Miniaturization of CPW-Fed Slot Antennas Using Reactive Terminations and Truncated Bilateral Ground Plane

Two miniaturized designs of coplanar waveguide (CPW)-fed slot antennas are proposed using reactive terminations and truncated bilateral ground plane. The slot radiators are shortened by employing meandered thin strips or interdigital capacitors (IDCs) as the reactive terminations, while the reduction in total antenna area is accomplished by the truncated bilateral ground plane. Design considerations to truncate the bilateral ground plane while maintaining satisfactory transmission characteristics of the feeding CPW are discussed. The slot radiators of the 5.8-GHz prototype designs both measure 0.03 lambda(0) x 0.13 lambda(0), and the ground planes occupy a small area of 0.21 lambda(0) x 0.13 lambda(0). The measured gains of the designs using inductive and capacitive terminations are 1 and 0.7 dBi, respectively. Also, it is shown that the design using IDCs can be further miniaturized. A 2.4-GHz prototype antenna is thus realized with a ground plane size, or total antenna area, of merely 0.088 lambda(0) x 0.062 lambda(0).