Pub Date : 2018-09-26DOI: 10.5772/INTECHOPEN.75384
W. J. Krzysztofik
As the growing demand for mobile communications is constantly increasing, the need for better coverage, improved capacity, and higher transmission quality rises. Thus, a more efficient use of the radio spectrum and communication systems availability are required. This chapter presents EM propagation models most commonly used for the design of wireless communication systems, computer networks WLAN and WPAN for urban and/ or in indoor environments. The review of commercial or University computer codes to assist design of WLAN and WPAN networks were done. An example of computer design and simulation of indoor Bluetooth and WLAN communication systems, in the building of Wroclaw University of Science and Technology, Wroclaw, Poland is shown in Chapter 8.
{"title":"Radio Network Planning and Propagation Models for Urban and Indoor Wireless Communication Networks","authors":"W. J. Krzysztofik","doi":"10.5772/INTECHOPEN.75384","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75384","url":null,"abstract":"As the growing demand for mobile communications is constantly increasing, the need for better coverage, improved capacity, and higher transmission quality rises. Thus, a more efficient use of the radio spectrum and communication systems availability are required. This chapter presents EM propagation models most commonly used for the design of wireless communication systems, computer networks WLAN and WPAN for urban and/ or in indoor environments. The review of commercial or University computer codes to assist design of WLAN and WPAN networks were done. An example of computer design and simulation of indoor Bluetooth and WLAN communication systems, in the building of Wroclaw University of Science and Technology, Wroclaw, Poland is shown in Chapter 8.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123870175","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 : 2018-09-26DOI: 10.5772/INTECHOPEN.75142
J. Kelner, C. Ziółkowski
In the proposed chapter, the authors present a geometric-statistical propagation model that defines three groups of received signal components, i.e., direct path, delayed scattering, and local scattering components. The multi-elliptical propagation model, which rep- resents the geometry of scatterer locations, is the basis for determining the delayed components. For the generation of the local components, a statistical distribution is used. The basis for this model is a power angular spectrum (PAS) of the received signal, which is closely related to a type of propagation environment and transmitter-receiver spatial positions. Therefore, we have an opportunity to evaluate the influence of the environment type and an object motion direction on the basic characteristics such as envelope distribu- tion, PAS, autocorrelation function, and spectral power density. The multi-elliptical model considers the propagation phenomena occurring in the azimuth plane. In the chapter, we will also show the 3D extension of modeling effects of propagation phenomena.
{"title":"Multi-Elliptical Geometry of Scatterers in Modeling Propagation Effect at Receiver","authors":"J. Kelner, C. Ziółkowski","doi":"10.5772/INTECHOPEN.75142","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75142","url":null,"abstract":"In the proposed chapter, the authors present a geometric-statistical propagation model that defines three groups of received signal components, i.e., direct path, delayed scattering, and local scattering components. The multi-elliptical propagation model, which rep- resents the geometry of scatterer locations, is the basis for determining the delayed components. For the generation of the local components, a statistical distribution is used. The basis for this model is a power angular spectrum (PAS) of the received signal, which is closely related to a type of propagation environment and transmitter-receiver spatial positions. Therefore, we have an opportunity to evaluate the influence of the environment type and an object motion direction on the basic characteristics such as envelope distribu- tion, PAS, autocorrelation function, and spectral power density. The multi-elliptical model considers the propagation phenomena occurring in the azimuth plane. In the chapter, we will also show the 3D extension of modeling effects of propagation phenomena.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133565033","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 : 2018-09-26DOI: 10.5772/INTECHOPEN.74938
Saeed Ahmed, M. Lisa
In this chapter, we investigate a magnetic line source diffraction problem concerned with a step. To study the diffraction problem in lossy medium, we follow the Wiener-Hopf technique and steepest decent method to solve it for impedance step. By equating the impedances of the step to zero, the solution reduces for magnetic line source diffraction by PEC step. Then we transform the obtained solution for PEMC step by using duality transformation. Perfect electromagnetic conductor (PEMC) theory is novel idea developed by Lindell and Sihvola. This media is interlinked with two conductors namely perfect electric conductor (PEC) and perfect magnetic conductor (PMC). Both PEC and PMC are the limiting cases of perfect electromagnetic conductor (PEMC). We study the magnetic line source diffraction by PEMC step placed in different soils (i) gravel sand (ii) sand and (iii) clay. By using the permittivity, permeability and conductivity of these lossy mediums we predict the loss effect on the diffracted field. Such kind of study is very useful in antenna and wave propagation for subsurface targets and to investigate antenna radiation patterns.
{"title":"Magnetic Line Source Diffraction by a PEMC Step in Lossy Medium","authors":"Saeed Ahmed, M. Lisa","doi":"10.5772/INTECHOPEN.74938","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74938","url":null,"abstract":"In this chapter, we investigate a magnetic line source diffraction problem concerned with a step. To study the diffraction problem in lossy medium, we follow the Wiener-Hopf technique and steepest decent method to solve it for impedance step. By equating the impedances of the step to zero, the solution reduces for magnetic line source diffraction by PEC step. Then we transform the obtained solution for PEMC step by using duality transformation. Perfect electromagnetic conductor (PEMC) theory is novel idea developed by Lindell and Sihvola. This media is interlinked with two conductors namely perfect electric conductor (PEC) and perfect magnetic conductor (PMC). Both PEC and PMC are the limiting cases of perfect electromagnetic conductor (PEMC). We study the magnetic line source diffraction by PEMC step placed in different soils (i) gravel sand (ii) sand and (iii) clay. By using the permittivity, permeability and conductivity of these lossy mediums we predict the loss effect on the diffracted field. Such kind of study is very useful in antenna and wave propagation for subsurface targets and to investigate antenna radiation patterns.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130151177","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 : 2018-09-26DOI: 10.5772/INTECHOPEN.74945
S. Çolak, N. T. Tokan
In the ultra-wideband (UWB) application frequency domain parameters such as gain, group delay isn’t sufficient to demonstrate the performance of the antenna. Besides frequency domain analysis, a time-domain analysis is required to characterize the transient behavior of UWB antennas for pulsed operations since pulse distortion of the UWB antenna reduces the system performance and decreases the signal to noise ratio (SNR) of the UWB communication system. Vivaldi antenna is a widely used UWB antenna, especially in microwave imaging applications. Performance of Vivaldi antennas is enhanced by adding corrugation on the edge of exponential flaring and/or grating elements on the slot area. From the measured scattering parameters of modified Vivaldi antennas, pulse preserving capabilities are observed. Pulse width extension and fidelity factor parameters are used to define the similarity between the transmitted and received pulse. The analysis is performed with angular dependence with respect to the signal transmitted at the main beam direction.
{"title":"Time-Domain Analysis of Modified Vivaldi Antennas","authors":"S. Çolak, N. T. Tokan","doi":"10.5772/INTECHOPEN.74945","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74945","url":null,"abstract":"In the ultra-wideband (UWB) application frequency domain parameters such as gain, group delay isn’t sufficient to demonstrate the performance of the antenna. Besides frequency domain analysis, a time-domain analysis is required to characterize the transient behavior of UWB antennas for pulsed operations since pulse distortion of the UWB antenna reduces the system performance and decreases the signal to noise ratio (SNR) of the UWB communication system. Vivaldi antenna is a widely used UWB antenna, especially in microwave imaging applications. Performance of Vivaldi antennas is enhanced by adding corrugation on the edge of exponential flaring and/or grating elements on the slot area. From the measured scattering parameters of modified Vivaldi antennas, pulse preserving capabilities are observed. Pulse width extension and fidelity factor parameters are used to define the similarity between the transmitted and received pulse. The analysis is performed with angular dependence with respect to the signal transmitted at the main beam direction.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"362 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133809639","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 : 2018-09-26DOI: 10.5772/INTECHOPEN.75059
H. Lui, F. Aldhubaib, S. Crozier, N. Shuley
Reliable radar target recognition has long been the holy grail of electromagnetic sensors. Target recognition based on the singularity expansion method (SEM) uses a time-domain electromagnetic signature and has been well studied over the last few decades. The SEM describes the late time period of the transient target signature as a sum of damped exponentials with natural resonant frequencies (NRFs). The aspect-independent and purely target geometry and material-dependent nature of the NRF set make it an excellent feature set for target characterization. In this chapter, we aim to review the background and the state of the art of resonance-based target recognition. The theoretical framework of SEM is introduced, followed by signal processing techniques that retrieve the target-dependent NRFs embedded in the transient electromagnetic target signatures. The extinction pulse, a well-known target recognition technique, is discussed. This chapter covers recent developments in using a polarimetric signature for target recognition, as well as using NRFs for subsurface sensing applications. The chapter concludes with some highlights of the ongoing challenges in the field.
{"title":"Ultra Wideband Transient Scattering and Its Applications to Automated Target Recognition","authors":"H. Lui, F. Aldhubaib, S. Crozier, N. Shuley","doi":"10.5772/INTECHOPEN.75059","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75059","url":null,"abstract":"Reliable radar target recognition has long been the holy grail of electromagnetic sensors. Target recognition based on the singularity expansion method (SEM) uses a time-domain electromagnetic signature and has been well studied over the last few decades. The SEM describes the late time period of the transient target signature as a sum of damped exponentials with natural resonant frequencies (NRFs). The aspect-independent and purely target geometry and material-dependent nature of the NRF set make it an excellent feature set for target characterization. In this chapter, we aim to review the background and the state of the art of resonance-based target recognition. The theoretical framework of SEM is introduced, followed by signal processing techniques that retrieve the target-dependent NRFs embedded in the transient electromagnetic target signatures. The extinction pulse, a well-known target recognition technique, is discussed. This chapter covers recent developments in using a polarimetric signature for target recognition, as well as using NRFs for subsurface sensing applications. The chapter concludes with some highlights of the ongoing challenges in the field.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126847194","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 : 2018-09-26DOI: 10.5772/INTECHOPEN.75123
Gregory A. Mitchell
This chapter will analyze the properties of electromagnetic wave propagation in anisotropic media. Of particular interest are positive index, anisotropic, and magneto-dielectric media. Engineered anisotropic media provide unique electromagnetic properties including a higher effective refractive index, high permeability with relatively low magnetic loss tangent at microwave frequencies, and lower density and weight than traditional media. This chapter presents research including plane wave solutions to propagation in anisotropic media, a mathematical derivation of birefringence in anisotropic media, modal decomposition of rectangular waveguides filled with anisotropic media, and the full derivation of anisotropic transverse resonance in a partially loaded waveguide. These are fundamental theories in the area of electromagnetic wave propagation that have been reformulated for fully anisotropic magneto-dielectric media. The ensuing results will aide interested parties in understanding wave behavior for anisotropic media to enhance designs for radio frequency devices based on anisotropic and magnetic media.
{"title":"Anisotropic Propagation of Electromagnetic Waves","authors":"Gregory A. Mitchell","doi":"10.5772/INTECHOPEN.75123","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75123","url":null,"abstract":"This chapter will analyze the properties of electromagnetic wave propagation in anisotropic media. Of particular interest are positive index, anisotropic, and magneto-dielectric media. Engineered anisotropic media provide unique electromagnetic properties including a higher effective refractive index, high permeability with relatively low magnetic loss tangent at microwave frequencies, and lower density and weight than traditional media. This chapter presents research including plane wave solutions to propagation in anisotropic media, a mathematical derivation of birefringence in anisotropic media, modal decomposition of rectangular waveguides filled with anisotropic media, and the full derivation of anisotropic transverse resonance in a partially loaded waveguide. These are fundamental theories in the area of electromagnetic wave propagation that have been reformulated for fully anisotropic magneto-dielectric media. The ensuing results will aide interested parties in understanding wave behavior for anisotropic media to enhance designs for radio frequency devices based on anisotropic and magnetic media.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121171041","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 : 2018-03-31DOI: 10.5772/INTECHOPEN.74937
S. Mota, A. Rocha
Teaching transmission lines and wave propagation is a challenging task because it involves quantities not easily observable and also because the underlying mathematical equations— functions of time, distance and using complex numbers—are not prone to an easy physical interpretation in a frequent framework of a superposition of traveling waves in distinct directions. In such a context, tools with a strong visualization and easy student interaction can improve the learning outputs. We describe here a few tools and give basic exercises to address the main learning topics.
{"title":"Teaching Transmission Line Propagation and Plane Wave Reflection Using Software Tools","authors":"S. Mota, A. Rocha","doi":"10.5772/INTECHOPEN.74937","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74937","url":null,"abstract":"Teaching transmission lines and wave propagation is a challenging task because it involves quantities not easily observable and also because the underlying mathematical equations— functions of time, distance and using complex numbers—are not prone to an easy physical interpretation in a frequent framework of a superposition of traveling waves in distinct directions. In such a context, tools with a strong visualization and easy student interaction can improve the learning outputs. We describe here a few tools and give basic exercises to address the main learning topics.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132315321","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 : 2018-02-28DOI: 10.5772/INTECHOPEN.74936
Karlo Queiroz da, Gleida Tayanna Conde de, G. S. Pinto, A. Pires
Graphene possesses good properties as unusually high electron mobility, atomic layer thick- ness, and unique mechanical flexibility, which made it one promising material in the design of terahertz antennas. In this book chapter, we present a numerical analysis of a broadband dipole-loop graphene antenna for application in terahertz communications. The bidimen sional method of moments (MoM-2D), with equivalent surface impedance of graphene, is used for numerical analysis. First, we review the principal characteristics of the conven tional rectangular graphene dipole. Then, we consider the broadband graphene antenna, composed by one rectangular dipole placed near and parallel to a circular-loop graphene element, where only the dipole is feed. In this analysis, we investigated the effects of the geo - metrical parameters and the chemical potential, of the graphene material, on the overall char acteristics of the compound antenna. Some results are compared with simulations performed with software based on finite element method. The results show that this simple compound graphene antenna can be used for broadband communications in the terahertz band.
{"title":"Numerical Analysis of Broadband Dipole-Loop Graphene Antenna for Applications in Terahertz Communications","authors":"Karlo Queiroz da, Gleida Tayanna Conde de, G. S. Pinto, A. Pires","doi":"10.5772/INTECHOPEN.74936","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.74936","url":null,"abstract":"Graphene possesses good properties as unusually high electron mobility, atomic layer thick- ness, and unique mechanical flexibility, which made it one promising material in the design of terahertz antennas. In this book chapter, we present a numerical analysis of a broadband dipole-loop graphene antenna for application in terahertz communications. The bidimen sional method of moments (MoM-2D), with equivalent surface impedance of graphene, is used for numerical analysis. First, we review the principal characteristics of the conven tional rectangular graphene dipole. Then, we consider the broadband graphene antenna, composed by one rectangular dipole placed near and parallel to a circular-loop graphene element, where only the dipole is feed. In this analysis, we investigated the effects of the geo - metrical parameters and the chemical potential, of the graphene material, on the overall char acteristics of the compound antenna. Some results are compared with simulations performed with software based on finite element method. The results show that this simple compound graphene antenna can be used for broadband communications in the terahertz band.","PeriodicalId":212695,"journal":{"name":"Antennas and Wave Propagation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131113343","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：