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

Abstract

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 $2.38 \leq f\;{\text{(GHz)}} \leq 11.80$ , together with group delay of ${\tau _g} \leq $ 0.8 ns and a compact size of $27 \times 31\;{\text{mm}}^2$ , 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.