In this paper, a new backscatter transponder type is introduced. The developed transponder regenerates a modulated, phase-coherent high-power response/ replica to an interrogating CW radar signal. To create the amplified phase-coherent transponder response, the switched injection locked oscillator (SILO) concept is applied. Compared with a usual passive backscatter transponder - known e.g. from UHF RFID systems - the reading range of a SILO transponder is substantially increased. It is demonstrated that a reading range above 20 m is easily obtained even with a 5.8 GHz, 15 MBit/s system.