A Compact Rhombus Shaped Antenna with Extended Stubs for Ultra-Wideband Applications

Ultra-wideband (UWB) is highly preferred for short distance communication. As a result of this significance, this project targets the design of a compact UWB antennas. This paper describes a printed UWB rhombus-shaped antenna with a partial ground plane. To achieve wideband response, two stubs and a notch are incorporated at both sides of the rhombus design and ground plane respectively. To excite the antenna, a simple microstrip feed line is employed. The suggested antenna is built on a 1.6 mm thick FR4 substrate. The proposed design is very compact with overall electrical size of 0.18λ × 0.25λ (14 × 18 mm²). The rhombus shaped antenna covers frequency ranging from 3.5 to 11 GHz with 7.5 GHz impedance bandwidth. The proposed design simulated and measured bandwidths are 83.33% and 80%, respectively. Radiation pattern in terms of E-field and H-field are discussed at 4, 5.5 and 10 GHz respectively. The proposed design has 65% radiation efficiency and 1.5 dBi peak gain. The proposed design is simulated in CST (Computer Simulation Technology) simulator and the simulated design is fabricated for the measured results. The simulated and measured findings are in close resemblance. The obtained results confirm the application of the proposed design for the ultra-wide band applications.     

Super Compact UWB Monopole Antenna for Small IoT Devices

This article introduces a novel, ultrawideband (UWB) planar monopole antenna printed on Roger RT/5880 substrate in a compact size for small Internet of Things (IoT) applications. The total electrical dimensions of the proposed compact UWB antenna are 0.19 λ_o × 0.215 λ_o × 0.0196 λ_o with the overall physical sizes of 15 mm × 17 mm × 1.548 mm at the lower resonance frequency of 3.8 GHz. The planar monopole antenna is fed through the linearly tapered microstrip line on a partially structured ground plane to achieve optimum impedance matching for UWB operation. The proposed compact UWB antenna has an operation bandwidth of 9.53 GHz from 3.026 GHz up to 12.556 GHz at −10 dB return loss with a fractional bandwidth (FBW) of about 122%. The numerically computed and experimentally measured results agree well in between. A detailed time-domain analysis is additionally accomplished to verify the radiation efficiency of the proposed antenna design for the ultra-wideband signal propagation. The fabricated prototype of a compact UWB antenna exhibits an omnidirectional radiation pattern with the low peak measured gain required of 2.55 dBi at 10 GHz and promising radiation efficiency of 90%. The proposed compact planar antenna has technical potential to be utilized in UWB and IoT applications.     

Small modified monopole antenna for UWB application

In this paper, we present a novel modified printed monopole antenna (PMA) for ultra-wideband (UWB) applications. The proposed antenna consists of a truncated ground plane and radiating patch with two tapered steps, which provides wideband behaviour and relatively good matching. Moreover, the effects of a modified trapezoid-shaped slot inserted in the radiating patch, on the impedance matching and radiation behaviour is investigated. The antenna has a small area of 14 x 20 mm² and offers an impedance bandwidth as high as 100% at a centre frequency of 7.45 GHz for S₁₁ < -10 dB, which has a frequency bandwidth increment of 18% with respect to the previous similar antenna. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behaviour within the UWB frequency range.     

V-Shaped Monopole Antenna with Chichena Itzia Inspired Defected Ground Structure for UWB Applications

Due to rapid growth in wireless communication technology, higher bandwidth requirement for advance telecommunication systems, capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired. In this paper, a compact Ultra-Wideband (UWB) V-shaped monopole antenna is presented. UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape. The proposed V-shaped is designed by incorporating a rectangle, and an inverted isosceles triangle using FR4 substrate. The size of the antenna is 25 mm×26 mm×1.6 mm. The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial, Scientific, and Medical (ISM), Worldwide Interoperability for Microwave Access (WiMAX), (IEEE 802.11/HIPERLAN band, 5G sub 6 GHz) which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission (FCC) with a maximum gain of 3.83 dB. The antenna is designed in Ansys HFSS. Results for key performance parameters of the antenna are presented. The measured results are in good agreement with the simulated results. Due to flat gain, uniform group delay, omni directional radiation pattern characteristics and well-matched impedance, the proposed antenna is suitable for WiMAX, ISM and heterogeneous wireless systems.     

Metamaterial-Based Compact Antenna with Defected Ground Structure for 5G and Beyond

In this paper, a unit cell of a single-negative metamaterial structure loaded with a meander line and defected ground structure (DGS) is investigated as the principle radiating element of an antenna. The unit cell antenna causes even or odd mode resonances similar to the unit cell structure depending on the orientation of the microstrip feed used to excite the unit cell. However, the orientation which gives low-frequency resonance is considered here. The unit cell antenna is then loaded with a meander line which is parallel to the split bearing side and connects the other two sides orthogonal to the split bearing side. This modified structure excites another mode of resonance at high frequency when a meander line defect is loaded on the metallic ground plane. Specific parameters of the meander line structure, the DGS shape, and the unit cell are optimized to place these two resonances at different frequencies with proper frequency intervals to enhance the bandwidth. Finally, the feed is placed in an offset position for better impedance matching without affecting the bandwidth The compact dimension of the antenna is 0.25 λL × 0.23 λL × 0.02 λL, where λL is the free space wavelength with respect to the center frequency of the impedance bandwidth. The proposed antenna is fabricated and measured. Experimental results reveal that the modified design gives monopole like radiation patterns which achieves a fractional operating bandwidth of 26.6%, from 3.26 to 4.26 GHz for |S11|<−10 dB and a pick gain of 1.26 dBi is realized. In addition, the simulated and measured cross-polarization levels are both less than −15 dB in the horizontal plane.     

Frequency Reconfigurable Antenna for Portable Wireless Applications

In this paper, the design and experimental evaluation of a hexagonal-shaped coplanar waveguide (CPW)-feed frequency reconfigurable antenna is presented using flame retardant (FR)-4 substrate with size of 37 × 35 × 1.6 mm³. The antenna is made tunable to three different modes through the status of two pin diodes to operate in four distinct frequency bands, i.e., 2.45 GHz wireless fidelity (Wi-Fi) in MODE 1, 3.3 GHz (5G sub-6 GHz band) in MODE 2, 2.1 GHz (3G Long Term Evolution (LTE)-advanced) and 3.50 GHz Worldwide Interoperability for Microwave Access (WiMAX) in MODE 3. The optimization through simulation modeling shows that the proposed antenna can provide adequate gain (1.44~2.2 dB), sufficient bandwidth (200~920 MHz) and high radiation efficiency (80%~95%) in the four resonating frequency bands. Voltage standing wave ratio (VSWR) < 1.5 is achieved for all bands with properly matched characteristics of the antenna. To validate the simulation results, fabrication of the proposed optimized design is performed, and experimental analysis is found to be in a considerable amount of agreement. Due to its reasonably small size and support of multiple frequency bands operation, the proposed antenna can support portable devices for handheld 5G and Wireless LAN (WLAN) applications.     

CPW-fed ultra wideband slot antenna with arc-shaped stub

An ultra wideband coplanar waveguide (CPW) fed slot antenna is presented. A rectangular slot antenna is excited by a 50-CPW with an arc-shaped tuning stub. For the proposed antenna, the 210 dB return loss bandwidth could reach 15.6 GHz (3.7-19.3 GHz), which is about 135% with respect to the centre frequency of 11.5 GHz. Details of the antenna design, simulation and measured results on the return loss and the E-and H-plane radiation patterns of the proposed antenna are presented.     

A Novel Compact Highly Isolated UWB MIMO Antenna with WLAN Notch

This paper presents a compact Multiple Input Multiple Output (MIMO) antenna with WLAN band notch for Ultra-Wideband (UWB) applications. The antenna is designed on 0.8 mm thick low-cost FR-4 substrate having a compact size of 22 mm × 30 mm. The proposed antenna comprises of two monopole patches on the top layer of substrate while having a shared ground on its bottom layer. The mutual coupling between adjacent patches has been reduced by using a novel stub with shared ground structure. The stub consists of complementary rectangular slots that disturb the surface current direction and thus result in reducing mutual coupling between two ports. A slot is etched in the radiating patch for WLAN band notch. The slot is used to suppress frequencies ranging from 5.1 to 5.9 GHz. The results show that the proposed antenna has a very good impedance bandwidth of |S11| < −10 dB within the frequency band from 3.1–14 GHz. A low mutual coupling of less than −23 dB is achieved within the entire UWB band. Furthermore, the antenna has a peak gain of 5.8 dB, low ECC < 0.002 and high Diversity Gain (DG > 9.98).     

Gain-Enhanced Metamaterial Based Antenna for 5G Communication Standards

Metamaterial surfaces play a vital role to achieve the surface waves suppression and in-phase reflection, in order to improve the antenna performance. In this paper, the performance comparison of a fifth generation (5G) antenna design is analyzed and compared with a metamaterial-based antenna for 5G communication system applications. Metamaterial surface is utilized as a reflector due to its in-phase reflection characteristic and high-impedance nature to improve the gain of an antenna. As conventional conducting ground plane does not give enough surface waves suppression which affects the antenna performance in terms of efficiency and gain etc. These factors are well considered in this work and improved by using the metamaterial surface. The radiating element of the proposed metamaterial based antenna is made up of copper material which is backed by the substrate, i.e., Rogers-4003 with a standard thickness, loss tangent and a relative permittivity of 1.524 mm, 0.0027 and 3.55, correspondingly. The proposed antenna with and without metamaterial surface operates at the central frequency of 3.32 GHz and 3.60 GHz, correspondingly. The traditional antenna yields a boresight gain of 2.76 dB which is further improved to 6.26 dB, using the metamaterial surface. The radiation efficiency of the proposed metamaterial-based 5G antenna is above 85% at the desired central frequency.     

Reconfigurable Compact Wideband Circularly Polarised Dielectric Resonator Antenna for Wireless Applications

In this work, a novel compact wideband reconfigurable circularly polarised (CP) dielectric resonator antenna (DRA) is presented. The L-shaped Dielectric resonator antenna is excited by an inverted question mark shaped feed. This arrangement of feed-line helps to generate two orthogonal modes inside the DR, which makes the design circularly polarised. A thin micro-strip line placed on the defected ground plane not only helps to generate a wideband response but also assist in the positioning of the two diode switches. These switches located at the left and right of the micro-strip line helps in performing two switching operations. The novel compact design offers the reconfigurability between 2.9–3.8 GHz which can be used for different important wireless applications. For the switching operation I, the achieved impedance bandwidth is 24% while axial ratio bandwidth (ARBW) is 42%. For this switching state, the design has 100% CP performance. Similarly, the switching operation II achieves 60% impedance bandwidth and 58.88% ARBW with 76.36% CP performance. The proposed design has a maximum measured gain of 3.4 dBi and 93% radiation efficiency. The proposed design is novel in terms of compactness and performance parameters. The prototype is fabricated for the performance analysis which shows that the simulated and measured results are in close agreement.     

Multilayer bandstop filter for ultra wideband systems

A multilayer broadside-coupled microstrip-slot-microstrip structure is used to design a bandstop filter with a wide passband for ultra wideband (UWB) applications. The design procedure for the proposed filter is based on the conformal mapping technique and the even- and odd-mode analysis. The theoretical analysis indicates that value of the coupling factor between the top and bottom layers of the structure can be used to control the width of the stopband, whereas centre of that band can be controlled by the length of the coupled structure. To limit the passband of the proposed bandstop filter to 3.1 ?10.6 GHz, which is the specified bandwidth for UWB systems, a broadside-coupled bandpass filter is integrated with the proposed device. The simulated and measured results show that the proposed device achieve ,0.5 dB insertion loss across most of the passband and .20 dB insertion loss at the stopband. The device also shows a flat group delay across the passband with ,0.15 ns peak-to-peak variation. Hence, it is a suitable choice for the UWB systems that require a distortionless operation.     

Compact wideband Koch fractal printed slot antenna

A compact wideband printed slot antenna, suitable for wireless local area network (WLAN) and satisfying the worldwide interoperability for microwave access (WiMAX) applications, is proposed here. The antenna is microstrip-fed and its structure is based on Koch fractal geometry where the resonance frequency of a conventional triangular slot antenna is lowered by applying Koch iterations. The antenna size inclusive of the ground plane is compact and has a wide operating bandwidth. The proposed second iteration Koch slot antenna operates from 2.33 to 6.19 GHz covering the 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands. The antenna exhibits omnidirectional radiation coverage with a gain better than 2.0 dBi in the entire operating band. Design equations for the proposed antenna are developed and their validity is confirmed on different substrates and for different slot sizes.     

A Compact 28 GHz Millimeter Wave Antenna for Future Wireless Communication

This article presents a novel modified chuck wagon dinner bell shaped millimeter wave (mm-wave) antenna at 28 GHz. The proposed design has ultra-thin Rogers 5880 substrate with relative permittivity of 2.2. The design consists of T shaped resonating elements and two open ended side stubs. The desired 28 GHz frequency response is achieved by careful parametric modeling of the proposed structure. The maximum achieved single element gain at the desired resonance frequency is 3.45 dBi. The efficiency of the proposed design over the operating band is more than 88%. The impedance bandwidth achieved for −10 dB reference value is nearly 2.9 GHz. The proposed antenna is transformed into four element linear array which increases the gain up to 10.5 dBi. The fabricated prototype is tested for the measured results. It is observed that measured results closely match the simulated results. By considering its simple structure and focused radiation patterns, the proposed design is well suited for IoT (Internet of Things), mmWave microwave sensing, 5G and future RF (Radio Frequency) front-ends.     

Zero-Index Metamaterial Superstrates UWB Antenna for Microwave ImagingDetection

Metamaterials (MTM) can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice. Note that the antenna is the element for realizing a microwave imaging (MWI) system since it is where signal transmission and absorption occur. Ultra-Wideband (UWB) antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna. The lack of conventional head imaging techniques, for instance, Magnetic Resonance Imaging (MRI) and Computerized Tomography (CT)-scan, has been demonstrated in the paper focusing on the point of failure of these techniques for prompt diagnosis and portable systems. Furthermore, the importance of MWI has been addressed elaborately to portray its effectiveness and aptness for a primary tumor diagnosis. Other than that, MTM element designs have been discussed thoroughly based on their performances towards the contributions to the better image resolution of MWI with detailed reasonings. This paper proposes the novel design of a Zeroindex Split Ring Resonator (SRR) MTM element superstrate with a UWB antenna implemented in MWI systems for detecting tumor. The novel design of the MTM enables the realization of a high gain of a superstrate UWB antenna with the highest gain of 5.70 dB. Besides that, the MTM imitates the conduct of the zeroreflection phase on the resonance frequency, which does not exist. An antenna with an MTM unit is of a 7 × 4 and 10 × 5 Zero-index SRR MTM element that acts as a superstrate plane to the antenna. Apart from that, Rogers (RT5880) substrate material is employed to fabricate the designed MTM unit cell, with the following characteristics: 0.51 mm thickness, the loss tangent of 0.02, as well as the relative permittivity of 2.2, with Computer Simulation Technology (CST) performing the simulation and design. Both MTM unit cells of 7 × 4 and 10 × 5 attained 0° with respect to the reflection phase at the 2.70 GHz frequency band. The first design, MTM Antenna Design 1, consists of a 7 × 4 MTM unit cell that observed a rise of 5.70 dB with a return loss (S11) −20.007dB at 2.70 GHz frequency. The second design, MTM Antenna Design 2, consists of 10 × 5 MTM unit cells that recorded a gain of 5.66 dB, having the return loss (S11) −19.734 dB at 2.70 GHz frequency. Comparing these two MTM elements superstrates with the antenna, one can notice that the 7 × 4 MTM element shape has a low number of the unit cell with high gain and is a better choice than the 10 × 5 MTM element in realizing MTM element superstrates antenna for MWI.     

Compact coplanar waveguide-fed ultra-wideband monopole-like slot antenna

A simple and compact coplanar waveguide (CPW)-fed ultra-wideband (UWB) monopole-like slot antenna is presented. The proposed antenna comprises a monopole-like slot and a CPW fork-shaped feeding structure, which is etched onto an FR4 printed circuit board (PCB) with an overall size of 26 mm x 29 mm x 1.5 mm. The simulation and experiment show that the proposed antenna achieves good impedance matching, consistent gain, stable radiation patterns and consistent group delay over an operating bandwidth of 2.7?12.4 GHz (128.5%). Furthermore, through adding two more grounded open-circuited stubs, the proposed antenna design features band-notched characteristic in the band of 5?6 GHz while maintaining the desirable performance over lower/upper UWB bands of 3.1?4.85 GHz/6.2?9.7 GHz.     

一种改善超宽带MIMO天线隔离性能的方法

多输入多输出(Multiple-InputMultiple-Output,MIMO)技术是现代通信技术的发展趋势,为移动通信的迅速更迭提供了极大支持.设计了一种二端口的超宽带MIMO天线,其-10 dB阻抗带宽从3.3 GHz扩展到9.1 GHz.通过在天线接地板上蚀刻一条宽缝隙,并在其中添加音叉型枝节,改善了超宽带M...     

新型古币形超宽带分形印刷天线的设计

共面波导和分形结构结合应用,在展宽天线带宽方面具有独特优势.提出了一种新型古币形超宽带分形天线,采用共面波导馈电,并加载分形缝隙,天线的阻抗带宽大幅提高.给出了天线的表面电流、回波损耗、方向图和增益结果.对3阶分形天线进行了加工与测试,测试结果表明,天线带宽达到2.6～16 GHz,带宽比大于6:1.仿真结果与测试结果基本吻合,为超宽带小型化天线的设计提供了新的思路．     

Wideband circularly polarised slot antenna

A wideband circularly polarised slot antenna is presented. The slot antenna is fed by four microstrip line feeds orientated to have relative phases of 0deg, 90deg, 180deg and 270deg using a feed network comprising a pair of broadband 90deg hybrid. The proposed antenna delivers measured and simulated impedance bandwidths of 77.8% (1.02-2.32 GHz) and 89.1% (1.02-2.66 GHz), respectively, for standing wave ratio (SWR) < 2, measured and simulated axial-ratio bandwidths of 88.9% (1-2.6 GHz) and 81% (1.1-2.6 GHz), respectively, for axial ratio < 3 dB and measured and simulated gain bandwidths of 33% (1.5-2.1 GHz) and 27% (1.6-2.1 GHz), respectively, for gain >3 dB. A good agreement is observed between simulation and measurement.     

Ultra-wideband antenna with improved gain characteristics

A ultra-wideband (UWB) antenna with improved gain characteristics is proposed. With the improvements, it is discussed in terms of the band notch and enhanced radiation patterns. Shaping the return loss as an approach in order to achieve these characteristics is introduced and a multi-resonant dipole structure is designed and experimented in frequency and time domains. The proposed UWB antenna provides the band notch with a sharp slope and improved gain deviation on azimuth plane for the UWB communication.     

Compact wideband antenna for wireless communications

A compact dual-band printed wire antenna for applications in wireless communications is presented. An additional shorted parasitic element to the F-shaped wire antenna is introduced to achieve a dual-band operation. As an example, a new antenna was designed and fabricated for wireless local area network applications that operate in the 2.4 and 5.2/5.8 GHz bands. The prototyped antenna offered two separate measured impedance bandwidths of 700 (2.35-3.05 GHz) and 2150 MHz (3.95-6.1 GHz), for a return loss less than -10 dB. A measured antenna gain of 1.78-1.9 dBi was observed across the lower band, whereas a measured antenna gain of 3.9-4.4 dBi was observed across the upper band. The measured radiation patterns were stable across the passband