Directional Radiation Pattern Research Articles

DESAIN ANTENA MIKROSTRIP E-SHAPED PATCH PADA FREKUENSI 5500 MHz UNTUK WIFI

Modifying the shape of the patch microstrip antenna is one way to solve the narrow bandwidth. E-Shaped patch microstrip antenna is obtained by modifying a rectangular patch mikrostrip antenna. The results on this research have succesfully compared the design and simulation antenna parameters between rectangular patch and E-shaped patch. It uses FR-4 as a substrate and works on 5500 MHz frequency for WiFi. The feeding method using a feedline method. The E-shaped patch microstrip antenna has a VSWR value of 1.04 and the antenna return loss is -33.73 dB, better than the rectangular patch. The gain of E-shaped patch is increased by almost 2.5 times and the bandwidth is increased by 10.18% compared to the rectangular patch. The radiation pattern of the two patches has the same directional radiation pattern.

3D-Printed Quasi-Cylindrical Bragg Reflector to Boost the Gain and Directivity of cm- and mm-Wave Antennas.

We demonstrate a concept for a large enhancement of the directivity and gain of readily available cm- and mm-wave antennas, i.e., without altering any property of the antenna design. Our concept exploits the high reflectivity of a Bragg reflector composed of three bilayers made of transparent materials. The cavity has a triangular aperture in order to resemble the idea of a horn-like, highly directive antenna. Importantly, we report gain enhancements of more than 400% in relation to the gain of the antenna without the Bragg structure, accompanied by a highly directive radiation pattern. The proposed structure is cost-effective and easy to fabricate with 3D-printing. Our results are presented for frequencies within the conventional WiFi frequencies, based on IEEE 802.11 standards, thus, enabling easily implementation by non-experts and needing only to be placed around the antenna to improve the directivity and gain of the signal.

Relay-Aided Wireless Sensor Network Discovery Algorithm for Dense Industrial IoT Utilizing ESPAR Antennas

Industrial Internet-of-Things (IIoT) applications require reliable and efficient wireless communication. Assuming dense wireless sensor networks (WSNs) operating in a harsh environment, a concept of a time-division multiple access (TDMA)-based WSN enriched with electronically steerable parasitic array radiator (ESPAR) antennas is proposed and examined in this work. The utilized antenna provides one omnidirectional and 12 directional radiation patterns that can be electronically switched by the sensor node. We introduce a relay discovery algorithm, which selects those sensor nodes with an ESPAR antenna capable to act as relay. The selection of the relay nodes is based on a certain link quality threshold that algorithm uses as input. The outcome is a reduction in the number of layers or hops with a guaranteed Quality of Service (QoS). To emphasize the physical aspect of the wireless propagation, we introduce the measured antenna radiation patterns and consider two different path-loss propagation models representing blockage-free and blockage-prone industrial environments. A number of network simulations were performed and signal-to-noise ratio (SNR) as a link quality measure was examined with respect to the network density and different measured radiation pattern settings. The main outcomes show a tradeoff between SNR per link and the percentage of nodes that can serve as relays. As a result, we propose network design guidelines that take under consideration the QoS range with respect to SNR together with an optimal number of antenna radiation patterns that should be selected as a tradeoff between latency, energy consumption, and reliability in a network.

A metamaterial‐based compact multiple‐input multiple‐output antenna with pattern diversity

A compact multiple-input multiple-output (MIMO) antenna is proposed with dual-mode pattern diversity. A two-port antenna with a single radiator is designed based on the composite right/left-handed transmission-line (CRLH-TL) theory. An omnidirectional radiation pattern is excited by the port 1, while a directional radiation pattern is excited by the port 2. When the omnidirectional radiation pattern is excited, the antenna can be regarded as a radial CRLH-TL-based resonator. When the directional radiation pattern is obtained, the antenna is modeled as a circular patch antenna. The two different radiation patterns are integrated in one antenna with low complexity and low cost. The electrical size of the proposed antenna is 0.6 × 0.6λ2 (at 3 GHz). A low profile of only 0.07λ is obtained. The antenna works at the 3 GHz band. The measured −10 dB bands for port 1 and port 2 are 2.71–3.06 GHz and 2.87–2.96 GHz, respectively. A low mutual coupling below −30 dB between the two radiators is achieved, which decrease the channel correlation significantly.

Directional and isolated UWB‐MIMO antenna‐based uniplanar UWB‐FSS array and T‐strip for bi‐static microwave imaging: Baggage‐scanner

This article presented a novel compact multi-input-multi-output (MIMO) hexagonal monopole antenna with a uniplanar compact frequency-selective-surface (FSS) array for microwave imaging (MWI). The ultra-wideband (UWB) dual-element linear MIMO antenna was designed on the FR4 substrate with 50 Ω coplanar waveguide feed, T-strip isolation, novel numerical calculation and equivalent circuit analyses. The main issues of realising high-resolution images based on planer UWB antenna for MWI are the low gain, omnidirectional pattern, design size and mutual coupling of MIMO design. A novel technique was proposed to solve a hybrid issue (mutual coupling) of the MIMO reflected-waves from the FSS array and direct-wave. The uniplanar UWB-FSS unit cell was compacted by combining a square-loop and cross-dipole with a size of 0.095λ × 0.095λ. The novel-isolated UWB-MIMO antenna and UWB-FSS array (IMAF) were integrated, after investigating the distance between the antenna and FSS. The fabricated IMAF with a stable gain improvement of 4.5 dBi higher than the antenna without FSS, directional radiation pattern, size of 30 × 73.8 × 21.6 mm3 observed that a low mutual coupling of −27 dB, and operation bandwidth of 3.0–11.7 GHz. Moreover, a handbag was scanned experimentally via the bi-static approach to detect a small concealed object. The MWI system based on the MIMO antenna with FSS was displayed image resolution of 55% higher than that of MIMO antenna without FSS. The new baggage-scanner approach confirmed that the proposed MIMO antenna with FSS array can lead the humanity for healthy MWI applications.

Directive Multiband Antenna Based on Rectangular Loop Array and Dumbbell-Shaped Slot Radiator.

In this article, a combination of rectangular loop array and slot radiator for multiband applications is presented. The antenna is configured by arranging, concentrically, a set of rectangular loop radiators excited by electromagnetic coupling provided by a dumbbell slot. The size of the loops is calculated to obtain the desired resonant frequencies, which are almost independent of the adjacent rings. The exciting slot is designed to operate in a wideband frequency range to cover the upper desired resonance. In addition, to obtain directive radiation patterns, a reflector shaped like a box is introduced, giving a stable gain, radiation pattern shape, and port matching at the selected frequencies. The configuration presents great results, since to the authors’ knowledge, even a similar configuration given in the open literature presents some disadvantages compared to this one; moreover, not just any structure can be employed as the resonating elements, obtaining multiband behavior at the same time.

Dual-Band Antenna Integrated With Solar Cells for WLAN Applications

A single-port dual-band antenna integrated with solar cells is reported for the 2.4/5-GHz wireless local area network (WLAN) applications. Thirty solar cells are adopted and integrated into the antenna structure for both energy harvesting and wireless communication. The solar cells can act as a director for the lower band, and the main radiation structure for the higher band. The slot and microstrip antennas are incorporated into the compact structure and multiple resonant modes are utilized for dual-band performance. The measurement results show that the lower band is from 2.27 to 2.5 GHz with an omnidirectional radiation pattern and the upper band is from 4.8 to 6.9 GHz with a directional radiation pattern. The proposed solar cell antenna can provide a dual-band performance with the ability of DC power generation, which can be a potential candidate for future green low-carbon communication.

Design of dual band slotted reconfigurable antenna using electronic switching circuit

This paper proposes a dual band reconfigurable microstrip slotted antenna for supporting the wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications, providing coverage where both directive and omni-directive radiations are needed. The design consists of a feedline, a ground plane with two slots and two gaps between them to provide the switching capability and a 1.6 mm thick flame retardant 4 (FR4) substrate (dielectric constant Ɛ=4.3, loss tangent δ=0.019), modeling an antenna size of 30x35x1.6 mm3. The EM simulation, which was carried out using the connected speech test (CST) studio suite 2017, generated dual wide bands of 40% (2-3 GHz) with -55 dB of S11 and 24% (5.2-6.6 GHz) higher than its predecessors with lower complexity and -60 dB of S11 in addition to the radiation pattern versatility while maintaining lower power consumption. Moreover, the antenna produced omnidirectional radiation patterns with over than 40% bandwith at 2.4 GHz and directional radiation patterns with 24% bandwith at the 5.8 GHz band. Furthermore, a comprehensive review of previously proposed designs has also been made and compared with current work.

Multifunctional Partially Reflective Surface for Smart Blocks.

In general, a partially reflective surface (PRS) is mainly used to increase the gain of an antenna; some metallic objects placed on the PRS degrades the antenna performance because the objects change the periodic structure of the PRS. Herein, we propose a multifunctional PRS for smart block application. When a passenger passes over a smart block, the fare can be simultaneously collected and presented through the LED display. This requires high gain antenna with LED structure. The high gain characteristic helps the antenna identify passengers only when they pass over the block. The multifunctional PRS has a structure in which an LED can be placed in the horizontal direction while increasing the antenna gain. We used the antenna’s polarization characteristics to prevent performance deterioration when LED lines are placed in the PRS. We built the proposed antenna and measured its performance: At 2.41 GHz, the efficiency was 81.4%, and the antenna gain was 18.3 dBi. Furthermore, the half-power beamwidth was 18°, confirming a directional radiation pattern.

Opportunistic control of fractal‐based MIMO antenna for sub‐6‐GHz 5G applications

SummaryThe proposed research work is on fractal MIMO antenna with microstrip feeding for lower sub‐6 GHz. The design construct's goal is to improve the isolation among the patches and is constructed with a combination of circular strip and rectangular strip slots, and rectangular slots are introduced on the ground plane. The fractal‐shaped MIMO structure composes of FR‐4 material and compact size of 25 × 35 mm2. The current 2 × 1 fractal MIMO radiator resonates at a frequency 3.5 GHz for lower sub‐6‐GHz applications with directional radiation patterns. In this structure, the performance characteristics of design antenna parameters like S‐parameters, surface current distributions, and radiation pattern of the fractal MIMO radiator are investigated. In addition to antenna parameters, MIMO parameters like diversity gain (DG), mean effective gain (MEG), channel capacity loss (CCL), total active reflection coefficient (TARC), and time‐domain analysis parameters are also evaluated. It has been observed that the MIMO parameters of the antenna are in the acceptable range. Fractal‐based prototype MIMO structures are fabricated as well as tested for effective radiation and impedance. The improvised MIMO design that's been installed on a printed circuit board with connector, device housing, compact size, and various types of housing shows better performance compared to the conventionally designed antennas.

Vivaldi Antenna Arrays Feed by Frequency-Independent Phase Shifter for High Directivity and Gain Used in Microwave Sensing and Communication Applications.

This paper describes a novel feed system for compact, wideband, high gain six-slot Vivaldi antenna arrays on a single substrate layer using a unique combination of power splitters based on binary T-junction power splitter topology, frequency-independent phase shifter, and a T-branch. The proposed antenna system consists of six Vivaldi antennas, three on the left, and three on the right arm. Each arm connects with T-junction power divider splitter topology, given that the right arm is linked through a frequency-independent phase shifter. Phase shifters ensure that the beam is symmetrical without splitting in a radiating plane so that highly directive radiation patterns occur. The optimal return losses (S-parameters) are well enriched by reforming Vivaldi’s feeding arms and optimizing Vivaldi slots and feeds. A novel feature of our design is that the antenna exhibits the arrangements of a T-junction power splitter with an out-of-phase feeding mechanism in one of the arms, followed by a T-branching feeding to even arrays of proper Vivaldi antenna arrangement contributing high realized gain and front-to-back ratio up to 14.12 dBi and 23.23 dB respectively applicable for not only ultra-wideband (UWB) application, also for sensing and position detecting. The high directivity over the entire UWB frequency band in both higher and lower frequency ranges ensures that the antenna can be used in microwave through-wall imaging along with resolution imaging for ground penetration radar (GPR) applications. The fabricated antenna parameters are in close agreement with the simulated and measured results and are deployed for the detection of targets inside the voids of the concrete brick.

An Ultrawideband Conical Monopole With Radome for Detection of Partial Discharges

Localized electric field strength in high-voltage (HV) equipment results in electrical discharges which radiate electromagnetic waves in ultrahigh frequency (UHF) range of 0.3-3 GHz. Due to the large antenna dimensions in UHF regime and lack of radome, existing UHF sensors have limited use in HV equipment for online partial discharge (PD) detection. In this work, we present the design and experimental verification of a UHF antenna with relatively small aperture and radome for PD detection. The proposed UHF sensor is a compact conical monopole with ground plane and protective radome. The monopole shape was optimized for broadband operation and directional radiation pattern using electromagnetic simulations. A cylindrical radome transparent to electromagnetic waves was designed without perturbing the radiation characteristics of the optimized UHF antenna. The 130 mm diameter fabricated sensor has directional radiation pattern, UHF bandwidth of 0.5 - 3 GHz and compact radome of 150 mm diameter. PD signals gathered for three defects in gas insulated test cells indicate better detection capability and sensitivity for the proposed UHF sensor than the reference sensor.The improved performance of the proposed sensor suggest that it could be used for PD detection in HV equipment such as gas insulated switch gear and transmission line.

Two-Row ESPAR Antenna With Simple Elevation and Azimuth Beam Switching

In this letter, we propose a two-row electronically steerable parasitic array radiator antenna designed for direction-of-arrival (DoA) estimation in Internet of Things (IoT) applications relying on simple microcontrollers. The antenna is capable of elevation and azimuth beam switching using a simple microcontroller-oriented steering circuit, and provides 18 directional radiation patterns, which can be grouped in 3 distinctive sets having different directions in the elevation. For each elevation direction, there are six different beam configurations that cover 360° in the horizontal plane. Measurements of the realized antenna prototype carried out in an anechoic chamber show good agreement with numerical simulations. The antenna prototype provides low sidelobe level, low half power beamwidth in both elevation and horizontal directions, and exhibit monotonous drop from the maximum value for all 18 radiation patterns. Therefore, the antenna is a good candidate for IoT nodes capable of DoA estimation in situations when radio frequency signals are impinging the antenna from different directions in elevation.

Fractal Inspired Metamaterial Superstrate for Gain Enhancement

In this paper, a fractal inspired metamaterial superstrate is proposed for the gain enhancement of microstrip patch antenna resonating at 2.4 GHz. Fractal structure is used as the metamaterial unit cell, which is designed on a FR4 substrate with a thickness of 1.6 mm. The metamaterial unit cell exhibits near-zero refractive index at 2.4 GHz. The superstrate consists of a 2×2 array of metamaterial unit cells which acts as a partial reflective surface of Fabry-Perot (FP) cavity. The distance between the antenna and the superstrate is optimized by the FP resonance condition. The antenna has a directional radiation pattern more than the microstrip patch antenna. The antenna gives a peak gain of 7 dBi with a gain enhancement of 4 dB and a beamwidth reduction of 23° and 2° along H plane and E plane respectively. The aperture efficiency of the antenna is 80.47%. The whole structure is simulated and analyzed using finite element method. The simulated and the measured results show good agreement.

Visible light communication for intelligent transportation systems: A review of the latest technologies

In seeking to improve traffic congestion and safety on roads and highways, there has been an increased interest in intelligent transportation systems (ITS). The emerging visible light communication (VLC) technology is a new candidate to enable wireless access in ITS. The purpose of this study is to present a comprehensive review of the current studies related to VLC. Since VLC facilitates illumination and data communication simultaneously, it reduces energy consumption significantly. Additionally, VLC is immune to electromagnetic interference, provides high data security, and utilizes unregulated visible light spectrum, showing promise as a potentially cheaper alternative to existing radio frequency (RF) based technology. Moreover, recent advances in semiconductor materials and solid-state technologies have enabled the development of efficient light-emitting diodes (LEDs) and laser diodes (LDs) which are used as transmitters in a VLC system. Although 10 s of Gbits/s data rate has been demonstrated in indoor VLC links, successful implementation of it in outdoor environments requires further research to overcome the challenges presented by environmental factors, unwanted lights, non-line of sight communication, directional radiation pattern, frequent fragmentation, and so on. Besides, in recent years, semiconductor LDs have been garnering more attention since they can transmit more data over longer distances due to their high quantum efficiency and modulation bandwidth compared to LEDs. As a result, urban planners, policy-makers, transportation engineers, and vehicle manufacturers are considering LD-based VLC to facilitate vehicle-to-vehicle and vehicle-to-infrastructure communication. Thus, this paper reviews and compares the most recent developments in VLC technologies, identifies their benefits and potential use in ITS applications, discusses the probable barriers for their implementation in our existing transportation infrastructure, and suggests future research directions and recommendations to overcome these challenges. • Recent developments in visible light communication (VLC) technology and its potential use in ITS applications are reviewed. • Light-emitting diodes (LEDs) and laser diodes (LDs) can be used as transmitters in VLC systems. • The overall performance of LDs is superior to that of the LEDs. • LDs can transmit more data over longer distances due to their high quantum efficiency and modulation bandwidth. • It is recommended to focus more on LD-based illumination in V2V and V2I communications.

Quantifying the Density of mmWave NR Deployments for Provisioning Multi-Layer VR Services

The 5G New Radio (NR) technology operating in millimeter wave (mmWave) frequency band is designed for support bandwidth-greedy applications requiring extraordinary rates at the access interface. However, the use of directional antenna radiation patterns, as well as extremely large path losses and blockage phenomenon, requires efficient algorithms to support these services. In this study, we consider the multi-layer virtual reality (VR) service that utilizes multicast capabilities for baseline layer and unicast transmissions for delivering an enhanced experience. By utilizing the tools of stochastic geometry and queuing theory we develop a simple algorithm allowing to estimate the deployment density of mmWave NR base stations (BS) supporting prescribed delivery guarantees. Our numerical results show that the highest gains of utilizing multicast service for distributing base layer is observed for high UE densities. Despite of its simplicity, the proposed multicast group formation scheme operates close to the state-of-the-art algorithms utilizing the widest beams with longest coverage distance in approximately 50–70% of cases when UE density is λ≥0.3. Among other parameters, QoS profile and UE density have a profound impact on the required density of NR BSs while the effect of blockers density is non-linear having the greatest impact on strict QoS profiles. Depending on the system and service parameters the required density of NR BSs may vary in the range of 20–250 BS/km2.

Complex shaped periodic corrugations for broadband Bull\u2019s Eye antennas

Periodically corrugated metallic antennas have been developed in recent years from microwave to THz frequencies, due to their advantages of highly directive radiation patterns, low profile and ease of fabrication. However, the limited gain bandwidth of such antennas remains one of their inherent disadvantages. In terms of design, the majority of the existing implementations in literature utilize the standard rectangular shaped corrugated unit cell. In this paper, we propose novel complex shaped corrugated unit cells that produce a broadband performance when assembled in a periodic configuration. Two broadband prototypes are presented at the Ku frequency band that are formed of hybrid shaped corrugations. The first prototype of six periodic rings achieves, for the first time, a flat gain simulated response with a maximum value of 15.7 dBi, 1-dB gain bandwidth of 16.4%, and an extended 3-dB gain bandwidth of 19.64%. The second novel prototype of five rings achieves an enhanced 3-dB gain bandwidth of 15.2% and maximum gain of 18.1 dBi.

Vibro-acoustic characteristics of a coupled pump-jet – Shafting system – SUBOFF model under distributed unsteady hydrodynamics by a pump-jet

This study presents the unsteady hydrodynamics of the excitations from a pump-jet running in the wake of a SUBOFF model and the vibro-acoustic characteristics of a coupled pump-jet – shafting system – SUBOFF model under unsteady excitations. The excitations of the pump-jet are obtained by CFD and the vibro-acoustic responses are predicted by coupled FEM/BEM. A mapping method based on radial basis function is established between CFD and structural mesh to apply the distributed pulsation forces on the wet surface of the pump-jet. The effect of the method used to apply the excitation forces on vibro-acoustic responses is investigated by applying distributed or equivalent pulsation forces at different areas of the pump-jet. Modal shapes, transmitted forces, sound radiation power, radiation directivity pattern and panel contributions are reported to illustrate the characteristics of the vibro-acoustic responses and the influence of the method used to apply the excitation forces on the responses. It is seen that the shaft frequency and the longitudinal mode resonant frequency of the shafting system are the typical characteristic frequencies with large magnitude in vibro-acoustic responses of the coupled system. Compared with applying concentrated forces applied at hub or 0.7 R, the responses produced by applying distributed forces on the whole pump-jet present modes and excitation characteristics with more reasonable magnitudes, illustrating the importance of applying distribute forces instead of concentrated forces. Besides, the contribution of the distributed forces on rotor is dominant since the responses of applying distributed forces on the pump-jet and applying distributed forces on rotor are similar.

Reconfigurable antenna with frequency and beam switching using transformer oil and PIN-diode for microwave applications

This paper introduces a design and analysis of a four directional radiation pattern antenna operating at 5.1 GHz. The proposed antenna consists of four center-fed copper arms placed over a substrate of relative permittivity εr = 2.2. The substrate is backed with copper ground sheet. The design of this antenna is then modified to be frequency reconfigurable antenna by placing transformer oil (liquid which is operated at high frequency) within a container between the substrate and the ground. The modified antenna can be operated at different frequency ranges from 5.21 GHz to 6.56 GHz by varying the oil height in the container. Four PIN diodes are then added between the antenna’s four arms and the feeding point in order to add beam reconfigurability feature to the modified antenna. Finally, multiple reconfigurable antennas are obtained to radiate in different directions at different operating frequencies with different gain and HPBW values.

A compact omnidirectional to directional frequency reconfigurable antenna for wireless sensor network applications

AbstractIn the proposed research paper, a novel compact, ultra-wideband electronically switchable dual-band omnidirectional to directional radiation pattern microstrip planar printed rectangular monopole antenna (PRMA) has been presented. The proposed antenna system has an optimum size of 0.26 λ0 × 0.28 λ0. A combination of radiators, reflectors, and two symmetrical grounds does place on the same layer of the rectangular microstrip PRMA. The frequency agility and the radiation pattern from omnidirectional to directional are achieved using two SMD PIN diodes (SMP1340-04LF). The directional radiation patterns with 180° phase shifts are achieved at the C-band frequency spectrum. The parametric study of the proposed antenna system was performed for different design parameters, and the antenna characteristics were analyzed. An antenna prototype is fabricated using the printed circuit board etching method by using RMI UV laser etching and cutting tools. The measurements of the proposed antenna are conducted in an anechoic chamber to validate the simulations. There are three states of operations due to two SMD PIN diodes being used in switching circuits. In state-I, the proposed antenna radiates at 6.185 GHz (5.275–6.6 75 GHz) in the Ф = 270° direction with a gain of 2.1 dBi, whereas in state-II, it radiates at 5.715 GHz (5.05–6.8 GHz) in the Ф = 90° direction with a gain of 2.1 dBi. In state-III, the antenna exhibits the X-band frequency with center frequency at 9.93 GHz (8.845–10.49 GHz), and the omnidirectional pattern offers a gain of 4.1 dBi. The features of the proposed antenna are suitable for high-speed wireless sensor network communication in industries such as chemical reactors in oil and gas and pharmaceuticals. It is also well suited for IoT and 5G-sub-6-GHz applications.