Abstract: A radar device, of the almost linearly frequency-modulated type of the transmission signal during the pulse, comprises a transmit circuit including a high-frequency oscillator (29), a transmit-receive aerial (7) and a receive circuit including a pulse compression element (33). According to the invention, inside the transmit circuit, an Impatt diode (17) of a diode switch (16) produces directly at microwave frequency a synchronizing signal of the oscillator (pulses modulated in accordance with negative frequency slopes). For this purpose, a clock pulse generator (26) commands a switch (25) arranged in series on the conductor (19) of the supply current of the Impatt diode (17) which current is substantially continuous, to conduct for the duration of each pulse to be transmitted.