Low-Profile UWB Millimeter-Wave Antenna Array Under Triple Resonant Modes Based on PCB Technology

In this article, a low-profile ultrawideband (UWB) planar antenna array for millimeter-wave (mmWave) applications is proposed. The antenna is about 1.2 mm thick and consists of only two substrate layers (including the adhesive layer). The parasitic strip line and shorting strips at the top of the antenna are stimulated by the microstrip line through the coupling slot. This design makes triple resonance modes exist in the working frequency band, which significantly improves the bandwidth. At the beginning, the antenna element generates a slot antenna mode and a microstrip line resonance mode. Then, four via holes are introduced to form a monopole sub-array through the coupling stimulation of the slot, which is the third resonant mode near 47 GHz. The four shorting strips on the top layer are designed to match the impedance and improve the shape of the radiation pattern. To obtain higher gain and more stable radiation patterns, a
$4\times4$
antenna array is designed, fabricated, and measured. The simulated and measured −10 dB impedance bandwidth of the proposed antenna array is 26.55–59.63 GHz and 28.44–59 GHz, respectively. The antenna array achieves 70.8% bandwidth and the maximum gain can reach 17.9 dBi. With notable performances, the UWB antenna array can be applied to mmWave wireless communication bands, such as n261 (27.5–28.35 GHz), n257 (26.5–29.5 GHz), n260 (37–40 GHz), n259 (39.5–43.5 GHz), IEEE802.11aj(45 GHz), and n262 (47.2–48.2 GHz) and other mmWave bands for wireless communications.