New considerations in the design of microstrip antennas

Printed microstrip antennas and arrays are known to have limitations in terms of bandwidth and efficiency, all imposed by the very presence of the dielectric substrate. Microstrip arrays printed on a very thin film and separated from the ground-plane by foam were successfully designed; however, the fabrication difficulties associated with the use of foam considerably increases the fabrication cost. In this paper, a new concept is presented. Rather than using a superstrata geometry, the "printed circuit" is etched out of metal and supported in "strategic points" by (metallic or nonmetallic) posts, The main motivation for this work was to obtain large microstrip arrays, which exhibit a higher efficiency than conventional ones, and can be fabricated using inexpensive large quantity production techniques. However, this technology was also used to develop many new types of microstrip antennas. Microstrip elements and arrays based on this technology were designed and fabricated at L, S, and C bands.