A Low‐Cost Circularly Polarized Stacked Patch Antenna for 5G_N78 Application

This letter presents a low‐cost, circularly polarized (CP), stacked patch antenna that exhibits a wider CP operating bandwidth compared to other low‐cost antennas of the similar type. The proposed antenna consists of two FR4 dielectric substrates, a metallic plane, and two air layers. The radiator is composed of a metallic elliptical ring and a split corner‐truncated patch, which operate at two axial ratio (AR) minimums. The performance of the AR is further enhanced by the metallic plane and a centrally symmetric defected ground structure (DGS). The dimensions of the antenna are 0.58λ₀ × 0.58λ₀ × 0.22λ₀, (where λ₀ is the free‐space wavelength at the center frequency). To validate the design, the antenna was fabricated and measured. The relative impedance bandwidth (IBW) of |S11 | < −10 dB is 32.7% (2.81–3.91 GHz). The relative AR bandwidth (ARBW) of AR < 3 dB is 13.2% (3.31–3.78 GHz). The overlap of these bandwidths essentially covers the 5 G_N78 band. Additionally, the measured average gain within the operating bandwidth is 5.30 dBi, with a peak gain of 6.28 dBi. This antenna is low‐cost and offers a CP operating bandwidth that meets the requirements of the 5 G_N78 band, while also maintaining competitive dimensions and gain. It is well‐suited for deployment in 5G base stations.