Connecting the Automotive Bands of Present and Future With a Tag for Inharmonic Radar at 76-81/134-141 GHz

Vulnerable road users like pedestrians, pedal-, and motorcyclists have accounted for an increasing proportion of traffic fatalities in the last 15 years. Simultaneously, harmonic radar systems have been implemented for applications where distinction between specific targets and surrounding clutter is required. However, the doubled frequencies conventionally used in harmonic radar systems are not licensed for automotive applications. Connecting the 76-81GHz automotive band with the 134-141GHz currently going through regulation instead necessitates what we propose to call inharmonic radar. Therefore, an innovative frequency modulation instead of doubling is required. This modulation is achieved and presented in this work with an active tag based on a novel 1.75 times fractional frequency multiplier. It successfully implements the required frequency conversion upward of-53dBm of input power with undesired spectral components suppressed by more than 20 dB.