A TEM cell (Transverse electromagnetic cell) is a kind of test chamber used to perform EMC (electromagnetic compatibility) or EMI (electromagnetic interference) testing of small-size electronic products such as wireless pagers, receivers, portable phones, ICs, etc. It is also used for the calibration of RF probes and biomedical experiments. The cell allows an engineer to perform radiated emission measurement testing as well as immunity testing on electronic products.  
This calculator will determine the power needed for the TEM Cell from the desired field level and height of the TEM cell.
The power needed for the TEM Cell is expressed as:

Where,
V/m – Desired Field Level
Height - Height of TEM Cell
Z – Impedance
Loss dB – System Losses