Flexible ultra-wideband polarisation diversity antenna with band-notch function

A CPW-fed polarisation diversity monopole antenna on a flexible PET film for ultra-wideband (UWB) systems is proposed. The antenna consists of two heptagonal monopoles that are orthogonally and symmetrically aligned to have extended ground planes. The antenna is able to cover the entire UWB bandwidth from 3.1 to 10.6 GHz and shows a good isolation of less than 20 dB at each port over the entire UWB bandwidth. Also, it has a band-notch function to avoid overlap with the 5 GHz wireless local area network band. It can be easily mounted on a conformal shape, because it is fabricated on a PET film that is flexible enough to be mounted on a curved surface. Both the time-domain and frequency-domain characteristics of the antenna have been investigated by using the normalised antenna transfer function. From the results, it is observed that the proposed antenna can support polarisation diversity for UWB communications.