Design of a Circularly Polarized Printed Antenna and its MIMO Configuration for Modern Ultra‐Wideband ( UWB ) Wireless Communication Systems: Simulation and Experimental Validation

Ultra-wideband (UWB) technology is extensively used in indoor navigation, medical applications, and Internet of Things devices due to its low power consumption and resilience against multipath fading and losses. This paper examines a multiple-input multiple-output (MIMO), circularly polarized (CP) dielectric resonator antenna for UWB systems. Compact form factor, high gain, wideband response, improved port isolation, and high data rates are the major design goals. This arrangement consists of two identical DRAs with self-decoupled orthogonal orientations eliminating the need for extra decoupling structures while achieving an impressive maximum isolation of 43 dB. The corner-edge feeding mechanism of the extended feedline generates two orthogonal E-fields, facilitating circular polarization. Additionally, a printed hook-shaped stub integrated with the ground plane enhances CP performance across the two operating bands without altering the DR structure. Fabrication and testing exhibit an impressive 133% impedance bandwidth (2.5–14 GHz) with high port isolation. For a 3 dB axial ratio reference, the single-element design exhibits axial ratio bandwidths (ARBW) of 1.2 GHz (3.6–4.8 GHz) and 0.8 GHz (9.3–10.1 GHz). Remarkably, the MIMO configuration achieves a single ARBW of 0.5 GHz (3.9–4.4 GHz). Detailed investigations of MIMO performance parameters, including diversity gain, envelope correlation coefficient, channel capacity loss, and total active reflection coefficient, underscore the design’s efficacy, making it a good choice for UWB wireless applications.

This paper presents a novel MIMO antenna configuration that utilizes cylindrical dielectric resonator antennas (CDRAs) integrated with substrate integrated waveguide (SIW) technology, tailored for wideband operation within the terahertz (THz) frequency range. A Defective Ground Structure (DGS) was incorporated into the two-port SIW-MIMO CDRA framework to achieve an enhanced bandwidth performance. Circular polarization (CP) is obtained across the desired frequency bands. The incorporation of a graphene layer on the CDRA surface alters the resonant behavior, resulting in a noticeable shift in the antenna’s operating frequencies. The antenna exhibits two separate wideband responses, achieving an impedance bandwidth of 1.51 THz from 4.6 to 6.11 THz and 2.05 THz across the 7.71 to 9.76 THz spectrum. Isolation exceeding ≤ –25 dB is consistently sustained over the operational bandwidth. Moreover, the antenna supports dual-band circular polarization, offering 3 dB axial ratio bandwidths (ARBWs) of 23.23% between (4.68–5.85 THz) and 15.56% between (8.02–9.50 THz). A peak gain of 6.02 dB is recorded, along with a high radiation efficiency of 78.26%. By modifying the feed lengths, the polarization characteristics can be effectively tuned, rendering the design adaptable for diverse THz applications. The antenna’s MIMO capabilities are validated through essential diversity performance indicators, including an Envelope Correlation Coefficient (ECC) below 0.01, a Channel Capacity Loss (CCL) under 0.5 bps Hz −1 , a Mean Effective Gain (MEG) of –3 dB or better, a Diversity Gain (DG) close to 10 dB, and a Total Active Reflection Coefficient (TARC) of less than –10 dB. Additionally, the application of a graphene coating plays a significant role in expanding the impedance bandwidth while enhancing both frequency agility and axial ratio tunability.

In this manuscript, a compact circularly polarized MIMO antenna with 100% 3-dB axial ratio attributes has been conceived for 5G NR Sub-6 GHz frequency bands. The simulated and measured findings indicate that the suggested antenna has an impedance bandwidth (−10 dB) in the range of 2.88–3.88 GHz; nonetheless, the measurements show a range of 3.0–4.4 GHz, with a 3-dB Axial ratio Bandwidth (ARBW) in the area of 2.73–5.42 GHz (Simulated) and 2.75–5.45 GHz (Measured), respectively. With left-handed circular polarization (Port-1 and Port-2) and right-handed circular polarization (Port-3 and Port-4), the antenna spans the proposed 5G band spanning N77 (3.3 to 4.2 GHz) and N78 (3.3 to 3.8 GHz). The suggested MIMO antenna design consists of a singular structure including an L-shaped radiating element and a rectangular ring-shaped ground plane, both co-planar. A compact MIMO module with two ports is constructed by reflecting the L-Shape radiator across the x-axis, while a MIMO module with four ports can be generated by reflecting the two-port antenna image across the y-axis. The functionality of the proposed module as an antenna have been validated by simulation, including the calculation and analysis of various antenna and diversity characteristics. The modelling results are then corroborated by the measurement outcomes of the constructed antenna. The suggested design is deemed suitable for use as a MIMO antenna due to its optimum value of envelope correlation coefficient (ECC), diversity gain (DG), channel capacity Loss (CCL), total active reflection coefficient (TARC), mean effective gain (MEG) and its isolation between the antenna components, which exceeds 18 dB. The suggested design demonstrates a high degree of concordance between the simulated and measured outcomes.

Design and packaging of polarization diversity 3D-UWB MIMO antenna with dual band notch characteristics for vehicular communication applications

Superlative split ring resonator shaped ultrawideband and high gain 1×2 MIMO antenna for Terahertz communication

Circularly polarized three-element MIMO antenna with diversity and polarization reconfigurability techniques

This work presents a miniaturized quad-element multi-input multi-output (MIMO) antenna with low mutual coupling, inherent isolation, and easy upgradability for an Internet of Things (IoT) based high-speed smart digital entertainment network using ultra-wideband (UWB) technology. Ultra Wideband (UWB) technology is anticipated to play a significant role in the future IoT based smart systems due to its ability to provide high precision location information, low power consumption, high data rates and secure communication. An elliptical quadrant-shaped radiator with a C-shaped protuberant ground plane is conceptualized as a quasi-monopole UWB antenna following the half-cut miniaturization approach with very compact dimensions of 18W11 mm2. The elliptical quadrant radiator in combination with C-shaped ground plane introduces multi-resonance characteristic in addition to providing better impedance matching with miniaturization and inherent high isolation for MIMO configuration. The single element antenna is then organized in an orthogonal arrangement with an edge-to-edge distance of 5 mm to develop a quad-element MIMO antenna system. The MIMO antenna structure realizes a wide bandwidth of 3.14-11.23 GHz (center frequency at 7.19 GHz), peak gain of 7.2 dBi, and radiation efficiency of above 60% with good isolation (>-20 dB) between the adjacent elements without employing any dedicated decoupling structure. The diversity performances of the proposed MIMO antenna are relatively good, with a very low envelope correlation coefficient (ECC) of less than 0.35 and diversity gain (DG) nearly at 10. Further, the total active reflection coefficient (TARC) <-10 dB and channel capacity loss (CCL) <0.4 bit/s/Hz, parameters are witnessed to be within acceptable limits. The simulated and measured results agree well, testifying that the proposed four-element MIMO antenna is suitable for UWB applications.

A four port flexible UWB MIMO antenna with enhanced isolation for wearable applications

A tree-shaped graphene-based microstrip multiple-input and multiple-output (MIMO) antenna for terahertz applications is proposed. The proposed MIMO antenna is designed on a 600 × 300 μm2 polyimide substrate. The designed MIMO antenna provides a wide impedance bandwidth of 88.14% (0.276–0.711 THz) due to the suggested modifications in the antenna configuration. The MIMO design parameters like total active reflection coefficient (TARC), mean effective gain (MEG), envelope correlation coefficient (ECC) and diversity gain (DG), channel capacity loss (CCL) are evaluated, and their values are found within acceptable limits. The proposed MIMO structure offers MEG ≤ − 3.0 dB, TARC ≤ − 10.0 dB, DG ≈ 10 dB, CCL < 0.5 bps/Hz/s and ECC < 0.01 at the resonant frequency. At the resonant frequency, the isolation between the radiating elements of the proposed MIMO antenna is recorded as − 52 dB. The variations in operating frequency and S-parameters are also analyzed as a function of the chemical potential (μc) of the graphene material. The parametric analysis, structural design evolution steps, surface current distribution, antenna characteristics parameters and diversity parameters are discussed in detail in this paper. The designed MIMO antenna is suitable for high-speed short-distance communication, video-rate imaging, biomedical imaging, sensing and security scanning in the THz frequency band.

This paper presents a compact CPW-fed MIMO antenna for UWB applications. The four-element CPW-fed antenna is designed as a radiator. The isolations between the same polarized elements and the orthogonally polarized elements are more than 20 and 25 dB, respectively. The floating parasitic element is used to improve isolation at a higher frequency. The simulated and measured 10 dB impedance bandwidth of the proposed MIMO UWB antenna is from 3.6 to 10.3 GHz. The return loss, isolation, radiation patterns, envelope correlation coefficient (ECC), total active reflection coefficient (TARC), diversity gain (DG), and channel capacity loss (CCL) are simulated and/or measured for the proposed antenna. ECCs are less than 0.0022, DGs are above 9.9 dB, TARC has minimum variations in different angles and CCLs are less than 0.4 bits/s/Hz at 10 dB impedance bandwidth. Due to which the proposed antenna can be used in portable UWB applications.

A novel four-port MIMO antenna with integrated parasitic elements for 5G NR n78 band applications

An improved mutual coupling compensation in circularly polarized (CP) multi-input multi-output (MIMO) dielectric resonator antenna (DRA) is presented in this paper. Using trimming approach, the mutual coupling (MC) between closely spaced DRA units at 0.3λ has been significantly reduced while axial ratio performance has been maintained. Mutual coupling reduction is obtained by trimming the DRA to ensure low mutual coupling below −20dB. The exclusive features of the proposed MIMO DRA include wide impedance matching bandwidth (BW), triple band circular polarization, and suppressed MC between the radiating elements. The impedance bandwidth matches perfectly with a triple band's 3 dB axial ratio (AR). It is designed with characteristic mode analysis with good agreement of the measurement that has been obtained. Using the probe feed method, the DRA and patch strip are coupled together to allow bandwidth widening of the pro-posed DRA. An impedance bandwidth of 34% at a lower frequency to around 2% at a higher frequency was achieved in all resonance frequencies. Thus, we refer to our newly designed DRA as a proposed method for effectively reducing the mutual coupling between DRAs. Additionally, the 3 dB AR bandwidth matched at 3.3 GHz, 4.6 GHz, and 6.3 GHz with a percentage of 11.66%, 3.04%, and 2.22% obtained at the three different frequencies. Note that the proposed DRA exhibits low mutual coupling (below −20 dB) at the targeted frequencies, which is suitable for better signal reception for MIMO applications. By computing, the metrics envelop correlation coefficient, diversity gain, channel capacity loss, and total active reflection coefficient, the MIMO performance of the proposed antenna is verified. The experiments show a close result between simulated and computed validation of the proposed DRA.

ABSTRACTThe design of an ultra‐wideband (UWB) multiple‐input multiple‐output (MIMO) antenna for smart fabric communications can significantly improve the reliability of wireless connections and overcome challenges such as channel fading and shadowing caused by the human body. This technology proves valuable for security applications, location tracking, and patient monitoring. Cotton fabric serves as the substrate material for the proposed textile antenna. With a connectivity‐aware graph neural network (CAGNN), a UWB MIMO antenna is designed with four octagonal radiators, each loaded with multiple slots, offering a frequency range of 2.9–12 GHz. The unit cell measures , and the MIMO antenna measures . Performance metrics, like channel capacity loss (CCL), diversity gain (DG), total active reflection coefficient (TARC), envelope correlation coefficient (ECC), and specific absorption rate (SAR), are considered. The efficiency of the proposed approach is compared with existing approaches. The proposed CAGNN‐DUWBMIMO technique is implemented. The proposed approach achieves 26.36%, 20.69%, and 30.29% better ECCs; 19.12%, 28.32%, and 27.84% better DGs; and 12.04%, 13.45%, and 22.80% better SARs compared with existing models: design with the analysis of a UWB MIMO antenna for smart fabric communications (DA‐UWBMIMO), design with the analysis of a UWB MIMO antenna for smart fabric communications (DDPT‐UWBMIMO), development including the comprehensive assessment of a double‐port textile UWB MIMO antenna for biomedical use (DDBW‐MIMOA), respectively.

This article demonstrates the design process for a unique, two-port, circularly polarized (CP) multiple input multiple outputs (MIMO) antenna for fifth-generation (5G) applications operating at sub-6 GHz. The proposed 2-port CP MIMO antenna comprises a patch antenna with a distinctive slot and a circular split ring resonator (SRR) at the ground plane. The circular patch antenna’s resonant frequency is moved to a lower frequency by the addition of a circular SRR at the ground plane. Investigating a special slot at the patch antenna can help in the enhancement of circular polarization and bandwidth. A sequence of parasitic elements in the shape of ‘h’ is placed in the space between the two antenna elements for decoupling. The minimum 20 dB inter isolation among the antenna elements in the proposed 2-port CP MIMO antenna’s operating band is made possible by these h-shaped parasitic elements. In addition, to ensure the proposed antenna is more reliable for 5G applications at sub-6 GHz, other diversity parameters including Envelop Correlation Co-efficient (ECC), Mean Effective Gain (MEG), Diversity Gain (DG), TARC (Total Active Reflection Co-efficient) and CCL (channel capacity loss) are also calculated . In comparison to existing MIMO systems of the same order, the proposed 2-port CP MIMO antenna appears to have the minimum channel capacity loss and excellent diversity performance. The proposed 2-port CP MIMO antenna achieves an impedance bandwidth of 3.3 to 3.6 GHz with impedance matching better than 10 dB and has an axial ratio bandwidth of 3.35 to 3.51 GHz with a steady radiation pattern in both planes over the operating frequency bands.

A quad-element multiple-input-multiple-output (MIMO) antenna with fractional bandwidth (FBW) of 52.42% (3.35–5.73 GHz) is proposed for LTE, WLAN (4.9/5 GHz), and 5G (sub-6 GHz) applications. The bandwidth is improved by introducing a tapered feed line and rectangular stubs in the partial ground plane. The maximum isolation of the proposed MIMO antenna is 27 dB. The diversity performance characteristics of the proposed antenna are studied in terms of the envelope correlation coefficient (ECC), diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), isolation between the ports, and channel capacity loss (CCL) and the values obtained are 0.003, 9.98 dB, ±3 dB, −4 dB, −10 dB, and 0.10 bits/s/Hz respectively. A model of the proposed antenna is fabricated on the FR-4 substrate having a dielectric constant of 4.4 and a loss tangent of 0.02 with an electrical dimension of 0.45λ0 × 0.45λ0. The measured results demonstrate a decent likeness to simulated ones in the entire operating frequency range.