UWB miniature antenna limitations and design issues

A small conformal ultra-wideband (UWB) antenna has many important commercial and military applications. This stems from a multitude of factors such as cost reduction, space, payload, and, most importantly, the number of antenna systems. A common approach to reducing the number of antennas on a platform is to use a single broadband element, such as a spiral antenna. However, the issue is complicated by the fact that a single antenna element may need to operate over more than 10:1 bandwidth, such as 20 MHz to 2000 MHz. To cover such a vast frequency range with a single antenna using conventional designs would require a large physical size to achieve a desirable gain. Therefore, miniaturization techniques, such as the use of dielectric materials or reactive loading, must be used in an attempt to increase the electrical size of the antenna without increasing its physical size. We focus on antenna miniaturization using dielectrics and discuss some of the design issues related to the actual implementation of a miniature antenna.