xxii Introduction Chapter 2 Chapter 2 begins with a description of the operational requirements for base station antennas and relates those requirements to antenna specification parameters and the means by which each of these param eters are controlled.The use of space-and polarization-diversity sys tems is described,and the required antenna parameters related to dual-polarized antennas are reviewed.As a major design consideration, the description of a variety of construction methods emphasizes both antenna performance and cost.The role of modern electromagnetic sim- ulation tools is dis sed in the context of base statio Avariety ot practical radiating elementsre decribedeth designer with potential starting points for new designs.Array designs are also examined.The general practice of multiplexing a number of transmitters and receivers into a common antenna system creates qementsfor avoiding passive intermodt ethods for mi imizing PIMs are thus ex ined.This includes descriptions of a variety of mechanical design approaches and provides a guide to good design practice. It has become general practice to control the elevation beam direction (beamtilt)of base station antennas.either locally or remotely.with the expectation being that this control will be integrated with the man affic loading and the opti nization of system capacity.Rer control is also being applied to the azimuth radiation pattern for chang- ing the beamwidth and pointing the beams to desired directions.These developments are described,together with some of the design consid- erations involved in their realization The measurement of base station an ena。 s is also discussed,along with techniq ques for ing sing com non pro blem encoun ed dur installation of base stations is often the occasion for objections related to potential visual and electromagnetic impact on the local environ- ment.These topics and alternative methods for reducing their impact are discussed and examples are provided.In the last part of the chapter, me suggestions are made about possible future developments of base station antennas Chapter 3 Chapter3 describes the commercial requirements for the performance of both indoor and outdoor base station antennas for various mobile phone systems.Conventional techniques for developing base station antennas are also reviewed.including directed dipoles and aperture-coupled patch antennas.The L-probe fed patch antenna is a wideband design that has attracted much interest in the antenna community in recent years due to its simple structure and low cost.By examining five different
Chapter 2 Chapter 2 begins with a description of the operational requirements for base station antennas and relates those requirements to antenna specification parameters and the means by which each of these parameters are controlled. The use of space- and polarization-diversity systems is described, and the required antenna parameters related to dual-polarized antennas are reviewed. As a major design consideration, the description of a variety of construction methods emphasizes both antenna performance and cost. The role of modern electromagnetic simulation tools is discussed in the context of base station antenna design. A variety of practical radiating elements are described to provide the designer with potential starting points for new designs. Array designs are also examined. The general practice of multiplexing a number of transmitters and receivers into a common antenna system creates severe requirements for avoiding passive intermodulation products (PIMs). Methods for minimizing PIMs are thus examined. This chapter includes descriptions of a variety of mechanical design approaches and provides a guide to good design practice. It has become general practice to control the elevation beam direction (beamtilt) of base station antennas, either locally or remotely, with the expectation being that this control will be integrated with the management of traffic loading and the optimization of system capacity. Remote control is also being applied to the azimuth radiation pattern for changing the beamwidth and pointing the beams to desired directions. These developments are described, together with some of the design considerations involved in their realization. The measurement of base station antenna arrays is also discussed, along with techniques for optimizing and diagnosing common problems encountered during design. The installation of base stations is often the occasion for objections related to potential visual and electromagnetic impact on the local environment. These topics and alternative methods for reducing their impact are discussed and examples are provided. In the last part of the chapter, some suggestions are made about possible future developments of base station antennas. Chapter 3 Chapter 3 describes the commercial requirements for the performance of both indoor and outdoor base station antennas for various mobile phone systems. Conventional techniques for developing base station antennas are also reviewed, including directed dipoles and aperture-coupled patch antennas. The L-probe fed patch antenna is a wideband design that has attracted much interest in the antenna community in recent years due to its simple structure and low cost. By examining five different xxii Introduction
Introduction xxili antenna designs with simulations and measurements,this chapter demonstrates that this new antenna structure is highly suitable for developing base station antennas for both 2G and 3G mobile wireless communication systems Chapter 4 Chapter 4 introduces advanced antenna technologies for the fixed GSM base stations in mobile wireless communication systems.It starts by describing the benefits obtained from advanced antennas in GSM base stations.Then we briefly review advanced antenna technologies,includ- ing antenna bea mtilt,higher order sectorization,fixed multibeam array antennas,steered beam array antennas,receiver-diversity,coverage concepts,three-sector omnidirectional patterns,modular high-gain anten nas,amplifier integrated sector antennas,and amplifier integrated multi- beam array antennas.After that,the case studies related to the antenna technologies just mentioned are included.This chapter highlights many practical engineering issues from a systems point of view Chapter5 Chapter 5 first presents the special aspects of mobile communication which oce py so many fre equency bands operating frequency bands or mult ple antenna arrays operating in different frequency bands are required Several designs are available to meet such practical requirements.The TDMA-based PDC and W-CDMA systems are briefly introduced for understanding the requirements of base stations.Then the practical desi gn consider highlighted from a system point of view.In 3G networks,one of the most important considerations in antenna configuration is increasing the number of subscribers or system capacity.Ways to select the antenna structures and design the actual antennas for increasing system capacity are suggested.The tech- nique to control vertical radiation patterns is elaborated from an engi ew chapter looks at five typical antenna designs,which have beer applied in practical wireless access systems.First,slim antennas with small widths,which may be single-band or multiple-band antennas,are preferred due to limited space for,and the high cost of,antenna installa- tions in Japan.A detailed case study is pres nted.Second,this chapter s that the hori ntal radia tion pa n a nna can controlled by adding metallic conductors in the vicinity of the existing base station antenna.Third,an omnidirectional vertical array antenna of width 0.09for spot cells is described.Fourth,booster antennas that have the high FB ratio and low sidelobe levels needed for the realization of a
antenna designs with simulations and measurements, this chapter demonstrates that this new antenna structure is highly suitable for developing base station antennas for both 2G and 3G mobile wireless communication systems. Chapter 4 Chapter 4 introduces advanced antenna technologies for the fixed GSMbase stations in mobile wireless communication systems. It starts by describing the benefits obtained from advanced antennas in GSM base stations. Then we briefly review advanced antenna technologies, including antenna beamtilt, higher order sectorization, fixed multibeam array antennas, steered beam array antennas, receiver-diversity, coverage concepts, three-sector omnidirectional patterns, modular high-gain antennas, amplifier integrated sector antennas, and amplifier integrated multibeam array antennas. After that, the case studies related to the antenna technologies just mentioned are included. This chapter highlights many practical engineering issues from a systems point of view. Chapter 5 Chapter 5 first presents the special aspects of mobile communication systems operating in Japan, which occupy so many frequency bands that antenna arrays with multiple operating frequency bands or multiple antenna arrays operating in different frequency bands are required. Several designs are available to meet such practical requirements. The TDMA-based PDC and W-CDMA systems are briefly introduced for understanding the requirements of base stations. Then the practical design considerations for antenna design are highlighted from a system point of view. In 3G networks, one of the most important considerations in antenna configuration is increasing the number of subscribers or system capacity. Ways to select the antenna structures and design the actual antennas for increasing system capacity are suggested. The technique to control vertical radiation patterns is elaborated from an engineering point of view. This chapter looks at five typical antenna designs, which have been applied in practical wireless access systems. First, slim antennas with small widths, which may be single-band or multiple-band antennas, are preferred due to limited space for, and the high cost of, antenna installations in Japan. A detailed case study is presented. Second, this chapter demonstrates that the horizontal radiation pattern of an antenna can be controlled by adding metallic conductors in the vicinity of the existing base station antenna. Third, an omnidirectional vertical array antenna of width 0.09l for spot cells is described. Fourth, booster antennas that have the high FB ratio and low sidelobe levels needed for the realization of a Introduction xxiii
xxiv Introduction reradiation system in a shadow area are presented.Fifth,we will show that the vertical radiati n pattern du to a numl f vertical array ele ments can be controlled by changing the phases of each array element. Chapter 6 Chapter 6 introduces several wideband unidirectional antenna designs based on microstrip antenna technology.All designs employ electrically thick substrates with a low dielectric constant for achieving wide imped ance idth performance.Mo eover,the se ant nnas us ing the tw L-probe feed,meandering probe feed,or differential-plate feed not only achieve wide impedance bandwidths,but also possess excellent electrica characteristics such as low cross polarization,high gain,and symmetrical E-plane radiation.After that,the chapter proceeds to illustrate a new type of wideband unidirectional ante enn na ele a comple tary ant s novel wideb band unidirectional antenna is compos ed ofa planar ele tric dipole and a shorted patch antenna that is equivalent to a magnetic dipole.A new r-shaped feeding strip,comprising an air microstrip line and an L-shaped coupled strip,is selected for exciting the dipole and the shorted patch.This configuration of antenna structure accomplishes such as wide in low cross polarization,I cklobe radiation,nearly identical E-and H-plane patterns,a stable radiation pattern,and steady antenna gain across the entire operating frequency band.In addition,two alternative feeding structures,T-strip and square-plate coupled lines,demonstrate the flexibility of antenna feed design.All antennas presented in this chap ter find in mar recent wire ss communication Chapter 7 Chapter 7 provides a general description of the standards and deploy- ment scenarios of wlan (WiFi).designs are considered from a system pective,including materials fabri cation p ess,tim to-market as loyment and installation The app cation of MIMO technol】 ogy in WLANsystems inordertoprovide reliabilityand high-speed wire less links is also discussed.In MIMO systems,antenna performance will greatly impact capacity through the cross-correlation of the signals in transmission and reception.The mutual coupling between the antennas will ther re,play y a critical role in ant a des which includes ele The optimized antenna designs with low mutual coupling will enhance the diversity performance of the MIMO systems.Furthermore,the MIMO systems are also advantageous for various types of diversity techniques,for instance,space,pattern, and polarization diversity when applied simultaneously
reradiation system in a shadow area are presented. Fifth, we will show that the vertical radiation pattern due to a number of vertical array elements can be controlled by changing the phases of each array element. Chapter 6 Chapter 6 introduces several wideband unidirectional antenna designs based on microstrip antenna technology. All designs employ electrically thick substrates with a low dielectric constant for achieving wide impedance bandwidth performance. Moreover, these antennas using the twin L-probe feed, meandering probe feed, or differential-plate feed not only achieve wide impedance bandwidths, but also possess excellent electrical characteristics such as low cross polarization, high gain, and symmetrical E-plane radiation. After that, the chapter proceeds to illustrate a new type of wideband unidirectional antenna element—a complementary antenna. This novel wideband unidirectional antenna is composed of a planar electric dipole and a shorted patch antenna that is equivalent to a magnetic dipole. A new Γ-shaped feeding strip, comprising an air microstrip line and an L-shaped coupled strip, is selected for exciting the dipole and the shorted patch. This configuration of antenna structure accomplishes excellent electrical characteristics, such as wide impedance bandwidth, low cross polarization, low backlobe radiation, nearly identical E- and H-plane patterns, a stable radiation pattern, and steady antenna gain across the entire operating frequency band. In addition, two alternative feeding structures, T-strip and square-plate coupled lines, demonstrate the flexibility of antenna feed design. All antennas presented in this chapter find practical applications in many recent wireless communication systems like 2G, 3G, WiFi, ZigBee, and so on. Chapter 7 Chapter 7 provides a general description of the standards and deployment scenarios of WLAN (WiFi). Designs are considered from a system perspective, including materials, fabrication process, time-to-market, as well as deployment and installation. The application of MIMO technology in WLAN systems in order to provide reliability and high-speed wireless links is also discussed. In MIMO systems, antenna performance will greatly impact capacity through the cross-correlation of the signals in transmission and reception. The mutual coupling between the antennas will, therefore, play a critical role in antenna design, which includes element selection and array configuration. The optimized antenna designs with low mutual coupling will enhance the diversity performance of the MIMO systems. Furthermore, the MIMO systems are also advantageous for various types of diversity techniques, for instance, space, pattern, and polarization diversity when applied simultaneously. xxiv Introduction
Introduction xxv Several state-of-the art antenna design solutions are presented as well.This includes outdoor point-to-point antennas,outdoor point- to-multiple point antennas,and indoor point-to-point antennas.The variou esign challenges and tradeoffs of these antennas are also dis cussed.Client-device antennas have very critical constraints in terms of cost and size,which severely limit antenna performance.As for the base station antennas in point-to-point(P2P)and/or point-to-multipoint (P2MP)systems,the challenges faced include the tradeoffs among the perform integration of multipe functions intoasingl antenna design,as well as integration of radio Based on the specifications and the antenna design considerations for wLan systems.several antenna designs and their practical chal lenges and tradeoffs are highlighted as case studies.The performance. simplicity,cost effectiveness,and manufacturability of the antenna de re emphasized.Se er al applied design ovations are high lighted,for example,embeddable antenn on multilayered substrates dual broadband antennas,integrated dual-band arrays,and arrays with broadband feeding network technologies A wireless personal area network (wPAn is a short range network for wirelessly interconnecting devices centered around an individual person's workspac a WPAN es the technology that allows communication within about 10 meters.There are many technologies such as Infrared,Bluetooth,HomeRF,ZigBee,ultra-wideband(UWB), radio frequency identification(RFID),and near-field communication (NFC).that have been used for WPAN applications.Some of them Infrared,Bluetooth,and RFID,for examp mature pro that hav b een developed for years.The others such as UWB and NFC are still being developed Chapter 8 Chapter 8 addresses the antenna designs for two WPAN technologies: RFID for assets tracking and UWB for target positioning. RFID technology has been developing rapidly in recent years,and it can be found in many industries loisics mamufacturing companies.and poods antenna is one of the key components in an RFID system.The detec- tion range and accuracy of RFID systems depend directly on reader antenna performance.The optimal antenna design always offers the RFID sys em long range,high accuracy,reduced fabrication cost,as well system configuration and implementation.Thef cies for RFID applications,which span from a low frequency of 125 KHz to the microwave frequency of 24 GHz,the selection of the antenna, and the design considerations for specific RFID applications feature distinct differences.Loop antennas have been the popular choice of
Several state-of-the art antenna design solutions are presented as well. This includes outdoor point-to-point antennas, outdoor pointto-multiple point antennas, and indoor point-to-point antennas. The various design challenges and tradeoffs of these antennas are also discussed. Client-device antennas have very critical constraints in terms of cost and size, which severely limit antenna performance. As for the base station antennas in point-to-point (P2P) and/or point-to-multipoint (P2MP) systems, the challenges faced include the tradeoffs among the performance, cost, size, integration of multiple functions into a single antenna design, as well as integration of antennas into radios. Based on the specifications and the antenna design considerations for WLAN systems, several antenna designs and their practical challenges and tradeoffs are highlighted as case studies. The performance, simplicity, cost effectiveness, and manufacturability of the antenna designs are emphasized. Several applied design innovations are highlighted, for example, embeddable antenna on multilayered substrates, dual broadband antennas, integrated dual-band arrays, and arrays with broadband feeding network technologies. A wireless personal area network (WPAN) is a short range network for wirelessly interconnecting devices centered around an individual person’s workspace. Typically, a WPAN uses the technology that allows communication within about 10 meters. There are many technologies such as Infrared, Bluetooth, HomeRF, ZigBee, ultra-wideband (UWB), radio frequency identification (RFID), and near-field communication (NFC), that have been used for WPAN applications. Some of them— Infrared, Bluetooth, and RFID, for example—are mature commercial products that have been developed for years. The others such as UWB and NFC are still being developed. Chapter 8 Chapter 8 addresses the antenna designs for two WPAN technologies: RFID for assets tracking and UWB for target positioning. RFID technology has been developing rapidly in recent years, and its applications can be found in many service industries, distribution logistics, manufacturing companies, and goods flow systems. The reader antenna is one of the key components in an RFID system. The detection range and accuracy of RFID systems depend directly on reader antenna performance. The optimal antenna design always offers the RFID system long range, high accuracy, reduced fabrication cost, as well as simplified system configuration and implementation. The frequencies for RFID applications, which span from a low frequency of 125 KHz to the microwave frequency of 24 GHz, the selection of the antenna, and the design considerations for specific RFID applications feature distinct differences. Loop antennas have been the popular choice of Introduction xxv
xxvi Introduction reader antennas for LF/HF RFID systems.For the RFID applications at UHF and MWF bands,a number of antennas can be use d as reader antennas,whereas the circularly polarized patch antenna has been the most widely used antenna. The technology of UWB positioning is still being developed.UWB of the freque ncy spectru tion of UWB.arrived multipath components ca 6 arply timed at a receiver to provide accurate time of arrival(TOA)estimates.This characteristic makes the UWB ideal for high-precision radio position- ing applications.Mono-station UWB positioning technology features a highly accurate simple system configuration and has great potential for ing applications.The six-element secto ed antenna array shown in this chapter demonstrates the requirements and design con- siderations for such a system.The antenna configuration,the antenna element design,and the method for controlling the antenna element's beamwidth are expected to be beneficial when designing sectored antenna arrays for indoor UWB positioning applications. References 2 3.J D.Kraus and R J.Ma rhefka,Antennas,3rd edition,New York:McGraw-Hill 4.R.S.Elliott. IEEE Pr lition. nna Theory:Analysis an IEEE Pre New York:Wiley- &Cr意5ealAnnnHianiheak,4hrhnNewarkMcrnHm ienc 2005 M.Luk and K.W.Leung (eds.),Dielectric Resonator Antennas,in Anten d Broadband Mic Antennas new York 10.New York:Wiley-Interscience.2006 and Superconducting Antens Small neering Handbook,4th edition,New York: 11.7.N.Chen (ed.).Antennas for Portable Devices,London:Wiley,2007
reader antennas for LF/HF RFID systems. For the RFID applications at UHF and MWF bands, a number of antennas can be used as reader antennas, whereas the circularly polarized patch antenna has been the most widely used antenna. The technology of UWB positioning is still being developed. UWB radios employ very short pulses that spread energy over a broad range of the frequency spectrum. Due to the inherently fine temporal resolution of UWB, arrived multipath components can be sharply timed at a receiver to provide accurate time of arrival (TOA) estimates. This characteristic makes the UWB ideal for high-precision radio positioning applications. Mono-station UWB positioning technology features a highly accurate simple system configuration and has great potential for indoor positioning applications. The six-element sectored antenna array shown in this chapter demonstrates the requirements and design considerations for such a system. The antenna configuration, the antenna element design, and the method for controlling the antenna element’s beamwidth are expected to be beneficial when designing sectored antenna arrays for indoor UWB positioning applications. References 1. Z. N. Chen and M. Y. W. Chia, Broadband Planar Antennas: Design and Applications, London: John Wiley & Sons, February 2006. 2. W. L. Stutzman and G. A. Thiele, Antenna Theory and Design, 2nd edition, New York: Artech House, 1997. 3. J. D. Kraus and R. J. Marhefka, Antennas, 3rd edition, New York: McGraw-Hill Education Singapore, 2001. 4. R. S. Elliott, Antenna Theory & Design, in IEEE Press Series on Electromagnetic Wave Theory, Rev sub-edition, New York: Wiley-IEEE Press, 2003. 5. C. A. Balanis, Antenna Theory: Analysis and Design, 3rd edition, New York: WileyInterscience, 2005. 6. J. J. Carr (ed.), Practical Antenna Handbook, 4th edition, New York: McGraw-Hill, 2001. 7. K. M. Luk and K. W. Leung (eds.), Dielectric Resonator Antennas, in Antennas Series, Cambridge, UK: Research Studies Press, 2002. 8. K. L. Wong, Compact and Broadband Microstrip Antennas, New York: Wiley-Interscience, 2002. 9. R. C. Hansen, Electrically Small, Superdirective, and Superconducting Antennas, New York: Wiley-Interscience, 2006. 10. J. Volakis (ed.), Antenna Engineering Handbook, 4th edition, New York: McGraw-Hill Professional, 2007. 11. Z. N. Chen (ed.), Antennas for Portable Devices, London: Wiley, 2007. xxvi Introduction