Wideband Vertically Polarized Magnetic Dipole Antenna for MIMO Applications

In this paper, a mode-superposed wideband vertically polarized(VP) half-mode substrate integrated waveguide (HMSIW) antenna with a double-layered structure is proposed. The conventional HMSIW antenna can be considered as a magnetic dipole antenna. It is constructed with the help of a three-sided closed cavity and opened at one side, yielding a very low impedance bandwidth (IBW) (below 5%) for the profile below 0.038 λ
0
(λ
0
is the free space wavelength at the centre frequency). In order to enhance the IBW of the HMSIW antenna, a double-layered structure with an air gap has been incorporated. The half-TE
110
and half-TE
310
are the two adjacent modes of the HMSIW. So, in this manuscript by combining these two adjacent modes by placing the two pairs of slots at the null position of half-TE
310
, the IBW of VP magnetic dipole is further increased. The proposed structure provides 26.40% of impedance bandwidth and 3.8 dBi as a peak endfire realized gain with the dimension as 1.259λ
L
× 0.363λ
L
× 0.038λ
L
. In order to design a four-port multi-input multi-output (MIMO) antenna, the proposed structure is arranged orthogonally. The proposed wideband VP MIMO antenna exhibit very good isolation, along with the MIMO parameters.