This article proposes a substrate integrated waveguide (SIW) antenna fed by microstrip transmission to operate in V-band and fifth generation (5G) (60/70 GHz band) applications. The proposed millimeter wave (mm-wave) antenna has an impedance bandwidth of 25.68 GHz (fractional bandwidth of 41%) between 49.77 and 75.45 GHz frequency and has a maximum realized gain of 3.75 dBi. Compared with other studies, the reported antenna has a size reduction of up to 73% with its 8 x 9.7 mm(2)(1.33 lambda x1.61 lambda) dimension. The designed SIW patch is also fed by grounded coplanar waveguide transmission and its results are compared with the one fed by microstrip transmission line. Another important feature of the proposed antenna is that it has a low production cost, since it is printed on a cheap FR4 substrate material. Therefore, the proposed antenna has the potential to meet all the necessary requirements to be used for V-band portable devices and applications. A 2 x 2 multiple-input multiple-output antenna based on the proposed antenna structure is also analyzed with respect to isolation, diversity gain and envelope correlation coefficient and acceptable results are obtained.