The 5th generation wireless systems (5G) have gradually come to application in recent year due to its apparent advantages compared with the previous 4 G, such as ultra-wideband, ultra-high speed, and ultra-low latency. As a key technique for 5G technology, massive MIMO (multiple input and multiple output) antennas increases sector throughput and capacity density using large numbers of antennas and Multi-user MIMO (MU-MIMO). MgTiO3-CaTiO3, (Ca1+xSm1-x)(Al1-xTix)O4, Li2TiO3 and fergusonite-type LnNbO4 (Ln=La, Nd, Sm etc.) microwave dielectric ceramics systems are potential K20 materials for massive MIMO of mini-station in 5G technology. Among them, fergusonite-type LnNbO4 materials possess low Qf (Q=1/dielectric loss) and large negative TCF (temperature coefficient of resonant frequency) values. In this talk, we will introduce the novel results on the improvements of Qf and TCF values of the fergusonite-type LnNbO4 materials by A and B site substitutions with Bi3+ and V5+ ions.