Enhancing UHF antenna functionality through dielectric inclusions and texturization

Dielectrics are used in antenna design to support the printed structure and to also reduce antenna resonance and size. However, to our knowledge, dielectric volumes have not been used in the design process (by modifying or texturizing the dielectric) to possibly alter the overall performance and behavior of the antenna. In this paper, we begin with a given metallic geometry and show how changes in dielectric loading (position and permittivity values) can be used to produce a variety of antenna configurations having broadband and multi-band characteristics while still pursuing size reduction. More specifically, using a 15 cm/spl times/15 cm/spl times/6 cm antenna geometry, we show various designs giving resonant frequencies down to 350 MHz (0.175/spl lambda//sub 0/ linear dimension) and having bandwidths that can reach as high as 23.5% at 520 MHz (0.261/spl lambda//sub 0/ linear dimension). Also shown are designs with dual band characteristics. An example broadband design is fabricated and measured.