Ultra-wideband Frequency Range Research Articles

Investigation of optically transparent metasurfaces for gain improvement of an ultrawideband antenna for wireless body area networks and vehicular communications

Abstract Due to higher frequencies which cause signal deterioration, 5G enabled antennas are prone to substantial attenuation. To circumvent this problem, several access points, signal repeaters, and base stations must be installed closer together on building windows, streetlights, and other infrastructure. Optically transparent antennas preserve the aesthetics of the windows by offering the requirements for access points and base stations for providing network connectivity to the cars and pedestrians passing by those buildings. Here we report an ultrawideband (UWB) high gain optically transparent antenna operating from 4-12 GHz. Indium tin oxide (ITO) coated glass has been used as an optically transparent substrate for designing the antenna and metasurface. Two optically transparent metasurfaces have been proposed for band-stop filtering action across the UWB frequency range 4-12 GHz. In absence of the metasurface, the antenna operates in the frequency band ranging from 3.8 to 15 GHz. Average gain enhancement is 5.2 dB with radiation efficiency higher than 93% across the UWB frequency band from 4-12 GHz. Numerical simulations have been carried out for analysis of the proposed antenna and metasurfaces. These simulations have been validated by experimental measurements of the fabricated prototypes.

RF NEMS switches based on graphene for low pull-in voltage and excellent RF performance

This study introduces a novel graphene RF NEMS capacitive switch and conducts an extensive analysis of its RF performance using CST and COMSOL Multiphysics software. The switch’s characteristic impedance matching is accomplished through a coplanar waveguide (CPW) structure, incorporating a dielectric layer topped with conductive graphene beam electrodes. Simulation results reveal that the monolayer graphene RF NEMS switch maintains an insertion loss of 0.003 ~ 0.015 dB and an isolation greater than 40 dB across an ultra-wideband (UWB) frequency range of DC ~ 140 GHz. Moreover, the switch demonstrates a switching time of 4.03 ps at a pull-in voltage of 1 V. The performance of multilayer graphene RF NEMS switches was also evaluated. The study further investigates the operational mechanism of the graphene RF NEMS switch and performs finite element analysis on the proposed design. The graphene RF NEMS switch discussed herein offers significant advantages, including minimal size, lightweight, cost-effectiveness, low pull-in voltage, rapid response time, excellent RF performance, and reduced space consumption in circuitry. Its potential applications span a range from L to F bands, encompassing data storage, communication systems, sensors, remote sensing and military uses.

Design of UWB Wearable Conformal Antenna for Body Area Networks

In this paper, a wearable ultra-wideband (UWB) micro-strip antenna is designed to meet the demand for Wireless Body Area Network (WBAN). This is a wearable textile antenna, which was formed on a jeans fabric substrate to reduce surface-wave losses. The single-fed circular strip monopole antenna provides good impedance matching over the entire UWB frequency range of 2.9∼10.6 GHz. The dielectric constant εr 2.2, and the loss tangent tan δ 0.04 of the jean substrates are measured by using the coaxial ring method. The proposed antenna consists of an improved circular radiation patch with the defective ground structure to expand the frequency band of the antenna and improve the radiation characteristics of the antenna with small dimensions of 20 × 30 × 1.4 mm3. In addition, structural deformation of the proposed antenna is performed to analyze the flexibility of the proposed antenna. The simulated SAR values follow the FCC limit, making it most suitable for wearable applications. Key Words: Antenna, S-Parameters, Far Field Directivity, Applications of Antenna, HFSS.

Performance analysis of the dual-band trapezoidal antenna array for ultra-wideband application

Designing a wireless transmission system with high data rates, high fidelity, and small size is a tough undertaking that has become more popular in the digital age. One of the most important components of wireless communication systems, such as wireless LANs, mobile WIMAX, and Bluetooth devices, is the design of an efficient antenna system. The new circular slot Trapezoidal patch antenna array, which operates in the ultra wide band frequency range of 3.1 GHz to 10.6 GHz, is introduced in this study. The FR4 substrate on which the antenna system is built has a dielectric constant of 4.4. The CST microwave studio suite is used to develop and analyze the performance of the compact structure patch antenna array. Antenna performance is examined in the frequency range of 2 GHz to 5 GHz. Antenna array resonance frequency is 3.1 GHz. By inserting a quarter wave line between the SMA connection and the micro stripline, 50 ohm impedance matching may be achieved. In comparison to previous studies, the intended antenna array has a minimum VSWR of 1.18, a maximum radiation efficiency of ?4.842 dB, and a directivity of 8.645 dBi. Using network analyzer, the test and simulation data were analyzed. The intended use of the antenna array system is for biomedical imaging and body area networks. Abbreviations: UWB: ultra wideband; EMI: electromagnetic interference; MIMO: multiple input multiple output; WLAN: wireless local area network; VSWR: voltage standing wave ratio; AVA: antipodal vivaldi antenna; DGS: defected ground structure; RF: radio frequency.

Gain enhancement of ultra-wideband hexagonal slot antenna using tessellated rhombic loops based reflector

Abstract A simple technique for gain enhancement of irregular hexagonal shaped ultra-wide band (UWB) slot antenna by inclusion of closely packed tessellated rhombic loop (TRL) based FSS is presented in this paper. The slot antenna is designed to cover entire UWB (3.1–10.6 GHz) frequency range with stable bi-directional radiation pattern. Also, it exhibits non-uniform boresight gain in zenith (θ = 0°) and nadir (θ = 180°) directions. The slot antenna is further loaded with TRL FSS at both slot and feed side separately to study distinct configurations of antenna integrated with FSS and evaluate the impact of the configurations of FSS on antenna performance. Later, an antenna and antenna loaded with TRL FSS prototype are developed for experimental validations. Through measurements it is found that the slot antenna covers entire UWB frequency band and provides a maximum of 4.31 dB gain in zenith direction while 4 dB gain in nadir direction. A gain enhancement of 2.44 dB in zenith and 3.8 dB in nadir directions are achieved when the slot antenna is integrated with TRL FSS along feed side and slot side separately. The measured results confirm the simulated results well.

Metamaterial Antenna for Microwave Imaging

Microwave imaging is a straightforward approach to detect scattering in a detected object. One application of microwave imaging is breast cancer detection, the most prevalent type of cancer in Indonesia and the leading cause of cancer-related deaths. The planar monopole antenna offers several advantages, including low bandwidth compared to microstrip antennas and a simple structure for easy and affordable fabrication. Metamaterial can be added to the antenna to operate within the ultra-wideband frequency range of 3,1-10,6 GHz. Metamaterial expands the bandwidth and offers advantages such as low fabrication costs and miniaturization potential. This study aims to design a planar monopole antenna with a hexagonal patch using metamaterial. The simulation results show a working frequency range of 3,0699 - 20,779 GHz, while the realized results are 2,6 - 11,3 GHz and 15,2 - 17 GHz. The simulated bandwidth value is 17,7091 GHz, whereas the realized bandwidth values are 8,7 GHz and 1,8 GHz. The return loss values are ≤ 10 dB and the VSWR values are ≤ 2. The gain at the frequency of 7,038 GHz is 1,963 dBi in simulation and 1,698 dBi in realization. Additionally, changes in electromagnetic parameters are observed when the antenna detects cancer.

A miniaturized spot-focusing microwave sensor for broad-band reflectivity measurements

This study presents a novel spot-focusing microwave sensor designed for on-site monitoring of absorbing materials and coatings, a critical process in assessing the performance of equipment in service. The sensor addresses the challenge of integrating miniaturization, wide bandwidth, and focused radiation-requirements that are typically at odds in microwave sensor design. The developed approach utilizing a multi-layer lens nesting structure to achieve narrow-beam radiation over an ultra-wideband (UWB) frequency range. Each layer of the lens system is engineered to concentrate beams within specific frequency bands, enabling consistent performance across a broad spectrum. In addition, we introduce a composite feeding structure characterized by exponential gradient slots that enhance UWB performance while minimizing cross-polarization effects. The sensor demonstrates exceptional capabilities, achieving over 8 dB of radiation gain and maintaining a voltage standing wave ratio (VSWR) under 2.5 within a 2–22 GHz frequency band. Its compact size (95 mm in diameter and 75 mm in height) does not compromise its ability to emit a Gaussian beam with a narrow radiation pattern of less than ±30°, simulating plane-wave characteristics essential for near-field on-site measuring. Accompanying the sensor is a novel on-site reflectivity measuring method that leverages time-domain gating technology to mitigate interference signal impact. Measurement results validate the sensor and method’s precision, with an average error margin of 0.78 dB. This breakthrough in sensor design and methodology marks a significant advancement in the on-site evaluation of absorbing materials and coatings.

Asymmetry stagger array structure ultra-wideband vibration harvester integrating magnetically coupled nonlinear effects

Traditional energy harvesters often have limitations in terms of bandwidth and power output, resulting in poor performance. This study reports a multi-strategy ultra-wideband energy harvesting device that utilizes an asymmetry, stagger array, magnetic coupling, and nonlinearity strategies to achieve high power output over an ultra-wideband frequency range without the need for external power input. The energy harvesting device consists of a base, two elastic beams, and two sets of asymmetric palm-shaped piezoelectric cantilever beam structures, each with a magnet attached at the tip. By reasonably arranging the palm-shaped mechanism and magnets, a magnetic coupling effect is introduced to achieve high power density output at non-resonant frequencies. Numerical analysis is conducted to evaluate the performance of the proposed structure, assess the influence of structural parameters, and establish a dynamic model to analyze the energy harvesting device. Experimental results demonstrate that the structure achieves a maximum power output of 60.49 mW at 19.9 Hz and 0.5 g, with a peak power density of approximately 8.065 × 103 W/m3. Within an ultra-wideband frequency range that spans 6 Hz to 64.2 Hz, the energy harvester maintains an output voltage which is more than 5 V. Furthermore, temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the energy harvesting device, eliminating the need for lithium batteries and ensuring stable signal transmission. The device can be utilized for condition monitoring in any unstable vibration environment, contributing to the realization of distributed monitoring in the Internet of Things (IoT).

A GRAPHENE-BASED MONOPOLE MICROSTRIP ANTENNA WITH TUNEABLE BANDGAP FOR UWB IMPLEMENTATIONS

Monopole Microstrip Antennas (M-MSAs) are widely used because of their price, ease of manufacturing, and compact size, making them ideal for portable applications. Nowadays, Ultrawide Band (UWB) technology, used in wireless applications, relies on this antenna. The UWB frequency range is 3.1 to 10.6 GHz, allowing low-power wireless applications such as wireless music, personal localization, radio frequency recognition, radar, and HD video dissemination. However, this frequency band's broadness increases interference. This contribution research formulates simulates, and optimises a modified small-square M-MSA that meets UWB technology's huge bandwidth requirements. A square radiated patch, a dielectric material with a thickness of 1 mm and 4.7 relative permittivity, a partly ground plane printed on the patch's face, and a coplanar waveguide feed make up the M-MSA design. The M-MSA design is modified to reduce the patch's bottom corners and change its proportions to enable compatibility with the UWB complete band. A U-shaped aperture on the patch should be etched to produce a bandgap in UWB frequencies, reducing interference. Filling the aperture with graphene allows bandgap tunability. The graphene's bandgap dissipates with DC voltage, but without biassing, its high impedance restricts aperture current flow. The bandgap's effect is seen at 3.87-4.85 GHz. After simulation and tweaking, gain and efficiency improved significantly. The bandgap region, which was chosen to reduce interference from military fixed communications, mobile communications, unmanned aerial vehicles, short-range radio links, satellite communications, and the low band of 5G, also exhibits a significant increase in attenuation and gain degradation.

A compact 4 × 4 reconfigurable MIMO antenna design with adjustable suppression of certain frequency bands within the UWB frequency range

This paper introduces a novel 4 × 4 multiple-input multiple-output (MIMO) antenna design with a reconfigurable operating band within the Ultra-Wideband (UWB) range. The antenna consists of four rectangular radiating elements arranged symmetrically and orthogonally on a defected ground plane. The design incorporates switching elements that allow adjustable and reversible suppression of specific bands within the UWB range, enabling the antenna to operate in three different modes: UWB, X-band, and dual-band with sub-6GHz and X-band. Thus, a single UWB antenna can serve as three different antennas, suppressing certain frequencies as required. To mitigate mutual coupling between adjacent antenna elements, four thin stubs are strategically placed at the center of the ground plane, forming a square with open corners. When one of the antenna elements is excited, this structure acts as an insulator, ensuring that the surface current is confined solely to that element and not induced in others. Experimental verification of the proposed design was performed by fabricating and testing the antenna. The results indicated good agreement between simulation and measurement data for various parameters, including S-parameters, radiation patterns, gains, and MIMO parameters such as envelope correlation coefficients (ECC), diversity gain (DG), mean effective gain (MEG), and total active reflection coefficient (TARC).

Loaded notched dual compact rectangular ultra-wideband applications monopole antenna

This work presents a rectangular of microstrip ultra wideband patch antenna for worldwide interoperability for microwave access (Wi-Max) and wireless local area network (WLAN) with a dual band-notched feature. The planned an antenna consists the rectangular of patch antenna with the largely deficient of ground structure. Through inserting slots in the radiating patch, dual notch characteristics may be produced. The suggested antenna is 20×30×1.6 mm 3 in volume. The first notch, made by slots operating at the first notch, produced by slots running at 3.5 GHz, for Wi-Max (from 3.3-3.7 GHz), while of a second, created by slots operating at 5.5 GHz, for WLAN (from 5.1-5.8 GHz). An antenna covers the whole ultra-wideband frequency range (3.1-10.6 GHz). Computer simulation technology (CST) 2021 simulation software used for simulate proposed of antenna. A simulated antenna’s emission pattern is almost omnidirectional, and the recommended antenna’s gain is approximately constant over the ultra-wideband (UWB) spectrum, excluding notch areas.

Design of slot loaded CPW feed ultra-wideband antenna with WLAN band notch characteristics

The fast development has been noticed during in the last few decades in the area of Ultra-wideband technologies. Throughout this manuscript, a novel ultra wideband (UWB) antenna with single band notched functions with CPW feed line is projected. The single band rejection is presented and analyzed at WLAN frequency. The proposed antenna was initially exhibits the voltage standing wave ratio (VSWR) bandwidth of 10.6 GHz with frequency range of 3.05 to 13.65 GHz. Further to achieve the WLAN band rejection at 5.5 GHz, an arc shaped slot has been presented in the geometry of radiating patch. The size of designed antenna is 27 × 27 mm2. It also shows that the VSWR ≤ 2 for the operating UWB frequency range, except stop band from 5.16 to 6.7 GHz for filtering the WLAN signal. A variety of UWB antenna applications can be found in medical and radar imaging as well as higher data rate Personal Area Networks (PANs). The designed antenna is simulated on the low cost FR4 glass epoxy substrate with dielectric constant 4.4 and thickness 1.6 mm. Performance parameters such as VSWR, radiation pattern and gain of proposed antenna are analyzed by using HFSS V13 simulator.

English

An ultra-wideband (UWB) antenna is designed, which is fed by a coplanar waveguide along with Dielectric ResonatorAntenna (DRA) is discussed. The patch of ultra-high-frequency antenna structure comprises many full circles and half circles, rearranging the two focal point orientation and dimension of radius such that the antenna works in ultra-wideband frequency range and a rectangular slot in the middle of the antenna patch to change the orientation of current distribution. The antenna is resonating at 8.9GHz with a reflection coefficient (S11) of -15.39dB, Gain is negative at resonating frequency, and Polarization at resonating frequency is linear. The proposed antenna is designed by mounting Cylindrical Dielectric Resonating Antenna (CDRA) on the rectangular slot made on the patch. By mounting a cylindrical DRA structure on the patch, the antenna is resonating at 3.6 GHz with a reflection coefficient (S11) value - 22.54dB, achieving a Gain of 3.44dB at resonating frequency. The Polarization achieved by placing cylindrical DRA is circular Polarization which is more useful in Ground Penetrating Radar (GPR) applications. The proposed antenna is practically designed, and performance characteristics are measured and verified with simulation results.

DESIGN OF WIDE BAND ANTENNAS WITH CPW FEED FOR WIRELESS COMMUNICATION APPLICATIONS

An Antenna is a metallic structure that transmits and receives radio waves. Antennas come in all shapes and sizes from tiny microstrip antenna for biomedical applications to very big parabolic reflector antennas for satellite communications. A Super Wideband Square Monopole Antenna is designed on Arlon AD260A and FR4 Epoxy with CPW-feed structure. Notched bands are obtained by embedding inverted E-shaped stub, using C-shaped parasitic element above radiating patch and etching rotated U- shaped slot in the ground plane. Proposed Antenna has the capability of operating in Ultra Wide band frequency range of (2.534-3.244)GHz with a minimum S11 value of -14.9846dB, (4.414-6.300)GHz with S11 value of -31.9643dB, (6.728-7.150)GHz with S11 value of - 12.3336dB and (13.481-15.870)GHz with S11 value of - 21.9915dB. The maximum gain obtained is 5.86dB in 3-D Omni directional pattern. The minimum VSWR obtained is 1.05. Key Words: Super Wideband, Ultra Wideband, CPW, X- Band, Ku-Band. 1.INTRODUCTION

A Compact Planar Monopole UWB MIMO Antenna for Short-Range Indoor Applications.

A compact, four-element planar MIMO (Multiple Input, Multiple Output) antenna that operates in an ultra-wideband is presented for diversity application. The orthogonal position of the unit cells replicates the single antenna thrice, thereby decreasing mutual coupling. A UWB MIMO antenna measuring 35 × 35 × 1.6 mm3 is built using a microstrip line (50 Ω impedance) on an FR4 substrate having a thickness of 1.6 mm. The ground plane and radiator of this antenna are adjusted in several ways to bring it within its operating constraints between the frequencies of 3.1 GHz and 10.6 GHz. This technique makes the antenna small and covers the entire ultra-wideband (UWB) frequency range. The NI USRP was used to test the proposed MIMO antenna to determine its real-time performance. Based on the computed results, we conclude that this proposed antenna has outstanding characteristics in terms of performance and is suitable for wireless ultra-wideband indoor communication and diversity utilization with a small size.

Photonic Generation of Background-Free Phase-Coded Pulses With Low Power Fluctuation Over the Multi-Octave Frequency Range

In this article, a photonic microwave signals generation scheme for background-free phase-coded (PC) radar pulse with multioctave tuning is experimentally demonstrated. Firstly, an optical frequency comb (OFC) demultiplexing technology based on optical injection locking (OIL) provides a power-equalized coherent optical local oscillator (LO) with ultra-broadband tuning capability. Then, a phase-modulated optical signal is produced based on the conversion intensity modulation to phase modulation. Finally, a background-free phase-coded signal can be obtained by beating the optical signal with LO at a balanced photodetector (BPD). The proposed scheme features a flat frequency response over an ultra-wideband frequency range without needing a broadband modulator and radio frequency (RF) synthesizer. A proof-of-concept experiment demonstrates that the power fluctuation of 0.5 Gbps background-free PC pulses is lower than 3.12 dB within 3∼24 GHz carrier frequency. Furthermore, the pulse compression performance and system stability are investigated, respectively.

Design of A 20-Bit Chipless RFID Tag Utilizing Multiple Resonators in UWB Frequency Range

Radio frequency identification (RFID) is a growing technology for monitoring and recognizing objects, persons, or animals via wireless communications. Precisely, RFID can operate longer range and has an ability to be automated without human control. Chipless RFID tag basically is a RFID tag that does not require a microchip in the transponder. The major impediments in designing chipless RFID tag are data encoding and transmission. The passive chipless RFID tag can be fabricated on any substrate material without external operating circuit, which is different compared to a conventional chipped RFID tag. In this paper, 20 resonators are used to design a 20-bit chipless RFID tag, which operates at the ultra-wideband (UWB) frequency range between 3.00 and 10.00 GHz. It is found that the additional resonators can encode data and increase the chipless RFID tag's encoding capacity significantly. In sum, multiple resonators enable the chipless RFID tag to encode data at different operating frequencies.

A monopole polarisation diversity antenna for high density packaging MIMO applications

Purpose This paper aims to propose a single element, dual feed, polarisation diversity antenna. The proposed antenna operates from 2.9 to 10.6 GHz for covering the entire ultra-wideband (UWB) frequency range. The antenna is designed for usage in massive multiple input multiple output (MIMO) and closed packaging applications. Design/methodology/approach The size of the antenna is 24 × 24 × 1.6 mm3. The radiating element of the antenna is derived from the Sierpinski–Knopp (SK) fractal geometry for miniaturization of the antenna size. The antenna has a single reflecting stub placed between the two orthogonal feeds, to improve isolation. Findings The proposed antenna system exhibits S11 < −10 dB, S21 < −15 dB and stable radiation characteristics in the entire operating region. It also offers an envelope correlation coefficient < 0.01, a diversity gain > 9.9 dB and a capacity loss < 0.4 bps/Hz. The simulated and measured outputs were compared and results were found to be in similarity. Originality/value The proposed UWB-MIMO antenna has significant size reduction through usage of SK fractal geometry for radiating element. The antenna uses a single radiating element with dual feed. The stub is between the antenna elements which provide a compact and miniaturized MIMO solution for high density packaging applications. The UWB-MIMO antenna provides an isolation better than −20 dB in the entire UWB operating band.

Semi-circular compact CPW-fed antenna for ultra-wideband applications

This paper presents a simple structure and small size antenna design with dimensions of 43×47 mm 2 to perform an ultra-wideband (UWB) frequency range using a semicircular co-planar waveguide (CPW). This antenna has been designed and simulated by the computer simulation technology (CST) microwave studio suit. In this work, we design an ultra-wideband antenna (about 2 GHz to 10 GHz) by feeding a semi-circular compact antenna via a co-planar waveguide for input impedance of 50 Ω. The CST simulation results show that our designed antenna has a very good impedance and radiation characteristic within the intended ultra-wideband. Because of the small size and the suitable shape, this antenna can be used in many wireless communication applications, such as a radio frequency identifier (RFID), indoor wireless local area network or wireless fidelity (WiFi), internet of things (IoT), millimeter waves communications (mmWave), global positioning system (GPS), and many applications of 6G systems.

LPF/dual-BPF/UWB-BPF reconfiguration utilizing DGS resonators and lumped capacitors

AbstractIn this work, three successive filter models based on defected ground structure (DGS) techniques are designed, fabricated, and tested to be utilized for different wireless applications. The filters are printed on a RO5880 substrate of an overall size of 22 × 11 × 0.8 mm3. Three DGSs are etched from the ground plane to achieve the suggested band stop features for all frequencies above 10 GHz. The first model is a low-pass filter that succeeded to pass all frequencies below 10 GHz, the second model is a bandpass filter that operated at 4.5 and 9 GHz after using a pair of interdigital capacitors, and the third model covered all ultra-wideband frequency range when a pair of lumped capacitors is utilized instead of the interdigital capacitors. Good consistency between simulated and measured outcomes is achieved for each of the three filters confirming their suitability to be embedded in small-sized wireless devices.