9. Micromachined Antennas

This Chapter presents different types of micromachined antennas at mm-wave frequencies. The design and fabrication of a Ka-band inset-fed microstrip patch antenna on a suspended 2 µm thick silicon-dioxide membrane using silicon bulk-micromachining technique have been discussed. The complete antenna structure is realized using post - CMOS and post-MMIC compatible metal dielectric deposition techniques. The parametric study to obtain the optimized inset length is also presented. Three different patch antennas integrated with micromachined SPDT and SP9T switches are presented at 60 GHz for different wireless applications at ISM band of 60 GHz. The utilization of SPDT switch in front end transmit/receive module is discussed with experimental investigation. The SP9T based antenna is a preliminary prototype for the proof of concept of antenna sectoring at 60 GHz for ISM applications. A 77 GHz micromachined polarization reconfigurable antenna is discussed, and it has capability to generate all polarization states. This antenna illustrates a measured return loss of >20 dB, −10 dB bandwidth of 10% and 14.3% in LP and CP cases respectively, at 77 GHz. A minimum best value of 1.1 dB axial ratio is accomplished at 77 GHz in circularly polarized state from this antenna. Next design and development of active micromachined antenna is presented. Finally, this Chapter concludes with design guideline for designing and developing micromachined cavity antenna including antenna arrays.