Direct RF undersampling receiver for high-SHF band digital beam forming

In this paper, we proposes the usage of direct RF undersampling receiver for digital beam forming in high-SHF (over 6GHz) band. The direct RF configuration can be reduce the size of individual receiver attached to each antenna elements and can be realize digital beam forming functionality which is applicable to Massive Multiple-Input-Multiple-Output (MIMO) in 5G system. Recent development of direct RF undersampling S/H CMOS IC in high-SHF band is also introduced.