Broadband Miniaturized Bowl-shaped Dipole Antenna For Base-station Applications

In this manuscript, a broadband miniaturized bowl-shaped dipole antenna is proposed for base-station applications. The antenna consists of four dipoles, metal sidewalls and coupling arms, and excited by four baluns with two power dividers. First, a miniaturized antenna with a length of 0.32λ is designed compared to a conventional dipole antenna with a size of 0.5λ, but the antenna as a whole operates at out-of-band high frequencies. Next, in order to shift the resonance point towards lower frequencies, the current path is extended by loading metal side-walls between neighboring dipole arms to bring the operating band in-band. Finally, coupling arms are added to improve the impedance matching and resonant strength. The results show that the proposed antenna has an impedance bandwidth of 690-960 MHz with a port isolation of more than 40 dB, a realized gain of about 9 ± 0.7 dBi, and a cross-polarization ratio of more than 31 dB under the size of 0.32λ×0.32λ×0.15λ (@690 MHz). Due to its broadband and small size, it gives more possibilities for future multi-band compatible communications.