Yagi-Uda antennas fabricated on thin GaAs membrane for millimeter wave applications

Planar antennas are key elements in microwave and millimeter wave systems for many applications. Micromachining technology has been proposed for the fabrication of millimeter wave circuits on very thin dielectric membranes. This approach offers many advantages. The Yagi-Uda antenna has become a standard for multi-element antenna arrays in the range from HF to UHF. The paper presents the design, manufacture and characterization of Yagi-Uda antenna structures fabricated on a GaAs semi-insulating thin membrane using micromachining technologies. The design methodology for the antennas is presented, followed by a description of the technological processes used for the GaAs micromachining. Experimental results for 45 GHz and 60 GHz antennas are presented. The simulated and measured return loss curves for the 60 GHz antenna show very good agreement. However, there is a frequency shift between the measured and simulated response of the 45 GHz antenna, which could be attributed to the measuring conditions. We are convinced that these GaAs membrane supported antennas can be monolithically integrated with millimeter wave active devices into high performance front-ends for smart microsystems.