Millimeter-wave planar array antennas for several radiation patterns and gains

Design techniques for planar array antennas with several radiation patterns and gains are developed in the millimeter-wave band. Waveguide antennas are advantageous for high gain uses because feeding loss is quite low compared with antennas fed by other planar transmission lines. On the other hand, microstrip antennas are not suitable for high gain applications because feeding loss is quite high when the aperture size is large. However, when the application requires only low gain, microstrip antennas are advantageous because the design flexibility depending on the printed patterns on the substrate is very high for several types of radiation patterns. This paper summarizes design techniques of high gain slotted waveguide planar array antennas and microstrip array antennas for several types of radiation patterns. Measured performance of the fabricated antennas is presented in this paper.