UWB dual-polarized microstrip antenna with high isolation

In this communication, a novel wideband differentially fed dual-polarized stacked patch antenna with tuned slot excitations for base station application is proposed. The antenna is composed of a driven patch excited by tuned slot excitations, a parasitic patch to enhance the impedance bandwidth, and a ground plane to obtain unidirectional radiation. Two pairs of the slot excitations etched on the opposite edges of the driven patch are used to obtain dual polarizations. Each tuned slot excitation has an open-ended slot and a $\Gamma $ -shaped feeding line. To connect to the differential circuit easily, a rotated feeding mechanism is adopted. A prototype of the proposed antenna is fabricated and tested. Measured results show that the antenna has a wide differential impedance bandwidth of 49.4% (1.66 to 2.75 GHz) for $\vert \text{S}_{\mathrm{ dd11}}\vert ~f-15 $ dB. In addition, a high differential port isolation of more than 37 dB, a stable radiation pattern with a 3 dB beamwidth of 61°±5°, and a stable gain around 8.7 dBi are obtained within the operational band. The proposed antenna features wideband, high port isolation, and stable gains, and it is a promising candidate for base station systems using differential signals.

A single-layer dual-polarized patch antenna loaded by T-shape microstrip stubs to achieve high port isolation is developed in this paper. This patch is side-fed in single-end form to simplify the connection to most RF chips. In addition, this patch only occupies single substrate layer with the ultra-low profile of 0.40λ0 × 0.40λ0 × 0.02λ0. High port isolation is realized by the loading effect of stubs. Simulated results show that this proposed antenna can cover 24GHz to 24.25GHz ISM band with peak realized gain of 5.2dBi and symmetrical broadside radiation pattern. Meanwhile the worst isolation between two orthogonally polarized ports is above 32dB considering PCB manufacturing tolerances.

The structure of two dual-band nearby antennas with high port isolation is proposed. The decoupling and matching network consist of only reactive elements so that it does not dissipate the input power. For dual-band antenna, it is usually easier to have high isolation in high frequency band (5GHz) due to its short wave length. Therefore, the decoupling design can be turned to improve low frequency band and not to influence the high frequency band as much as possible. Besides, the matching circuit is still required to match both low and high bands for maintaining good impedance matching. Measurement results demonstrate the good performance of the proposed configuration.

In this paper, a novel compact multiple-input multiple-output (MIMO) antenna with enhanced port isolation is proposed for ultra-wideband (UWB) applications. The UWB MIMO antenna contains two coplanar annular monopoles etched on the front side of the FR-4 substrate. The dielectric substrate has a relative permittivity of 4.4 and a size of 80 mm × 40 mm × 1.6 mm. The irregular ground is printed on the back side of the substrate. In order to enhance the port isolation between the two monopoles, the expanded ground is exploited in the proposed design. In addition, the ground is etched with some slots to achieve good impedance matching. Both the simulated and measured results show that the proposed antenna achieves good impedance matching as well as high port isolation over the entire UWB band. Moreover, the proposed antenna has good spatial diversity characteristics. In summary, the proposed UWB MIMO antenna can be well applied to the ultra-wideband wireless communication system.

This work presents a wideband hybrid-fed ±45o linear dual-polarized patch antenna design for sub- 6 GHz 5G base stations. Two polarizations are created by a slot-coupling with rectangular H-slot (+45) and a capacitive coupling with modified L-probe (−45). Antenna exhibits wideband −10 dB impedance bandwidths of 40.7% and 35.6% for slot-fed and probe-fed ports, respectively. Due to the special design of suspended stacked patches with hybrid-fed excitations, high port isolation ( 38 dB) are achieved. Symmetric and directional radiation patterns with stable gain are obtained in E and H planes for each polarization. Compared to its bandwidth, antenna is low-profile (10.6 mm) with front-to-back ratio greater than 22 dB. Simulations and experimental results are reported and discussed.

In this communication, we propose a shared-radiator design concept for dual-band base station antenna arrays. To realize the concept, novel differentially fed dual-polarized slot antenna is devised to be the high-band (HB, 3.4–3.6 GHz) radiator, while the large slot ground can be reused as the radiating arm of the low-band (LB, 0.69–0.96 GHz) crossed dipole. Reflective cavities are introduced to back the HB antennas, building clear and independent radiating environments for the two operating bands. A dual-band base station antenna array with one LB dipole antenna and four HB slot antennas is designed, by adopting the proposed integration concept. Good impedance matching (voltage standing wave ratio <1.5) and high port isolation (>29.5 dB in the LB and >26.6 dB in the HB) are obtained. Stable radiation patterns are also achieved in the two bands.

In this paper, the design, simulation results, and measurements of a coaxial-fed dual-polarized patch antenna with high port isolation are presented. The proposed antenna consists of two cross center-fed patch dipole antennas against a reflector as ground plane, while the patch antenna contains two pairs of X-shaped slots along the diagonals and two pairs of T-shaped slots along the centerlines. The proposed antenna achieves a -10 dB with bandwidth of 470–730 MHz and demonstrates the dual polarization in both directions. Stable radiation patterns at slanted polarization have been obtained within the band. Measurements show two linear polarizations with an isolation of more than 33 dB over the operating frequency band. The proposed antenna can be used for Digital television applications (DTV).

The following topics are dealt with: integrated circuit design; low-power electronics; CMOS integrated circuits; CMOS analogue integrated circuits; operational amplifiers; system-on-chip; field programmable gate arrays; power engineering computing; Ge-Si alloys; wide band gap semiconductors.

A novel dual-polarized magneto-electric dipole antenna with wideband performance is presented in this communication. The folded jagged edges of the radiating patch contribute to a better impedance matching, as well as a compact size. The antenna is fed by a crossed coupling structure, thus dual-polarizations and a high port isolation are obtained. A parametric study is performed for providing practical design guidelines. Simulation results show that an impedance bandwidth of 100% for VSWR ≤ 2.0 from 1GHz to 3GHz is achieved. Stable radiation patterns with low crosspolarization levels are also obtained across the operation band.

A wideband highly isolated multiple-input-multiple-output patch antenna with an artificial magnetic conductor (AMC) ground plane is proposed in this letter. The antenna, which is rotationally symmetrical, is constructed by V-shaped patches coupled by a bowtie dipole. The bowtie dipole and the V-shaped parasitic patches produce two resonant modes that are coupled together. Therefore, a wide impedance bandwidth is obtained. Thanks to the orthogonal feeding and the rotationally symmetrical geometry, the antenna exhibits high port isolation as well as symmetrical radiation patterns with a compact size of 40 × 40 × 1.524 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . By placing an AMC ground plane with a distance of 10.5 mm below the radiating element, the antenna can achieve a unidirectional high gain with a lower height of the profile compared to that with perfect electrical conductor ground. Measured results show the antenna has an impedance bandwidth of 31.0% (3.0-4.1 GHz) with port isolation better than 25 dB. The peak gain can reach 7.1 dBi with stable and symmetrical radiation patterns.

In this paper, a compact ultrawideband (UWB) multiple-input multiple-output (MIMO) antenna is presented. The proposed MIMO antenna consists of a monopole antenna element and a slot antenna element. The slot antenna is fabricated based on the origin structure of the monopole antenna, which reduces the overall size of the MIMO antenna. The proposed MIMO antenna operates over a wide band ranging from 4.6GHz to 10.1GHz, in which operating band, high isolation over 21dB is obtained. The simulation results shows that the proposed MIMO antenna has wide operating band, good isolation characteristic and low correlation coefficient, which is suitable for portable UWB applications.

A coax-feed dual-polarised patch antenna with low cross-polarisation and high port isolation is presented. The proposed antenna contains two pairs of narrow slots along the diagonals and two pairs of T-shaped slots along the centrelines, which change the path of the current and keep the cross-polarisation under −38 dB. By introducing two short pins, the isolation between the two ports remains more than 40 dB in the whole bandwidth. Moreover, the proposed antenna achieving a 10 dB return loss bandwidth of 2.15–2.72 GHz has a compact structure, thus making it easy to be extended to form an array, which can be used as the base station antenna for WiMAX applications.

A compact dual-frequency microstrip multiple-input multiple-output (MIMO) antenna with high isolation is proposed in this paper. The proposed dual-frequency microstrip MIMO antenna operates at 2.58 GHz and 4.8 GHz. In addition, a new defective ground structure is proposed, which can effectively reduce the coupling of the MIMO antenna at the two operating frequencies. Then, two rectangular metal strips are loaded between the two radiating patches to further reduce the coupling of the MIMO antenna at the high resonant frequency. Finally, the coupling coefficients S12 at 2.58 GHz and 4.8 GHz have been reduced by 22 dB and 19 dB, respectively. Therefore, the isolation between the antenna elements is effectively improved.

A five port integrated antenna with high isolation for cognitive radio (CR) application was investigated in this study. The design approach involves both the state of operation in terms of ultra-wideband (UWB) and narrowband (NB), where the former is for sensing and the latter is for the sake of communication. The antenna in UWB state comprises an elliptical patch with a narrow cut on the top whereas four simple comb-like patterns are used to perform the task in NB range. In three of the NB antennas, Complementary Split Ring Resonators (CSRR) are used for impedance matching, in contrast to a Double Circular Ring Resonator (DCRR) in another NB antenna. In order to achieve remarkable inter port isolation, two meander lines of same electrical length are introduced between UWB and NB antennas where the first meander line (ML1) is positioned parallel and the second meander line (ML2) is tilted by an angle of 30° with respect to UWB. The potential outcome of the proposed design senses UWB spectrum from 1.9 GHz − 11.77 GHz along with seven communication tasks simultaneously in terms of single and dual band operations with remarkable gain and high isolation of <-22 dB in all ports.

A dual-polarized filtering dipole antenna with enhanced bandwidth and high selectivity is presented in this paper. The proposed antenna adopts the cross-dipole structure, containing two radiation units orthogonal to each other to achieve ± 45° linear polarizations. For each dipole unit, the parasitic elements placed perpendicular and parallel to it introduce radiation nulls at lower and higher frequencies, respectively. Through a pair of slits etched on each parasitic element, the roll-off rate at the upper passband edge is further optimized. In addition, the two radiation nulls can be controlled independently by adjusting the inner and outer lengths of the Uslot on the coupling path. To demonstrate the feasibility of this design, the compact dual-polarized filtering antenna is fabricated. Measured results show that the proposed antenna characterizes wide impedance bandwidth, high port isolation, flat in-band gain, sharp band-edge roll-off, and low cross-polarization level.