipolar optical waveguide (OW) can be employed both as an optical modulator and as an optical detector. The RTD also provides electrical gain over a wide bandwidth. The RTD-OW modelling results confirm preliminary experimental results, foreseeing modulation depths up to 23 dB and negative chirp in the wavelength range analysed (1500 nm to 1600 nm).","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"223 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116638894","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412393
Z. Szczepaniak, A. Arvaniti
In this paper the self-limiting effect in microwave limiters using transistors with Schottky junction was investigated. The mathematical analysis how the input power detection influences on output power characteristic was presented. The analysis was done on the basis of the transistor IV curves. The calculations and measurement results of a realized limiter circuit was also presented.
{"title":"Analysis of microwave X-band HEMT limiters based on self-limiting effect","authors":"Z. Szczepaniak, A. Arvaniti","doi":"10.1109/EDMO.2004.1412393","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412393","url":null,"abstract":"In this paper the self-limiting effect in microwave limiters using transistors with Schottky junction was investigated. The mathematical analysis how the input power detection influences on output power characteristic was presented. The analysis was done on the basis of the transistor IV curves. The calculations and measurement results of a realized limiter circuit was also presented.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126872207","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412391
A. Muller, G. Konstantinidis, D. Neculoiu, D. Vasilache, Z. Hazopulos, A. Pantazis, A. Stavrinidis, C. Buiculescu, I. Petrini
This paper discusses novel micromachined GaAs circuits for millimeter wave applications. A low loss line filter structure for 45 GHz, a Yagi-Uda antenna for 45 GHz and a micromachined receiver with Yagi-Uda antenna are primarily presented. The manufacturing of membrane supported filters, antenna and receiver structures have confirmed the capabilities of GaAs micromachining in manufacturing of high performance circuits for millimeter wave communication systems.
{"title":"Novel micromachined GaAs circuits for millimeter wave applications","authors":"A. Muller, G. Konstantinidis, D. Neculoiu, D. Vasilache, Z. Hazopulos, A. Pantazis, A. Stavrinidis, C. Buiculescu, I. Petrini","doi":"10.1109/EDMO.2004.1412391","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412391","url":null,"abstract":"This paper discusses novel micromachined GaAs circuits for millimeter wave applications. A low loss line filter structure for 45 GHz, a Yagi-Uda antenna for 45 GHz and a micromachined receiver with Yagi-Uda antenna are primarily presented. The manufacturing of membrane supported filters, antenna and receiver structures have confirmed the capabilities of GaAs micromachining in manufacturing of high performance circuits for millimeter wave communication systems.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121302410","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412408
N. Chauville, D. Chatelain, B. V. van Wyk
GPRS access technology is not well-adapted for providing a data service to rural areas where there exist very localized demands for service. Under these circumstances, WiMax could be a better solution for providing access. This paper deals with the way to interface a WiMax network, based on a point to point configuration, to a GSM/GPRS core network, using a PC equipped with a linux kernel modified in order to add a new protocol under IP layer.
{"title":"WiMax access over GSM/GPRS in rural areas","authors":"N. Chauville, D. Chatelain, B. V. van Wyk","doi":"10.1109/EDMO.2004.1412408","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412408","url":null,"abstract":"GPRS access technology is not well-adapted for providing a data service to rural areas where there exist very localized demands for service. Under these circumstances, WiMax could be a better solution for providing access. This paper deals with the way to interface a WiMax network, based on a point to point configuration, to a GSM/GPRS core network, using a PC equipped with a linux kernel modified in order to add a new protocol under IP layer.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134014706","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412389
A. R. Jha
This paper reveals state-of-the-art performance capabilities and projections for the AlGaN/GaN-HEMT and AlGaN/GaN-HBT devices for mm-wave applications. Wide band gap, appropriate doping impurities, and strong atomic bonds make these III-V nitride materials most attractive for microwave devices. Research studies performed by the author indicate that the nitride-based GaN-HEMTs and -HBTs when fabricated on silicon carbide substrate are capable of providing highest power density and power-added efficiency (PAE) at mm-wave frequencies. Deployment of a group III-V material with wide gap band (3.49 eV) and silicon carbide (6H-SiC) substrate with high room-temperature thermal conductivity close to 4.5 W/cm./spl deg/C is necessary for the development of high-power, high-efficiency GaN-HEMT and -HBT devices operating at mm-wave frequencies. Device reliability under high operating temperatures is strictly dependent on the thermal conductivity of the GaN film and substrate used. Note the operating voltages of GaN devices are five to ten times of those for GaAs devices.
{"title":"Advances in III-V transistors (HEMTs and HBTs) for mm-wave applications","authors":"A. R. Jha","doi":"10.1109/EDMO.2004.1412389","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412389","url":null,"abstract":"This paper reveals state-of-the-art performance capabilities and projections for the AlGaN/GaN-HEMT and AlGaN/GaN-HBT devices for mm-wave applications. Wide band gap, appropriate doping impurities, and strong atomic bonds make these III-V nitride materials most attractive for microwave devices. Research studies performed by the author indicate that the nitride-based GaN-HEMTs and -HBTs when fabricated on silicon carbide substrate are capable of providing highest power density and power-added efficiency (PAE) at mm-wave frequencies. Deployment of a group III-V material with wide gap band (3.49 eV) and silicon carbide (6H-SiC) substrate with high room-temperature thermal conductivity close to 4.5 W/cm./spl deg/C is necessary for the development of high-power, high-efficiency GaN-HEMT and -HBT devices operating at mm-wave frequencies. Device reliability under high operating temperatures is strictly dependent on the thermal conductivity of the GaN film and substrate used. Note the operating voltages of GaN devices are five to ten times of those for GaAs devices.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127997963","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412411
J. Pretorius
In this article, the absorber studied is used to insulate a confined area from incident electromagnetic waves. The aim is to block all microwaves from entering the confined area. Application of such absorbers is in the communication field where radio and cell phone signals are unwanted. When an electromagnetic wave hits ferrite particles, the magnetic field part of the wave is cancelled. Using normal wood that is transparent to radio waves, with fine particles of ferrimagnetic material sandwiched in the wood, radio waves are blocked, which allow several networks to operate close by without interference.
{"title":"Design and manufacture of a ferrimagnetic wave absorber for cellular phone radiations","authors":"J. Pretorius","doi":"10.1109/EDMO.2004.1412411","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412411","url":null,"abstract":"In this article, the absorber studied is used to insulate a confined area from incident electromagnetic waves. The aim is to block all microwaves from entering the confined area. Application of such absorbers is in the communication field where radio and cell phone signals are unwanted. When an electromagnetic wave hits ferrite particles, the magnetic field part of the wave is cancelled. Using normal wood that is transparent to radio waves, with fine particles of ferrimagnetic material sandwiched in the wood, radio waves are blocked, which allow several networks to operate close by without interference.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127949326","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412412
J. Rugamba, L. Snyman, A. Kurien
A study was conducted to ascertain the viability of using smart antennas in GSM cellular networks in Africa to control interference, increase capacity, transmission power savings and cost-effectiveness. It was shown that a smart antenna could steer the signal in the specified directions arrival. In the simulation, the radiation patterns properly steered towards -30/spl deg/ and 60/spl deg/ angles of mobile location. It was also shown that, the probability to drop a call in presence of interference (outage probability) with use of smart antennas could reduce from 1 to 0.001, meaning fewer call drops in presence of interference. It was further illustrated that, when the received power requirement at the mobile remains the same with M-element array (smart antenna) at the base station, the output power from amplifiers is reduced by M/sup -2/ and total transmit power is reduced by M/sup -1/. Business case analyses showed that, capital spent on infrastructure is recouped quickly when smart antennas are deployed. With 15% deployment in a 20 BTS urban network (case study), cell capacity increase, number of base stations reduction, transmission power savings and antenna tilting cost savings amounted to more than R108 million/5 year period (case study).
{"title":"Viability of using intelligent (smart) antenna systems in GSM cellular networks in Africa","authors":"J. Rugamba, L. Snyman, A. Kurien","doi":"10.1109/EDMO.2004.1412412","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412412","url":null,"abstract":"A study was conducted to ascertain the viability of using smart antennas in GSM cellular networks in Africa to control interference, increase capacity, transmission power savings and cost-effectiveness. It was shown that a smart antenna could steer the signal in the specified directions arrival. In the simulation, the radiation patterns properly steered towards -30/spl deg/ and 60/spl deg/ angles of mobile location. It was also shown that, the probability to drop a call in presence of interference (outage probability) with use of smart antennas could reduce from 1 to 0.001, meaning fewer call drops in presence of interference. It was further illustrated that, when the received power requirement at the mobile remains the same with M-element array (smart antenna) at the base station, the output power from amplifiers is reduced by M/sup -2/ and total transmit power is reduced by M/sup -1/. Business case analyses showed that, capital spent on infrastructure is recouped quickly when smart antennas are deployed. With 15% deployment in a 20 BTS urban network (case study), cell capacity increase, number of base stations reduction, transmission power savings and antenna tilting cost savings amounted to more than R108 million/5 year period (case study).","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131442980","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412394
C. Weichsel, O. Pagni, N. Somhlahlo, E. van Wyk, A. Leitch
We present systematic studies of the current-voltage characteristics of palladium Schottky diodes on ZnO layers grown on GaAs and demonstrate the advantages of using GaAs as a substrate. In terms of possible applications of the Pd/ZnO/GaAs system for gas sensing devices, transparent electronics and optoelectronics we study the sensitivity of these devices to hydrogen gas and light.
{"title":"Palladium Schottky diodes on ZnO thin films grown on GaAs","authors":"C. Weichsel, O. Pagni, N. Somhlahlo, E. van Wyk, A. Leitch","doi":"10.1109/EDMO.2004.1412394","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412394","url":null,"abstract":"We present systematic studies of the current-voltage characteristics of palladium Schottky diodes on ZnO layers grown on GaAs and demonstrate the advantages of using GaAs as a substrate. In terms of possible applications of the Pd/ZnO/GaAs system for gas sensing devices, transparent electronics and optoelectronics we study the sensitivity of these devices to hydrogen gas and light.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"159 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132000029","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412402
L. Snyman, J. Matjila, H. Aharoni, M. Plessis
In this paper we report on the dependency of quantum efficiency of an avalanching light emitting junction on the current from an adjacent lying forward biased junction. The phenomenon is observed in a three terminal silicon CMOS bipolar junction light emitting device (Si CMOS BJT LED). Our observations show that the overall quantum efficiency and light emission from these type of devices can be improved to the N/sub Q/=10/sup -4/ regime. The device has the potential of being fully integratable with any standard CMOS integrated circuitry with no adaptation to the CMOS design and processing procedures and light emissions can be confined to submicron dimensions. The optical emissions is about four orders higher than the low frequency detectivity for silicon CMOS detectors of comparable dimension. Our two junction, three terminal device also enable modulation of the light emission by a third terminal contact while using two terminals for biasing. The reverse bias avalanche configuration of the avalanching light emitting junction offers modulation capabilities of the device to within the GHz range.
{"title":"Increasing the efficiency of three terminal silicon CMOS LED's through current density and carrier injection techniques","authors":"L. Snyman, J. Matjila, H. Aharoni, M. Plessis","doi":"10.1109/EDMO.2004.1412402","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412402","url":null,"abstract":"In this paper we report on the dependency of quantum efficiency of an avalanching light emitting junction on the current from an adjacent lying forward biased junction. The phenomenon is observed in a three terminal silicon CMOS bipolar junction light emitting device (Si CMOS BJT LED). Our observations show that the overall quantum efficiency and light emission from these type of devices can be improved to the N/sub Q/=10/sup -4/ regime. The device has the potential of being fully integratable with any standard CMOS integrated circuitry with no adaptation to the CMOS design and processing procedures and light emissions can be confined to submicron dimensions. The optical emissions is about four orders higher than the low frequency detectivity for silicon CMOS detectors of comparable dimension. Our two junction, three terminal device also enable modulation of the light emission by a third terminal contact while using two terminals for biasing. The reverse bias avalanche configuration of the avalanching light emitting junction offers modulation capabilities of the device to within the GHz range.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126597943","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 : 2004-11-08DOI: 10.1109/EDMO.2004.1412399
S. Sinha, M. du Plessis
High costs, bulkiness, and larger power consumption makes transceiver integration and miniaturization a desired option to discretely implemented transceivers. Furthermore, a frequency synthesizer forms an important part of high-frequency transceivers. In this paper, the design of a fully-integrated dual loop frequency synthesizer is detailed. Previously, frequency synthesizers have already been implemented using CMOS technology. The synthesizer discussed in this paper deploys a dual loop architecture with a high-frequency LC voltage controlled oscillator (VCO) forming part of one of the loops. As opposed to previous architectures, the synthesizer discussed in this paper utilises an active-inductor LC VCO as opposed to a passive-inductor LC VCO deployed in earlier synthesizer implementations. Amongst others, an important advantage of this implementation is the higher quality, Q-factor of the active inductor at the trade-off of increased noise and power dissipation. The synthesizer generates signals in the microwave frequency (2.4-2.5 GHz) range with a 1 MHz resolution. Using the 0.35 /spl mu/m BiCMOS process, simulations showed a phase noise of -117 dBc/Hz at an offset of 1 MHz and reference sidebands at -80 dBc, both these parameters with respect to a 2.45 GHz carrier.
{"title":"Design of an active-inductor dual-loop frequency synthesizer","authors":"S. Sinha, M. du Plessis","doi":"10.1109/EDMO.2004.1412399","DOIUrl":"https://doi.org/10.1109/EDMO.2004.1412399","url":null,"abstract":"High costs, bulkiness, and larger power consumption makes transceiver integration and miniaturization a desired option to discretely implemented transceivers. Furthermore, a frequency synthesizer forms an important part of high-frequency transceivers. In this paper, the design of a fully-integrated dual loop frequency synthesizer is detailed. Previously, frequency synthesizers have already been implemented using CMOS technology. The synthesizer discussed in this paper deploys a dual loop architecture with a high-frequency LC voltage controlled oscillator (VCO) forming part of one of the loops. As opposed to previous architectures, the synthesizer discussed in this paper utilises an active-inductor LC VCO as opposed to a passive-inductor LC VCO deployed in earlier synthesizer implementations. Amongst others, an important advantage of this implementation is the higher quality, Q-factor of the active inductor at the trade-off of increased noise and power dissipation. The synthesizer generates signals in the microwave frequency (2.4-2.5 GHz) range with a 1 MHz resolution. Using the 0.35 /spl mu/m BiCMOS process, simulations showed a phase noise of -117 dBc/Hz at an offset of 1 MHz and reference sidebands at -80 dBc, both these parameters with respect to a 2.45 GHz carrier.","PeriodicalId":424447,"journal":{"name":"12th International Symposium on Electron Devices for Microwave and Optoelectronic Applications, 2004. EDMO 2004.","volume":"330 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134430885","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：