VCO in Radar Transceiver

[Gkini19]

Hi All,

I was looking at several papers of radar transceiver that operates at 77GHz to 88 GHz focusing on the VCO and Chirp PLL architecture.

So if we want the output of the VCO to be 77GHz to 88 GHz, all the papers for radar transceivers use VCO with a multiplier to generate frequencies in the range of 77GHz to 88 GHz. (Say 20 * 4 or 38*2 )

What would be the technical reason to use multipliers? why can't we just have an architecture of the VCO that operates at 77 GHz?

Please let me know

[HarryA]

• You may find some useful information on Wikipedia here: https://en.wikipedia.org/wiki/Voltage-controlled_oscillator

I believe it is a trade off between the noise created by high frequency VCOs and that introduced by the multipliers. A low frequency VCO has less noise so using a multiplier to get the high frequency gives the best overall performance. But I can not find the literature that discusses that.