It’s the K-band cousin of the X-band HB100 used by [Mathieu] in a project we covered a few years back, but thanks to the shorter wavelength the module is much smaller — just an inch square.

Vehicle Speed Detection with HB100 X-Band Motion Sensor and Arduino UNO Determine viability of the HB100 and test vehicle detection and speed measurement algorithms. This was a developmental step to a ...

HB100 – Insights The HB100 module consists of Dielectric Resonator Oscillator (DRO), microwave mixer and patch antenna. The module operates at +5 Vdc for Continious wave (CW) operation, but module can ...

If powering directly from the Arduino, consider a seperate, regulated 5 V supply exclusively for the doppler sensor and its conditioning. Otherwise, you can expand on this circuit, and add a late ...