Radar detector/security device for automobiles

A car radar detector/security device comprising:

• a horn antenna structure provided with local oscillation means, a horn antenna that radiates a local oscillation frequency from the local oscillation means to the outside and receives radar waves from the outside, and a mixing chamber leading from said horn antenna, said horn antenna structure comprising means to output an intermediate frequency signal as a result of mixing in the mixing chamber an applied frequency signal with said radar wave detected by the horn antenna, means to detect a frequency signal that is reflected from a dielectric body of said local oscillation frequency radiated to the outside via said horn antenna, and means to output a low frequency signal which is a beat of said local oscillation frequency and said feedback frequency signal reflected from said dielectric body which has undergone a Doppler shift produced by the motion of said dielectric body;
• a radar wave detection circuit that detects said intermediate frequency signal output from said horn antenna structure with the detection of said radar wave and operates a warning means;
• a security circuit that detects said low frequency signal that is the beat component produced by said feedback frequency signal and operates an annuniciating means;
• and
• a mode switching means for selecting either the radar detection circuit or the security circuit.