Micromachined air‐filled patch antennas for millimeter‐wave applications

Air-filled patch antennas for millimeter-wave (mm-wave) applications are demonstrated using silicon-based micromachining techniques. The antennas are fed by rectangular coaxial lines and made of five gold plated layers bonded together. Each layer is made by deep reactive etching on silicon. The patches are suspended by stubs, without using any dielectric materials. The dielectric free structure not only avoids dielectric losses but also eliminates spurious surface modes that often trouble substrate supported patch antennas at mm-wave frequencies. The predicted gain of the patch is as high as 9.4 dBi with a patch dimension of 3.27 mm by 3.54 mm at 38 GHz. A radiation pattern measurement has been performed and results shown.