Two-port MIMO Antenna Research Articles

Design of Compact Multiband MIMO Antenna Based on Ground Neutralization Line Decoupling

A compact, multiband two-port MIMO antenna is proposed in this paper for various wireless transmission networks, where the overall size of the antenna is only 30 × 20 × 1.6 mm3. The proposed MIMO antenna consists of two radiating patches, each of which comprises a semicircle and a semi-regular hexagon, as well as the surface-etched C-slot and U-slot to tailor the antenna’s return loss characteristics. In proposed antenna, a parasitic branch forms when the ground plane’s meandering branches are symmetrically distributed. On one hand, it can increase the ground plane’s effective area and enhance the antenna’s return loss characteristics. A neutralization line, on the other hand, is generated, thereby limiting the current transmission on the ground plane. A cross-shaped slit in the ground’s center is also employed to further promote isolation between the radiation elements. According to obtained results, the antenna can cover the frequency bands 0.67-7.29 GHz, 8.07-12.11 GHz, 14.07-15.41 GHz, and 16.04-22 GHz (S11<−10 dB). Moreover, an RF isolation larger than 18 dB exists between the two ports. Lastly, in terms of ECC, DG, TARC, CCL, and MEG, the diversity performances are all satisfactory.

Design of low profile, compact, high gain and broadband metasurface-based MIMO antenna for 5G/WiMAX/WLAN applications

ABSTRACT We have presented two-port MIMO antenna designs with low-profile material. Two different MIMO antenna designs are prepared and investigated to observe their effect on the gain, bandwidth, etc. The designs are prepared based on metasurface concepts with one design having a circular ring metasurface design and second having circular disk metasurface design. The designs are showing broadband response covering frequency range of 1.85 GHz to 4.27 GHz. The bandwidth of 2.320 GHz is achieved for this metasurface MIMO antenna design. The gain and directivity results show that highest gain of 5.88 dB and directivity of 6.39 dB are achieved with circular ring metasurface MIMO antenna design. Both metasurface MIMO antenna designs are fabricated, and measured results are also provided to verify the simulation results. The broadband and high gain design are applicable for 5G communication, WiMAX and WLAN applications.

A two-port UWB MIMO antenna with an EBG structure for WLAN/ISM applications

A two-port disc-shaped multiple-input-multiple-output (MIMO) antenna is investigated for ultra-wideband (UWB) systems. The inter-element isolation is improved by inserting an electromagnetic band-gap (EBG) structure between the monopole radiators. The MIMO antenna with EBG offers a wide impedance bandwidth (S11 ≤ −10 dB) of 120 % (3–12 GHz), isolation of 25 dB, and peak gain >5 dBi over the UWB range. The low-profile MIMO antenna is printed on the FR-4 substrate and has a size of 30 × 60 × 1.6 mm3.

Miniaturization and performance enhancement of super wide band four element MIMO antenna using DNG metamaterial for THz applications

A compact semi-hexagonal-shaped MIMO antenna loaded with a planar SRR (split-ring resonator) structure is presented for Terahertz applications. The single radiating element consists of a semi-hexagonal shape metallic patch loaded with SRR-CC (Split ring Resonator-Connected C shape) metamaterial unit cell to enhance the impedance bandwidth as well as gain of the proposed antenna. The proposed antenna element can be easily extended into two-port and four-port MIMO antenna configurations. Four radiating elements of the proposed antenna are printed on 122.4*122.4 μm2 quartz substrate having a thickness of 10 μm. The radiating elements are placed orthogonally to achieve high isolation and miniaturization in the MIMO system. The proposed antenna exhibits super-wide impedance bandwidth (S11 ≤ − 10 dB) in the range of 0.9–10.1 THz (with fractional bandwidth of 168% at f0 = 5.5 THz) while isolation of antenna is more than 20 dB in the whole operating band. The peak gain of the antenna is 7.51 dBi with more than 95% radiation efficiency in the entire band. The stable radiation pattern, high gain, high radiation efficiency, and good diversity performance of the proposed antenna make it suitable for many THz applications such as breast cancer detection, sugar measurement, drug detection.

Tri-band MIMO antenna design based on characteristic modes manipulation

Several MIMO antennas based on the theory of characteristic modes have been proposed, but few of them introduce systematic design methods for microstrip MIMO antenna to obtain three frequency bands and as well as to reduce mutual coupling between the MIMO units. In this paper, a tri-band MIMO antenna is designed under the guidance of characteristic mode analysis. Firstly, the characteristic modes of the basic rectangular microstrip antenna are adjusted by loading rectangular spiral shaped stub and L-shaped slot at its proper positions to form a tri-band antenna unit. Next, based on the analysis of Modal significance and modal current distributions, the mode causing mutual coupling of the initial two-port MIMO antenna is determined, and then the meandering neutralization line connecting two adjacent edges and the rectangular gap in the middle of the common ground plane are designed as decoupling structures, which improve the isolation to more than 18 dB between two units with a distance of only 7.4 mm. Finally, the measured results prove the correctness and feasibility of the proposed systematic design process for the MIMO antenna, in terms of its compact size 32 mm ×26 mm, envelope correlation coefficient (ECC) less than 0.35, peak gain greater than 1.26 dBi and radiation efficiency greater than 76% in the three desired frequency bands (2.35–2.5 GHz, 3.25–3.85 GHz, and 4.4–6.2 GHz).

Circular shape MIMO antenna sensor for breast tumor detection

Abstract In this paper, a compact circular shape ultra-wide microstrip antenna is proposed for the detection of breast tumor. The proposed antenna is a two-port MIMO antenna of 1 × 2 elements. The dimensions of the proposed antenna are 34 mm × 18mm × 1.6 mm. It is designed over a lower-cost FR-4 epoxy substrate with a partial ground plane. The antenna is operated between the frequency range of 3.1–9.6 GHz. Isolation between the antenna element is less than −22 dB from 3.1 GHz to 7 GHz and −25 dB between 7 GHz and 10.6 GHz. The obtained ECC of the designed MIMO antenna is less than 0.01 and also DG is almost 10 dB in the entire UWB range. Further, the 3D breast phantom model is also simulated for analysis of the effect of SAR. Due to the variation in the electrical properties of cancerous cells and healthy cells it is possible to identify the cancerous tumor using SAR analysis. The obtained maximum Average SAR value without a tumor is 41.97 W/kg and with a cancerous tumor is 72 W/kg. Also, the variation in reflection coefficient helps to detect the tumor of the same composition but having different locations and having different sizes inside breast phantom. The principal component analysis is done to change the multi-variation in reflection coefficients data value to a single point value for better analysis.

A compact planar dual band two‐port MIMO antenna with high isolation and efficiency

A dual-band two-port MIMO antenna with high isolation and efficiency is proposed in this article. Each antenna element is composed of a rotated U-shaped strip and an L-shaped strip. The MIMO antenna is optimized to operate in 2.5–2.7 GHz and 4.8–5 GHz, which can cover the 5G bands of China Mobile. The defected ground structure consists of a slant square loop with a T-shaped slit and a U-shaped slot. A rectangle parasitic strip is placed in the U-shaped slot. The use of defected ground structure and parasitic strip makes the antenna obtain good isolation which is better than −17.96 dB and − 20.1 dB at the lower and higher frequency bands. To evaluate the antenna diversity, envelope correlation coefficient (ECC) is analyzed which is lower than 0.0006 and 0.12 at the lower and higher frequency bands, respectively. The measured gains are 4.35 dBi and 4.6 dBi, while the measured efficiencies are 63.23% and 68.69% at 2.6 GHz and 4.9 GHz, respectively. The prototype of antenna is fabricated to verify the functioning of proposed antenna design.

A novel approach for low mutual coupling and ultra-compact Two Port MIMO antenna development for UWB wireless application

In this paper, a novel MIMO antenna operating in the UWB frequency band is presented. The proposed new antenna shape is derived from the conventional circular ring patch antenna having a partial ground plane. An array of three Quad-G Shaped Metamaterial structures was used between the antenna elements of the two-port MIMO antenna to expand the bandwidth in the lower frequency band of UWB application (below 5.567 GHz) and reduce the mutual coupling in such expanded band. The proposed MIMO antenna operates over a bandwidth of 8GHz from 4 GHz to 12 GHz. Over the entire bandwidth, the mutual coupling between antenna elements is less than -19.0 dB with an inter-element separation (sep) of λ/6 mm. The overall optimized dimensions of the proposed antenna are 0.34λ×0.22λ×0.021λ for a free-space wavelength, λ, calculated at 4GHz. The radiation pattern of the proposed MIMO antenna was analyzed using the Combined Results Technique (CRT) integrated into the CST microwave studio. The obtained peak radiation efficiency and gain are 83.0% and 5.57 dB respectively. The MIMO Performance metrics such as envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), Mean Effective Gain (MEG), Total Active reflection Coefficient (TARC), and multiplexing efficiency are evaluated and compared to the standard values. The proposed antenna was compared to other antennas in the literature. It has been found that the key benefit of the present method was observed in achieving the highly miniaturized overall antenna dimension having good MIMO system performance metrics and better radiation characteristics. The proposed antenna was fabricated and measured. The measured and simulated values are found to be in good agreement.

Dual-Band (28/38 GHz) Wideband MIMO Antenna for 5G Mobile Applications

A dual-band wideband composite patch antenna constructed from a modified circular primary patch and secondary parasitic patch element is presented in this work. A microstrip feed line is employed to inset-feed the primary patch. The secondary patch is fed indirectly through edge coupling with the main patch. The composite antenna is printed on Rogers Ro3003™ with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon _{\mathrm {r}}=3$ </tex-math></inline-formula> and thickness 0.25 mm. The antenna design stages are presented in detail. A MIMO antenna system is constructed from two elements of the proposed composite patch with two different configurations. A prototype is fabricated for the single element and the two-port MIMO antenna configurations. Numerical and experimental results are presented showing good performance regarding impedance matching at the operating bands 28 and 38 GHz, bandwidth, radiation patterns, and gain. The impedance matching bandwidths are 1.23 GHz at 28 GHz and about 1.06 GHz at 38 GHz. The minimum value of the reflection coefficient for 28 GHz 28 GHz band is −34.5 and is −27.3 dB for 38 GHz. The gain of the radiation pattern has a peak of 6.6 dBi at 28 GHz and 5.86 dBi at 38 GHz. For both bands, the radiation patterns are balloon-like omnidirectional. The antenna total dimensions are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.5\times 8.8\times0.25$ </tex-math></inline-formula> excluding the transmission line. The MIMO system with two-ports for both proposed configurations has appropriate values for ECC and the DG which are calculated through electromagnetic simulations.

A Compact Eight-port CPW-fed UWB MIMO Antenna with Band-notched Characteristic

A compact eight-port coplanar waveguide (CPW)-fed ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with band-notched characteristics in a small size of 54×54×0.8 mm3 is proposed in this paper. The eight-port MIMO antenna consists of four two-port MIMO antennas. For each two-port MIMO antenna, two monopole antenna elements are printed on the FR4 substrate and placed perpendicularly to each other. To increase impedance bandwidth and improve the isolation, a stub is positioned in the middle of two radiating elements. The band-notched characteristic are achieved by etching two L-shaped resonator slots on each radiating elements, respectively. The S11 reflection coefficients, coupling isolation, radiation patterns, peak gain and radiation efficiencies of the MIMO antenna are measured. The MIMO performance of the proposed antenna is analyzed and evaluated by the envelope correlation coefficient (ECC) and total active reflection coefficient (TARC).

Single split-ring resonator loaded self-decoupled dual-polarized MIMO antenna for mid-band 5G and C-band applications

This paper presents the design and development of a dual-band and dual-polarized two-port multiple-input-multiple-output (MIMO) antenna for mid-band 5G (3.4–3.6 GHz), and C-band (4–8 GHz) applications. The antenna design is very simple and it mainly consists of a circular-shaped single split-ring resonator on the top side of the substrate which is coupled with the microstrip line feed line. The bottom side is comprised of a rectangular-shaped defected ground structure. Due to this dual-band response is obtained and the first band shows linear polarization and the second band provides circular polarization. The entire dimensions of the intended two-port MIMO antenna are 46 mm × 21 mm × 1.6 mm. The antenna measured results offer a wider impedance bandwidth (IBW) of 20.22% and 44.07% for the two bands centered at 3.54 GHz and 6.33 GHz respectively. Also, the proposed MIMO antenna shows minimum isolation of 15 dB for the two frequency bands with a smaller edge-to-edge spacing of 4 mm (0.04λ0) between the two antenna elements. Moreover, the second band provides an axial ratio bandwidth of 3.97% centered at 6.78 GHz. The antenna shows excellent IBW, good isolation between the single antenna elements without the use of any decoupling mechanism, better antenna gain, and improved envelope correlation coefficient by maintaining smaller antenna size compared to similar types of existing two-port MIMO antennas in literature.

Ultrawide band two-port MIMO diversity antenna with triple notch bands, stable gain and suppressed mutual coupling

Two-port MIMO antenna is proposed for ultrawide band wireless applications with triple notch bands. The proposed antenna is offering the operating frequency band ranging from 3.1 GHz to 10.6 GHz. Three notch bands at 4.56, 7.25, and 9.08 GHz are introduced to eliminate the interference with exiting bands. Moreover, a prototype of the proposed structure is fabricated, and simulated results are validated with measured experimental results. The proposed antenna shows the almost stable radiation characteristics throughout the operating band with an almost stable gain of about 5 dBi. Mutual coupling between both ports is suppressed to the value of −25 dB within the operating frequency band. Diversity characteristics for a MIMO performance are analysed in terms of envelope correlation coefficient, total active reflection coefficient, diversity gain, multiplexing efficiency, and mean effective gain. The proposed antenna is easily integrable with the other MMIC devices as it carries a simple structure.

COMPACT TWO-PORT MIMO ANTENNA WITH HIGH ISOLATION USING PARASITIC REFLECTORS FOR UWB, X AND KU BAND APPLICATIONS

COMPACT TWO-PORT MIMO ANTENNA WITH HIGH ISOLATION USING PARASITIC REFLECTORS FOR UWB, X AND KU BAND APPLICATIONS

An ultra-compact two-port UWB-MIMO antenna with dual band-notched characteristics

In this paper, an ultra-compact two-port MIMO antenna working in the frequency range of 3.1–10.6 GHz with dual band-notched characteristics is presented. The MIMO antenna consists of two identical octagonal-shaped radiating elements placed adjacent to each other with a connected ground plane. The overall size of the proposed two-port UWB-MIMO antenna is 19 × 30 × 0.8 mm3. In the ground plane of antenna elements, a T-shaped stub is introduced to create band-notch at 5.5 GHz. Also, an open-ended half-guided-wavelength resonator slot is introduced along the upper edge of the octagonal radiator to obtain a broader notched-band (4.37–5.95 GHz). The second band-notch is created around 7 GHz (6.52–7.45 GHz) by etching another open-ended slot from the radiating patch. The two-notch bands reject interference due to HiperLAN, WiMAX, INSAT/Super-extended C-band, downlink of X-band satellite communication and RFID service bands. A pair of L-shaped slits are introduced in the feed line to improve impedance matching, for the frequency band available between the two notches. The proposed design is fabricated on an FR-4 substrate and minimum isolation greater than 18 dB (a major portion >22 dB) and envelope correlation coefficient (ECC) less than 0.13 are obtained. The antenna gain varies in the range of 1.2–2.91 dBi with a variation of 1.71 dBi only. A radiation efficiency, greater than 70% is achieved throughout the operating frequency band.

A compact integrated Bluetooth UWB dual-band notch antenna for automotive communications

This article presents a compact integrated Bluetooth UWB antenna with lower and upper WLAN dual-band notch characteristics for automotive communications. The proposed antenna consists of a quasi U-shape patch, four stubs and the ground plane with a stepped slot. The designed antenna operates over 2.39–2.49GHz and 3.1–11.4GHz bands with S11<-10dB corresponding to Bluetooth and UWB, and has two rejected bands of 4.97–5.48GHz (lower WLAN) and 5.69–5.99GHz (upper WLAN). Besides, housing effects of the proposed antenna are investigated in presence of approximate in-vehicular environment and simulated results show that the stable performance is suitable for automotive communications. Finally, a simple two-port MIMO antenna is designed and its performance is appropriate for MIMO/diversity application.

Systematic Shape Optimization of Symmetric MIMO Antennas Using Characteristic Modes

We introduce a systematic approach to the shape optimization of compact, single-aperture MIMO antennas. Because the characteristic modes of a radiator represent its complete set of possible responses to an excitation, any port on the antenna must display the properties of a combination of one or more of these characteristic modes. By restricting our consideration to a class of symmetric antennas, the lowest order characteristic modes of a structure can be separated with practical decoupling networks, studied, and excited independently. We show that the quality factor of each characteristic mode effectively bounds the performance of any individual port excitation, and can be used to evaluate the fitness of the antenna for multiport excitation. Under this framework, we apply a genetic algorithm (GA) to synthesize low $Q$ MIMO antennas while minimizing conductor area. Feed locations are specified on the optimized shape based on the weighted excitation strength of the desired modes, and a two-port MIMO antenna is implemented and measured, verifying the proposed theory.

Design of Two-port MIMO Antennas without Space for Isolation

The deployment of mobile femtocellular networks can enhance the service quality for the users inside the vehicles. The deployment of mobile femtocells generates a lot of handover calls. Also, numbers of group handover scenarios are found in mobile femtocellular network deployment. The ability to seamlessly switch between the femtocells and the macrocell networks is a key concern for femtocell network deployment. However, until now there is no effective and complete handover scheme for the mobile femtocell network deployment. Also handover between the backhaul networks is a major concern for the mobile femtocellular network deployment. In this paper, we propose handover control between the access networks for the individual handover cases. Call flows for the handover between the backhaul networks of the macrocell-to-macrocell case are proposed in this paper. We also propose the link switching for the FSO based backhaul networks. The proposed resource allocation scheme ensures the negligible handover call dropping probability as well as higher bandwidth utilization.