Miniaturized tunable metamaterial antenna design and modeling in the low UHF band

Conventionally, efficient antennas operating over more than a few percent bandwidth require dimensions approaching a wavelength or more. In the low UHF band, such antennas will have sizes on the order of a meter. Artificial magnetic conducting (AMC) substrates have been shown to reduce the profile (height) of these antennas, but at the expense of operating bandwidth. Adding tunability has restored the flexibility of dynamically adjusting the communication channel over a wide range, but the lateral dimensions of the antenna are still quite large. Here we introduce a miniaturized low-profile antenna system based on a tunable AMC substrate beneath a tunable small antenna element. This system allows a channel bandwidth of about 0.5% with the flexibility of adjusting this channel from about 330 to over 400 MHz, all while using an antenna element that is still only a fraction of a wavelength in its largest dimension.