DESIGN OF COMPACT, WIDEBAND DUAL-POLARIZED MULTI-DIPOLE ANTENNA FOR 2G/3G/LTE BASE STATION APPLICATIONS
Progress In Electromagnetics Research C
In this paper, a wideband dual-polarized multi-dipole antenna with a compact radiator size is developed for 2G/3G/LTE base station applications. The original antenna is composed of a pair of crossed square loop dipoles (SLDs) and two big Y-shaped feeding lines. Thanks to the adopted capacitive coupling, a wide impedance bandwidth is obtained with dual resonant modes in the low and middle frequency bands. Owing to the circular chamfers in the crossed SLDs, the dual resonant modes are away from
... ch other. Thus, a compact radiator size is implemented, and it is about 0.382λ 0 × 0.382λ 0 (λ 0 is the wavelength at center frequency of operation). To further widen the operating bandwidth of the antenna, a pair of crossed rectangular loop dipoles (RLDs) and four small Y-shaped feeding lines are introduced to generate a new resonant mode at high frequency. As a result, the impedance bandwidth of the proposed antenna is enhanced. Based on the optimized dimensions of the simulated antenna model, a prototype is developed, fabricated and tested. Measured results show that the proposed antenna has a relative impedance bandwidth of 53.9% from 1.68 to 2.92 GHz at two ports for VSWR < 1.5. Within the operating impedance bandwidth, the measured port-to-port isolation is better than 30 dB. In addition, a stable gain of 8.2 ± 0.5 dBi and a stable radiation pattern with 66 • ± 4 • half-power beamwidth (HPBW) in the horizontal plane are achieved across the whole bandwidth of operation for dual polarizations. Finally, the proposed antenna is suitable for base station applications.