Ultra-wideband Bandwidth Research Articles

A novel ultra-wideband rasorber based on triple lossy layers

Abstract By surpassing the limitations of transmission efficiency found in traditional double-lossy-layers rasorbers, a novel rasorber with three distinct lossy absorption layers is presented, offering low insertion loss and ultra-wideband bandwidth. Compared to conventional rasorbers which have non-negligible insertion loss and large thickness, our design extends the bandwidth in the higher frequency band without increasing thickness, while maintaining high transmission efficiency. To further broaden the absorption band, an additional lossy layer resonating at lower frequency band, with high transmission above the resonance frequency was incorporated into the previous design. The composite structure is developed by the equivalent circuit model (ECM) whose results are in accord well with the simulation results. The simulated results demonstrate that an insertion loss of 0.37 dB at 10 GHz, and a 159.5% 10 dB reflection reduction bandwidth from 2.04 to 18.05 GHz are attained under normal incidence. A manufactured specimen of the proposed structure is measured to validate our design.

Gain enhancement of compact CPW‐Fed ultra‐wideband antenna using an FSS reflector

AbstractIn this paper, an enhancement gain of compact CPW‐Fed antenna using a single layer frequency selective surfaces (FSSs) reflector for ultra‐wideband (UWB) applications is presented. A hexagonal CPW‐Fed antenna with a size of 30 × 30 mm2 is realized to provide a UWB bandwidth operation. In this study, a novel design of an FSS unit cell with reduction and a small size of 8 × 8 mm2 is proposed. It allows one to achieve a UWB band‐stop response between 3 and 11.5 GHz. The FSS reflector has 7 × 7 units with a total size of 56 × 56 mm2. This reflector is placed below the antenna at a distance of 20 mm. The main objective of this contribution is to improve the gain level of the antenna, where the proposed antenna achieves an improvement of realized gain of 6.2 dBi with increasing from 2.2 to 8.4 dBi. The antenna became more directive after the integration of the FSS reflector with a directional radiation pattern. The numerical and experimental results are in good concordance with the simulated one. This study is performed in terms of voltage standing wave ratio, radiation pattern, realized gain, and radiation efficiency.

Cascaded Frequency Selective Surfaces with Matryoshka Geometry for Ultra-Wideband Bandwidth

The purpose of this paper is to present cascaded frequency selective surfaces (FSSs) with matryoshka geometry to increase the effective bandwidth. We carry out an analysis of the influence of the spacing between the surfaces on the FSSs frequency response. The application involves a two-layer cascaded FSS, one as a band-stop filter with a matryoshka geometry and the other as a band-pass filter with inverted or negative matryoshka geometry. With this framework, it is possible to extend an ultra-wideband (UWB) of a bandwidth up to 2 GHz in the 1.8 GHz to 3.8 GHz range with just two layers and an air gap of 12 mm, in addition to a bandwidth of 2 GHz to 3.2 GHz with a smaller 4 mm gap between layers.

Exploiting Anchor Links for NLOS Combating in UWB Localization

UWB (Ultra-wideband) has been shown to be a promising technology to provide accurate positioning for the Internet of Things. However, its performance significantly degrades in practice due to Non-Line-Of-Sight (NLOS) issues. Various approaches have implicitly or explicitly explored the problem. In this article, we propose RefLoc , which leverages the unique benefits of UWB to address the NLOS problem. While we find that NLOS links can vary significantly in the same environment, LOS links possess similar features that can be captured by the high bandwidth of UWB. Specifically, the high-level idea of RefLoc is to first identify links among anchors with known positions and leverage those links as references for tag link identification. To achieve this, we address the practical challenges of deriving anchor link status, extracting qualified link features, and inferring tag links with anchor links. We implement RefLoc on commercial hardware and conduct extensive experiments in different environments. The evaluation results show that RefLoc achieves an average NLOS identification accuracy of 96% in various environments, improving the state-of-the-art by 10%, and reduces 80% localization error with little overhead.

Hexagonal ring‐inspired antenna for UWB and V2X applications

AbstractThis paper presents a small‐sized, planar antenna fabrication for ultra‐wideband (UWB) and vehicle‐to‐everything (V2X) applications. The design is inspired by a hexagonal ring, providing an UWB bandwidth of 16.61 GHz (from 3.33 to 19.94 GHz) and a fractional bandwidth of 142.75%. A suitably placed inverted‐U slot in the feed line helps in achieving the WLAN notch band (from 5.04 to 6.01 GHz). The overall design footprint is 0.17 × 0.23 λ02 in size, provides stable radiation characteristics, and a gain of 4 dBi in the pass‐band with stable time‐domain performance. The proposed antenna also covers both 3.5 GHz (LTE‐42 Band) and 5.9 GHz (DSRC Band), therefore being suitable for modern UWB frontends and V2X communication.

Optimization of Ultra-Wideband bandwidth for the design of microstrip monopole antennas using Defected Ground Structure and star-shaped patche

This paper presents a design of a monopole microstrip antenna developed to support Ultra-wideband (3.1 -10.6 GHz) technology wireless communication systems. An antenna with minimalist dimensions operates on C-Band (wireless LAN) and X-Band (downlink satellite) frequencies. The antenna profile has a star shape patch on the top side and the use of the Defected Ground Structure (DGS) technique on the bottom side on RT DUROID substrate media. The design uses a simulation method using software and measurement tests on antenna prototypes to obtain parameters and antenna performance characteristics. The results of the measurement test, the bandwidth return loss < -10 dB has a difference of 40% (absolute) and 0.7% (Fractional) lower than the simulation when VSWR < 2. The radiation pattern forms an omnidirectional with a maximum directivity (Gain) of 5.18dBi with polarization vertical. Overall, the UWB monopole antenna design results have a low profile, compact, small size, and support mobile communication devices.

Highly selective multiple-notched UWB-MIMO antenna with low correlation using an innovative parasitic decoupling structure

In ultra-wideband (UWB) communications, highly selective notch bands are required to avoid interference with other licensed bands. This study presents a highly selective triple-notch UWB-MIMO antenna, which consists of a four-radiating patch antenna and an isolator. The single-element antenna consists of a radiating patch, substrate, ground plane, electromagnetic bandgap (EBG) structures, and split ring resonators (SRR). To achieve the designated UWB bandwidth, the lower edges of the antenna patch are cut by a quarter-circle radius. The three sharp notches are achieved by utilizing four EBGs and two SRRs at the back of the antenna. The notch bandwidth can also be controlled by changing the parameters such as the width and length of the EBG structure and SRR. The single antenna is then translated into 4-port MIMO systems. The high correlation between elements is reduced by inserting a unique parasitic decoupling structure. The decoupling structure is designed in a way that reduces the mutual coupling in all passbands. The proposed antenna offers a (|S11| < –10 dB) of 3.1 – 11.8 GHz impedance bandwidth. The proposed MIMO antenna having an overall size of 54 × 54 × 1.52 mm3 is fabricated to verify the simulation results. The MIMO antenna shows exceptional diversity properties, including better isolation between unit elements of MIMO antenna (>20 dB), a diversity gain (DG) very close to 10 dB (>9.99 dB), an envelope correlation coefficient which is less than 0.001, and suitable mean effective gain is also in the defined range. The suggested parasitic element UWB – MIMO antenna thus supports its suitability for use in UWB communication networks.

Aerodynamic slotted SIW-to-MS line transition using mitered end taper for satellite and RADAR communications

PurposeThis paper aims to present the design development and measurement of two aerodynamic slotted X-bands back-to-back planer substrate-integrated rectangular waveguide (SIRWG/SIW) to Microstrip (MS) line transition for satellite and RADAR applications. It facilitates the realization of nonplanar (waveguide-based) circuits into planar form for easy integration with other planar (microstrip) devices, circuits and systems. This paper describes the design of a SIW to microstrip transition. The transition is broadband covering the frequency range of 8–12 GHz. The design and interconnection of microwave components like filters, power dividers, resonators, satellite dishes, sensors, transmitters and transponders are further aided by these transitions. A common planar interconnect is designed with better reflection coefficient/return loss (RL) (S11/S22 ≤ 10 dB), transmission coefficient/insertion loss (IL) (S12/S21: 0–3.0 dB) and ultra-wideband bandwidth on low profile FR-4 substrate for X-band and Ku-band functioning to interconnect modern era MIC/MMIC circuits, components and devices.Design/methodology/approachTwo series of metal via (6 via/row) have been used so that all surface current and electric field vectors are confined within the metallic via-wall in SIW length. Introduced aerodynamic slots in tapered portions achieve excellent impedance matching and tapered junctions with SIW are mitered for fine tuning to achieve minimum reflections and improved transmissions at X-band center frequency.FindingsUsing this method, the measured IL and RLs are found in concord with simulated results in full X-band (8.22–12.4 GHz). RLC T-equivalent and p-equivalent electrical circuits of the proposed design are presented at the end.Practical implicationsThe measurement of the prototype has been carried out by an available low-cost X-band microwave bench and with a Keysight E4416A power meter in the microwave laboratory.Originality/valueThe transition is fabricated on FR-4 substrate with compact size 14 mm × 21.35 mm × 1.6 mm and hence economical with IL lie within limits 0.6–1 dB and RL is lower than −10 dB in bandwidth 7.05–17.10 GHz. Because of such outstanding fractional bandwidth (FBW: 100.5%), the transition could also be useful for Ku-band with IL close to 1.6 dB.

A parametric study on strawberry radiated shaped monopole antenna for ultrawide-band applications

This article gives a parametric study on strawberry-shaped monopole antennas for ultra-wideband (UWB) systems. The antenna design consisted of three different parametric design steps to structure the strawberry radiated monopole antenna. The scheduled strawberry monopole antenna was simulated on an FR4 substrate in a low profile for UWB applications. The total physical dimension is 26 mm×26 mm×1.6 mm, corresponding to the centre frequency of 7.5 GHz. The strawberry antenna is fed via a coplanar waveguide (CPW) to attain the best impedance matching for UWB systems. The presented monopole antenna has an impedance UWB bandwidth of 11.0 GHz from 2.6 GHz up to 13.6 GHz at −10 dB return loss. The simulated UWB strawberry monopole antenna displays an omnidirectional radiation behaviour with a simulated gain of 7.3 dB at 13.6 GHz, a directivity of 7.5 dBi at 13.6 GHz and favourable radiation efficiency of 97%. The proposed monopole UWB strawberry antenna has the technological possibility to be used for UWB applications.

An Elliptical-Shaped Dual-Band UWB Notch Antenna for Wireless Applications

This paper discusses an elliptical ultrawideband (UWB) antenna and a dual-band UWB notch antenna. To achieve a UWB bandwidth, two corner cuts are etched into the rectangular slot on the partial ground plane. An inverted-U-shaped and conductor-shaped resonator are utilized to achieve dual-band notch characteristics on a partial ground plane. The suggested antenna has an overall dimension of 24×32 mm2. The suggested UWB antenna has a gain of 4.9 dB, a bandwidth of 2.5–11 GHz, a linear phase response, a group delay of less than 1 ns, and a steady radiation pattern. The suggested UWB notch rejects WLAN and ITU bands from 5.2–5.7 GHz and 7.2–8.5 GHz, respectively, with an impedance bandwidth of 2.5–11 GHz. The UWB notch antenna features a linear phase, a group delay of less than 1 ns, and a stable radiation pattern.

Terahertz-Band Channel and Beam Split Estimation via Array Perturbation Model

For the demonstration of ultra-wideband bandwidth and pencil-beamforming, the terahertz (THz)-band has been envisioned as one of the key enabling technologies for the sixth generation networks. However, the acquisition of the THz channel entails several unique challenges such as severe path loss and beam-split. Prior works usually employ ultra-massive arrays and additional hardware components comprised of time-delayers to compensate for these loses. In order to provide a cost-effective solution, this paper introduces a sparse-Bayesian-learning (SBL) technique for joint channel and beam-split estimation. Specifically, we first model the beam-split as an array perturbation inspired from array signal processing. Next, a low-complexity approach is developed by exploiting the line-of-sight-dominant feature of THz channel to reduce the computational complexity involved in the proposed SBL technique for channel estimation (SBCE). Additionally, based on federated-learning, we implement a model-free technique to the proposed model-based SBCE solution. Further to that, we examine the near-field considerations of THz channel, and introduce the range-dependent near-field beam-split. The theoretical performance bounds, i.e., Cram\'er-Rao lower bounds, are derived both for near- and far-field parameters, e.g., user directions, beam-split and ranges. Numerical simulations demonstrate that SBCE outperforms the existing approaches and exhibits lower hardware cost.

Design of a Novel Circularly Polarized MIMO Antenna with Enhanced Isolation for Ultra-wideband Communication

In this paper, we propose a circularly polarized (CP) ultra-wideband (UWB) MIMO antenna. Compared with common linearly polarized (LP) UWB antenna, the proposed antenna can excite circular polarization (CP) mode for WLAN communication and its impedance bandwidth can also fully cover UWB spectrum. It consists of identical circularly polarized antennas. Each unit adopts circular monopole with extended orthogonal rectangle patch to realize broadband and symmetrical rectangular ground with slot in the diagonal of each antenna unit to achieve circular polarization for WLAN band. It has a very compact size and the dimension is 25 × 51 × 0.8 mm3. The impedance bandwidth of the proposed antenna is from 3.1 GHz to 13.5 GHz, with average gain of 4 dBi, fully covering UWB bandwidth and enhanced by 38%. At the same time, circular polarization is achieved by embedding two symmetrical rectangular slot structures in the two opposite corners of every antenna unit. The extended orthogonal rectangle patch is introduced to enhance impedance bandwidth and broaden axial ratio (AR) bandwidth. The measured 3 dB axial ratio (AR) bandwidth is 1.8 GHz (4.7-6.5 GHz), fully covering WLAN band. Meanwhile, the slit slot between antenna units and rectangular openings are introduced to achieve high isolation. The proposed antenna keeps ECC (envelope correlation coefficient) below 0.01, which showing good isolation and diversity characteristics. The proposed antenna can simultaneously operate in the UWB spectrum and exhibit circularly polarized (CP) radiation characteristic in WLAN.

Ultra-Wideband Full-Metal Planar Array Antenna With a Combination of Ridge Gap Waveguide and E-Plane Groove Gap Waveguide

An ultrawideband (UWB) full-metal planar array antenna based on a combination of ridge gap waveguide (RGW) and E-plane groove gap waveguide (E-GGW) is presented for millimeter-wave (mmWave) applications. First, the radiation element of a double-step double-ridged slot structure is proposed and designed. By removing the vertical walls of the cavity in the H-plane, the impedance matching characteristics presents a UWB bandwidth of 53%. Second, a UWB double-layer feeding network is achieved by combining RGWs and double-side-pin E-GGWs for the radiation elements. Finally, an 8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 8 full-metal planar array antenna with the presented elements and network is designed, prototyped, and measured. The measured results agree well with the simulated results. The proposed antenna provides an impedance matching bandwidth ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert &lt; -10$ </tex-math></inline-formula> dB) of 46.8% from 18.8 to 30.3 GHz. The maximum gain is 27.7 dBi at 27 GHz and a stable gain of 26 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm ~1.7$ </tex-math></inline-formula> dBi is obtained over the operation band.

Design and analysis of multilayer multipermittivity circularly polarized DRA for ultra‐wideband applications

AbstractIn this article, a circularly polarized dielectric resonator antenna is designed with ultra‐wideband (UWB) features. The structure comprises a cross‐shaped multilayer multipermittivity (MLMP) rectangular dielectric resonator, a chimney‐shaped patch, and an air gap between the ground plane and the dielectric resonator (DR). To obtain the UWB, the upper layer of DR is rotated around the z‐axis. The proposed antenna has measured UWB bandwidth of around 179.4% (0.8–14.8 GHz) below −10 dB, with three bands of 3 dB axial ratio bandwidth of 97.8% (1.0–2.8 GHz), 38% (5.65–8.3 GHz), and 20% (12.1–14.8 GHz), respectively. The average gain of the proposed antenna is 5.64 dBi, which is consistent with the hardware measurements. The proposed antenna is suitable for covering the ultra high frequency (UHF) to Ku microwave frequency band.

Dodecagon-Shaped Frequency Reconfigurable Antenna Practically Loaded with 3-Delta Structures for ISM Band and Wireless Applications

An edge fed, dual band, quarter-wave transformer coupled, monopole, ultra-wideband (UWB), dodecagon-shaped miniaturized frequency reconfigurable antenna for ISM and wireless applications is designed, analysed and investigated. The impedance transformer is utilized in the structure for impedance matching and hence results in lower reflection coefficient values. The antenna uses defected ground structure (DGS) in the bottom and radiating patch that is practically loaded with three numbers of delta structures. The use of DGS reduces the value of gain and provides ultra-wideband bandwidth across the designed frequency. The addition of three delta structures in the patch improves the value of gain. Miniaturizing in the size of the antenna has been achieved by reducing the ground along the width that led to a total 30.41% size reduction in the fundamental circular patch antenna. The antenna exhibits two bands 1.82–3.61 GHz and 5.24–12.43 GHz thus antenna is suitable for ISM band, PCS, 5G, Wi-Fi/WiMAX/WLAN and other wireless applications. The fabricated antenna is frequency reconfigured by utilizing the switching property of four numbers of PIN diodes (BAP64-02V). Frequency reconfigurable antenna is used flexibly and versatile for various microwave applications based on the switching conditions (more than eight digital combination cases) of PIN diodes. The prototype measured results provide good agreements with the simulated reflection coefficients values in some mode of operations. Antenna radiating patch and ground is etched on FR-4 substrate of dimension 52 mm × 59 mm × 1.6 mm using printed circuit board technology.

ULoc

A myriad of IoT applications, ranging from tracking assets in hospitals, logistics, and construction industries to indoor tracking in large indoor spaces, demand centimeter-accurate localization that is robust to blockages from hands, furniture, or other occlusions in the environment. With this need, in the recent past, Ultra Wide Band (UWB) based localization and tracking has become popular. Its popularity is driven by its proposed high bandwidth and protocol specifically designed for localization of specialized "tags". This high bandwidth of UWB provides a fine resolution of the time-of-travel of the signal that can be translated to the location of the tag with centimeter-grade accuracy in a controlled environment. Unfortunately, we find that high latency and high-power consumption of these time-of-travel methods are the major culprits which prevent such a system from deploying multiple tags in the environment. Thus, we developed ULoc, a scalable, low-power, and cm-accurate UWB localization and tracking system. In ULoc, we custom build a multi-antenna UWB anchor that enables azimuth and polar angle of arrival (henceforth shortened to '3D-AoA') measurements, with just the reception of a single packet from the tag. By combining multiple UWB anchors, ULoc can localize the tag in 3D space. The single-packet location estimation reduces the latency of the entire system by at least 3×, as compared with state of art multi-packet UWB localization protocols, making UWB based localization scalable. ULoc's design also reduces the power consumption per location estimate at the tag by 9×, as compared to state-of-art time-of-travel algorithms. We further develop a novel 3D-AoA based 3D localization that shows a stationary localization accuracy of 3.6 cm which is 1.8× better than the state-of-the-art two-way ranging (TWR) systems. We further developed a temporal tracking system that achieves a tracking accuracy of 10 cm in mobile conditions which is 4.3× better than the state-of-the-art TWR systems.

Design and analysis of helical antenna for short-range ultra-high-speed THz wireless applications

Terahertz (THz) band antennas are becoming a more attractive field of research due to the wide range of applications and advantages in future communications. A design of a helical antenna for ultra-high-speed THz wireless applications over short-range communication is proposed. The proposed antenna provides ultra-wideband bandwidth, high directional gain, low-cost, and circular polarization features. The proposed antenna design shows interesting results with respect to a fractional bandwidth of 65.40% and impedance bandwidth of 0.50992 THz for VSWR ≤2. Simulation results also show that maximum directivity, its realized gain and radiation efficiency of the proposed antenna is 12.1 dBi, 11.8 dBi, and 95.31% at 1 THz, respectively. The proposed antenna is performed, simulated and analysed by using the commercial CST microwave studio software. The simulation results display noticeable improvements in terms of fractional bandwidth, directivity and gain compared with other related-works. The proposed antenna can be used for several THz wireless applications, mainly for ultra-high-speed THz wireless applications over a short-range communication, such as Wi-Fi, base station, and medical applications.

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

In this article, the design, fabrication, testing, and packaging of a Substrate Integrated Waveguide(SIW) based polarization diversity 3D eight-port Ultra-Wideband (UWB) MIMO antenna introduced with dual-band notch characteristics for vehicular communication applications. In this proposed UWB MIMO design, we employed a SIW technique to achieve UWB bandwidth with a compact size of 60 × 60 mm3. The SIW based metallic via integrated with L-shaped parasitic slot stub and radiator to notch the WLAN and L-shaped stub connected at the ground plane to notch the X-band. The SIW based radiators are placed in the vertical and horizontal plane to realize the polarization diversity. In addition to providing polarization diversity, the antenna’s direction also contributes a reliable link with communication equipment. The antenna performance metrics such as reflection coefficient(Sii), mutual coupling(Sij), the peak gain, radiation pattern, radiation efficiency, Envelope Correlation Coefficient (ECC), Diversity Gain (DG), Total Active Reflection Coefficient (TARC), Channel Capacity Loss (CCL) and Mean Effective Gain(MEG). The proposed 3D antenna performance analyzed when mounted inside the different types of housing. Hence, the proposed polarization diversity antenna is suitable for vehicular communication applications.

Compact stepped slot antenna for ultra-wideband applications

AbstractIn this paper, a compact stepped slot antenna for ultra-wideband (UWB) applications is proposed. A very small size and UWB bandwidth operation are achieved by integrating a stepped slot in the back side of the antenna. This stepped slot is excited by using a 50 Ω-feed line in the top side of the antenna. The antenna is characterized by an impedance bandwidth between 3.05 GHz and more than 12 GHz. The dimensions of the antenna are 17 mm × 8 mm × 1.27 mm, which leads to the most compact size compared with other works in the literature. The integrated stepped slot is divided into additional elementary slots, where each elementary slot has a matching point. Adding these elementary slots allows to increase further the operating bandwidth. The radiation pattern of the compact stepped slot antenna is omnidirectional in the H-plane and bidirectional in the E-plane. The measurement results agree well with the simulated ones in terms of impedance matching and radiation pattern.

Design and Analysis of a Compact UWB-MIMO Antenna with Improved Isolation for UWB/WLAN Applications

For space limited ultra-wideband (UWB) communication system, the small foot print of the multi-input multi-output (MIMO) antenna is highly desirable. A significant subject of the investigation is the creation of a small MIMO antenna with enhanced isolation and large operating bandwidth. To accomplish this object, a compact size two-port UWB-MIMO antenna is presented in this article. The proposed antenna consists of opposite faced semi-circular monopole radiating elements. The opposite orientation of the radiating elements is offered low envelope correlation coefficient (ECC) and good pattern diversity. The improved bandwidth and enhanced isolation are achieved by etching the ground plane with a rectangular defected ground structure structure. Antenna size optimization is taking placed with evolution of the compact size single UWB antenna element. The computer simulation tool is used to complete the design and optimization process. The optimized size of the proposed antenna is 20 × 20 mm2 or electrical size of 0.469 λ0 × 0.469 λ0. The fabricated prototype of the antenna is experimentally evaluated and validated by the comparison of the simulated and measured results. However, obtained results show well agreement. The proposed antenna has extended UWB bandwidth 2–12 GHz (fractional bandwidth of 142.8%) and improved isolation of less than 25 dB, and low value of ECC (0.05). The antenna size, isolation, operating bandwidth, and ECC are compared with previously reported work. Furthermore, the proposed antenna is preferable for WLAN and UWB applications.