A Compact Dual-Polarized Printed Dipole Antenna With High Isolation for Wideband Base Station Applications

Abstract

A novel compact wideband dual-polarized printed dipole antenna for base station application is presented. The proposed antenna is composed of four assembled substrates. Two pairs of identical arrow-shaped conductive lines on the tophat substrate form two orthogonal polarized dipoles. Two baluns connected with 50 Ω coaxial cables are integrated on another two vertical substrates to excite the dipoles. The other horizontal board at bottom provides grounding. A rectangular box-shaped reflector is also used to enhance its stability in radiation patterns over the operating frequencies. It achieves 22% size reduction from the conventional printed half-wavelength cross-dipole, and 43.2% impedance bandwidth (VSWR < 2), while maintaining a stable radiation pattern with measured Cross-Polarization Degradation (XPD) better than −22 dB at boresight and an average peak gain of 8.4 dBi for a 65 • Azimuth Beamwidth base station application at 700/800/900 MHz bands. With the scalable miniature structure, it may also find itself suitable for side-by-side multiband Multi-Input Multi-Output (MIMO) or Large-Scale Antenna (LSA) 5G base station applications. A 4 × 4 array prototype of the LSA is also designed and fabricated, and it achieves 27.8% impedance bandwidth (VSWR < 1.5) with well decorrelated element performance and array XPD better than −20 dB across as large as 30 • tilting range.

Broadband circularly polarized Z-shaped dipole antenna with parasitic strips

“…In order to further broaden the AR bandwidth, two coplanar parasitic strips are introduced. The Z‐shaped dipole antenna is simply fed by a printed balun, which is usually used to feed dual‐polarized dipole antenna to achieve balanced feeding and wideband impedance matching. A prototype of the CP antenna has been fabricated and tested.…”

Wideband Fabry-Perot Resonator Antenna With Single-Layer Partially Reflective Surface

“…But a complex feeding network is indispensable when an antenna array is used as the excitation to feed the FPRA instead of a simple antenna. In consequence, choosing a simple feeding source with satisfactory performances, as the proposed antenna in [2] and giving the suitable design on PRS structure, are what antenna engineers should do. Some 1-D EBG resonator antennas with two layers dielectric slabs or multilayer superstrates as PRS achieved a 30% 3-dB gain bandwidth which was notable [3,4].…”

A Scalable Compact Wideband Dual-Polarized Printed Dipole Antenna for Base Station Applications

“…However, the physical height of these printed dipole antennas usually exceeds 0.25λ 0 (λ 0 is the free-space wavelength at the central operating frequency), and the transverse overall length exceeds 0.5λ 0 , which makes it difficult to be deployed in a size limited antenna application, e.g., multi-band side-by-side configuration or LSA, which requires even smaller adjacent spacing (0.5λ 0 Vs. 0.75λ 0 of conventional 10 • down tilt antenna) for the large 3D beamforming tilting range to achieve the boost of overall system's capacity. Recently, several compact wideband dipole antennas have been reported in [9][10][11]. Liu in [9] used a square patch director and an octagon ring as a parasitic element on top of the dual-polarized cross dipole to improve the bandwidth, as well as to achieve a size reduction.…”

“…More specifically, a comparison on the transvers length L, physical height H and bandwidth of a printed dipole with integrated balun (antenna A) [6], a size-reduced printed dipole with triangular patch (antenna B) [11] and the proposed antenna C are listed in Table 1. It can be observed that all of them achieved wide impedance bandwidth over 40% (VSWR < 2).…”