Magnetic field strength

[kubeek]

Hi, i´m having trouble with calculating magnetic field, namely conversion between A/m and Tesla.

In the rfid standard it is said that the operating field should be between 1.5 and 7.5 A/m, however in the attached app note the calculations for the coil design on page 4 are done with Wb/m2, which is Tesla.

Since this all happens in air with ur=1, can I assume that 1T=1A/m?
If so, the equations are giving me unbelievable numbers..

 

[vlad777]

Tesla is flux density, but A/m I think is H-field.

The equation is:
H=B/(u0*ur)

H is H-field
B is flux density

 

[kubeek]

Thanks, i also found it... The difference between permeability and relative permeability got me again, which is why I assumed they should be the same, even though they have different units which should have striken me before.
1T=12.56*10^-7 A/m

Now the numbers make much more sense.