I'm working in a tracking solution based on RFiD, that consists on tags without any type of battery or power source. When the antenna generates the signal in the correct frequency, an induction process occur in the tag, generating a response to the antenna (containing the tag's id number). The problem is: we need to place tags inside of an metal tripod (aluminium or iron, about 5mm of thickness), that has a few holes (1 cm each one). The frequency used is 900mhz. I believe that: - Could be a Faraday cage. The metal of the tripod is blocking the antenna's eletric field, so the tag isn't receiving the necessary amount of power to answer. - The metal is distorting the frequency, so the tag cannot receive any signal. I've some success using a piece of wire, connected to the metal in the tag and passing it to outside by one of the holes (like an antenna). If the wire touches the metal surface (it's properly isolated), the signal is interrupted. It's possible to pass a radiofrequency trough the cage? Using a frequency of 120khz or 13.5mhz could help (there are another tags with those frequencies. The 120khz one has a bad read range)? How can I calculate the effects of the cage (I've read that is calculated by the Gauss law)? I need some help to calculate it's effects on the radio signal frequency and intensity.