Wideband Endfire Antenna Array for 5G mmWave Mobile Terminals

In this paper, a compact endfire antenna array with low-profile, small clearance, and wideband operation is proposed for millimeter-wave (mmWave) fifth-generation (5G) mobile terminals. The wideband operation is achieved by exciting two identical bow-tie dipoles inserted on both sides of a multilayer substrate fed by an asymmetric open-end stripline to slotline transition. The antenna performance is significantly improved by introducing a set of vertical metallic vias. The proposed antenna element can achieve 29 % from 24.2 GHz to 32.4 GHz with a peak realized gain that varies from 3.5 dBi to 4.5 dBi. A linear 4-element antenna array is arranged and fabricated to verify the proposed antenna beamforming capabilities. The simulated and measured bandwidth achieves a wide range of 34.4 % (24-34 GHz) to support 26, 28, and 30 GHz 5G mmWave bands with an isolation level better than 20 dB and a peak realized gain over the interested bands ranging from 7.56 to 8.14 dBi. The simulated array scanning angle is ± 68 • at 28 GHz within 3-dB gain deterioration. Furthermore, the simulated spherical coverage has met the requirements of 3GPP standards which make the proposed antenna array a promising candidate to be integrated within mmWave 5G mobile devices. INDEX TERMS 5G, antenna array, beamforming, endfire, mmWave bands, mobile terminal, wideband

Wideband Endfire Antenna Array for 5G mmWave Mobile Terminals

In this paper, a compact endfire antenna array with low-profile, small clearance, and wideband operation is proposed for millimeter-wave (mmWave) fifth-generation (5G) mobile terminals. The wideband operation is achieved by exciting two identical bow-tie dipoles inserted on both sides of a multilayer substrate fed by an asymmetric open-end stripline to slotline transition. The antenna performance is significantly improved by introducing a set of vertical metallic vias. The proposed antenna element can achieve 29 % from 24.2 GHz to 32.4 GHz with a peak realized gain that varies from 3.5 dBi to 4.5 dBi. A linear 4-element antenna array is arranged and fabricated to verify the proposed antenna beamforming capabilities. The simulated and measured bandwidth achieves a wide range of 34.4 % (24-34 GHz) to support 26, 28, and 30 GHz 5G mmWave bands with an isolation level better than 20 dB and a peak realized gain over the interested bands ranging from 7.56 to 8.14 dBi. The simulated array scanning angle is ±68° at 28 GHz within 3-dB gain deterioration. Furthermore, the simulated spherical coverage has met the requirements of 3GPP standards which make the proposed antenna array a promising candidate to be integrated within mmWave 5G mobile devices