Pub Date : 2008-12-01DOI: 10.1109/RFM.2008.4897377
A. Ramli, S. M. Idrus, A. Supa’at
Optical wireless or Free Space Optics (FSO) has received considerable attention as an alternative to existing Radio Frequency (RF) communication system. This is due to the growing demand for wireless broadband communications and congestion on bandwidth of RF spectrum. In optical wireless application, the performance of the receiver is significantly determines the overall performance of optical wireless link. Receiver is required to have large aperture. Accordingly, the detector is required to have a large detection area which produces high photodetector capacitance and limits the receiver bandwidth. In this paper, the front-end optical receiver designs especially for wireless application have been focused where a fundamental requirement is the achievement of wide dynamic range and broad bandwidth. Through a review on reported works, the bootstrapping technique is found effectively reduces the photodetector capacitance associated with the large area photodetector. Consequently, the overall bandwidth of the system can be improved.
{"title":"Optical wireless front-end receiver design","authors":"A. Ramli, S. M. Idrus, A. Supa’at","doi":"10.1109/RFM.2008.4897377","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897377","url":null,"abstract":"Optical wireless or Free Space Optics (FSO) has received considerable attention as an alternative to existing Radio Frequency (RF) communication system. This is due to the growing demand for wireless broadband communications and congestion on bandwidth of RF spectrum. In optical wireless application, the performance of the receiver is significantly determines the overall performance of optical wireless link. Receiver is required to have large aperture. Accordingly, the detector is required to have a large detection area which produces high photodetector capacitance and limits the receiver bandwidth. In this paper, the front-end optical receiver designs especially for wireless application have been focused where a fundamental requirement is the achievement of wide dynamic range and broad bandwidth. Through a review on reported works, the bootstrapping technique is found effectively reduces the photodetector capacitance associated with the large area photodetector. Consequently, the overall bandwidth of the system can be improved.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131224439","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897415
U. Okonkwo, R. Ngah, T. A. Rahman
Channel characterization and state information play important role in the realization of optimal performance in communication systems. In mobile communication systems, the channel is realistically nonstationary and is often modeled equivalently as time-frequency integral operator with finite supports in time and frequency, employing the Fourier kernel and fixed window as the analyzing functions which result in poor time-frequency resolution and is unsuitable for representation of nonstationary systems. And as such this form of characterization is not adequate in accurately tracking channel variations especially in fast fading and frequency selective channels. In this paper, we present a method of mobile radio channel characterization and description in the wavelet-domain which promises a better joint time-frequency variations representation assuming nonstationary channel condition and very suitable for mobile broadband communication system.
{"title":"Wavelet-domain channel characterization for mobile broadband communication systems","authors":"U. Okonkwo, R. Ngah, T. A. Rahman","doi":"10.1109/RFM.2008.4897415","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897415","url":null,"abstract":"Channel characterization and state information play important role in the realization of optimal performance in communication systems. In mobile communication systems, the channel is realistically nonstationary and is often modeled equivalently as time-frequency integral operator with finite supports in time and frequency, employing the Fourier kernel and fixed window as the analyzing functions which result in poor time-frequency resolution and is unsuitable for representation of nonstationary systems. And as such this form of characterization is not adequate in accurately tracking channel variations especially in fast fading and frequency selective channels. In this paper, we present a method of mobile radio channel characterization and description in the wavelet-domain which promises a better joint time-frequency variations representation assuming nonstationary channel condition and very suitable for mobile broadband communication system.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115384724","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897436
R. Rashid, W. M. A. E. W. Embong, N. Fisal
We propose an enhanced lightweight medium access control (eL-MAC) protocol which combines scheduled based MAC mechanism and adaptive multi-timeslot allocation (AMTA). Wireless sensor network (WSN) consists of tiny wireless devices typically cooperate with each other to aggregate sensor data to the base station. It is increasingly being used in a wide range of environmental application. Such applications like habitat monitoring, large-scale industrial monitoring and urban population monitoring require years of operation period with low rate data transmission. Hence, providing a reliable data transmission and efficiency in energy usage are critical in order to prolong the network lifetime. eL-MAC solves the problems that normally happen in WSN such as idle listening, over hearing and hidden terminal problem, by introducing a slotting communication mechanism where node only transmits in its own timeslot and sleep in other time slot if there is no activity. Furthermore, eL-MAC allows multiple timeslots to be occupied by a node according to the traffic requirement. The simulation result shows our protocol prolongs the network lifetime compared to LMAC mechanism, without reducing the channel utilization.
{"title":"Enhanced lightweight medium access protocol with adaptive multi-timeslot allocation for wireless sensor network","authors":"R. Rashid, W. M. A. E. W. Embong, N. Fisal","doi":"10.1109/RFM.2008.4897436","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897436","url":null,"abstract":"We propose an enhanced lightweight medium access control (eL-MAC) protocol which combines scheduled based MAC mechanism and adaptive multi-timeslot allocation (AMTA). Wireless sensor network (WSN) consists of tiny wireless devices typically cooperate with each other to aggregate sensor data to the base station. It is increasingly being used in a wide range of environmental application. Such applications like habitat monitoring, large-scale industrial monitoring and urban population monitoring require years of operation period with low rate data transmission. Hence, providing a reliable data transmission and efficiency in energy usage are critical in order to prolong the network lifetime. eL-MAC solves the problems that normally happen in WSN such as idle listening, over hearing and hidden terminal problem, by introducing a slotting communication mechanism where node only transmits in its own timeslot and sleep in other time slot if there is no activity. Furthermore, eL-MAC allows multiple timeslots to be occupied by a node according to the traffic requirement. The simulation result shows our protocol prolongs the network lifetime compared to LMAC mechanism, without reducing the channel utilization.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"330 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113956146","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897382
A. Al-hetar, A. Supa’at, A. .. Mohammad, I. Yulianti
A thermal analysis and structure of ridge and buried (conventional) single mode waveguides with a metal heater are presented. The numerical simulation shows the power consumption of the present ridge waveguide is almost a third of that for conventional one and the response time is half of that of the conventional one.
{"title":"Thermal analysis for ridge and buried waveguides with a metal heater","authors":"A. Al-hetar, A. Supa’at, A. .. Mohammad, I. Yulianti","doi":"10.1109/RFM.2008.4897382","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897382","url":null,"abstract":"A thermal analysis and structure of ridge and buried (conventional) single mode waveguides with a metal heater are presented. The numerical simulation shows the power consumption of the present ridge waveguide is almost a third of that for conventional one and the response time is half of that of the conventional one.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123213383","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897422
N. Zakaria, A. A. Sulaiman, Muhammad Asyraf Abd Latip
A circular microstrip antenna is designed in order to obtain the required parameter responses from 2.4 GHz-2.5 GHz by using GENESYS software based on the method of cavity model due of simplicity and easier to analyze. This circular patch is fed by microstrip line and RT Duroid 5870 is used with the specified information include the dielectric constant of substrate (isinr = 2.33) the resonant frequency (fr = 2.45GHz) and substrate height (h=0.5 mm). The circular microstrip antenna exhibits appropriate required parameters depend on the feed point position, size of the circular patch and length of the microstrip line. A prototype of a circular microstrip antenna has been built and tested by Vector Network Analyzer. The agreement between the measured and simulated results is slightly differ caused by several factors that would be discussed in result part.
{"title":"Design of a circular microstrip antenna","authors":"N. Zakaria, A. A. Sulaiman, Muhammad Asyraf Abd Latip","doi":"10.1109/RFM.2008.4897422","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897422","url":null,"abstract":"A circular microstrip antenna is designed in order to obtain the required parameter responses from 2.4 GHz-2.5 GHz by using GENESYS software based on the method of cavity model due of simplicity and easier to analyze. This circular patch is fed by microstrip line and RT Duroid 5870 is used with the specified information include the dielectric constant of substrate (isinr = 2.33) the resonant frequency (fr = 2.45GHz) and substrate height (h=0.5 mm). The circular microstrip antenna exhibits appropriate required parameters depend on the feed point position, size of the circular patch and length of the microstrip line. A prototype of a circular microstrip antenna has been built and tested by Vector Network Analyzer. The agreement between the measured and simulated results is slightly differ caused by several factors that would be discussed in result part.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123390527","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897392
Mohammad M. Tajdini, A. A. Shishegar
In this paper, a novel closed form expression is derived to find the Green' s function of a horizontal electric current in a parallel-plate waveguide. It is achieved by expanding the Green' s function into a series of Gaussian functions. This new method is called the Gaussian Green' s function (GGF) method. The main advantage of the GGF method lies in its precision as well as rapid convergence. Numerical results confirm that the closed form expression yields less than 0.2% error compared to the numerical integration of the spectral integral. Furthermore, it is verified that this method can be in excellent agreement with the complex images (CI) method.
{"title":"The Gaussian expansion of the Green's function of an electric current in a parallel-plate waveguide","authors":"Mohammad M. Tajdini, A. A. Shishegar","doi":"10.1109/RFM.2008.4897392","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897392","url":null,"abstract":"In this paper, a novel closed form expression is derived to find the Green' s function of a horizontal electric current in a parallel-plate waveguide. It is achieved by expanding the Green' s function into a series of Gaussian functions. This new method is called the Gaussian Green' s function (GGF) method. The main advantage of the GGF method lies in its precision as well as rapid convergence. Numerical results confirm that the closed form expression yields less than 0.2% error compared to the numerical integration of the spectral integral. Furthermore, it is verified that this method can be in excellent agreement with the complex images (CI) method.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124889909","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897452
S. Yusof, A. Zamani
Orthogonal frequency division multiplexing (OFDM) is proven a successful technique in wireless communication system which is sensitive to carrier frequency offset (CFO). The effect of CFO introduces intercarrier interference (ICI) to OFDM system. The purpose of this paper is to reduce ICI using ICI self-cancellation in MIMO-OFDM system by data allocation in space-time-frequency (STF). This paper also presents data allocation of complex pair to reduce peak-to-average power ratio (PAPR). Simulations by comparing STF MIMO-OFDM with conventional OFDM show an optimistic result especially at a high Eb/No.
{"title":"Intercarrier interference self-cancellation for space-time-frequency MIMO-OFDM system","authors":"S. Yusof, A. Zamani","doi":"10.1109/RFM.2008.4897452","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897452","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) is proven a successful technique in wireless communication system which is sensitive to carrier frequency offset (CFO). The effect of CFO introduces intercarrier interference (ICI) to OFDM system. The purpose of this paper is to reduce ICI using ICI self-cancellation in MIMO-OFDM system by data allocation in space-time-frequency (STF). This paper also presents data allocation of complex pair to reduce peak-to-average power ratio (PAPR). Simulations by comparing STF MIMO-OFDM with conventional OFDM show an optimistic result especially at a high Eb/No.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125192047","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897428
T. Prakoso, R. Ngah, T. A. Rahman
Antenna return loss and gain as function of frequency are not readily accommodated in many communication system software. This paper proposes solution to the problem by representing the antenna in two-port network s-parameter. The representation exploits the analogy between antenna and two port network. Simulation using communication system software shows that the proposed method is validated.
{"title":"Representation of antenna in two-port network s-parameter","authors":"T. Prakoso, R. Ngah, T. A. Rahman","doi":"10.1109/RFM.2008.4897428","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897428","url":null,"abstract":"Antenna return loss and gain as function of frequency are not readily accommodated in many communication system software. This paper proposes solution to the problem by representing the antenna in two-port network s-parameter. The representation exploits the analogy between antenna and two port network. Simulation using communication system software shows that the proposed method is validated.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126295490","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897383
K. Yazbek, O. Harfoush
We aim to design a microwave synthesizer using a PLL and taking into account the EMC/EMI problems. These problems are more important when using two synthesizers in a communication system, one for the transmitter with direct frequency modulation of the oscillator (VCO), and another as a local oscillator for the receiver. EMC/EMI issues have been treated in this work from a practical point of view: layout, type of used components, and distribution of power supply.
{"title":"Practical EMC considerations in designing PCB for RF and microwave communications systems","authors":"K. Yazbek, O. Harfoush","doi":"10.1109/RFM.2008.4897383","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897383","url":null,"abstract":"We aim to design a microwave synthesizer using a PLL and taking into account the EMC/EMI problems. These problems are more important when using two synthesizers in a communication system, one for the transmitter with direct frequency modulation of the oscillator (VCO), and another as a local oscillator for the receiver. EMC/EMI issues have been treated in this work from a practical point of view: layout, type of used components, and distribution of power supply.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127323694","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 : 2008-12-01DOI: 10.1109/RFM.2008.4897373
M. H. Jusoh, N. Ya'acob, H. Saad, A. A. Sulaiman, N. Baba, R. A. Awang, Z. I. Khan
The ionospheric Total Electron Content (TEC) measurements were investigated at Universiti Teknologi Malaysia, UTMJ on 20 February - 20 March 2007. The observation was made 14 days before earthquake and 14 days after earthquake. TEC is extracted using GPS dual frequency data which in RINEX format that supplied by JUPEM (Jabatan Ukur dan Pemetaaan Malaysia). In order to reveal possible earthquake precursor through the changes variation of TEC reading, Southern Sumatra Indonesia earthquake that happened on 6th March 2007 is chosen as a study case. The results show that satellite facilities may detect earthquake precursors in ionosphere 5-11 days or a few hours before main shock and various grounds based or satellite observation have shown strong perturbation of the ionosphere after earthquake. The results show a good agreement with other researchers who studied other earthquakes.
2007年2月20日至3月20日，马来西亚科技大学(UTMJ)对电离层总电子含量(TEC)的测量进行了研究。观测分别在震前14天和震后14天进行。TEC是使用由JUPEM (Jabatan Ukur dan pemetaan Malaysia)提供的RINEX格式的GPS双频数据提取的。为了通过TEC读数的变化变化揭示可能的地震前兆，本文选择2007年3月6日发生的印度尼西亚苏门答腊岛南部地震作为研究案例。结果表明，卫星设施可在主震前5 ~ 11天或数小时探测到电离层的地震前兆，各种地面观测或卫星观测均显示出地震后电离层的强烈扰动。研究结果与其他研究其他地震的研究人员的结果很一致。
{"title":"Earthquake prediction technique based on GPS dual frequency system in equatorial region","authors":"M. H. Jusoh, N. Ya'acob, H. Saad, A. A. Sulaiman, N. Baba, R. A. Awang, Z. I. Khan","doi":"10.1109/RFM.2008.4897373","DOIUrl":"https://doi.org/10.1109/RFM.2008.4897373","url":null,"abstract":"The ionospheric Total Electron Content (TEC) measurements were investigated at Universiti Teknologi Malaysia, UTMJ on 20 February - 20 March 2007. The observation was made 14 days before earthquake and 14 days after earthquake. TEC is extracted using GPS dual frequency data which in RINEX format that supplied by JUPEM (Jabatan Ukur dan Pemetaaan Malaysia). In order to reveal possible earthquake precursor through the changes variation of TEC reading, Southern Sumatra Indonesia earthquake that happened on 6th March 2007 is chosen as a study case. The results show that satellite facilities may detect earthquake precursors in ionosphere 5-11 days or a few hours before main shock and various grounds based or satellite observation have shown strong perturbation of the ionosphere after earthquake. The results show a good agreement with other researchers who studied other earthquakes.","PeriodicalId":329128,"journal":{"name":"2008 IEEE International RF and Microwave Conference","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114790299","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}
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