A Miniaturized Wideband Dual-Polarized Antenna Based on Mode-Control Principle for Base-Station Applications

Abstract

In this paper, a miniaturized wideband dual-polarized antenna and its array are proposed and demonstrated for practical base-station applications. ''Mode-control'' principle is employed to facilitate both miniaturization and bandwidth-enhancement of the proposed antenna element. To be more specific, by inserting meander lines into a traditional crossed loop-dipole antenna, its first resonant mode can be shifted to a lower frequency without increasing the aperture size, implying that a total size reduction can be achieved. Meanwhile, by embedding a pair of crossed straight strips into the coupling region of the crossed loop-dipole antenna, its second resonant mode can be moved to a higher frequency with a good impedance matching, thereby improving the impedance bandwidth significantly. A prototype of the proposed antenna with a small radiator size of only 0.33λ × 0.33λ (λ is the wavelength at the center frequency of 2.2 GHz) is designed, fabricated and measured. Measurements show that in the target frequency band from 1.71 GHz to 2.69 GHz, i.e., 2G/3G/4G bands, a relatively good impedance matching with the VSWR of less than 1.65 and a high isolation of greater than 28 dB are obtained by the proposed antenna element. Also, a stable gain of 8.7±0.5 dBi and a stable 3-dB beamwidth of 64.8±2.7 • at the H-plane are respectively achieved. A multipleinput-multiple-output (MIMO) antenna array consisting of two subarrays with electrical down-tilt is further developed for practical base-station applications. Each subarray is composed of ten antenna elements. The overall width of the array is only 260 mm, which is much narrower than that of typical industrial products (∼305 mm). Measured results show that the antenna array has also achieved good performances such as wide impedance bandwidth, high isolations among different ports, and stable radiations over the 2G/3G/4G bands.

A compact broadband antenna for ultra high frequency and L band on 5G new radio base stations

“…In recent years, a number of bandwidth‐enhanced broadband dual‐polarised antennas have been developed for base‐station applications [3–22]. Some of these wideband antennas achieve a limited relative bandwidth of less than 60% for return loss (RL) > 15 dB or voltage standing wave ratio (VSWR) < 1.5 [3–14]. The bandwidth of a dual‐polarised antenna in [15] is enhanced to 67% for RL > 15 dB by introducing parasitic elements.…”

A Compact Wideband Dual-Polarized Base Station Antenna Using Asymmetric Dipole

“…For base station application, it is also critical to effectively reduce the volume of the antenna which normally relies on the special structure design of the radiators [20]- [22]. For example, in [20], multiple resonance points are generated through the connecting line to meet the design requirements on size and bandwidth.…”

A compact multimode broadband dual‐polarized base station antenna for LTE and 5G applications

“…In Reference 6, the coupling between bow‐tied dipoles is utilized, but the expansion range of the bandwidth is limited. The method of adding a straight dipole is loaded in the gap between adjacent dipoles has been applied in References7,8. In Reference 9, mixed Balun feed structure is adopted to improve impedance matching.…”