The thinkRF RTSA measures dBm at the antenna input RFIN. However, if an antenna is connected to the RFIN, there may be a requirement to provide a measure of Electric Field Strength (V/m or dBV/m) at the antenna.
dBV/m (deciBel Volt per meter) is particularly relevant in the field of Electromagnetic Compatibility (EMC) testing and regulatory compliance, where it is used to assess the levels of electromagnetic interference (EMI) or electromagnetic radiation generated by electronic devices and equipment. It helps determine whether the emissions from a device comply with established EMC standards and regulations.
dBm stands for "decibels relative to one milliwatt," and is a unit of measurement used to express power levels. dBm quantifies the ratio of a power level to one milliwatt (1 mW) as a logarithmic value.
dBm is commonly used in RF engineering to express the power output or received signal strength of electronic devices, such as transmitters, receivers, amplifiers, and antennas. It provides a compact way to represent a wide range of power levels.
This tool converts dBm as measured by the RTSA at any frequency to dBuV/m. The calculation required Antenna Gain, input impedance and operating frequency.
dBuV/m can be converted to dBV/m, dBmV/m or dBnV/m.
As an example, at a frequency of 2500 MHz, an omnidirectional antenna has a max gain of 4.7 dBi. With an input impedance of 50 Ω, and a received power of -90 dBm, the field intensity is 50.5 dBµV/m or -9.5 dBmV/m.