The invention relates to a radar device for transmitting a signal in a frequency band, and comprising: a control means (1); an oscillator (2) wherein an input of said oscillator (2) is connected to the control means (1) by means of a converter (9), this oscillator (2) being able to be actuated by said control means (1) in order to generate the signal, and the signal generated by the oscillator (2) being able to be tapped at an output of said oscillator (2); at least one transmission antenna (3) for transmitting the signal which is at the oscillator (2) output, this transmission antenna (3) being connected to said oscillator (2) output; and at least one receiver channel for receiving a receiver signal, processing said receiver signal, and relaying this processed receiver signal to the control means (1), the receiver channel comprising at least one receiver antenna (4) and one mixer (5) for mixing the receiver signal with the signal at the oscillator (2) output, this mixer being connected to said oscillator (2) output, said oscillator (2) output being connected to an input of the control means (1), and the control means (1) being suitable and configured for actuating said oscillator (2), for the purpose of identifying a channel-failure, such that first signal components (
K ) are generated comprising signal fragments (
K i ) whose frequencies (
f i K ) have a lower cut-off frequency (
f E1 ) of the frequency band and an upper cut-off frequency (
f E2 ) of the frequency band, wherein the signal fragments (
K i ) with a lower cut-off frequency (
f E1 ) and the signal fragments (
K i ) with an upper cut-off frequency (
f E2 ) can be generated alternately.