Antenna engineering handbook john l volakis, thomas f eibert 4th edition
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Antenna engineering handbook john l volakis, thomas f eibert 4th edition
DR. JOHN L. VOLAKIS____A NTEN N A ENGINEERING ■ ha n dbookF o u R ĩ H EDITIONSource: ANTENNA ENGINEERING HANDBOOKp • A • R • T • 1Introduction and Fun Antenna engineering handbook john l volakis, thomas f eibert 4th edition ndamentalsIntroduction and FundamentalsSource: ANTENNA ENGINEERING HANDBOOK_______Chapter 1___Fundamentals of Antennas, Arrays, and Mobile CommunicationsThomas F. EibertUniversitat StuttgartJohn L VolakisThe Ohio State UniversityCONTENTS1.1INTRODUCTION.............................. 1-41.2HUYGENS'AND Antenna engineering handbook john l volakis, thomas f eibert 4th edition EQUIVALENCE PRINCIPLES........ 1-51.3HERTZIAN AND FITZGERALD ELEMENTARY RADIATORS. 1-71.4FAR-FIELD ANTENNA PROPERTIES, POWERTRANSFER,AND RECIPROCITY.Antenna engineering handbook john l volakis, thomas f eibert 4th edition
........................... 1-81.5ANTENNAS AS ELECTROMAGNETIC CIRCUITS..... 1-111.6POLARIZATION............................. 1-141.7DIRECTIVITY PATTERDR. JOHN L. VOLAKIS____A NTEN N A ENGINEERING ■ ha n dbookF o u R ĩ H EDITIONSource: ANTENNA ENGINEERING HANDBOOKp • A • R • T • 1Introduction and Fun Antenna engineering handbook john l volakis, thomas f eibert 4th edition NDAMENTALS OF ANTENNA ARRAYS........... 1-271.1BASIC CONCEPTS IN MOBILE COMMUNICATIONS.. 1-32Fundamentals of Antennas. Arrays, and Mobile Commur45295CHAPTER ONE1.1 INTRODUCTIONAntennas are key components of any wireless communication system.12 They are the devices that allow for the transfer of a si Antenna engineering handbook john l volakis, thomas f eibert 4th edition gnal (in a wired system) to waves that, in turn, propagate through space and can be received by another antenna. The receiving antenna is responsibleAntenna engineering handbook john l volakis, thomas f eibert 4th edition
for the reciprocal process, i.e.. that of turning an electromagnetic wave into a signal or voltage at its terminals that can subsequently be processedDR. JOHN L. VOLAKIS____A NTEN N A ENGINEERING ■ ha n dbookF o u R ĩ H EDITIONSource: ANTENNA ENGINEERING HANDBOOKp • A • R • T • 1Introduction and Fun Antenna engineering handbook john l volakis, thomas f eibert 4th edition e fairly well understood? The dipole antenna (a straight wire, fed at the center by a two-wire transmission line) was the first antenna ever used and is also one of the best understood.12 For effective reception and transmission, it must be approximately Ấ/2 long (Ấ = wavelength) at the frequency of Antenna engineering handbook john l volakis, thomas f eibert 4th edition operation (or multiples of this length). Thus, it must be fairly long (or high) when used at low frequencies (Ẳ = I m at 300 MHz), and even at higherAntenna engineering handbook john l volakis, thomas f eibert 4th edition
frequencies (UHF and greater), its protruding nature makes it quite undesirable. Further, its low' gain (2.15 dB). lack of directionality, and extremDR. JOHN L. VOLAKIS____A NTEN N A ENGINEERING ■ ha n dbookF o u R ĩ H EDITIONSource: ANTENNA ENGINEERING HANDBOOKp • A • R • T • 1Introduction and Fun Antenna engineering handbook john l volakis, thomas f eibert 4th edition ception) W'as considered a breakthrough in antenna technology when introduced in the early 1920s because of its much higher gain of 8-14 dB. Log-periodic wire antennas introduced in the late 1950s and 1960s and wire spirals allow ed for both gain and bandwidth increases. On the other hand, even toda Antenna engineering handbook john l volakis, thomas f eibert 4th edition y high gain antennas rely on large reflectors (dish antennas) and waveguide arrays (used for many radar systems).Until the late 1970s. antenna designAntenna engineering handbook john l volakis, thomas f eibert 4th edition
was based primarily on practical approaches using off-the-shelf antennas such as various wire geometries (dipoles, Yagi-Uda. log-periodics. spirals), DR. JOHN L. VOLAKIS____A NTEN N A ENGINEERING ■ ha n dbookF o u R ĩ H EDITIONSource: ANTENNA ENGINEERING HANDBOOKp • A • R • T • 1Introduction and Fun Antenna engineering handbook john l volakis, thomas f eibert 4th edition uirements that characterize antennas, such as gain, input impedance, bandwidth, pattern beamwidth, and sidelobe levels (see References 4 and 5 for a description of these quantities). Antenna development required extensive testing and experimentation and was. therefore, funded primarily by government Antenna engineering handbook john l volakis, thomas f eibert 4th edition s. However, in recent years, dramatic growth in computing speed and development of effective computational techniques for realistic antenna geometriesAntenna engineering handbook john l volakis, thomas f eibert 4th edition
has allowed for low-cost virtual antenna design. Undoubtedly, the explosive growth of wireless communications and microwave sensors, microwave imaginDR. JOHN L. VOLAKIS____A NTEN N A ENGINEERING ■ ha n dbookF o u R ĩ H EDITIONSource: ANTENNA ENGINEERING HANDBOOKp • A • R • T • 1Introduction and Fun Antenna engineering handbook john l volakis, thomas f eibert 4th edition odern computational techniques for low-cost designs. Requirements forDR. JOHN L. VOLAKIS____A NTEN N A ENGINEERING ■ ha n dbookF o u R ĩ H EDITIONSource: ANTENNA ENGINEERING HANDBOOKp • A • R • T • 1Introduction and FunGọi ngay
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