This is an Electromagnetic Compatibility (EMC) function calculator script that may not be accessible with your browser.
e
Engineer
~
Virtual
Tools
EMI / EMC Calculator
~ Default Z = 50 Ω, Enter Z = 377 Ω for EM fields ~
Ω
>----- Conversion Selector ----->
Shielding (dB) --> % Attenuation
% Attenuation --> Shielding (dB)
P --> Far Field (V/m)
Freq (MHz) --> Path Loss (dB)
Antenna Factor --> Gain
Gain --> Antenna Factor
V/m --> mW/cm2, W/m2, A/m
mW/cm2 --> V/m, W/m2, A/m
dBµA --> dBmA
dBmA --> dBµA
dBµV --> dBµA
dBµA --> dBµV
µT --> dBpT
Tesla --> Wb/m2
Tesla --> A/m
Freq (MHz) --> Wavelength (m)
Wavelength (m) --> Freq (MHz)
W
V
dBm
dBw
Copyright © Charlie Bautsch (Radioing.com). Version 02
Calculator Notes
Electric field conversions are based on far field calculations and the characteristic impedance of free space (120π Ω or 377 Ω). When the distance (d) from the source exceeds λ/2π, the wave impedance (ratio of the E-field to the H-field) becomes constant at 377 ohms in free space. This is defined as the far field.
Magnetic flux density (T) conversions are based on the permeability in free space (μ
_{o}
= 4
π
x 10
^{-7}
Henrys/m
).
H
= Magnetic field strength in amps per meter (A/m).
E
= Electric field strength in volts per meter (V/m). This applies to far field calculations (d > λ/2π). Far field is generally at least 1/6 wavelengths from the antenna.
E
_{(V/m)}
= (5.5*sqrt(PG))/d.
P
= Power (watts) into the antenna feedpoint. This applies to antenna far field calculations using E
_{(V/m)}
.
dB
= Decibel, (10 Log
_{10}
P).
π
= pi = 3.14159265.
µ
= micro = 10E-6.
m
= milli = 10E-3.
dBw
= Decibels relative to one watt.
dBm
= Decibels relative to one milliwatt.
dBV
= Decibels relative to one volt.
dBµV
= Decibels relative to one microvolt.
dBµA
= Decibels relative to one microamp.
dBpT
= Magnetic flux density (B) in decibels relative to one pico Tesla (pT).
V
= Volts.
A
= Amps.
W
= Watts.
m
= Meters, unit of length (39.37 inches).
W/m2
= Watts per square meter (power density).
mW/cm2
= Milliwatts per square centimeter (power density).
V/m
= Volts per meter (electric field strength).
dBm/m2
= Electric field power density in decibels relative to one milliwatt per square meter.
dBW/m2
= Electric field power density in decibels relative to one watt per square meter.
Gain (G)
= Antenna far field numeric gain relative to an isotropic radiator (antenna that radiates equally in all directions, 360 degree beamwidth).
dBi
= Decibels-isotropic, relative to an isotropic radiator.
T
= Teslas. Flux Density (T) = (Wb)/(m2).
µT
= MicroTeslas.
Wb
= Webers. Flux (Wb) = Flux Density (T) x Area (m2).
A/m
= Amperes per meter.
Shielding (SdB)
= Shielding effectiveness in decibels. Shielding effectiveness (S) is the ratio of the EMI field strength outside the shield to the field strength inside the shield.
Attenuation (%Att)
= Percentage attenuation of a shield.
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