Wideband Circularly Polarized Antipodal Curvedly Tapered Slot Antenna Array for 5G Applications

This paper presents and characterizes a novel high gain circularly polarized (CP) antenna array for 5G applications. The array element is an antipodal curvedly tapered slot antenna (ACTSA) generating circularly polarized field. The CP ACTSA fed by substrate integrated waveguide (SIW) is convenient to integrate with substrates. By introducing two sheet metals on the two sides of the rectangular Rogers 6002 substrate, an impedance bandwidth of 18.2%, a wide 3-dB axial ratio (AR) bandwidth of 16.9%, and stable gain of 8 +/- 0.6 dBic over the operating band are achieved. By employing the proposed CP ACTSA as radiating elements, a 4x4 high-gain wideband antenna array is proposed for 5G E-band and W-band millimeter-wave applications. Fabrications are carried out using wire cutting electrical discharge machine and print circuit board process, which have advantages of low cost. The whole feeding network is realized by SIW with low insertion loss at millimeter-wave band. Benefiting from the wide impedance and AR bandwidth of the new antenna element, good impedance matching and AR characteristics can be achieved over the whole working frequency band from 81 to 95 GHz by this antenna array. Gain up to 18.5 +/- 1.3 dBic is also obtained.