Transponder interrogator with two coplanar frame aerials

摘要

The arrangement has one frame aerial which is of single type, while the second aerial is of the counter-coiled double frame type. The single frame aerial is coupled only to the receivers, and the double frame aerial is coupled only to the transmitters of the interrogator. Preferably the two frame aerials with the receivers and/or transmitters in the interrogator form a resonant circuit at the respective operational frequency. Typically the surface area of the single frame aerial is less than half of that of the double frame aerial.