A 28 GHz Beam Steerable Elliptic Microstrip Array Antenna for 5G Applications

This paper discusses the design, fabrication, and measurement of a two-layer, $2 \times 10$ elliptic, microstrip series fed antenna array operating at 28 GHz for 5G and mm-wave user equipment. A branch line coupler was used as a feeding network that can generate three beams. The peak gain value of each beam was 13 dBi at 28 GHz. The gain value was above 10 dBi within a beam coverage of −45° to 45°, and the peak gain value for the 26.5 GHz to 29.5 GHz band was above 10 dBi. The impedance bandwidth of the proposed design was below −10 dB in the 26.5 GHz to 29.5 GHz band. The dimensions of the $2\times 10$ antenna array with coupler were $80\times 40\times 0.203$ mm3 on Rogers RO4003 substrate. This design is suitable for 5G mobile user applications due to its low cost and compactness.