The use of mm- and sub-mm- waves is becoming increasing interest to be applied in Beyond 5G communication scenarios. The large bandwidth availability in the higher frequencies will enable the expected growth in the capacity of communication networks and devices, which is reaching the saturation with current solutions relaying on lower frequencies, narrow bandwidths and high computational effort. In this work, the use of wideband, low-cost plastic lens antennas is proposed for Beyond 5G scenarios with multiple fixed beams (point-to-multipoint, small cells). Three wideband antenna designs at G-band (140-220GHz) are presented, addressing important requirements in the future antenna systems.