Millimeter-wave technologies are growing for sensing and communication applications in recent years. The service of the 5G mobile communication systems has already begun and currently the service area is extending from hot spots gradually. The development of the RF technologies of mobile communication systems shifts higher frequency band such as Teraherz-wave band for Beyond 5G systems toward 2030 as a next stage.

High-gain antennas for high S/N ratio and high angular resolution can be designed in the millimeter-wave and Teraherz-wave bands even though the physical size of the antenna is small. Beam-scanning function is attractive to detect the target in sensing systems and to cover wide area with high gain in communication systems. Technologies of planar array antennas and multiple beam antennas are required for these applications.

This talk presents the distinct features of the planar antennas, multiple beam antennas and lens antennas. The designs and the principles of the various antennas are explained. The key technologies of the planar array antennas and the lens antennas for beam-scanning in the millimeter-wave and Teraherz-wave bands are presented in this talk. Transmission line transitions to connect RF-IC and waveguide feeding horn antennas for primary radiators of lens antennas are also mentioned in this talk.