Satellite mobile communication systems have rapidly come into widespread use and user have begun to require high speed multimedia services in mobile environments in any place; even if high speed train. In response to these demands, mobile satellite communication system is the key solution to provide high speed multimedia services in high speed train. Nowadays the high speed portable system has been developed for example WiMAX, Wibro and so on. But these system can't provide high speed internet services because of the train speed. To figure out this problem, mobile satellite communication fits this environment. And mobile satellite communication system can play in a role of backhaul for WiMAX or Wibro system. But there is disadvantage in mobile satellite communication system, signal may suffer shadowing, power arche, trees and tunnels. Shadowing, power arches and trees degrades the network performance, it can be overcomed by use of packet FEC. But it is difficult to provide internet service in tunnel. To figure out this problem, we adopt the gap filler system which relay from/to satellite to/from terminal in tunnel. In this paper we introduce and compare the various types of gap filler, transparent and non-transparent types and finally how our gap filler system is configured.
{"title":"The gap filler technology for mobile satellite system","authors":"J. Ryu, M. Shin, S. Han, D. Jang, Hojin Lee","doi":"10.1109/ASMS.2008.13","DOIUrl":"https://doi.org/10.1109/ASMS.2008.13","url":null,"abstract":"Satellite mobile communication systems have rapidly come into widespread use and user have begun to require high speed multimedia services in mobile environments in any place; even if high speed train. In response to these demands, mobile satellite communication system is the key solution to provide high speed multimedia services in high speed train. Nowadays the high speed portable system has been developed for example WiMAX, Wibro and so on. But these system can't provide high speed internet services because of the train speed. To figure out this problem, mobile satellite communication fits this environment. And mobile satellite communication system can play in a role of backhaul for WiMAX or Wibro system. But there is disadvantage in mobile satellite communication system, signal may suffer shadowing, power arche, trees and tunnels. Shadowing, power arches and trees degrades the network performance, it can be overcomed by use of packet FEC. But it is difficult to provide internet service in tunnel. To figure out this problem, we adopt the gap filler system which relay from/to satellite to/from terminal in tunnel. In this paper we introduce and compare the various types of gap filler, transparent and non-transparent types and finally how our gap filler system is configured.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128957297","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 : 2007-12-06DOI: 10.1109/APS.2007.4396267
B. Glover, K. Whites
This paper measured the complex permittivity of 0.1wt.% (0.32 vol.%) SWNT-loaded petroleum jelly from 0.9-6 GHz. The imaginary part of the effective permittivity was increased dramatically while the real part was comparatively insensitive. Furthermore, calculations show that easily realized tri-component artificial dielectrics can compensate for this small increase in the real permittivity. These results are representative of many low-permittivity, low-loss, and moldable dielectrics where carbon nanotubes can be well distributed throughout the volume. Finally, a design procedure for a tri-component artificial dielectric was given which gives significant flexibility and ease in manufacturing broadband, lossy dielectric materials beginning with a carbon nanotube loaded dielectric.
{"title":"Engineering lossy artificial dielectrics using single-walled carbon nanotubes","authors":"B. Glover, K. Whites","doi":"10.1109/APS.2007.4396267","DOIUrl":"https://doi.org/10.1109/APS.2007.4396267","url":null,"abstract":"This paper measured the complex permittivity of 0.1wt.% (0.32 vol.%) SWNT-loaded petroleum jelly from 0.9-6 GHz. The imaginary part of the effective permittivity was increased dramatically while the real part was comparatively insensitive. Furthermore, calculations show that easily realized tri-component artificial dielectrics can compensate for this small increase in the real permittivity. These results are representative of many low-permittivity, low-loss, and moldable dielectrics where carbon nanotubes can be well distributed throughout the volume. Finally, a design procedure for a tri-component artificial dielectric was given which gives significant flexibility and ease in manufacturing broadband, lossy dielectric materials beginning with a carbon nanotube loaded dielectric.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129581403","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 : 2007-12-06DOI: 10.1109/APS.2007.4395826
E. Walton, T. Lee, G. Paynter, J. Snow, C. Buxton
The present state of the art for the gain measurement of antennas on ground vehicles is to build a hemispherical scanner and then use a perfectly reflecting ground surface (so that reflection theory can "complete the sphere") or an absorbing floor (to eliminate ground reflections so that the below-ground spherical data can be set to zero.) Then, the data is transformed to the far field through the use of the spherical mode expansion technique. In this realistic ground scenario, we show the use of direct plane wave synthesis along with known values (bore-hole measurements) of the ground reflection coefficients to compute the ground vehicle antenna far field patterns.
{"title":"Development of a hemispherical near field antenna measurement range for use on a realistic ground","authors":"E. Walton, T. Lee, G. Paynter, J. Snow, C. Buxton","doi":"10.1109/APS.2007.4395826","DOIUrl":"https://doi.org/10.1109/APS.2007.4395826","url":null,"abstract":"The present state of the art for the gain measurement of antennas on ground vehicles is to build a hemispherical scanner and then use a perfectly reflecting ground surface (so that reflection theory can \"complete the sphere\") or an absorbing floor (to eliminate ground reflections so that the below-ground spherical data can be set to zero.) Then, the data is transformed to the far field through the use of the spherical mode expansion technique. In this realistic ground scenario, we show the use of direct plane wave synthesis along with known values (bore-hole measurements) of the ground reflection coefficients to compute the ground vehicle antenna far field patterns.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122559550","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 : 2007-12-06DOI: 10.1109/APS.2007.4396406
A.A. Nosich, Y. Gandel, T. Magath, A. Altintas
A new diffraction synthesis method is proposed for computing quasioptical 2-D reflector beam splitters in the E-polarization case. It is a combination of a numerical gradient (NG) optimization and an efficient analysis method based on singular integral equations (SIEs) which are discretized using a fast and accurate numerical Nystrom-type method of discrete singularities (MDS). The results of design are shown for a 40-quasioptical power splitter obtained from an offset parabolic reflector fed by in-focus beam source.
{"title":"Numerical diffraction synthesis of 2-D quasioptical power splitter","authors":"A.A. Nosich, Y. Gandel, T. Magath, A. Altintas","doi":"10.1109/APS.2007.4396406","DOIUrl":"https://doi.org/10.1109/APS.2007.4396406","url":null,"abstract":"A new diffraction synthesis method is proposed for computing quasioptical 2-D reflector beam splitters in the E-polarization case. It is a combination of a numerical gradient (NG) optimization and an efficient analysis method based on singular integral equations (SIEs) which are discretized using a fast and accurate numerical Nystrom-type method of discrete singularities (MDS). The results of design are shown for a 40-quasioptical power splitter obtained from an offset parabolic reflector fed by in-focus beam source.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114655032","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 : 2007-12-06DOI: 10.1109/APS.2007.4395976
M. Su, I. El-Kady, E. Shaner, C. Christodoulou
This paper concentrates on another application of photonic crystals: It shows photonic crystals can be used to selectively enhance and modify the light spectra of InAs self assembled quantum dot (SAQD) emissions in mid-IR wavelengths. Quantum dots, when used as light sources, offer unique advantages. It is therefore possible to develop new devices based solely on this property of SAQD based light sources. Before SAQD light sources could be used, however, improvements must be made on their emission spectra, which is rather broad (approximately 24 THz in our case) due to inhomogeneous broadening in SAQD energy levels. The purpose of this work is to theoretically investigate interactions between a photonic crystal and a light source placed into a central defect cavity. The photonic crystal serves to confine lateral propagation of light, which in turn interacts strongly with the central cavity and modifies emission characteristics of the light source.
{"title":"Selective enhancement of mid-ir quantum dot electroluminescent emissions using defect mode photonic crystal cavities","authors":"M. Su, I. El-Kady, E. Shaner, C. Christodoulou","doi":"10.1109/APS.2007.4395976","DOIUrl":"https://doi.org/10.1109/APS.2007.4395976","url":null,"abstract":"This paper concentrates on another application of photonic crystals: It shows photonic crystals can be used to selectively enhance and modify the light spectra of InAs self assembled quantum dot (SAQD) emissions in mid-IR wavelengths. Quantum dots, when used as light sources, offer unique advantages. It is therefore possible to develop new devices based solely on this property of SAQD based light sources. Before SAQD light sources could be used, however, improvements must be made on their emission spectra, which is rather broad (approximately 24 THz in our case) due to inhomogeneous broadening in SAQD energy levels. The purpose of this work is to theoretically investigate interactions between a photonic crystal and a light source placed into a central defect cavity. The photonic crystal serves to confine lateral propagation of light, which in turn interacts strongly with the central cavity and modifies emission characteristics of the light source.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125965646","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 : 2007-07-23DOI: 10.1109/IGARSS.2007.4422911
D. Liao, E. Michielssen, K. Sarabandi
In this paper, an FMM-accelerated and high-order accurate Nystorm's solver for analyzing wave propagation over large terrains with arbitrary profiles is implemented. The current implementation can be a valuable tool for validating existing asymptotic-based algorithms; in particular, it can be a convenient alternative for obtaining diffraction coefficient parameters, as is shown here for a canonical class of smooth dielectric surfaces.
{"title":"Simulation of terrain propagation and diffraction using a 2D high-order accurate FMM-accelerated Nyström’s solver","authors":"D. Liao, E. Michielssen, K. Sarabandi","doi":"10.1109/IGARSS.2007.4422911","DOIUrl":"https://doi.org/10.1109/IGARSS.2007.4422911","url":null,"abstract":"In this paper, an FMM-accelerated and high-order accurate Nystorm's solver for analyzing wave propagation over large terrains with arbitrary profiles is implemented. The current implementation can be a valuable tool for validating existing asymptotic-based algorithms; in particular, it can be a convenient alternative for obtaining diffraction coefficient parameters, as is shown here for a canonical class of smooth dielectric surfaces.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122505347","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 : 2007-06-09DOI: 10.1109/APS.2007.4396090
Shao-Chang Lu, J. Row, C. Sim, Shiao-Wen Wu
It is well-known that the circular polarization (CP) bandwidth of a microstrip antenna is greatly related to its impedance characteristic. Several broadband antenna structures have been proposed and studied, such as using a thick substrate with low permittivity and a multi-resonator structure. Another method to enhance the impedance bandwidth is using slot antennas instead of the microstrip antennas. In this paper, a new CP design developed from the ring slot antenna is proposed. The antenna structure composed of a wide slot and a parasitic patch is with wideband characteristics. By adjusting the distance between the wide respectively, which are obviously higher than that of a same-size microstrip antenna. Also, the CP designs of wide slot antennas have been investigated to further improve the CP bandwidth. By protruding a T-shaped [3] or an L-shaped strip [4] from the ground plane, the CP bandwidth of the wide slot antenna can reach to 18 %. However, the available designs for the slot antenna with more than 20 % CP bandwidth are relatively few in the open articles. In this paper, a new CP design developed from the ring slot antenna is proposed. The antenna structure composed of a wide slot and a parasitic patch is with wideband characteristics. By adjusting the distance between the wide slot and parasitic patch, the CP bandwidth can be varied between 5 and 45%. Details of the proposed designs and the obtained results are shown and discussed.
{"title":"Design of broadband slot antennas for circular polarization","authors":"Shao-Chang Lu, J. Row, C. Sim, Shiao-Wen Wu","doi":"10.1109/APS.2007.4396090","DOIUrl":"https://doi.org/10.1109/APS.2007.4396090","url":null,"abstract":"It is well-known that the circular polarization (CP) bandwidth of a microstrip antenna is greatly related to its impedance characteristic. Several broadband antenna structures have been proposed and studied, such as using a thick substrate with low permittivity and a multi-resonator structure. Another method to enhance the impedance bandwidth is using slot antennas instead of the microstrip antennas. In this paper, a new CP design developed from the ring slot antenna is proposed. The antenna structure composed of a wide slot and a parasitic patch is with wideband characteristics. By adjusting the distance between the wide respectively, which are obviously higher than that of a same-size microstrip antenna. Also, the CP designs of wide slot antennas have been investigated to further improve the CP bandwidth. By protruding a T-shaped [3] or an L-shaped strip [4] from the ground plane, the CP bandwidth of the wide slot antenna can reach to 18 %. However, the available designs for the slot antenna with more than 20 % CP bandwidth are relatively few in the open articles. In this paper, a new CP design developed from the ring slot antenna is proposed. The antenna structure composed of a wide slot and a parasitic patch is with wideband characteristics. By adjusting the distance between the wide slot and parasitic patch, the CP bandwidth can be varied between 5 and 45%. Details of the proposed designs and the obtained results are shown and discussed.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"319 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115361828","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 : 2007-06-09DOI: 10.1109/APS.2007.4396170
W. Yamada, N. Kita, A. Ando
The IEEE802.11a standard for indoor wireless LAN systems was released commercially and is wide spread in the marketplace. To achieve higher throughput, IEEE802.11n was proposed and is now undergoing standardization. The MIMO-OFDM technique, which employs multiple antennas for transmission and reception, is the core technology for IEEE802.11n (Foshini and Gans, 1998). This technique requires estimation of channel state information (CSI) on the receiving side. Using the technique called adaptive MIMO-OFDM (Telatar, 1999) in which CSI is applied to both the transmitting and receiving sides, an even higher throughput is achieved. To achieve the maximum performance from adaptive MIMO-OFDM, we must accurately estimate the CSI for all the subcarriers; however, numerous calculations are needed to obtain this estimation. So, to actualize the adaptive MIMO-OFDM system, the calculation load must be decreased. This can be accomplished by applying one CSI to other subcarriers. However, channel error exists between the actual channel and the applied CSI. The channel error also plays a role in decreasing the communications quality (Medard, 2000). The communications quality when using the adaptive MIMO-OFDM technique that has CSI error was evaluated by simulation (Narula et al., 1998). However, there are few measurement evaluation reports on CSI error. This paper focuses on the ratio between the power of the eigenvalue and the interference power that suppresses the communication quality based on the measurement results. We propose an empirical formula for predicting the signal to interference ratio (SIR), which is the ratio between the power of the eigenvalue and the interference power. This SIR empirical formula helps to predict the communication quality and simplify the simulation.
用于室内无线局域网系统的IEEE802.11a标准已经发布并在市场上广泛传播。为了实现更高的吞吐量，提出了IEEE802.11n，目前正在进行标准化。MIMO-OFDM技术采用多天线进行传输和接收，是IEEE802.11n的核心技术(Foshini and Gans, 1998)。这种技术需要在接收端估计信道状态信息(CSI)。使用称为自适应MIMO-OFDM (Telatar, 1999)的技术，其中CSI应用于发射和接收双方，实现了更高的吞吐量。为了实现自适应MIMO-OFDM的最大性能，必须准确估计所有子载波的CSI;然而，需要进行大量的计算来获得这个估计。因此，要实现自适应MIMO-OFDM系统，必须降低计算量。这可以通过将一个CSI应用于其他子载波来实现。但是，实际信道与应用的CSI之间存在信道误差。信道误差也会降低通信质量(Medard, 2000)。通过仿真对具有CSI误差的自适应MIMO-OFDM技术的通信质量进行了评价(Narula et al.， 1998)。然而，关于CSI误差的测量评价报道很少。本文在测量结果的基础上，重点研究了特征值的功率与抑制通信质量的干扰功率之比。我们提出了一个预测信号干扰比(SIR)的经验公式，SIR是特征值的功率与干扰功率之比。该SIR经验公式有助于预测通信质量，简化仿真。
{"title":"Empirical formula of effect on channel estimation error for adaptive MIMO-OFDM based WLAN system","authors":"W. Yamada, N. Kita, A. Ando","doi":"10.1109/APS.2007.4396170","DOIUrl":"https://doi.org/10.1109/APS.2007.4396170","url":null,"abstract":"The IEEE802.11a standard for indoor wireless LAN systems was released commercially and is wide spread in the marketplace. To achieve higher throughput, IEEE802.11n was proposed and is now undergoing standardization. The MIMO-OFDM technique, which employs multiple antennas for transmission and reception, is the core technology for IEEE802.11n (Foshini and Gans, 1998). This technique requires estimation of channel state information (CSI) on the receiving side. Using the technique called adaptive MIMO-OFDM (Telatar, 1999) in which CSI is applied to both the transmitting and receiving sides, an even higher throughput is achieved. To achieve the maximum performance from adaptive MIMO-OFDM, we must accurately estimate the CSI for all the subcarriers; however, numerous calculations are needed to obtain this estimation. So, to actualize the adaptive MIMO-OFDM system, the calculation load must be decreased. This can be accomplished by applying one CSI to other subcarriers. However, channel error exists between the actual channel and the applied CSI. The channel error also plays a role in decreasing the communications quality (Medard, 2000). The communications quality when using the adaptive MIMO-OFDM technique that has CSI error was evaluated by simulation (Narula et al., 1998). However, there are few measurement evaluation reports on CSI error. This paper focuses on the ratio between the power of the eigenvalue and the interference power that suppresses the communication quality based on the measurement results. We propose an empirical formula for predicting the signal to interference ratio (SIR), which is the ratio between the power of the eigenvalue and the interference power. This SIR empirical formula helps to predict the communication quality and simplify the simulation.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115640192","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 : 2007-06-09DOI: 10.1109/APS.2007.4396129
Yue Gao, Xiao-dong Chen, Z. Ying, C. Parini
Multiple input multiple output (MIMO) technology has been regarded as a practical approach to achieve significant increases of wireless channel capacity or reliability. Recently, the antenna's effect on MIMO system has been investigated intensively, in order to predict the true spectral efficiencies of MIMO systems in a real environment whereby realistic mobile terminals are used. Separation between multiple antenna elements is the most critical parameter affecting mutual coupling. Analytical studies have shown that for minimal or no mutual coupling, the distance between typical antenna elements needs to be at least half wavelength. However, the large separation between antenna elements is not attainable on a mobile terminal. There are a number of suggestions on how to build diversity antennas on a mobile terminal with low mutual coupling. In this context, we have developed a modified planar invert-F antenna (PIFA) and built a dual element array operating in 5.2GHz band with a separation of less than half wavelength (0.35 wavelength) and an isolation better than 28dB, as presented in our previous studies. It is noticed that mutual coupling depends on the frequency of received/transmitted signals since the distance is expressed in terms of the wavelength. Therefore, a dual-element diversity PIFA operating at the lower frequency (2.5GHz band) with an even closer separation (0.17 wavelength) has been studied in this paper.
{"title":"Further investigation of a dual-element diversity PIFA for MIMO applications at 2.5 GHz band","authors":"Yue Gao, Xiao-dong Chen, Z. Ying, C. Parini","doi":"10.1109/APS.2007.4396129","DOIUrl":"https://doi.org/10.1109/APS.2007.4396129","url":null,"abstract":"Multiple input multiple output (MIMO) technology has been regarded as a practical approach to achieve significant increases of wireless channel capacity or reliability. Recently, the antenna's effect on MIMO system has been investigated intensively, in order to predict the true spectral efficiencies of MIMO systems in a real environment whereby realistic mobile terminals are used. Separation between multiple antenna elements is the most critical parameter affecting mutual coupling. Analytical studies have shown that for minimal or no mutual coupling, the distance between typical antenna elements needs to be at least half wavelength. However, the large separation between antenna elements is not attainable on a mobile terminal. There are a number of suggestions on how to build diversity antennas on a mobile terminal with low mutual coupling. In this context, we have developed a modified planar invert-F antenna (PIFA) and built a dual element array operating in 5.2GHz band with a separation of less than half wavelength (0.35 wavelength) and an isolation better than 28dB, as presented in our previous studies. It is noticed that mutual coupling depends on the frequency of received/transmitted signals since the distance is expressed in terms of the wavelength. Therefore, a dual-element diversity PIFA operating at the lower frequency (2.5GHz band) with an even closer separation (0.17 wavelength) has been studied in this paper.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123123402","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 : 2007-06-09DOI: 10.1109/APS.2007.4395805
Yuan Yao, Zhenghe Feng
In this paper, we propose a novel ultra-wideband Wilkinson power divider with symmetric defected ground structure (DGS) having frequency band-notch characteristic. The Wilkinson power divider was invented in 1960 and has wide applications in microwave circuits and antenna feeds. But it has a narrow bandwidth. Several schemes have been devised to increase its bandwidth. The main proposal used series connection of several sections having considerably increased bandwidth and high isolation between outputs for equal power divider. We use connection of three sections to obtain the UWB Wilkinson power divider. It is well known that the DGS of the microstrip line is implemented by making artificial defect on the ground and the ground defect provides a resonance property in transfer characteristic. In the microstrip line, DGS on the ground plane provides band rejection characteristic at some resonance frequency corresponding to the size of defect on the ground. In this paper, band-notch characteristic is achieved by inserting a symmetric spiral DGS under the microstrip line of the power divider. Experimental results of the constructed prototype are presented.
{"title":"A band-notched ultra-wideband 1 to 4 wilkinson power divider using symmetric defected ground structure","authors":"Yuan Yao, Zhenghe Feng","doi":"10.1109/APS.2007.4395805","DOIUrl":"https://doi.org/10.1109/APS.2007.4395805","url":null,"abstract":"In this paper, we propose a novel ultra-wideband Wilkinson power divider with symmetric defected ground structure (DGS) having frequency band-notch characteristic. The Wilkinson power divider was invented in 1960 and has wide applications in microwave circuits and antenna feeds. But it has a narrow bandwidth. Several schemes have been devised to increase its bandwidth. The main proposal used series connection of several sections having considerably increased bandwidth and high isolation between outputs for equal power divider. We use connection of three sections to obtain the UWB Wilkinson power divider. It is well known that the DGS of the microstrip line is implemented by making artificial defect on the ground and the ground defect provides a resonance property in transfer characteristic. In the microstrip line, DGS on the ground plane provides band rejection characteristic at some resonance frequency corresponding to the size of defect on the ground. In this paper, band-notch characteristic is achieved by inserting a symmetric spiral DGS under the microstrip line of the power divider. Experimental results of the constructed prototype are presented.","PeriodicalId":117975,"journal":{"name":"2007 IEEE Antennas and Propagation Society International Symposium","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124399357","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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