Patent ID: 8102307

Claim:
Doppler radar sensor, comprising: at least one mixer structure ( 310 , 410 ) including a transmission line section ( 320 ); said at least one mixture structure resides in said line between an oscillator ( 32 ) and a receiving and transmission means ( 34 ); mixer diodes ( 118 a , 118 b ), said mixer diodes are in electrical communication with different points of said transmission line to pick off a signal wave; said transmission line section ( 320 ) has the length of a multiple of half a wavelength of said signal wave; said transmission line section ( 320 ) has a different characteristic impedance as compared to said lines coming from said oscillator ( 32 ) and from said receiving and transmission means ( 34 ); an oscillator signal ratio, said oscillator signal ratio defined as the ratio of said signal sent to said receiving and transmission means to said signal sent to said mixture structure ( 310 , 410 ); said impedance of said transmission line section ( 320 ) is adjustable thereby changing said oscillator signal ratio.