"Millimeter-wave" wireless applications are emerging at frequencies from 24 to 110 GHz. Anticipated uses of this spectrum include data transfer, highway safety, intelligent transport, mobile satellite communications, civilian ultrawideband radar, etc. In contrast to most wireless services offered at lower frequencies, typical millimeter-wave applications need to steer or redirect wireless signals in order to track a mobile target or user. Unfortunately, current techniques for millimeter-wave beam steering are limited mainly to aerospace/defense applications due to the exuberant cost of the...