Design of a CPW-Fed Compact MIMO Antenna for Next Generation Vehicle to Everything (V2X) Communication

This article presents a compact Co-Planar Waveguide (CPW) fed antenna for next-generation Vehicular Communications. The antenna is designed by employing two rectangular stacked patch structures and slots, making the antenna resonate at dual frequency bands. The analytical study of antenna design is carried out using the governing microstrip patch equations. On optimizing the patch's dimensions for CPW structures, the desired frequency range of operation is obtained for the single element antenna structure. The designed antenna resonates at 3.5 GHz (LTE-42 Band) and 5.9 GHz (DSRC Band), yielding this antenna to be a prime component for Vehicular to Everything (V2X) Communication. The optimized single-element antenna structure is 35 mm?×?20 mm designed on an FR-4 substrate of thickness 1.6 mm. The substrate has a dielectric constant of 4.4 and a loss tangent value of 0.001. Further, the antenna structure is developed as a 4-element MIMO configuration with the distance between adjacent antenna elements to be 10 mm. The adjacent antennas in the MIMO configuration are positioned orthogonal to each other, thereby exhibiting better isolation between the antenna elements. The antenna has a reflection coefficient value of?<??10 dB within the bandwidth of interest and VSWR less than 2. The Gain value of the designed antenna ranges between 2.8 and 2.9 dBi at 3.5 GHz and between 3.6 and 3.7 dBi at 5.89 GHz. The overall efficiency of the antenna element is between 60 and 80% at both frequency bands. MIMO parameters are analyzed by calculating the Channel Capacity Loss (CL), Diversity Gain (DG), Envelope Correlation Coefficient (ECC) and Total Active Reflection Co-Efficient (TARC). The designed antenna is fabricated and tested, which shows the measured results coincide with the simulated antenna results. The overall dimension of the MIMO configured antenna design is 60 mm × 60 mm × 1.6 mm, which is highly compact and is a suitable candidate for deployment of Vehicle to Vehicle (V2V), Vehicle to Infrastructure (V2I), and Vehicle to Network (V2N) scenarios.

     

Design of novel compact eight-element lotus shaped UWB-MIMO antenna with triple-notch characteristics on hollow substrate

The design of novel compact two-element and eight-element lotus shaped multiple-input-multiple-output (MIMO) antenna system employing pattern diversity with enhanced isolation characteristics is presented. The proposed two-element antenna system is arranged rotationally on a square-hollow substrate resulting in an eight-element MIMO antenna system employing pattern diversity. The developed eight-element MIMO antenna system resonates in the frequency range 3.1 to 14.6 GHz housing the complete UWB band with triple band-notch characteristics at 3.7–4.5 GHz (C-band satellite down link [3.7–4.2 GHz]), 5.1–5.9 GHz (WLAN) and 6.8–8.25 GHz (X-band satellite down link (7.25–7.75 GHz) and up link (7.9–8.4 GHz)) bands. The antenna system gives element-to-element isolation of more than 25 dB in the majority of the operating band with a peak gain of 6.8 dBi and a maximum 90% efficiency. The important MIMO metrics like ECC (envelope correlation coefficient), DG (diversity gain), total active reflection coefficient (TARC), channel capacity losses (CCL) and MEG (mean effective gain) are presented for both two-element and eight-element to estimate the performance the proposed antennas in multi-antenna environments. The both two- and eight-element designs are fabricated and the measured results of those are well agreed with simulation results.     

A triband swastika shaped patch antenna with reduced mutual coupling for wireless mimo systems

A novel compact Swastika shaped patch antenna is designed in the present work, which can be used for Multiple Input Multiple Output (MIMO) systems. The proposed two element MIMO system resonates at a triband of 3.3 GHz, 5.8 GHz, and 7.1 GHz with an improved impedance bandwidth of 37% and a reduced mutual coupling of ?33 dB. These results are better compared to a normal E shaped patch antenna designed with same size and thickness, achieved without using any additional decoupling methods. A 2??2 MIMO system employing the Swastika shaped patch antennas is analyzed using computational electromagnetic ray tracing software for an indoor environment. The results show an improvement in the capacity compared to a 2??2 MIMO system developed with dipole antennas. The proposed antenna is a good choice for MIMO systems operating for several Ultra WideBand (UWB) applications.     

Multi-Element Wideband Planar Antenna for Wireless Applications

A wideband, multi-standard MIMO antenna with hexagonal geometry and slot is proposed for DCS/PCS/LTE/UMTS applications while keeping the real time application at prime to provide high data rate, low latency, high capacity, non-line-of communication, and reliability with continuity. The designed prototype covers 1.64–2.50 GHz frequency band with percentage bandwidth of 41.55% and resonates at 2.1 GHz. The isolation of more than 10 dB is achieved in the 2:1 VSWR frequency band. The total bandwidth of the MIMO antenna is 860 MHz. The designed MIMO has peak gain of 5.4 dBi, ECC?<?0.06, radiation efficiency?>?88%, and total efficiency?>?71%. The TARC active bandwidth is 600 MHz with best excitation angles of 45°, 45° at ports. The hexagonal slot is used for the control of induced current for better isolation. The proposed MIMO antenna evaluates the SAR performance at resonant frequency for listening, holding, and watching positions, and is found under the required safety norms.

     

Broadband Multiple Input Multiple Output antenna for sub-6-GHz 5G communications

This paper presents the design of a miniaturized broadband monopole antenna for 5G and Wireless Local Area Network (WLAN) applications in mobile handsets. The proposed monopole evolved from a rectangular geometry of size 12 × 5 mm. The slot and stub loading techniques are used to improve the impedance matching offered by the antenna. Furthermore, bandwidth broadening is achieved using lumped elements loaded onto the aperture of the antenna. The proposed miniaturized antenna exhibits a measured impedance bandwidth of 63.6% (3.0–5.8 GHz) covering the 5G spectrum allocations under sub-6 GHz and the WLAN services. The antenna elements are replicated along the sides of the mock mobile handset PCB to study the functionality of the eight-element MIMO antenna. The prototype MIMO antenna fabricated and tested in the laboratory offers a peak gain of 3 dBi and total efficiency greater than 72%. Owing to miniaturization, the spatial distribution of the antenna element provides a low envelope correlation (ECC) of less than 0.2 and good diversity gain (DG) greater than 7.8 dB. In addition, the mean effective gain (MEG), channel capacity loss (CCL), multiplexing efficiency (ME), and total active reflection coefficient (TARC) are evaluated and presented. The estimated MIMO metrics are within the desired range of operation and hence make the antenna suitable for a complex propagation environment. The prototype antenna is developed on a thin microwave laminate with low-loss characteristics and tested under laboratory conditions. The outcomes indicate that the proposed eight-element antenna can be applied to 5G MIMO communications.     

多用途双频双极化双通道MIMO 室内基站天线

多输入多输出(Multiple Input Multiple Output,MIMO)天线是MIMO技术的关键,现代无线通信领域的迅速发展对MIMO天线提出了许多新的要求.该文利用微带天线的低剖面特性,采用双线馈电的方式实现了两款双端口的MIMO天线,其中一款基于正方形辐射贴片,两个端口都工作于2.4GHz并且具有相同的辐射特性;改变贴片的尺寸可以得到另一款双频MIMO天线,分别工作于2.4GHz和3.5GHz,可以同时覆盖LTE(Long Term Evolution)、WiMAX(Worldwide Interoperability for Microwave Access)频段与WiFi(Wireless Fidelity)的部分频段,该天线的最大增益可达8dB,并且两个端口对应两个互相垂直的极化,满足室内基站的需要.     

A Chaucer microstrip fractal antenna for mobile applications

In this paper a Chaucer fractal patch antenna integrated with split ring structure is simulated using Ansoft’s (HFSS), as well as fabricated and tested using VNA. The obtained results indicate that the proposed antenna resonates at 2.4 GHz in the ISM band. In addition, the structure offers multi-band operation with the fair value of return loss, gain, and bandwidth, impedance and directivity in the entire range of frequency operation.     

Broadband sub-6 GHz flower-shaped MIMO antenna with high isolation using theory of characteristic mode analysis (TCMA) for 5G NR bands and WLAN applications

A small size neutralization line integrated flower-shaped MIMO antenna is designed and analyzed for sub-6 GHz type 5G NR frequency bands like n79 (4400–5000 MHz), n78 (3300–3800 MHz), n77 (3300–4200 MHz), and WLAN (5150–5825 MHz) applications. The novel approach of theory of characteristic mode analysis (TCMA) is introduced to provide physical insight of the designed structure and its characteristics behavior. Due to the suggested modifications in the geometry, the isolation among the patches is greatly increased. The overall miniaturized dimension of the MIMO antenna is 25 × 40 mm². The edge-edge spacing among the elements is 0.0233λ. The prototype antenna is fabricated and measured that shows good agreement compared with simulated results. The designed MIMO antenna without the presence of decoupling structure offers an isolation of 28 dB, gain of 3.6 dBi, and radiation efficiency of 69.7% at the resonant frequency. The proposed MIMO antenna covers a broad range of frequency band from 3.296 to 5.962 GHz with −10 dB impedance bandwidth of 2666 MHz and maintains a good isolation of greater than 50 dB for the entire operating band. The tested radiation efficiency and gain are 85.3% and 6.22 dBi at 3.5 GHz. Moreover, the diversity parameters of the neutralization line integrated MIMO antenna, that is, channel capacity loss (CCL) isolation, mean effective gain (MEG), total active reflection coefficient (TARC) diversity gain (DG), and envelope correlation coefficient (ECC), are analyzed and discussed in this article.     

Compact body-worn MIMO antenna with high port isolation for UWB applications

This article investigates the mutual coupling reduction of a compact two elements wearable ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna. The ground plane of the proposed wearable MIMO antenna structure consists of three connected square ring-shaped stubs and two rectangular slots of narrow height. These ground stubs and slots minimize the mutual coupling effect between antennas and provide high isolation. The suggested MIMO antenna functions from the 1.87 to 13.82 GHz frequency spectrum covering WLAN (2.4–2.484 GHz), UWB (3.1–10.6 GHz), and X band (8–12 GHz) with 152.32% fractional bandwidth. It sustains port isolation above 27 dB throughout the 2 to 13.82 GHz frequency band. Inside the whole working frequency band, the suggested antenna offers a tiny envelope correlation coefficient (ECC < 0.098), greater diversity gain (DG > 9.93 dB), minimum channel capacity loss (CCL < 0.32 bits/s/Hz), and slight magnitude variation in mean effective gain of antenna ports (< 0.1 dB). The recommended antenna yields a SAR level below the designated threshold (<1.6 W/kg), affirming its suitability for body-worn applications. The designed MIMO antenna structure has an overall volume of 32 × 48 × 1.5 mm³.     

A Compact Semi-circular Slot MIMO Antenna with Enhanced Isolation for Sub-6 GHz 5G WLAN Applications

In this paper, a novel compact semi-circular slot (SCS) 2 × 2 MIMO antenna is presented for 5G NR sub-6 GHz applications with high isolation. The proposed antenna consists of a semi-circular slot in ground plane, U-shaped stub, and 50-ohm microstrip feed line. The novelty of this paper are the Semi-Circular Slot acts a radiator, the port isolation  is enhanced using a simple conductor strip as a neutralization line, very compact in size, low ECC, and good impedance matching. The overall size of the proposed SCS MIMO antenna is 16 mm x 21 mm, and FR4 substrate is used with thickness of 1.6 mm. The two SCS antenna elements are separated by edge-to-edge distance of 1mm (\(=0.019\lambda _{0}\)). The proposed compact MIMO antenna design is simulated using Ansys HFSS. To validate SCS MIMO antenna, a prototype was fabricated and tested. The measured results are attained at 5.5 GHz with isolation greater than 25dB, impedance bandwidth (S11\(<-10\) dB) covers from 5.10 GHz to 5.80 GHz with return loss of ? 39.5 dB. The MIMO antenna parameters, ECC, CCL, TARC, and MEG are studied, and the values are obtained within acceptable limits. The measured and simulated antenna results are almost similar. This compact MIMO antenna is suitable for 5G communications in sub-6 GHz wifi-5 band applications.

     

4 Element compact triple band MIMO antenna for sub-6 GHz 5G wireless applications

Wireless Networks - A compact 4 element MIMO antenna operating in three Sub-6&nbsp;GHz 5G bands is proposed. The single element antenna consists of a square-shaped patch where circular and...     

一种面向5G通信的宽带8单元MIMO天线设计

提出了一种面向5G的宽带8端口多输入多输出（multiple-input multiple-output,MIMO）天线.天线单元采用多枝节单极子结构,能够激发多模态,且能覆盖多频段.同时,采用弯折结构来实现小型化,且在相邻单元之间设计T形突出地结构来提高隔离度.仿真和实测结果显示,该天线在3~7.1 GHz内回波损耗大于10 dB,在3.3~7.1 GHz内隔离度高于15 dB.因为进行了有效的去耦,天线体现出明显的辐射分集特性,天线在目标sub-6 GHz频段内的包络相关系数（envelope correlation coefficient,ECC）接近0.在一8×8 MIMO系统中,计算得到的峰值遍历信道容量为43 bps/Hz,达到传统2×2 MIMO上限值的3.74倍.该8单元MIMO天线具有良好的分集和复用能力,能满足5G通信在sub-6 GHz的高速数据传输需要.     

一种用于5G 移动通信终端的双频MIMO天线系统

为满足5G 移动通信系统对信道容量的要求,提出了一种应用于5G 移动终端的双频多输入多输出(MIMO)天线系统。它由沿移动终端两个长边垂直放置的八个天线单元组成。该天线系统可以覆盖中国工业和信息化部(MIIT)所规划的3.3 ~ 3.6 GHz 和4.8 ~ 5 GHz 两个频段,且低频段和高频段的天线效率分别高于61% 和50%。通过优化各天线的相对位置和放置方向,使得各端口之间的隔离度优于15 dB。为更好评估天线系统性能,计算了MIMO天线的包络相关系数(ECC)和信道容量(CC)。所得该MIMO 天线系统在工作频段内ECC均小于0.1,且信道容量峰值可以达到36.8 bps/ Hz。同时,制作并测量了MIMO 天线样品,测试结果与仿真结果表现出良好的一致性。     

A reconfigurable wideband MIMO antenna combines RF energy harvesting

This article introduces a novel and groundbreaking approach combining multiple-input-multiple-output (MIMO) technology with radio frequency (RF) energy harvesting. The proposed antenna consists of two semi-circular monopole antenna components, optimized with dimensions of 89 × 51.02 × 1.6 mm³, that share a common ground plane to achieve MIMO characteristics. A series of split-ring resonators on the ground plane significantly enhances the isolation between the two radiating components. Band-notched features are performed in the 3.5 GHz WiMAX and 5.5 GHz WLAN bands through modified C-shaped slots in the radiating patch and two rectangular split-ring resonators serving as parasitic devices near the feed line. The reconfiguration of band-notching is made possible by controlling the modes of the embedded PIN diodes. The two antenna elements maintain mutual coupling below −18 dB from 1.5–13 GHz, achieving an impressive 158.62% impedance bandwidth. The antenna's efficiency and gain experience significant drop, indicating effective interference suppression at the center frequencies of the notch bands, and its performance in MIMO systems is assessed through parameters including envelope correlation coefficient, port isolation, radiation patterns, efficiency, gain, and diversity gain. The simulated properties of the designed antenna closely align with the measured outcomes, demonstrating its reliability and consistency. Moreover, the article evaluates the antenna's potential for RF energy harvesting, achieving a maximum harvested energy of 4.88 V. This proposed antenna can be used in multiple applications, like wideband, band-notching MIMO, and RF energy harvesting. This proposed antenna is an efficient, reconfigurable wideband MIMO antenna with novel RF energy harvesting capability.     

A low-profile internet of things-controlled frequency reconfigurable triple band antenna for microwave sensing applications

This paper presents the design and analysis of IoT (Internet of Things) controlled frequency reconfigurable triple-band antenna for WiMAX, ISM (Industrial, Scientific, and Medical) band, and X band microwave sensing applications. The designed antenna is constructed on polyimide substrate with a limited ground plane with compact dimensions of 27.5?×?8?×?0.6 mm³. The fabricated antenna is sensing the microwave signals that fall under WiMAX, ISM, & WLAN, and X band with a tunable frequency range of 3.2–3.9, 5.1–6.5, and 8.2–12 GHz, respectively. The operating frequency bands can be tuned by PIN diodes and which will be controlled by using the IoT-based NodeMCU module. The designed antenna resonates at 3.5, 5.9, and 8.45 GHz when the PIN diodes are in ON state and resonating at 3.79, 5.8, and 10.48 GHz when PIN diodes are in OFF state. The proposed antenna has bidirectional radiation at upper-frequency bands and unidirectional at lower frequency bands with gain ranging from 2.2 to 3.25 dB. The proposed frequency reconfigurable triple-band antenna has a more than 90% radiation efficiency at all the operating frequencies in the ON state. A good similarity between the measured (Antenna measurement setup with Vector Network Analyzer) and simulated results (CST Microwave Studio) is observed. In the real-time environment, the proposed reconfigurable antenna is tested by the CDAC (Centre for Development of Advanced Computing, India) Cmote unit found its suitability to microwave sensing applications.

     

具有双陷波特性的UWB-MIMO天线

提出了一款具有双陷波特性的紧凑型超宽带多输入多输出(ultra wideband multiple-input multiple-output, UWB-MIMO)天线. 天线由两个辐射元件组成,整体尺寸为41 mm×25 mm×1.6 mm. 通过在天线的接地平面中引入两个叠加的T型结构获得良好的隔离度;同时,通过在天线上刻蚀C型槽和U型槽实现双陷波特性,有效抑制了无线局域网(wireless local area networks, WLAN)和X波段通信卫星的干扰;并从表面电流分布的角度分析了陷波原理. 实验结果表明:所设计的MIMO天线的阻抗带宽为2.8~13.4 GHz,两个陷波频带分别为4.8~5.94 GHz和6.9~8.23 GHz;在整个工作带宽内,隔离度大于15 dB. 说明MIMO天线具有良好的辐射特性、稳定的增益和较低的包络相关系数(envelope correlation coefficient, ECC)(<0.1),适用于UWB-MIMO系统应用.     

A miniaturized uniplanar MIMO antenna for n79/n46/millimeter-wave applications

This research suggests a compact uniplanar multiple-input multiple-output (MIMO) with four ports for n79/n46/millimeter-wave (mm-wave) applications. The size of the quad MIMO is only 30 × 30 × 0.8 mm³. MIMO system consists of four identical Z-shaped radiators and common ground on the same plane and no decoupling structures are used for isolation. The system covers the bandwidth of 1.9 GHz (4.4–6.3 GHz) with a mid-frequency of 5.6 GHz and also covers the high-band frequencies ranging from 18 to 30 GHz with a bandwidth of 12 GHz. The suggested quad MIMO is fabricated on an FR-4 board, and the measured outcomes are well in line with the simulated results. An isolation value of −11 dB has been achieved for mid-band frequency and −24 dB has been attained for mm-wave bands. Through the value of DG = 10 dB, ECC < 0.07, TARC < −3 dB, MEG < −5 dB, and the ratio of MEG = 1 dB, uniplanar quad MIMO shows acceptable MIMO diversity performance. The entire system was evaluated for the users' hand specific absorption rate (SAR) impacts and is within the limits. After the complete analysis of the miniature quad MIMO antenna, an 8-port, and a 16-port uniplanar MIMO are simulated for smartphone-sized dielectric substrates and the performances were examined. The suggested MIMO system provides an efficient single-layer MIMO antenna to 5G smartphones with high bandwidth and low SAR. The proposed quad MIMO systems are suitable for both the sub-6 GHz band and the mm-wave band.     

Mutual Coupling Reduction of MIMO Antenna Array Using Meta-FCRR

In order to reduce mutual coupling interference of between both adjacent antenna elements, a practical scheme for metamaterial is reported in this paper. The study shows that the permittivity and permeability of metamaterial based on fold complementary ring resonator (FCRR) can well be anastomosed in electromagnetic field. The antenna array using co-planar waveguide mode to expound the multiple input multiple output (MIMO) performance are further proposed. The results of simulated antenna array with FCRR indicate that the coupling of about 30.5 dB, 14 dB and 20.2 dB are reduced at resonance frequency (at 2.4 GHz, 6.15 GHz and 9.2 GHz). Meanwhile the experimental measure results can meet the simulation data. Additionally, the envelope correlation coefficient (ECC), diversity gain (DG), voltage standing wave ratio (VSWR) are better characteristics in contrasting to without FCRR, making the solution viable for MIMO antenna arrays.

     

Bandwidth and frequency agile MIMO antenna for cognitive vehicular communications

A reconfigurable MIMO antenna for heterogeneous vehicular networks is reported in this paper. The frequency and bandwidth characteristics of the MIMO antenna can be reconfigured to meet multi-standard and multi-frequency requirements in automobiles. The antenna element evolved from an edge-chamfered ultra-wideband (UWB) antenna operating from 2.1 to >15 GHz. The bandwidth reconfiguration is achieved through the selection of excitation paths connecting the feed and radiator. The feedline selection is performed using PIN diodes, making the antenna operate in three distinct modes, namely, UWB mode (Mode 1: 2.1–>15 GHz), industrial, scientific and medical/Internet of Things (ISM/IoT) mode (Mode 2: 2.45 GHz), and wireless local area network (WLAN) mode (Mode 3: 5–6 GHz). The feed path corresponding to Mode 2 and Mode 3 is incorporated with a suitable filtering network to shape the frequency response of the antenna based on the user's requirements. Owing to the requirement of cognitive selection of frequency bands, the frequency tunability in Mode 2 is realized using varactor diodes. The varactor-incorporated feed path reconfigures the center frequency between 2.45 and 3.5 GHz. The proposed MIMO antenna offers gain and total efficiency greater than 2.94 dBi and 76%, respectively. The prototype of the 4-port MIMO antenna is being fabricated to test its functionality in real time.     

Compact,Isolation Enhanced,Band-Notched SWB–MIMO Antenna Suited for Wireless Personal Communications

Herein, a Conductor Backed Co-Planar Waveguide fed, compact, slotted Multiple–Input–Multiple–Output or MIMO antenna having Super Wideband (SWB) response and tunable band-notching feature is presented. In addition, an improved method for cut-off frequency prediction of the antenna is formulated. A super wide frequency response from 01.21 to 34.0 GHz and notches at Wireless Local Area Networks or WLAN bands (04.92–05.83 GHz) and Worldwide Inter-operability for Microwave Access or WiMAX bands (03.30 GHz–03.70 GHz) are obtained. By fine tuning the dimensions of the Split Ring Resonator Structure introduced in the radiating element, band-notched characteristics centered at 05.50 GHz WLAN band is obtained. A second band notch having centre frequency at 03.50 GHz for the WiMAX band is obtained by the introduction of a Spiral Microstrip Defected Structure in the feeding segment. The antenna is 20?×?36?×?1 mm³ in dimension. Acceptable gain all through the functional bandwidth, excepting the notched bands makes the MIMO antenna a novel contender for SWB operations particularly for Wireless Personal Communications.