This paper proposes the design and simulation of 2×2 circular patch antenna array working at 28 GHz by using four inset feed micro strip circular patch antennas to achieve beam forming with directivity around 13dB which is required to overcome part of high path loss challenge for high data rate mm-5G mobile station application. Four element 2x2 array consists of two 1x2 circular patch antenna arrays based on power divider and quarter wavelength transition lines as a matching circuit. The designed antenna array is simulated on RT/duroid 5880 dielectric substrate with properties of 0.5mm thickness, dielectric constant ε _r =2.2, and tangent loss of 0.0009 by using Computer System Technology (CST) software. The performances in terms of return loss, 3D–radiation pattern is evaluated at 28 GHz frequency band. The design also includes the possibility of inserting four identical 2x2 antenna arrays at four edges of mobile station substrate to achieve broad space coverage by steering the beams of the mobile station arrays.

A quasi-Yagi microstrip patch antenna with four directors and truncated ground plane has been designed and fabricated to have an ultra-wide bandwidth, high gain, low return loss and better directivity with center frequency at 3.40 GHz. After optimization, the proposed antenna yields an ultra-wide bandwidth of 1.20 GHz with lower and upper cutoff frequencies at 3.12 GHz and 4.32 GHz, respectively. High gain of 5.25 dB, return loss of -28 dB and directivity of 6.28 dB are obtained at resonance frequency of 3.40 GHz. The measured results of fabricated antenna have shown excellent agreement with the simulation results providing bandwidth of 1.34 GHz with lower and upper cutoff frequencies at 3.04 GHz and 4.38 GHz, respectively. The antenna gain of 5.33 dB, return loss of -44 dB are obtained at resonance frequency of 3.36 GHz. The dimension of the antenna is only of 65 mm x 45 mm ensuring compact in size.