An active UHF RFID transponder for fawn saving during pasture mowing The present publication describes an innovative concept for fawn saving during pasture mowing in spring time. Conventional approaches like scaring by dogs or scarecrows are ineffective and time consuming especially for large areas. Other technical solutions have different drawbacks or insufficient search performance. Within the active UHF RFID localization system the processes of identifying fawns and rescuing them during mowing are separated. To recover them during the mowing sequence the fawns, covered in high and thick grass, are marked with active UHF RFID Transponders. The UHFRFID Transponder is attached to the eavesdropper of the fawn. By using chip antennae an overall size of a one euro coin was achieved despite working within the UHF band. Due to the unknown position of the transponder in high grass the directivity of the chip antennae was measured with consideration of co-and cross-polarization. An efficient power management enables a lifetime of about one month. In addition, the UHF RFID Transponder is supplied with an environment-friendly zinc air battery.