I require the measurement of RF power from a port, and I am considering using a zero-bias RF detector in order the measure the power being delivered through the port.
These devices give a voltage output which is roughly linear to the logarithm of the power being received at the port, ie., power in dBm.
All these detectors have a parameter known as Flatness vs. Frequency, and they mention the values in dB. I think that this may be referring to the amount of change of the output voltage as the RF frequency of the input power is changed, but I am unable to figure out how it works quantitatively, and whether the deviation is sufficient for my application.
For example, one of the detectors which I am considering shows a flatness vs. Frequency of (+/-)0.5 dB max. What does this mean, and how can I make sense of these numbers?