Industrial , Scientific And Medical Research Articles

Meandering Pattern 433 MHz Antennas for Ingestible Capsules

A number of design challenges are associated with in-body devices, especially ingestible capsules, including selection of operation frequency and antenna design. Operation frequency, miniaturization, gain, and interference with the environment and the internal components of ingestible capsules are all challenging factors. In this work, we design and measure the performance of miniature antennas that can be included in ingestible capsules. The meandering pattern designs are implemented with a 433 MHz center frequency which is within one of the industrial, scientific and medical (ISM) bands. The antenna patterns are rolled into cylinders to reflect their configuration inside a capsule. The effects of different antenna design features, environmental dielectric changes, and the battery locations relative to the antenna traces are explored. We show that the optimized antenna can offer acceptable performance even when the center frequency shifts due to the modulation of the dielectric constant of the media and by the insertion of batteries. Both simulations and measurements provide insight into how the meandering antenna should be designed for the desired frequency that can be expanded to other ingestible and implantable systems.

Simulation study of microstrip antenna for 2.45 GHz applications based on octagon shaped

In late years, microstrip patch antennas have been widely used in various communication systems due to their lightness in weight, smallness in size, low manufacturing cost and, reasonable gain. Therefore, various figures and dimensions of microstrip patch antennas are available. This paper presents an octagonal ring-shaped multi-slot patch antenna with a single resonant frequency at 2.45 GHz of the Industrial Scientific and Medical (ISM) band with an omnidirectional pattern based on the Tikrit university logo. The unique structure of the octagon figure is demonstrated by adding trigonal patches on the sides and top of the rectangular microstrip patch antenna to achieve the eight-pointed star figure. The Octagon ring shape is achieved by inserting a single octagon slot and multi slots of a rectangular, square, triangle to maintain the operating frequency. The reduction in the size of the antenna is carried out by adding an octagon/rectangular patch to the partial ground plane. The suggested antenna is plotted and simulated on a substrate board FR-4 of dimensions 60 × 46 × 1.6 mm3 using CST Microwave Studio 2017. The results show compact size, 2.9 dBi gain, improved S11 response of −23.18 dB at 2.45 GHz, size reduction of 10.44%, and omnidirectional radiation pattern that can be utilized to harvest radio frequency (RF) energy from Wi-Fi and bluetooth (2.4–2.5 GHz).

DGS-based wideband MIMO antenna for on–off body communication with port isolation enhancement operating at 2.45 GHz industrial scientific and medical band

A wide band, dual radiator Multiple input multiple output (MIMO) antenna resonating at 2.4 GHz Industrial Scientific and Medical (ISM) band is designed and analysed for the body-centric wireless communication. Defected ground structure (DGS) is used to reduce the antenna size and to achieve wide bandwidth. Moreover, a decoupling slot is also etched in the ground plane to improve the port isolation. Proposed 2 × 1 array MIMO structure has occupied the volume of 90 × 40 × 0.8 mm3. Rectangular and cylindrical shaped multi-layered tissue models are used for simulation and pork tissue is used for the measurement of antenna performance. Broad 10-dB bandwidth of 1250/900 MHz, port isolation of 21/20 dB, gain of 5.53/5.07 dBi with, SAR value of 0.628/0.627 W/kg is achieved for the flat/deformed state of antenna. Results show that the proposed DGS-based antenna is reliable to operate on different tissue environment for body area network.

Dielectric properties of Mexican sauces for microwave-assisted pasteurization process.

The dielectric properties and specifically the complex relative permittivity of foods are key elements for the design of pasteurization processes with high frequency electromagnetic waves. Mexican sauces are recognized worldwide for their flavor and nutritional properties. In this work, the complex permittivity of four of the most representative sauces of Mexican cuisine (chipotle chili, habanero chili, red and green sauce) is presented. The permittivity was measured with the open coaxial probe method at temperatures of 25, 40, 55, 70, 85 °C and in the frequency range of 500MHz to 6GHz. Additionally, moisture content, specific heat, viscosity, water activity, density and electrical conductivity are reported, these last three at 25 °C. Dielectric properties were affected by the sauce formulation. The loss factor of each sauce sample at any temperature presents significant changes in relation to the frequency. At 915 and 2,450MHz, , which would cause a thermal runaway effect or the uncontrolled rise in temperature in the sauces during the microwave pasteurization. At 5,800MHz, , which would give better control for microwave heating than at 915 and 2,450MHz. At 915MHz, the loss factor of all sauces is higher than at 2,450 and 5,800MHz, therefore, more rapid heating can be produced. Moreover, at 915MHz, microwaves exhibit higher penetration depth than at 2,450 and 5,800MHz; therefore, at 915MHz, the greatest uniform microwave dielectric heating would be achieved. Thus, 915MHz is the frequency recommended for the studied sauces pasteurization. PRACTICAL APPLICATION: This work provides the dielectric properties of Mexican sauces at different temperatures and their penetration depths in the microwave range, which are key information for further microwave-assisted pasteurization process and for getting safer sauces for consumers. Moreover, this research supplies suggestions about what frequency for ISM (Industrial, Scientific and Medical) applications is the best for microwave-assisted pasteurization according to the penetration depth of the electromagnetic wave in the sauces and microwave dielectric heating speed of the sauces.

High gain antenna at 915 MHz for off grid wireless networks

This paper presents a high gain antenna for off-grid wireless networks at 915 MHz. The requirements for compact size and high gain antenna are needed in the industrial, scientific and medical (ISM) band for better performance and coverage. Hence, microstrip planar substrate is proposed to overcome the size challenges. The proposed antenna is designed based on rectangular patch with air gap technique. The proposed antenna is optimized using computer simulation technology software (CST) and fabricated on low profile FR-4 substrate. The measured performance agreed well with the simulated one. The reflection of less than -10 dB is obtained with high gain of 6.928 dB at desired frequency. Overall, this antenna can be a good candidate for the off-grid wireless network applications.

A Triband Rectifier Toward Millimeter-Wave Frequencies for Energy Harvesting and Wireless Power-Transfer Applications

This letter presents an efficient single-cell triband rectifier matched at millimeter-wave frequencies of 24, 28, and 38 GHz using a novel, compact multiband impedance matching network (IMN). The proposed multiband IMN is scalable and is used to design a miniaturized rectifier at the desired frequencies. The actual impedance of rectifier was measured using through-reflect-line (TRL) calibration for accurate design. A prototype of rectifier was realized on Rogers 5880 substrate. The rectifier is capable of harvesting dc output simultaneously from three different millimeter-wave frequency bands including two 5G communication bands and industrial, scientific and medical (ISM) band at 24 GHz. The maximum simulated efficiencies obtained at 24, 28, and 38 GHz are 44.3%, 42.7%, and 43.6% at an input power of about 15.6 dBm and the measured efficiencies are 44%, 41.3%, and 39.7% at an input power of 17.5 dBm, respectively. This rectifier finds its applications as an energy harvester and wireless power transmitter for self-sustainable low-power batteryless systems.

Design of a Compact Dual-Band Antenna for On-/Off Body Communication

In this paper, a compact, dual-band, patch antenna structure for body-centric relay node communication is presented. The antenna is designed to operate at Industrial, Scientific and Medical (ISM) bands at 2.45 GHz for receiving data from intra-body sensor nodes and 5.0 GHz for transmitting signal to external monitoring device. The antenna is designed by using coplanar waveguide feed and etching two open-end slots on radiating patch. Overall antenna dimensions are 15 mm × 28 mm × 1.57 mm. Effective dielectric constant for the multiple dielectric layers, due to its heterogeneous tissue structure, has been calculated. Antenna performance is measured both in free space and on tissue model. On body, a wide bandwidth of 250 and 370 MHz is obtained that enhances antenna robustness to operate on different types of body tissues. Radiation pattern toward the surface of body at 2.45 GHz and directional pattern normal to the surface of body at 5.0 GHz are achieved. High directivity of 7.18 dBi at 5.0 GHz is obtained which is good to maintain robust communication link with the external control unit. Small size, good radiation characteristics and low SAR value make the antenna a good choice for operating in close proximity to human body.

Design and development of Ni0.75Zn0.25Fe2O4/MWCNT microstrip patch antenna (MPA) for ISM band spectrum applications

This research paper represents the design and development of a microstrip patch antenna (MPA) for the ISM (Industrial, Scientific and Medical) band spectrum applications. The main objective of this paper is to analyze the performance of the MPA design using new engineering materials (Ni0.75Zn0.25Fe2O4/MWCNT) synthesized through chemical vapour deposition (CVD) method by utilizing the use of waste cooking oil (WCO) as a carbon source which acts as a printed radiating patch in order to replace a copper or gold (conventional) radiating patch in previous literature. The proposed antenna is fabricated on kapton substrate with dielectric constant, εr = 3.4 and loss tangent, tan δ = 0.004. The conducting patch is Ni0.75Zn0.25Fe2O4/MWCNT and ground antenna material is copper. The results demonstrate that the antenna is capable to comprehend return loss (RL) of – 24.03 dB at frequency of 2.43 GHz with bandwidth of 1.00 GHz and voltage standing wave ratio (VSWR) of 1.14. The antenna has overall dimensions of 33.60 × 41.74 × 0.025 mm3.

Highly efficient artificial magnetic conductor enabled CPW fed compact antenna for BAN wearable applications

Abstract In this paper a coplanar waveguide feed (CPW) monopole antenna backed with artificial magnetic conductor (AMC) structure for efficient radiation has been presented for off-body wearable applications. A split ring resonator (SRR) having thiner and longer lines to produce higher inductance and six splits with smaller gaps for high capacitance have been placed underneath CPW fed monopole to achieve resonance mode at a lower frequency. Higher values of inductance and capacitance produce resonant modes at relatively lower frequencies resulting in highly miniaturized antenna. The desired −10dB S11 bandwidth has been optimized firstly, by tuning/optimizing flow of surface currents with the help of several slots/slits and later by realizing AMC reflector with the help of full ground backed foam. The proposed antenna covers 2.45 GHz industrial, scientific and medical (ISM) band body area network (BAN) application and posses good front to back ratio (FBR) and thereby low and acceptable values of specific absorption rate (SAR). The proposed antenna has been designed and simulated using Ansys high frequency structured simulator and tested using vector network analyzer and anechoic chamber. The simulated and measured results well agree with each other.

Low-Power RFED Wake-Up Receiver Design for Low-Cost Wireless Sensor Network Applications.

The development of wake-up receivers (WuR) has recently received a lot of interest from both academia and industry researchers, primarily because of their major impact on the improvement of the performance of wireless sensor networks (WSNs). In this paper, we present the development of three different radiofrequency envelope detection (RFED) based WuRs operating at the 868 MHz industrial, scientific and medical (ISM) band. These circuits can find application in densely populated WSNs, which are fundamental components of Internet-of-Things (IoT) or Internet-of-Everything (IoE) applications. The aim of this work is to provide circuits with high integrability and a low cost-per-node, so as to facilitate the implementation of sensor nodes in low-cost IoT applications. In order to demonstrate the feasibility of implementing a WuR with commercially available off-chip components, the design of an RFED WuR in a PCB mount is presented. The circuit is validated in a real scenario by testing the WuR in a system with a pattern recognizer (AS3933), an MCU (MSP430G2553 from TI), a transceiver (CC1101 from TI) and a T/R switch (ADG918). The WuR has no active components and features a sensitivity of about −50 dBm, with a total size of 22.5 × 51.8 mm2. To facilitate the integration of the WuR in compact systems and low-cost applications, two designs in a commercial UMC 65 nm CMOS process are also explored. Firstly, an RFED WuR with integrated transformer providing a passive voltage gain of 18 dB is demonstrated. The circuit achieves a sensitivity as low as −62 dBm and a power consumption of only 528 nW, with a total area of 634 × 391 μm2. Secondly, so as to reduce the area of the circuit, a design of a tuned-RF WuR with integrated current-reuse active inductor is presented. In this case, the WuR features a sensitivity of −55 dBm with a power consumption of 43.5 μW and a total area of 272 × 464 μm2, obtaining a significant area reduction at the expense of higher power consumption. The alternatives presented show a very low die footprint with a performance in line with most of the state-of-the-art contributions, making the topologies attractive in scenarios where high integrability and low cost-per-node are necessary.

Feasibility of Backscatter Communication Using LoRAWAN Signals for Deep Implanted Devices and Wearable Applications.

This paper presents a method for low data rate transmission for devices implanted in the body using backscattered Long Range (LoRa) signals. The method uses an antenna loaded with a switch that changes between two load impedances at the rate of a modulating oscillator. Consequently, the LoRa signal transmitted by a LoRa node is reflected in the adjacent channels and can be detected with a LoRa gateway tuned to the shifted channels. A prototype developed to operate at Medical Implant Communication Service (MICS) and the Industrial Scientific and Medical (ISM) 433 MHz band is presented. The prototype uses a commercial ceramic antenna with a matched network tuned to the frequency band with high radiation efficiency. The effect of the coating material covering the antenna was studied. Simulated and experimental results using a phantom show that it is feasible to read data from deep implanted devices placed a few meters from the body because of the high sensitivity of commercial LoRa receivers.

Power Distribution of Device-to-Device Communications Under Nakagami Fading Channel

Recently, device-to-device (D2D) communication was designated to work in cellular networks as a new standard to boost their performances. This kind of communication can occur either underlay to the existing cellular infrastructure, or overlay in the industrial scientific and medical (ISM) unused band. In this paper, we consider the case that D2D transmissions take place concurrently with the usual cellular players in the same spectrum band, and thus, controlling the interference caused by the cellular user equipments (UEs) is of crucial importance. In this work, we consider the uplink transmission of a tier of D2D users. Using network model based on stochastic geometry, we express the general cumulative distribution function (CDF) of the D2D transmit power under Nakagami fading channel. Special cases as CDF of the transmit power for Rayleigh fading and noiseless environment were derived. Besides, an upper bound of the general CDF expression is proposed. To deal with D2D lifetime, first, we express the expectation of the transmit power, then we determine the expectation of the devices lifetime and finally, we give an upper bound of this lifetime expectation. Through simulation, the obtained numerical results confirm the effectiveness of the proposed analytic schemes.

A fully-textile wideband AMC-backed antenna for wristband WiMAX and medical applications

AbstractProposed is a wideband, low profile, fully flexible, and all-textile-based slotted triangular antenna loaded with a 2 × 2 textile-inspired artificial magnetic conductor to be worn on the wrist. The integrated antenna design is designed to cover the frequency band from 3.1 to 6.5 GHz. The integrated design has two main resonances, where the first one is at 3.5 GHz, which can serve the WiMAX communication standard, while the second is at 5.8 GHz, which can serve the Industrial, Scientific and Medical (ISM)-band. The incorporated textile materials are composed of the conductive and dielectric fabrics that are realized by ShieldIt and Felt, respectively. When simulated against the human model wrist, the integrated antenna design displayed a realized gain of 6.71 dBi and radiation efficiency of 79.1%, at 3.5 GHz. Furthermore, at 5.8 GHz, it displayed a realized gain of 7.82 dBi and total efficiency performances of 66.1%. Moreover, it accomplished very low SAR levels within the antenna frequency band. Averaged over 1 g of tissue, it exhibited maximum SAR levels of 3.28 × 10−6 and 9.37 × 10−7 W/kg at 3.5 and 5.8 GHz, respectively. For the bent scenarios, the integrated antenna design displayed robustness when bent at an angle of 20 and 40°. Finally, measurement results are illustrated and analyzed. Based on the presented results, the suggested all-textile integrated antenna design might be designated for integration with the wristband to monitor the user health conditions through many possible frequency channels.

Compact wearable dual wideband circularly polarized L-strip fed slotted textile antenna with parasitic elements for ISM band applications

This paper presents an L-strip fed compact wearable dual wide band circularly polarized textile antenna (DWCPTA) with a pair of parasitic elements and dual wide band operations at frequencies 2.45 and 5.80 GHz for industrial, scientific and medical (ISM) band applications. The antenna is printed on top of denim (jeans) substrate having dielectric constant 1.7 and thickness of 1.43 mm with wide slot ground plane on back side. The proposed DWCPTA of size 40 × 40 × 1.43 mm3 achieves -10 dB simulation impedance bandwidth of 89.16% (2.3 – 6.0 GHz) and 3-dB axial ratio bandwidth (ARBW) of 47.55% (2.34 – 3.80 GHz) and 12.60% (5.20 – 5.90 GHz) and essentially, low specific absorption rate (SAR) values of 0.8 and 0.95 W/Kg over 10 g of human tissues for wide band operations at frequencies 2.45 and 5.80 GHz respectively. The proposed DWCPTA is designed, fabricated and tested, which shows good agreement between measured and simulated ones.

Design of an aperture coupled MIMO antenna for on-body communication and performance enhancement with dielectric back reflector

Abstract Compact antennas with robust on-body performance are achieving more interest for wearable sensor nodes. In this paper, a modified aperture coupled multiple input multiple output (MIMO) antenna operating at 2.45 GHz industrial scientific and medical (ISM) band is presented for wearable devices. 8-shaped radiator with L-shaped ground slot is used to miniaturize the antenna dimensions. A dielectric reflector is added below the antenna to reduce the back radiations towards the body tissue. On-body performance is analysed on three layered equivalent tissue phantom model. Antenna shows reflection coefficient of −40 dB, efficiency of 58% and directivity of 6.7 dBi when operated in close proximity of body tissue with dielectric reflector. unidirectional radiation pattern and low specific absorption rate makes antenna suitable for on-body communication. Further, diversity performance is measured in terms of envelope correlation coefficient (ECC) and diversity gain (DG). Value of ECC is 0.045 and DG is 9.7 dB at 2.45 GHz. Antenna robustness is examined by bending the structure along x-axis. Performance of the proposed structure makes it a suitable candidate for on-body communication.

Wideband textile multiple‐input‐multiple‐output antenna for industrial, scientific and medical (ISM) /wearable applications

A compact, wideband, two-element textile multiple-input-multiple-output (MIMO) antenna is presented for industrial, scientific and medical (ISM)/wearable applications. The proposed structure is composed of the Felt material substrate, and the ground plane and radiating patch are formed using ShielditTM Super conductive material. The designed MIMO antenna offers a wide impedance matching bandwidth (S11 ≤ −10 dB) of 2.00−6.23 GHz, a very low mutual coupling of (S21,max) −29.26 dB, low envelope correlation coefficient <0.01, high diversity gain ∼9.95 dB, and realized gain of more than 2.88 dBi, over the entire band. The prototype of the proposed antenna geometry is fabricated, and it has a size of 76 × 37 mm2. The proposed antenna could be a good candidate for wearable electronic devices due to its compact size, all textile layers, easy integration, robustness, and reasonable on-body performance.

Projeto de uma Antena Planar Dipolo Curvado para Aplicação na Comunicação da Indústria 4.0

This article contemplates a qualitative analysis of the operation of a Curved Planar Dipole Antenna, of the line meander type and its applicability in the Internet of Things (IoT). Technology originated in the midst of the intelligent technological development of the current period, considered as the Fourth Industrial Revolution or Industry 4.0 and marked by the improvement of systems that promote automation of tasks, control and data sharing in wireless networks in real time. IoT is associated with facilitated connectivity between the physical and digital world through the internet or miniaturized elements, generating optimization in the manufacturing and routine processes. Particularly, planar antennas stand out in this regard, as they provide the transmission or reception of signals by means of electromagnetic waves, have low manufacturing cost, small volume and weight and are built according to the desired purpose. Thus, the proposed objective was to design, simulate and analyze a meander line antenna that operates in the 2.4GHz ISM (Industrial, Scientific and Medical) frequency range, verifying its effectiveness in the IoT. However, with the aid of the HFSS® software, satisfactory results regarding the resonance frequency and radiation diagram of the studied device are obtained in a computer simulation environment.

Characterization of sparse WLAN data traffic in opportunistic indoor environments as a prior for coexistence scenarios of modern wireless technologies

CR enabled radio environment provides the seamless operating framework to cope with the requirements of next generation wireless systems like higher data rates, massive machine time communication and interference free coexistence scenarios of wireless technologies. Traffic characterization studies assist to optimize coexistence framework by providing necessary information about the usage patterns of wireless services in observed radio bands. Prior knowledge about the observed sparse wireless local area network (WLAN) data traffic is a key for opportunistic radio resource allocation and utilization in the given coexistence scenarios of WLAN either with cellular systems (including 5G-NR/4G Long Term Evolution (LTE)) or with low power wireless systems (including Bluetooth and ZigBee). Parametric methodology is adapted to model the sparse WLAN data traffic observed in 2.4 GHz Industrial, Scientific and Medical (ISM) band as spectral and temporal activity. The multivariate Gaussian mixture model (MGMM) is proposed in both scenarios where either dependency is considered between the observed WLAN data traffic or assuming that the observed traffic is independent and identically distributed (i.i.d). It is to be validated that in order to have an efficient characterization of sparse WLAN data traffic, the dependency (correlation) between neighbored frequency subbands must be considered. By considering the dependency either between neighbored frequency subbands or neighbored time domain signals actually help to characterize the sparse WLAN data traffic in more realistic way which could not be possible by assuming them i.i.d. Such statistics to characterize sparse data traffic really help as user activity for efficient allocation and utilization of radio resources in CR enabled coexistence scenarios of wireless technologies where WLAN acitivity is considered nominal either as secondary user or classify it grey spectrum as primary user.

Spectrum Occupancy and Interference Model Based on Network Experimentation in Hospital

Emerging healthcare radio technologies are designed to operate in the 2.4GHz industrial, scientific and medical (ISM) band. Since both standardized (Bluetooth and Wi-Fi) and non-standardized (proprietary) devices use the same frequency band, the aggregate interference may significantly affect the performance of medical wireless systems. This paper characterizes the spatiotemporal spectrum occupancy and proposes models for the aggregate interference in hospital environments. In particular, time–frequency and cluster-based statistical models for the aggregate interference are developed based on network experimentation. The proposed models enable the design of wireless networks for e-health applications and medical services.

A Compact Highly Efficient Π-Section CRLH Antenna Loaded With Textile AMC for Wireless Body Area Network Applications

An ultrathin, compact, and highly efficient antenna based on the π-section composite right/left-handed (CRLH) methodology is presented. It operates at 2.45 GHz of the Industrial, Scientific and Medical (ISM) band with a physical size of 25 mm × 25 mm, a realized gain of 2.34 dBi, and a total efficiency of 87% in free space. Nevertheless, to maintain resonance at 2.45 GHz with body-loading scenarios, a high separation was required, leading to an overall large size. To circumvent that, an all-textile 2 × 2 artificial magnetic conductor (AMC) array was placed in-between the antenna and the human body. In free space, the low-profile integrated design exhibited a gain of 7.63 dBi (enhancement of 5.29 dBi) and total efficiency of 96.4%. The integrated design achieved a gain and total efficiency enhancements by 14.88 dBi and 72.4%, respectively, as well as, lower specific absorption rate (SAR) levels, in comparison with the CRLH antenna alone, for human loading cases. Results are achieved through circuit model and full-wave electromagnetic simulations. In addition, the CRLH antenna and AMC array structure were fabricated and measurements were undertaken, which agreed well with the simulated ones. Therefore, the integrated design is highly suggested to be recognized in wireless body area network (WBAN) and medical applications.