This is an obscure type of antenna, called sometimes cigar antenna, that works pretty much like Yagi - most of you will know it as (non-satellite) TV antenna - but instead of rods it has disks. It was used in Lunokhod 1 and 2, Soviet moon rovers launched in 1970 and 1973 respectively
i’ve lifted this photo from linked page, which elaborates on these antennas in detail