A Novel Dual-Polarized Filtering Antenna for 5G Base Station Applications

This study introduces a wideband and compact filtering antenna with dual-polarization for 5G base station usage. The proposed design, which combines meander lines and parasitic grid structures, achieves a broad operating bandwidth and an excellent gain suppression level in the unwanted 2/3/4G band. To verify the design concept, a prototype of the design was fabricated and tested. According to the test results, the proposed design can cover 3.16 GHz to 4.75 GHz. The isolation between the two ports exceeds 30 dB in the target n77 band (3.3-4.2 GHz). Additionally, the gain rejection level is higher than 13 dB in 1.7-2.7 GHz

A Wideband Triple-Mode Differentially-Fed Microstrip Patch Antenna

© 2021 IEEE. This is the accepted manuscript version of an article which has been published in final form at https://dx.doi.org/10.1109/LAWP.2021.3074302A wideband differentially-fed microstrip patch antenna (MPA) with tripe-resonant modes is presented in this letter. The proposed triple-mode MPA is realized by combining two dual-mode MPAs (MPA-I and MPA-II) with different resonant frequency ratios. Firstly, the TM0,1 mode and TM0,1/2 mode of dual-mode MPA-I can be concurrently excited by adding a pair of coupling shorted patches beside the strip MPA. The ratio of f0,1/2/f0,1 can be easily adjusted by moving the shorting pins between the strip MPA and shorted patches. Secondly, by properly designing the dimensions of a conventional MPA, the TM0,1 and TM2,1 modes of dual-mode MPA-II are simultaneously excited. To further reduce the ratio of f2,1/f0,1, four slots are elaborately etched on the conventional MPA. Finally, by combining the two dual-mode MPAs, a triple-mode MPA with the frequency ratio of f0,1/2:f2,1:f0,1 = 1.2:1.1:1 is realized. To verify the design concept, a prototype of triple-mode MPA was fabricated and measured. Experimental results show that the proposed microstrip antenna achieves a wide bandwidth of 26.5%, a low cross-polarization of -23 dB, and high harmonic suppression.Peer reviewe

Wideband Dual-Polarized Filtering Antenna for Base Station Applications

A compact wideband dual-polarized filtering antenna based on tightly coupled cross dipoles is presented in this letter. The enhancement of impedance bandwidth is realized by introducing four impedance equalizers to equalize the input resistances of the two inherent resonant modes of tightly coupled cross dipole antenna. The enhancement of the selectivity is realized by introducing two radiation nulls in 5G sub-6 GHz n77 and n79 bands. The radiation null in n77 band is obtained by introducing the cross strips in the center of the antenna. The radiation null in the n79 band is achieved by the introduction of open-end branches. The manipulation of their key parameters allows for independent control over both radiation nulls. The validity of the antenna's design principle was confirmed by carrying out fabrication and measurements. The results obtained showcase the antenna's broad fractional bandwidth of 63.4% and exceptional port isolation of 31 dB. High out-of-band rejection levels in n77 and n79 bands are also obtained. In addition, since the whole radiator of the presented antenna is coplanar, it offers the advantage of a simple structure and convenient manufacturing, making it highly suitable for the use in base stations operating across multiple bands

Wideband Dual-Polarized Antenna with High Selectivity for 5G Sub-6GHz Base Station Applications

A dual-polarized antenna with wide impedance bandwidth and high selectivity is presented for the use of 5G sub-6GHz base stations. By strategically introducing a novel coupled dual-mode grid structure, two additional resonant modes (One is in-band, another one is out-of-band) as well as two radiation nulls can be obtained to enhance the impedance bandwidth and out-of-band rejection level of the widely used tightly coupled cross-dipole antenna. The two radiation nulls introduced by the grid structure are located at the two edges of the desired frequency band. To further improve the gain suppression level in higher out-of-band, a new radiation null is obtained by symmetrically introducing four T-shaped strips. Apart from these additional radiation nulls, this antenna also exhibits two inherent radiation nulls originating from its feed structure and reflector. The measured results demonstrate that the proposed antenna exhibits a wide impedance bandwidth of 39.5% (ranging from 3.07 GHz to 4.58 GHz), excellent isolation of over 31 dB, and a notable out-of-band rejection level exceeding 17.6 dB and 19.2 dB in the frequency bands of 1.7 GHz-2.7 GHz and 4.8 GHz- 5.0 GHz

A Novel Differentially-Fed Dual-Polarized Filtering Antenna for Base Station

The theory, design and experiments of a wideband dual-polarized filtering antenna are presented. A novel technique, which combines the use of open loops, parasitic loop, and extended ground plane, is proposed to realize two upper band radiation nulls and a lower band radiation null. Thanks to these radiation nulls, the proposed antenna obtains a sharp cut-off at the edges of the operating band. To achieve wideband performance, another novel technique of exciting multiple resonant modes of the crossed dipoles and parasitic loop is proposed. The measured results demonstrate that this antenna achieves a wide impedance bandwidth from 1.7 to 3.01 GHz (56%), high isolation of 38dB, low cross-polarization within the working frequency band and also filtering performance. At 3.17 GHz, the gain of the antenna will drop rapidly to -18.1 dBi, which is 26.4 dB lower than the average in-band gain. These advantages make the proposed antenna a good candidate for base station applications

Dual-Band Ten-Element MIMO Array Based on Dual-Mode IFAs for 5G Terminal Applications

A dual-band ten-element MIMO array based on dual-mode inverted-F antennas (IFAs) for 5G terminal applications is presented in this paper. The proposed dual-mode IFA is composed of two radiators, which are etched on the outer and inner surfaces of the side-edge frame. The outer part of the antenna generates the low-order mode at 3.5 GHz, while the inner part radiates another one-quarter-wavelength mode at 4.9 GHz. In this way, the IFA can achieve dual-band operation within a compact size of 10.6 × 5.3 × 0.8 mm 3 . Based on the proposed antenna, a dual-band ten-element multiple-input and multiple-output (MIMO) array is developed for 5G terminal applications. By combining neutralization line structures with decoupling branches, the isolations between the elements are improved. To validate the design concept, a prototype of the ten-element MIMO array is designed, fabricated, and measured. The experimental results show that the proposed antenna can cover the 3.3-3.6 GHz and 4.8-5.0 GHz bands with good isolation and high efficiency. Furthermore, the envelope correlation coefficient (ECC), and channel capacity are also calculated to verify the MIMO performances for 5G sub-6GHz applications

Decoupling of Dual-Band Dual-Polarized Base Station Array Antenna

Dual-band dual-polarized arrays (DBDPA) using interleaved configuration have drawn industry attention as a promising way to improve channel capacity in a package that has a minimum width. By integrating high-performance filtering elements, a novel interleaved DBDPA for base station use is presented in this paper. For the first time, a radiation null is introduced into the low-band (LB) antenna using the intrinsic suppression mode of folded dipole. Then, to enhance the gain-suppression level in out-of-band to 16 dB, four rectangular loops are introduced under the radiator. To achieve high selectivity for high-band (HB) antenna, a meander line loop is introduced and analyzed for the first time in this paper. Simulations indicate that the presented HB antenna achieves 17 dB of out-of-band rejection and 243 dB/GHz of roll-off rate. The combined use of these two filtering elements finally enables the realization of a DBDPA with low mutual coupling and low cross-band scattering. According to the measurements, this antenna covers two wide frequency ranges of 2.26- 2.73 GHz and 2.98- 4.3 GHz with a 25 dB cross-band isolation level

Dual-Band Eight-Element MIMO Array Using Multi-Slot Decoupling Technique for 5G Terminals

This paper presents a dual-band eight-element multiple-input multiple-output (MIMO) array using a multi-slot decoupling technique for the fifth generation (5G) mobile communication. By employing a compact dual-loop antenna element, the proposed array obtains two broad bandwidths of 12.2% and 15.4% for sub-6GHz operation. To reduce the mutual coupling between antenna elements, a novel dual-band decoupling method is proposed by employing a multi-slot structure. The proposed MIMO array achieves 15.5-dB and 19.0-dB isolations across the two operating bands. Furthermore, three decoupling modes generated by different bent slots can be independently tuned. Zero ground clearance is also realized by the coplanar arrangement of the antenna elements and decoupling structures. The proposed MIMO array was simulated, fabricated, and measured. Experimental results agree well with the simulations, showing that the dual-band MIMO array has good impedance matching, high isolation, and high efficiency. In addition, the envelope correlation coefficient and channel capacity are calculated and analyzed to validate the MIMO performance of the 5G terminal array. Such a dual-band high-isolation eight-element MIMO array with zero ground clearance is a promising candidate for 5G or future mobile applications

Compact Wideband Folded Dipole Antenna With Multi-Resonant Modes

A compact and wideband folded dipole antenna with multi-resonant modes is presented in this paper. Three resonant modes are obtained by using a modified planar folded dipole and its coupled feeding structure. Incorporating with the shorting pins and parasitic patches, multiple resonant modes in the antenna are manipulated, shifted, and then combined for increasing the impedance bandwidth. Using this concept, a prototype of multi-mode folded dipole is designed, fabricated, and measured. The experimental results show that the proposed antenna achieves a bandwidth of 80% from 1.57 GHz to 3.68 GHz, while occupying a compact size of 0.3λ0×0.15λ0×0.05λ0 (λ0 is the wavelength in free space at the lowest operating frequency). Furthermore, a simple and effective design to achieve good omnidirectional radiation performance is developed by placing two proposed folded dipoles back to back. The antenna exhibits a flat gain variation of less than 1.27 dB over a broad bandwidth (82%) in the horizontal plane. Such a compact, wideband, planar antenna is a promising candidate for indoor signal coverage, wireless access points, and micro base stations in 2G/3G/4G/5G and WLAN/WiMAX wireless comminution systems

A Compact Dual-Polarized Filtering Antenna with Steep Cut-Off for Base-Station Applications

© 2022 IEEE - All rights reserved. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TAP.2022.3161280 ​​​​​​​A dual-polarized filtering antenna with steep cut-off and compact size is developed for base station applications. In this design, four controllable radiation nulls are obtained by utilizing split rings, slotted T-shaped branches, a single-stub tuner, and a parasitic loop. Split rings are firstly used as the dipole arms to obtain the 1st radiation null at upper out-of-band. Four T-shaped branches working as DGS are printed under the crossed dipoles to achieve the 2nd radiation null. The connected outer conductors of the differential feed structure acting as a single-stub tuner can provide the 3rd radiation null to further enhance the upper-band rejection. Finally, a parasitic loop is incorporated around the split rings, and the out-of-band rejection of the lower-band is further enhanced by the 4th radiation null. More importantly, the impedance bandwidth of the antenna can be expended with two newly introduced resonant modes. As a result, a compact filtering antenna with a wide operational bandwidth of 1.7- 3.01 GHz (56%) is realized for |Sdd11| < -15 dB with the isolation higher than 38 dB. The out-of-band suppression is higher than 18.4 dB in 3.1-4.5 GHz and more than 47 dB in 0.8-1.1 GHz.Peer reviewedFinal Accepted Versio