Design of WLAN/LTE/UWB Antenna with Improved Pattern Uniformity Using Ground-Cooperative Radiating Structure

The radiating effect of metal ground is rarely considered in most antenna designs. In this communication, we show that a properly designed metal ground can serve as a cooperative lower frequency radiator for reducing the antenna dimensions, broadening impedance bandwidth, and achieving almost uniform omnidirectional patterns over a wide frequency band. By introducing a ground-cooperative radiating structure (GCRS) into the metal ground of a prototype defected hexagonal monopole antenna (HMA), a more compact and broadband planar antenna of almost uniform omnidirectional patterns and stable linear polarizations is developed. The new antenna exhibits excellent omnidirectional radiation uniformity over the frequency range of 2.38 <= f (GHz) <= 11.80, together with group delay of tau(g) <= 0.8 ns and a compact size of 27 x 31 mm(2), which makes it very promising for applications in wireless local area network (WLAN), long-term evolution (LTE), and ultrawideband (UWB) systems as a compact multifunctional antenna to reduce the number of antennas installed in wireless devices for accessing multiple wireless networks.