A device for operating an RFID writing/reading device with transmitted signal suppression includes the RFID writing/reading device and a reflection modulator. The RFID writing/reading device includes a transmitter, a receiver with a signal processor, a directional coupler with a first, a second, a third and a fourth port, and an antenna. The reflection modulator is connected to the fourth port of the directional coupler. The reflection modulator includes a first setting element and a second setting element. The reflection modulator is configured to reflect a copy of a transmitted signal from the RFID writing/reading device, the amplitude and phase of which copy have been weighted, to the directional coupler. The directional coupler is configured to add the weighted copy of the transmitted signal to a received signal from the antenna in the directional coupler.