Reflection Coefficient Of Antenna Research Articles

Isolation enhancement of a two- orthogonal printed elliptical slot MIMO antenna array with EBG structure for millimeter wave 5G applications

This work investigates a high-isolation Orthogonal Printed Elliptical Slot Antenna (OPESA) array with Multiple Inputs and Multiple Outputs (MIMO). A unique composite Electromagnetic Band-Gap (EBG) structure consisting of a vertical six rings positioned between single element antennas were devised and investigated with the aim of reducing mutual interaction between antenna components. A distinct feeble electric field that could successfully inhibit the Mutual Coupling (MC) among the antenna components is easily produced by the suggested composite EBG construction. One type of decoupling constructions throughout the antenna growth was carefully examined at together the theoretical and physical levels in order to offer a clear representation of the suggested antenna array’s design concept and decoupling technique. The antenna array design process was cleverly separated into three stages. In order to verify the suggested decoupling idea, the array Scheme was constructed, assessed, and measured. Studying the antenna gain, radiation pattern, and reflection coefficient, it was found that the simulated and measured findings were very consistent. According to the models, the array has an extreme radiation efficiency of about 91%, a minor value of Envelope Correlation Coefficient (ECC < 1.8 × 10−4), and a maximal gain of 11.5 dBi. The electrical size, highest isolating grade and the recommended MIMO antenna’s 90 dB isolating bandwidth (BW) were assessed. The planned antenna has several appealing features that set it apart from previous similar designs. These features include a low design complexity, a great Diversity Gain rate (DG > 9.99 dB), the BW of the proposed antenna extends from 25 GHz to more than 40 GHz, an enormously great isolation level (about 90 dB), and compressed dimensions (51 mm × 30 × 1.6 mm). For verifying the recommended antenna for MIMO. the suggested MIMO antenna design’s radiation efficiency, a thorough time-domain study is suggested.

Low-Cost L-Band to Ku-Band Frequency Reconfigurable BAR64-02V Controlled Antenna for Satellite, Military, and Radar Applications

A miniaturized edge-fed multi-band wideband (WB) sensor complementary split ring resonator (CSRR) and two folded pedal arms loaded antenna for wireless, ISM, military, Radar, and satellite applications is fabricated, tested, and investigated. The reduced ground plane at the bottom to makes the gain positive and leads to improvement in the radiation efficiency. Loading of antenna patch with two folded bicycle pedal-shaped arms results in an increased total electrical length and hence antenna could be tuned up to higher frequency bands. The appended two folded pedal arms enhance the value of gain and CSRR loading introduces additional resonant frequencies below −10dB reflection coefficient. The symmetrical ground width compression results in total antenna size miniaturization to 43.33% concerning the conventional circular microstrip antenna designed at a frequency of 2.45GHz. The antenna has a bidirectional radiation pattern with a gain of 5.21dBi and a radiation efficiency of 90.50%. The antenna exhibits four bands (2.13–2.58GHz), (2.77–3.89GHz), (5.65–6.56GHz), and (7.77–12.98GHz) within a frequency sweep of 1–15GHz, therefore it, is the most suitable element for Bluetooth, PCS, ISM band, 3G/4G/5G, Wi-MAX/WLAN/ Wi-Fi, and wireless, satellite, military, and RADAR applications. These bands are frequency reconfigured by two BAP64-02V PIN diodes in the pedal-arms fold locations with four switching combinations. The measured (frequency sweep: 1–23GHz) and simulated antenna reflection coefficient values are found in match except for a frequency range of 12–14 GHz. The antenna was fabricated on a low-cost FR-4 that holds well <12 GHz frequencies, and >12 GHz frequencies values this shows nonlinear and frequency dispersion.

Adaptive triple-fed antenna and thinned RF-chip integration into ultra thin flexible polymer foil

AbstractAttaching a wireless transmission system comprising a radio frequency (RF)-chip and a dipole antenna to dielectric material of largely different permittivity leads to strong variation of the antenna feed impedance. Due to the severe impedance mismatch between the RF-chip and the antenna, the performance of the system may deteriorate drastically. The proposed antenna provides three feed points, which show respective feed-point match to 100 Ohm balanced feeds for three different dielectric environments (free-space and half-spaces of permittivity 4 and 42, respectively). Thereby, the RF-chip incorporates three 100 Ohm balanced output ports that are connected to the antenna from whom only one can be selected to provide the output signal. The respective other two output ports are shorted by an internal switching circuit that is controlled by external DC voltages. The measurement of the reflection coefficient of the stand-alone antenna and the chip agree well with the simulations, allowing to interconnect these two components. Further, the radiation pattern of the whole system is measured for two different scenarios showing good functionalities.

Bio-based substrate for flexible electronics - application to a 2.45 GHz wearable patch antenna

In this paper, a bio-based and biocompatible polymer, Cellulose Laurate (CL), is proposed for flexible radio-frequency (RF) electronics. The synthesis of CL films together with their characterizations (chemical, thermal, mechanical and dielectric) are presented. The results obtained allow considering this material for RF flexible applications as a possible alternative to petrosourced substrates. Therefore, CL has been used to fabricate a flexible patch antenna that operates in an industrial, scientific and medical (ISM) frequency band. The central frequency selected is 2.45 GHz. The antenna fabrication process is based on the combination of laser structuring and the use of copper adhesive tape. Measurements of the antenna reflection coefficient and radiation patterns show that CL is a good candidate as a RF substrate. Furthermore, it is demonstrated that the antenna performance is only slightly impacted under bending conditions.

A 0.18 μm CMOS Millimeter Wave Antenna-on-Chip with Artificial Magnetic Conductor Design

This paper presents a small-size broadband slot monopole chip antenna for millimeter wave application. Using a 0.18 μm CMOS process, through metal_1, the artificial magnetic conductor (AMC) of the metal layer increased the impedance bandwidth of the chip antenna. The additional inverted C branch was used to achieve a better reflection coefficient. By adding an AMC and inverted C branch, the operating frequency of the chip antenna went to 33.8–110 GHz below the reflection coefficient of −10 dB, and its fractional bandwidth was 103.4%. The maximum gain was −6.3 dBi at 72 GHz. The overall chip size was 1.2 × 1.2 (mm2). Through measurement and verification, the proposed antenna reflection coefficient was close to the simulation trend and had better resonance. The frequency range of the chip antenna proposed in this paper covered the 5G NR FR2 band (24.2 GHz–52.6 GHz) and W-band (75 GHz–110 GHz). The proposed chip antenna can be applied to the Internet of Things, Industry 4.0, biomedical electronics, near field sensing and other related fields.

Designed on 0.18 μm CMOS Process Small Size Broadband Millimeter Wave Chip Antenna

This paper proposes a small-size broadband triangular monopole chip antenna for millimeter wave band applications. Process using 0.18 μm CMOS process and antenna design using Met-al_6. Triangular patch design and feed line length analysis to achieve a better reflection coefficient and also dig three circular slots at the grounding point to achieve better impedance matching. The operating frequency of the chip antenna is 62–100 GHz below the reflection coefficient −10 dB standard, with a fractional bandwidth of 54%. The maximum gain is −0.4 dBi at 64 GHz. The efficiency is 40.9%. The overall chip size is 1.2 × 1.2 (mm2). After measurement and verification, the proposed antenna reflection coefficient is similar to the simulation trend and has better resonance. The chip antenna frequency range proposed in this article covers the 5G NR FR2 frequency band. The proposed chip antenna can be applied in related fields such as the Internet of Things, Industry 4.0, and biomedical electronics.

QUALITY EVALUATION OF UHF RFID ANTENNAS AND PASSIVE TAGS ON PAPER SUBSTRATES

The effect of antenna design modification, paper substrates and relative electrical permittivity of background materials on the reflection coefficient of UHF RFID antennas was studied. Simulation software was used to modify the design and calculate the reflection coefficient of the antennas. By modifying the coupling of the dipole with the induction loop of the antennas, areduction of the simulated reflection coefficient was achieved compared to thecommercial antenna. The positive effect of antenna modification was also confirmed by measuring thereflection coefficient of antennas printed on paper by thermal transfer printing, placed on extruded polystyrene and particle board. The reflection coefficient of the modified antennas was lower when placed on extruded polystyrene, whose relative electrical permittivity was lower than particle board. After installing the memory chip to the antennas printed on paper and paperboard, the identification, reading and recording range of passive UHF RFID tags were measured after they were placed on thicker paperboard, extruded polystyrene and particle board. The positive effect of antenna modification on improving the communication quality of passive UHF RFID tags placed on background materials with a relative electrical permittivity of 2.4 to 6.7 wasconfirmed.

Development of Numerical Modeling for Finding Reflection and Transmission Coefficients in an Engineering Learning Paradigm of Computational Thinking

In electromagnetics and antenna engineering, reflection and transmission coefficients are important parameters to be evaluated statistically and numerically to obtain effective computer simulations. This paper proposes a pedagogy to understand the development methodology of numerical reflection and transmission coefficient models. The proposed method employs relatively easy mathematics instead of the conventional ways that use difficult mathematics. These are then simulated as computer models. The study in this paper included a medium comprising of air and glass placed in it. Firstly, the region was divided into a gridded structure where the grids were mathematically formulated. Points on the grid were distinguished between different media using electrical permittivity and conductivity. The grids included boundary conditions and electric field wave propagation through them. Both boundary conditions and field equations were numerically modelled and discretized using the finite difference method with a proportional h2 error. This method provided a system of linear equations, which were then solved linearly to obtain the required reflection and transmission coefficients. An important aspect of the presented work is to provide an example approach for computational thinking (CT), which is now considered an important part of any engineering curriculum

Elliptical UHF sensor for partial discharge detection

In this article, simplified geometries for microstrip antennas were evaluated and optimized, to select one appropriate geometry, aiming for its application of partial discharge (PD) detection, as a UHF sensor. To improve the performance of the proposed antenna, cascaded frequency selective surfaces (FSS), using double square loops as a unit cell element, were designed and evaluated. Antenna reflection coefficient measurements without and with the integrated FSS were performed and compared with simulated results. The results show that the insertion of the FSSs did not impact the operational bandwidth of the antenna, which comprises 100% of the characteristic frequency range, of the PD activity (300–1500 MHz). The insertion of the FSSs resulted in an average gain of 4 dBi, concerning the isolated antenna, increasing the sensitivity for PD detection, within the proposed frequency range. We evaluated the PD detection of the structure through measurements in three devices, a bar of a hydro generator, an oil tank with electrodes in the flat-tip configuration, and a potential transformer (PT). The proposed UHF sensor for PD detection could detect PD activity in all three scenarios and for levels lower than 10 mV.

Design and Study of the Performance of Patch Antenna with Double C Slot for MIMO-OFDM Based Communications Systems for Media Technology

Mobile phones, server stacks, and other high-bitrate devices demand greater bandwidth from antennas. More bandwidth means higher bitrates and more data sent. MIMO antennas simultaneously deliver and receive data. MIMO antennas can broadcast data to unreachable places with little noise. Multiple data streams and multipath propagation boost performance and data quality. Many antennas allow MIMO systems to send and receive data at regular intervals. These antennas can perform beamforming and determine a signal's 3-D route. OFDM increases bitrates at the same frequency by multiplexing without guard bands. Multiple orthogonal carrier frequencies increase data in the same bandwidth and avoid carrier distortion. Air gaps, parasitic patches, and substrate modifications are methods to increase bandwidth and beam width for patch antennas. The conventional patch pattern has been modified and refined for maximum success. This article proposes a patch antenna with double C slots. This new design features a large bandwidth, wide beamwidth, and multidirectional transmission pattern. The gain, VSWR, and reflection coefficient of this patch antenna meets the MIMO-OFDM systems with 5G standard. Hence the proposed antenna design is recommended to employ in the MIMO-OFDM system for 5G applications.

Design of EM Sensor for Non-Contact Detection of Defective Wire Harness in Conveyor System.

For a non-contact detection of defective wire harness in conveyor system, a new method using the electromagnetic (EM) sensor is proposed in this paper. A dual-feed and multi array microstrip patch antenna operating at 5.8 GHz is utilized to design the EM sensor. When the wire harness is located above patch antenna, the equivalent circuit of each patch antenna and wire harness can be modeled as shunt resistor, capacitor, and inductor. Moreover, a capacitive coupling between the patch antenna and the wire harness is generated. Next, the shunt resistor of wire harness increases due to the defect of the wire so that the reflection coefficient of the patch antenna is lower than that of the wire without defect; thus, the defect of wire harness can be detected by magnitude of reflection coefficient at resonant frequency. The performances of the designed EM sensor are verified and compared by the equivalent circuit modeling, full-wave simulation, and measurement.

Analysis of slotted matching antenna for millimeter wave applications

Millimeter wave applications gives an efficient solution to furnish peak data rates in indoor wireless access systems. Propagation of the signal will get up-shot because of few considerations in advanced communication appliances. Superior output and high directivity antennas are mandatory to overcome these consequences. By installing unequal slots in the structure, the tree-shaped unequal slotted antenna is analyzed for the variations in impedance, directivity changes and reflection coefficient. The better quality results have been observed for the proposed structure while compare with existing structures. The maximum simulation reflection coefficient(S11) of tree-shaped unequal slotted antenna is 45.12 dB, directivity is 6.54 dBi with the efficiency of 60 % and at 60 GHz, and the measurement value of 36.35 is observed which covers the complete RADAR applications which have an unlicensed bandwidth. The dimension of tree-shaped unequal slotted antenna is observed as 12*7*0.508 mm3. The proposed tree-shaped unequal slotted antenna is well suited for millimeter-wave appliances such as Microcell, Femtocell and macrocell applications because of its good bandwidth and less dimension.

Analysis, Optimization, and Hardware Implementation of Dipole Antenna Array for Wireless Applications

The antenna pattern synthesis is one of the significant problems in the phased array antenna. Pattern synthesis refers to the optimized weight excitation of each antenna element in order to steer the beam electronically without mechanically rotating the antenna. It can be achieved by using a combination of phase shifters and attenuator circuits. In this paper, a 2 by 2 dipole antennas with an RF beamforming circuit has been designed to steer the main beam along the azimuth plane. The main beam coverage from 100° to 140° with a step size of 10° has been successfully optimized using a hybrid of the induced EMF method and a genetic algorithm. The optimization results were compared to the full-wave simulation technique implemented in Empire XCCel. The design is realistically implemented at 2.45 GHz, with both simulation and measurement results shown. The measured reflection coefficient of the phased array antenna is −48 dB at 2.56 GHz. The feasibility of the beam synthesis has been validated successfully with the main beam being steered at 110°. The possibility of a fabrication discrepancy resulting in minor radiation degradation is also discussed in this research. The dipole antenna system with RF beamformer circuit can be applied to indoor positioning systems such as Wi-Fi, wireless local area network (WLAN), and fifth-generation.

UWB Bowtie Antenna for Medical Microwave Imaging Applications

This work presents a design and experimental validation of a compact ultrawideband (UWB) bowtie antenna and balanced-to-unbalanced (balun) circuit for medical microwave imaging (MWI) applications working in the frequency band of 1–6 GHz. The UWB balun is perpendicularly attached to the planar bowtie arms, whose dimensions were miniaturized by rounding the bowtie edges. The antenna reflection coefficient was lower than −12 dB for tissues with a higher water content. The antenna possesses a high radiation efficiency (over 80%) and very low backward radiation. The predicted and measured specific absorption rate (SAR) distributions together with the electric field <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert E\vert $ </tex-math></inline-formula> distribution proved a symmetrical radiation pattern. The potential of the presented antenna element was demonstrated by successful reconstruction of the images from the measured data by MWI methods. For this purpose, an MWI system equipped with eight antennas was implemented. The radar approach was used to determine the region of interest (ROI) where the area for microwave tomography reconstruction was identified. The dielectric properties within the ROI were reconstructed by using the Born approximation method at 1 GHz. This confirmed that the antenna can be used as the basis for more accurate multifrequency MWI systems and can be implemented in UWB MWI hybrid systems.

Antenna for 5G Mobile Communication at 28 GHz

Fifth generation (5G) mobile communications has become one of the trendiest issues in recent years, especially in the development of wireless technology for communications. As such, 5G mobile communications will also suffer severe path loss, due to the high frequency bands. This work presents the antennas for 5G mobile communication at 28 GHz on Rogers RT5880 with a dielectric constant, εr of 2.2, loss tangent, tan δ of 0.0009 and thickness, h of 0.787 mm. A rectangular microstrip patch are proposed in this work which consist of a single element and array configurations with two and four elements. Microstrip feed line and inset feed line are implemented to observe their performances. It can be observed from the simulation results that the gain and directivity increase from a single element up until four elements array antenna for both the microstrip feed line and inset feed line of the rectangular microstrip patch antenna. This confirm to the fact that array antenna produces high gain and directivity which could overcome the challenge of high free space path loss in millimeter-wave. The spacing between each element in the array antenna are spaced accordingly and not so close with each other in order to suppress the mutual coupling between the elements. It is shown that the mutual coupling is greatly reduced based on the greater values of reflection coefficient in two-element and four-element array antennas. Based on the gain, directivity and reflection coefficient, inset feed line antennas perform better than microstrip feed line antennas. In terms of dimensions, the size of the antenna with an inset feed line reduces as compared to microstrip feed line as the number of elements increases. Thus, it is safe to conclude that inset feed line antennas outperform microstrip feed line antennas when it comes to gain, directivity, reflection coefficient, and dimensions of antennas. Therefore, the proposed array antennas in this work are suitable to be used in 5G mobile communications.

Circular monopole filtering antenna with improved sideband selectivity and in-band impedance using circular-stub-load resonator

Abstract In the design of the filter antenna, the filter unit with the same structure as the radiation patch not only improves the selectivity of the band edge, but also helps to improve the in-band impedance. In this design, a compact circular monopole filtering antenna with improved sideband selectivity and in-band impedance using a circular-stub-load resonator is proposed. To obtain better sideband selection characteristics and in-band impedance characteristics, and reduce the mismatch problem caused by the introduction of the filter, a branch-loaded filter with the same resonance mode as the antenna radiation patch is designed. In addition, different shape branch loading structures of the bandpass filter are also studied. The experimental results show that when the loading unit of the filter and the radiation structure of the antenna have the same structure, both good in-band impedance characteristics and sideband selectivity characteristics can be obtained from the filter antenna. The antenna reflection coefficient bandwidth is from 3 to 11 GHz (114%), and the maximum reflection coefficient is only −15 dB, showing good in-band impedance characteristics and sideband selection characteristics. The filter antenna realizes the integration of antenna filtering without increasing the size, and the final size of the antenna is 30 × 25 mm2.

A test method for active reflection coefficient of array antenna

The mutual coupling effect of array antenna can usually be characterized by the dominance of active reflection coefficient. A test method of active reflection coefficient is proposed in this paper. the theory of antenna active reflection coefficient is analyzed, and the array antenna modeling and active reflection coefficient simulation results are introduced by HFSS. the hardware composition and function of antenna active reflection coefficient test system are introduced. the comparison between test results and simulation results is analyzed. The results are in good agreement. Compared with the traditional test methods, the designed test system has the characteristics of intuitive test results, fast measurement speed, high sensitivity, large dynamic range, small measurement error and strong expansibility.

Classification of motor faults based on transmission coefficient and reflection coefficient of omni-directional antenna using DCNN

The most commonly used electrical rotary machines in the field are induction machines. In this paper, we propose an antenna based approach for the classification of motor faults in induction motors using the reflection coefficient S11 and the transmission coefficient S21 of the antenna. The spectrograms of S11 and S21 is seen to possess unique signatures for various fault conditions that are used for the classification. To learn the required characteristics and classification boundaries, deep convolution neural network (DCNN) is applied to the spectrogram of the S-parameter. DCNN has been found to reach classification accuracy 93% using S11, 98.1% using S21 and 100% using both S11 and S21. The effect of antenna operating frequency, its location and duration of signal on the classification accuracy is also presented and discussed.

Microstip Antenna Reflection Coefficient with X Slot Addition Method for 5G Connection

The development of cellular technology has now entered the 5th generation (5G), this 5th generation provides 3 types of services, eMBB (enhanced Mobile BroadBand), URLLC (Ultra-Reliable and Low-Latency Communications) and mMTC (massive Machine Type of Communications). One of the important devices in 5G technology is an antenna device which is able to support these 3 services. 5G technology requires an antenna that has high performance. There are various types of antennas, one of which is a microstrip antenna. Microstrip antenna is one of the most widely used antennas in telecommunications because of its light mass, small dimensions and easy fabrication. There are various ways or methods that can be done to overcome the narrow bandwidth of microstrip antennas, by increasing the thickness of the substrate, using parasitic elements, reducing the value of the dielectric constant, adding inserts to the feeder, or by modifying the patch by adding slots on the patch antenna. In this study to improve the performance value of the microstrip antenna, the researchers discussed increasing the reflection coefficient by adding X Slots to a microstrip antenna with a working frequency of 3.5 GHz for 5G communication. The results of this study showed an increase in the reflection coefficient of 67%, and an increase in bandwidth of 5%.

Human Activity Classification Using On-Body Miniaturized Antennas.

EM waves are extremely powerful when it comes to propagation of information during communication. There is no alternative to EM waves in such applications. However, the use of EM waves or antennas in general has not been explored fully as sensors for measuring the change in physical environment. This particular aspect has been exploited and the present work focuses on the application of antennas into the domain of classification. We propose accurate human activity classification (HAC) using on body miniaturized antennas. A simple patch antenna has been designed in order to be employed on human body for HAC. The antenna has been tested with respect to its Specific Absorption Ratio (SAR) values in order to make it body-mountable. The antenna has been fabricated and tested on human body while performing daily activities. The reflection co-efficient of antennas is a function of human motion activities and this principle is exploited to achieve the desired results. To explore different approaches, a miniaturized circularly polarized antenna is then designed and tested. The results of the two antennas are then compared. Dynamic Time Warping (DTW) algorithm has been used for the analysis of the Reflection co-efficient of the antenna. Excellent activity classification performance has been obtained using both the antennas, the miniaturized antenna giving better results.