A Deformed-Film UWB Antenna

Recently, microwave ultra-wideband (UWB) technology has attracted much attention in high speed wireless communications, imaging and radar applications. Antennas with very wide impedance bandwidth and stable radiations are required for such systems. Among many UWB antennas, planar types are low profile, light weight, low cost and suitable for mobile devices [1]. However, the planar antennas may not radiate omni-directionally at all operating frequencies because they generally have wide structures and are not rotationally symmetrical. A roll monopole antenna which is constructed by twisting a planar radiator into a roll shape has been proposed for improving radiation characteristics, but the bandwidth of the antenna was limited [2]. In this paper, we will propose a deformed film UWB antenna for operating at the FCC approved UWB of 3.1-10.6 GHz. The antenna is constructed by deforming a planar dipole which has a glass-shaped radiation element [3]. The antenna is optimized for the UWB operation in its planar form and can be deformed by different manners such as folding, meandering or twisting, without much influence on input characteristics. The deformation not only miniaturizes the antenna but also improves its radiation characteristics. To investigate experimentally the antenna, a prototype with a dimension of 20x33 mm is fabricated and then the antenna is deformed by rolling into a circular rod with a diameter of 6.5 mm, or meandering it into a square rod with a cross-sectional dimension of 6x5 mm. It is demonstrated that the deformed antennas still operate at the UWB and have better omni-directional radiation patterns than the antenna in its planar form.