With the rapid growth of wireless communications and associated demand for high data-rates, many future antennas must be ultra-wideband (UWB). A single antenna is certainly a most attractive solution to handling the large bandwidth requirements. Designing such an antenna that is concurrently of low-profile is necessary for mounting on a variety of grounds and airborne vehicles. This thesis presents a new low-profile UWB antenna concept. The concept is based on a shorted low-profile patch strategically fed on the open side to obtain wide bandwidth. For miniaturizing the proposed antenna and widening its bandwidth, it was loaded with ferrite bars placed between the patch plate and the ground plane. Much of the design effort for this antenna is focused on the location and shape of the ferrite bars. Minimization of antenna weight is also performed. The developed ferrite-loaded shorted-patch concept is compared with a low-profile monopole to demonstrate its superior bandwidth and gain performance over the frequency range from 30 MHz to 400 MHz. Prototype versions of various ferrite-loaded shorted-patch antennas were fabricated and measured for validation. A version of these was the design that has a planar patch as small as λ/16 in diameter and a height of only λ/200 at the lowest operational frequency.
We note that the ferrite loading design led to 5 to 14 dB gain improvement in the low frequency range below 50 MHz. The resulting gain was actually close to the optimal Fano-Bode limit. An important aspect of the ferrite loading design was the use of commercially available materials. Although these were lossy at high frequencies, their strategic placement resulted in minimal gain reduction.