Quasi-hemispherical-pattern antenna with complementary magnetic radiations

A compact microstrip antenna with a low profile of 0.03λ is proposed to obtain a hemispherical pattern, where λ is the free-space wavelength corresponding to the operation frequency 2.4 GHz. When the side length of the ground is infinite, the 3-dB beamwidths in the xz plane and yz plane are all 180° and the radiation pattern in the xy plane has a gain fluctuation less than 3 dB. When side length of the ground is 2λ, the simulated and measured 3-dB beamwidth in the xz plane are 156° and 157°, respectively; the simulated and measured 3-dB beamwidth in the yz plane are 160° and 155°, respectively. An excellent hemispherical pattern and a near-hemispherical pattern can be obtained when the ground is infinite and finite, respectively.