.net barcode reader free Dipole antenna elements in Software

Draw Data Matrix ECC200 in Software Dipole antenna elements

Dipole antenna elements
ECC200 Decoder In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
ECC200 Generation In None
Using Barcode maker for Software Control to generate, create Data Matrix ECC200 image in Software applications.
The dipole is a two-pole antenna (Fig 19-20) that can be modeled as either a single radiator fed at the center (Fig 19-20A) or a pair of radiators fed back to back (Fig 19-20B) RF current from the source oscillates back and forth in the radiator element, causing an electromagnetic wave to propagate in a direction perpendicular to the radiator element The polarity of any electromagnetic field is the direction of the electrical field vector (see Chap 2) In the dipole, the polarization is parallel to the radiator element: a horizontal element produces a horizontally polarized signal, while a vertical element produces a vertically polarized signal
Scan Data Matrix In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
ECC200 Generation In Visual C#
Using Barcode printer for Visual Studio .NET Control to generate, create Data Matrix image in .NET framework applications.
The isotropic antenna
Encode Data Matrix In VS .NET
Using Barcode encoder for ASP.NET Control to generate, create ECC200 image in ASP.NET applications.
Data Matrix Drawer In .NET
Using Barcode generator for Visual Studio .NET Control to generate, create Data Matrix 2d barcode image in VS .NET applications.
Generator V
Data Matrix Maker In Visual Basic .NET
Using Barcode generator for .NET framework Control to generate, create DataMatrix image in VS .NET applications.
Code-128 Generator In None
Using Barcode encoder for Software Control to generate, create Code 128C image in Software applications.
Current
Create ANSI/AIM Code 39 In None
Using Barcode generator for Software Control to generate, create USS Code 39 image in Software applications.
UPCA Creator In None
Using Barcode generation for Software Control to generate, create UPC-A Supplement 5 image in Software applications.
Radiator
Paint Barcode In None
Using Barcode generator for Software Control to generate, create barcode image in Software applications.
Encode Data Matrix 2d Barcode In None
Using Barcode encoder for Software Control to generate, create DataMatrix image in Software applications.
V = c = 3 108 m/s
Code 2 Of 7 Printer In None
Using Barcode creation for Software Control to generate, create Uniform Symbology Specification Codabar image in Software applications.
Data Matrix 2d Barcode Generation In None
Using Barcode maker for Online Control to generate, create Data Matrix 2d barcode image in Online applications.
19-20A Basic dipole antenna showing propagation
Generate Data Matrix 2d Barcode In None
Using Barcode maker for Font Control to generate, create Data Matrix 2d barcode image in Font applications.
Barcode Encoder In Java
Using Barcode printer for Android Control to generate, create bar code image in Android applications.
19-20B Basic dipole antenna
Barcode Creator In .NET Framework
Using Barcode creation for Reporting Service Control to generate, create bar code image in Reporting Service applications.
Recognizing Code 3/9 In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
Figure 19-21 shows the radiator patterns for the dipole viewed from two perspectives Figure 19-21A shows the pattern of a horizontal half-wavelength dipole as viewed from above This plot shows the directivity of the dipole: maximum radiation is found in two lobes perpendicular to the radiator length The plot in Fig 19-21B shows the end-on pattern of the dipole This omnidirectional pattern serves for a vertically polarized dipole viewed from above The end-on pattern of a horizontal dipole would be similar, except that it is distorted by ground effects unless the antenna is a very large number of wavelengths above the ground
EAN128 Printer In VS .NET
Using Barcode drawer for Reporting Service Control to generate, create GS1-128 image in Reporting Service applications.
Making Barcode In VS .NET
Using Barcode generator for VS .NET Control to generate, create bar code image in Visual Studio .NET applications.
398 Microwave waveguides and antennas
Dipole 19-21A Dipole pattern (horizontal)
Dipole 19-21B Dipole pattern (vertical)
A microwave dipole is shown in Fig 19-22 The antenna radiator element consists of a short conductor at the end of a section of waveguide Although most lowfrequency dipoles are a half-wavelength, microwave dipoles might be either a half-wavelength, less than a half-wavelength, or greater than a half-wavelength, depending upon application For example, because most microwave dipoles are used to illuminate a reflector antenna of some sort, the length of the dipole depends upon the exact illumination function required for proper operation of the reflector Most, however, will be a half-wavelength
Antenna directivity and gain
The dipole discussed illustrated a fundamental property of the type of antenna generally used at microwave frequencies: directivity and gain These two concepts are different but so interrelated that they are usually discussed at the same time Because of the directivity, the antenna focuses energy in only two directions, which
The isotropic antenna
means that all of the energy is found in those directions (Fig 19-21A), rather than being distributed over a spherical surface Thus, the dipole has a gain approximately 21 dB greater than isotropic In other words, the measured power density at any point will be 21 dB higher than the calculated isotropic power density for the same RF input power to the antenna Directivity The directivity of an antenna is a measure of its ability to direct RF energy in a limited direction, rather than in all (spherical) directions equally As shown in Fig 19-21A, the horizontal directivity of the dipole forms a bidirectional figure-8 pattern Two methods for showing unidirectional antenna patterns are shown in Fig 19-23 The method of Fig 19-23A is a polar plot viewed from above The main lobe is centered on 0 The plot of Fig 19-23B is a rectangular method for displaying the same information This pattern follows a (sin x)/x function or, for power, [(sin x)/x]2 Directivity D is a measure of relative power densities: D Or, referenced to isotropic, D where D is the directivity Pmax is the maximum power Pav is the average power is the solid angle subtended by the main lobe 4 [1925] Pmax Pav [1924]
19-22 Microwave dipole radiator
Dipole
Waveguide
400 Microwave waveguides and antennas
0-Degrees
3 dB BW
Main lobe
19-23A Directional antenna pattern (top view)
Sidelobe
Backlobe a = 3-dB beamwidth
The term is a solid angle, which emphasizes the fact that antenna patterns must be examined in at least two extents: horizontal and vertical A common method for specifying antenna directivity is beamwidth (BW) The definition of BW is the angular displacement between points on the main lobe (see Figs 19-23A and 19-23B), where the power density drops to one-half ( 3 dB) of its maximum main lobe power density This angle is shown in Fig 19-23A as a In an ideal antenna system, 100 percent of the radiated power is in the main lobe, and there are no other lobes But in real antennas certain design and installation anomalies cause additional minor lobes, such as the sidelobes and backlobe shown in Fig 19-23A Several problems derive from the minor lobes First is the loss of usable power For a given power density required at a distant receiver site, the transmitter must supply whatever additional power is needed to make up for the minor lobe losses The second problem is intersystem interference A major application of directional antennas is the prevention of mutual interference between nearby cochan-
Copyright © OnBarcode.com . All rights reserved.