Some modern smoke grenade launchers for vehicles also have an anti-radar ability, the rounds contain metal flakes to mess up the radar signal.
I don't know when these were introduced into widespread service but it's a safe bet that they become available shortly after the widespread use of ground based radar systems to track foot & vehicle traffic.
There's some examples of the different types available to the US on the following site: -
https://inetres.com/gp/military/cv/w...launchers.html