Gain measurement of antennas using RFID

Abstract

This paper presents a method for contactless gain measurements of 50 Ohm antennas. The method is based on connecting a special passive RFID chip assembly, matched to 50 Ohm in the wide band, to the antenna and measuring the read sensitivity of the resulting tag in the tag characterization system. The gain of the antenna is then calculated from previous calibrated measurement done with reference antenna of known gain, such as dipole. We illustrate the method with experimental measurements on several antennas. The main advantage of this method is that it does not require any external cables and can be used for characterization of small antennas inside modern mobile wireless devices.