Micromachined microstrip patch antenna with controlled mutual coupling andsurface waves

In this paper, silicon micromachining has been used to demonstrate the poss ibility of building high performance microwave and millimeter-wave antennas . To suppress higher order substrate modes and increase the bandwidth of a patch antenna, silicon substrate has been used and material has been select ively removed under the patch area. In addition, the effect of etched groov es around a patch element has been studied for performance improvement. It has been shown that micromachined substrate structure can effectively suppr ess unwanted surface wave modes resulting in improved radiation efficiency. Moreover, effective dielectric constant curves for the shielded micromachi ned substrates are provided for accurate design of patch antennas. We have demonstrated that mutual coupling between the radiating patch elements due to surface waves can be controlled using various micromachined substrate co nfigurations.