Travelling-wave planar array antennas for beamscanning systems in millimeter-wave band

Millimeter-wave planar antennas are developed in this work. Travelling-wave feeding systems are advantageous for simple configuration and low-loss operation in millimeter-wave band, compared with tournament parallel feeding systems. Waveguide antennas can be applied to both sub-arrays for electrical beam-scanning antennas and two-dimensional pencil-beam antennas, because feeding loss is essentially small. Microstrip antennas are appropriate only for sub-arrays. Features and advantages of waveguide antennas and microstrip antennas designed for beam-scanning systems are discussed in this paper.