|
|
| Line 1: |
Line 1: |
| {{move portions from|Antenna effective length|date=July 2013}}
| | Ed is what people call me and my wife doesn't like it at all. Since I was eighteen I've been operating as a bookkeeper but soon my spouse and I will begin our personal business. For years he's been residing in Alaska and he doesn't plan on altering it. She is really fond of caving but she doesn't have the time lately.<br><br>Here is my page - [http://isaworld.pe.kr/?document_srl=392088 live psychic reading] |
| {{Antennas|Characteristics}}
| |
| | |
| In [[telecommunications]], the '''antenna factor''' is defined as the [[ratio]] of the incident [[electromagnetic field]] strength to the [[voltage]] ''V'' (units: V or µV) on the line connection of an [[antenna (radio)|antenna]].
| |
| | |
| For an electric field antenna, the field strength is in units of V/m or µV/m and the resulting antenna factor ''AF'' is in units of 1/m: | |
| | |
| : <math>AF = \frac EV</math>
| |
| | |
| If all quantities are expressed logarithmically in [[decibel]]s instead of [[SI unit]]s, the above equation becomes
| |
| | |
| : <math>
| |
| AF_{\mathrm{dBm}^{-1}} =
| |
| E_\mathrm{\mathrm{dBV/m}} - V_{\mathrm{dBV}} =
| |
| E_\mathrm{\mathrm{dB}\mu\mathrm{V/m}} - V_{\mathrm{dB}\mu\mathrm{V}}
| |
| </math>
| |
| | |
| For a magnetic field antenna, the field strength is in units of A/m and the resulting antenna factor is in units of A/(Vm). For the relationship between the electric and magnetic fields, see the [[impedance of free space]].
| |
| | |
| In a 50 Ω system, the antenna factor is related to the [[antenna gain]] ''G'' and the wavelength λ via:
| |
| | |
| : <math>
| |
| AF = \frac{9.73}{\lambda \sqrt{G} }
| |
| </math>
| |
| | |
| The variable G means antenna gain (dimensionless) and it can be written in terms of effective aperture A to obtain the final expression considering the [[impedance of free space]] (376.7Ω) and the load as 50Ω.
| |
| The antenna effective aperture can be written as A = (λ<sup>2</sup>G)/4π.
| |
| | |
| ==References==
| |
| * [http://www.tdkrfsolutions.com/DataPDFs/antenna_paper_part3.pdf Interpreting Antenna Performance Parameters for EMC Applications]
| |
| * [http://www.djmelectronics.com/articles/emc-antenna-parameters-p3.html Interpreting Antenna Performance Parameters for EMC Applications]{{Dead link|date=July 2010}} An excellent page with summaries of all the relevant equations
| |
| * [http://www.antenna-theory.com/definitions/antennafactor.php Antenna Theory]
| |
| | |
| | |
| [[Category:Antennas (radio)]]
| |
Ed is what people call me and my wife doesn't like it at all. Since I was eighteen I've been operating as a bookkeeper but soon my spouse and I will begin our personal business. For years he's been residing in Alaska and he doesn't plan on altering it. She is really fond of caving but she doesn't have the time lately.
Here is my page - live psychic reading