This work aims at realizing an antenna with a stable radiation pattern for base station applications. A novel high-efficiency shared-aperture triple-band dipole array antenna configuration is proposed in sub-6 GHz microcell base stations in environments where bi-directional radiation patterns are preferred. The radiators of the antenna are composed of double-sided square dipole array structures and two novel long-side monopoles. To verify the principle, the antenna with an overall size of 0.3λ 0 � 0.33λ 0 � 0.002λ 0 (λ 0 is the free-space wavelength at 900 MHz) is fabricated and measured. The measurements confirm impedance bandwidths of 9.5% (840-924 MHz), 21.9% (3-3.74 GHz), and 12.2% (4.9-5.54 GHz), respectively. The second frequency band covers the 5G sub-6 GHz NR frequency band n78, mainly used in China and some other countries, and the LTE 42/43 bands . The first and the third bands are also suitable for GSM 900, 5 GHz WiFi and are potential candidates for future 5G developments. The boresight gain is greater than 1, 6, and 10 dBi in these bands, respectively. The measured results also demonstrate that the proposed configuration has stable radiation patterns across the three frequency bands.

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A broadband dipole antenna and an integrated cavity section responsible for increasing bandwidth are introduced, designed, and successfully fabricated. This simple and highly effective cavity is added at the dipoles input, where the concentric coaxial feed line becomes its inner conductor, and the dipoles cylinder becomes its outer conductor. This coaxial‐fed dipole antenna could be easily fabricated due to its simple mechanical structure. A version of this type of dipole antenna, with a total length of less than 38 cm (0.44λ) and a radius of about 5 cm, is designed once symmetrically and once with an asymmetrical down‐tilted radiation pattern. The new proposed cavity part can increase the antenna's bandwidth up to 100%, which is highly superior compared to conventional counterparts. Furthermore, the antenna's radiation pattern is stable throughout the bandwidth. The minimum realized gain at the solid angle of θ (for instance, θ between 90 and 120°) is perfectly above zero within the frequency range. The antenna measurement results are in acceptable agreement with the simulations.