Design and analysis of broadband high-gain and omnidirectional printed antenna with radiated loads

A novel coplanar waveguide planar antenna, which is broadband, high-gain and omnidirectional, is proposed and analysed. The antenna radiation efficiency is improved by introducing a kind of monopole radiator as a non-consumption radiated terminal load. The out-of-roundness of the antenna´s H-plane (x-z plane) is decreased by introducing horizontal stubs as non-effective radiated loads. The simulated and experimental results indicate that the operating band of the proposed antenna is 4.65-5.61 GHz with a reflection coefficient less than - 10 dB (relative bandwidth 18.7%), the out-of-roundness of the radiation pattern in the horizontal plane (H-plane or x-z plane) is less than 1.5 dB and the maximum gain achievable in the elevation plane (E-plane or x-y plane) is more than 5.0 dB in the operating band. The pattern bandwidth well matches the impedance bandwidth. Moreover, the gain per wavelength of the novel antenna exceeds 3.0 dB, which is beneficial for antenna miniaturisation.