Broadband multimode antenna and its array for wireless communication base stations

Abstract

A wideband dual‐polarized antenna coupling cross resonator is proposed for LTE700/GSM850/GSM900 base stations. An additional resonance is introduced to obtain strong coupling between the dipole and resonator. Moreover, the input impedance of the proposed antenna is steadily close to 50 Ω, which results in better impedance matching. Therefore, a wide bandwidth can be achieved with multiresonance. A prototype is fabricated to verify the proposed design. The measured results show that the antenna has a fractional bandwidth of 35.7% from 690 MHz to 990 MHz for |S11| less than −15 dB. Stable radiation patterns as well as gain are also obtained over the entire operating band. Moreover, a five‐element antenna array with an electrical downtilt of 0° to 14° is developed for modern base station applications. Measurement shows that a wide impedance bandwidth of 34.7% (690 MHz to 980 MHz), stable HPBW (3‐dB beamwidth) of 65 ± 5°, and high gain of 13.8 ± 0.6 dBi are achieved with electrical downtilts of 0°, 7°, and 14°.

Keywords

• Antenna Array
• Broadband
• Dual‐Polarized
• Electrical Downtilt
• Multimode
• Resonator