GHz Industrial, Scientific And Medical Band Research Articles

An Ultra – Wideband Compact Meander Line Antenna for Brain Implants and Biotelemetry Applications in the 2.45 GHz ISM Band

This paper proposed the meander line based wideband implantable antenna for brain implant applications operated at the industrial, scientific and medical (ISM) band (2.4 – 2.48 GHz). The proposed antenna, with minuscule dimensions of 10mm×10mm and 0.635 mm thickness of Rogers RT/Duroid 6010 material (εr=10.2,tanδ=0.0023) is adopted as a substrate and 0.2 mm thickness of superstrate layer. Incorporating a meandering line as a radiator and shorting a pin allows impedance matching, minimizes antenna area, and enhances bandwidth. To evaluate the efficacy of the implantable antenna, used both a homogeneous brain phantom and a seven-layer heterogeneous brain phantom including layers of skin, fat, cortical bone, dura, cerebrospinal fluid, grey and white matter. The proposed antenna was located below the dura and in the cerebrospinal fluid at the depth of 15.5 mm. The proposed antenna was fabricated and validated the result using mimicking gel as well as in minced pork, the obtained peak gain is -17.3 dBi and the impedance bandwidth is 828 MHz. The specific absorption rate was calculated both the seven-layer brain phantom model [516 W/kg (1-g) and 82 W/kg (10-g)] and realistic human head model [232.7 W/kg (1-g) and 48.65 W/kg (10-g)] meets the IEEE safety requirements, ensuring brain tissue safety. Furthermore, to confirm the stability and dependability of the biotelemetry link and verify the coverage of implantable antenna the link budget analysis is carried out for 10-meter distance.

Analysis of muscle implanted antenna performance with the variation of implantation depth

Abstract Implantation depth of Implantable Medical Devices (IMDs) is an important factor of communication quality between implantable antennas in IMDs and external devices. Therefore, it is required to study the effect of implantation depth on implantable antenna performance. In this article, dependence of resonant frequency and scattering parameters of a two-antenna system where one miniaturized meander-line antenna is placed within human muscle tissue layer operating at 2.45 GHz ISM (industrial, scientific and medical) band and a rectangular patch antenna placed outside human body, are tested. Here 15 values of implantation depth ranging over 5–35 mm inside muscle layer are taken and for each case resonant frequency and scattering parameters (S 11 and S 21) of the system are recorded. Statistical analysis has been performed to observe how these performance parameters are dependent on depth of implantation which may be varied at the time of surgery.

A High Performance All-Textile Wearable Antenna for Wristband Application.

A compact, conformal, all-textile wearable antenna is proposed in this paper for the 2.45 GHz ISM (Industrial, Scientific and Medical) band. The integrated design consists of a monopole radiator backed by a 2 × 1 Electromagnetic Band Gap (EBG) array, resulting in a small form factor suitable for wristband applications. An EBG unit cell is optimized to work in the desired operating band, the results of which are further explored to achieve bandwidth maximization via floating EBG ground. A monopole radiator is made to work in association with the EBG layer to produce the resonance in the ISM band with plausible radiation characteristics. The fabricated design is tested for free space performance analysis and subjected to human body loading. The proposed antenna design achieves bandwidth of 2.39 GHz to 2.54 GHz with a compact footprint of 35.4 × 82.4 mm2. The experimental investigations reveal that the reported design adequately retains its performance while operating in close proximity to human beings. The presented Specific Absorption Rate (SAR) analysis reveals 0.297 W/kg calculated at 0.5 W input power, which certifies that the proposed antenna is safe for use in wearable devices.

Cavity Backed Slot Antenna Fed by a Stripline with SIW Structure and Vertical Coaxial Transition for Microwave Solid-State Heating Applications

This paper presents a new approach to feed multimode cavities used as microwave applicators for industrial and domestic microwave ovens using solid-state sources operating in the 2.45 GHz ISM (Industrial, Scientific and Medical) band (commonly used for industrial microwave applications). The feeding structure consists of a slot on the top side of the applicator cavity. The slot is fed by a shielded asymmetric stripline with a Substrate Integrated Waveguide structure (to preserve the stripline Transversal Electro-Magnetic (TEM) operation within the shield) and is N-connectorized. A first design of the antenna was obtained using state-of-the-art antenna theory assuming free-space radiation. Then, it was refined using a commercial simulation tool based on the Finite Element Method in the frequency domain to achieve VSWR values lower than 1.5 in the source bandwidth (from 2.42 to 2.48 GHz) when the antenna radiates into the applicator cavity. The design parameters of all the components making up this feeding structure are discussed throughout the paper. A prototype was built and measured in the laboratory. The experimental results are presented at the end of the paper along with the simulated ones, showing a very good agreement.

Ultra-low-power wideband NMOS LC-VCO design for autonomous connected objects

In this paper, a fully integrated sub threshold LC voltage controlled oscillator (VCO) is presented. A design methodology is also proposed to find the optimal parameters lowering the power consumption. This methodology has been applied to design oscillators for different frequency bands. Furthermore, an adaptive body biasing technique has been used to improve the startup constrains and allows a high immunity to PVT (process, voltage and temperature) variations. A VCO operating in 5 GHz ISM (Industrial, Scientific and Medical) band has been realized with the proposed methodology in 0.13 μm CMOS. It consumes only 468 μW from 0.39 V supply voltage. This makes it possible to meet the required specifications of autonomous connected objects and IoT applications. The measured oscillation frequency can be tuned from 5.14 to 5.44 GHz. The obtained phase noise is approximately equal to − 112 dBc/Hz in post-layout simulation (PLS) and − 104.5 dBc/Hz in measure.

Performance analysis of LoRa in the 2.4 GHz ISM band: coexistence issues with Wi-Fi

Within realization of the visions of the Internet-of-Things (IoT), Low Power Wide Area Networks (LPWANs) are undoubtedly one of the fields that attract high interest from both academic and industrial fields. To ensure reliable data exchange between low power and low data rate devices across long distances, which are the main aims of LPWAs, it is necessary to utilize advanced wireless communication technologies. Emerging LPWA technologies, for instance Long-Range (LoRa) and SigFox, offer many benefits for IoT. These technologies have been primarily developed for sub-GHz frequency bands, but, in the future, their deployment is also considered in the 2.4 GHz industrial, scientific and medical (ISM) bands. However, these unlicensed ISM bands are also used by other technologies for Wireless Local Area Network (WLAN also denoted as Wi-Fi) connectivity and other services, and therefore, coexistence issues can occur here in the future. The main aim of this paper is to perform a performance analysis of the LoRa radio signals interfered by Wi-Fi, using interferers confirming to different IEEE 802.11 family standards, in the 2.4 GHz ISM band. For this purpose, an automated measurement setup and methodology on Physical (PHY) layer are proposed and used. In general, the evaluated results confirm theoretical assumptions on high robustness of LoRa against interferences. However, our results reveal that this robustness of LoRa is highly depending not only on the used LoRa system parameters, but also on the interferer properties and the assumed coexistence scenarios (co-channel, in-band and adjacent channel interferences).

Dual-Band Circular Polarized Flexible Implantable Antenna Using Reactive Impedance Substrate

This communication presents a compact wideband implantable loop antenna with circular polarization (CP) characteristics at 920 MHz industrial scientific and medical (ISM) (902–928 MHz) band and 2.45 GHz ISM band (2.40–2.48 GHz). To widen the impedance bandwidth (IBW) and improve the axial ratio (AR) behavior of the antenna, a reactive impedance substrate (RIS) is exploited. Meandering each arm of the loop makes the antenna compact in size, while the generation of surface wave by the RIS and open-ended configuration of the antenna collectively renders circular polarized wave. The performance of the antenna is analyzed using a single-layer skin model and other existing phantom models. The key feature of the proposed antenna is its dual-band CP behavior, which persists even at the flexion deformation of the human skin. An IBW of 123% with a 3 dB AR bandwidth of 15% and 8.7% is obtained at the planar state of the skin implantable antenna. To validate the simulated results, in vitro measurements were experimentally performed. Also, to find the maximum transmission range of the antenna for biotelemetry communication, the link margin has been analyzed. Finally, to use the antenna inside the biomedical device, the effect of microelectronic components is investigated.

Design Architectures of the CMOS Power Amplifier for 2.4 GHz ISM Band Applications: An Overview

Power amplifiers (PAs) are among the most crucial functional blocks in the radio frequency (RF) frontend for reliable wireless communication. PAs amplify and boost the input signal to the required output power. The signal is amplified to make it sufficiently high for the transmitter to propagate the required distance to the receiver. Attempted advancements of PA have focused on attaining high-performance RF signals for transmitters. Such PAs are expected to require low power consumption while producing a relatively high output power with a high efficiency. However, current PA designs in nanometer and micrometer complementary metal–oxide semiconductor (CMOS) technology present inevitable drawbacks, such as oxide breakdown and hot electron effect. A well-defined architecture, including a linear and simple functional block synthesis, is critical in designing CMOS PA for various applications. This article describes the different state-of-the art design architectures of CMOS PA, including their circuit operations, and analyzes the performance of PAs for 2.4 GHz ISM (industrial, scientific, and medical) band applications.

A Modified Meander Line Microstrip Patch Antenna With Enhanced Bandwidth for 2.4 GHz ISM-Band Internet of Things (IoT) Applications

Internet of Things (IoT) based application requires integration with the wireless communication technology to make the application data readily available. In this paper, a modified meander shape microstrip patch antenna has been proposed for IoT applications at 2.4 GHz ISM (Industrial, Scientific and Medical) band. The dimension of the antenna is 40×10×1.6 mm 3 . The antenna design is comprised of an inverse S-shape meander line connected with a slotted rectangular box. A capacitive load (C-load) and parasitic patch with the shaped ground are applied to the design. Investigations show that the antenna designed with an inverse S-shape patch and connecting rectangular box in the microstrip line has a higher efficiency and gain compare to the conventional meander shape antenna. The C-load is applied to the feed line to match the impedance. Moreover, parametric studies are carried out to investigate the flexibility of the antenna. Results show that, the gain and efficiency can be improved through adjusting the rectangular box with applying parasitic element and the shaped ground. The parasitic element has high impact on the bandwidth of the antenna of 12.5%. The finalized antenna has a peak gain of -0.256 dBi (measured) and 1.347 dBi (Simulated) with 79% radiation efficiency at 2.4 GHz. To prove the efficiency and eligibility in IoT applications, the measurement of the power delivered and received by the antenna at 2.4 GHz is performed and compared with the results of a dipole antenna. The antenna is integrated with 2.4 GHz radio frequency module and IoT sensors to validate the performance. The antenna novelty relies on the size compactness with high fractional bandwidth that is validated through the IoT application environment.

Dual‐band implantable antenna with circular polarisation property for ingestible capsule application

A novel capsule antenna with dual-band performance and small occupation of inner capsule space is proposed. The antenna is designed by combining rigid Rogers substrate with flexible polyimide, which takes full utilisation of capsule inner surface and the system ground for implanted electronics. The antenna structure is based on two identical orthogonal strips, each connected with one conformal L-strip. In addition, a shorting pin is introduced, bringing in a fundamental resonance at 1.4 GHz industrial, scientific and medical (ISM) band with linear polarisation. Besides, with the adoption of the shorting pin, two extra resonant modes are excited and split in higher band, generating two orthogonal electric fields with equal amplitude and π /2 phase difference; therefore, covering another ISM band at 2.45 GHz with circular polarisation property. Finally, the simulation results show a wide impedance bandwidth of 16.2% at 1.4 GHz ISM band (for | S 11 | <;-10 dB), and a broad axial ratio (AR) bandwidth of 34.8% at 2.45 GHz ISM band (for | S 11 | <; -10 dB and AR <;3 dB), with dual-band operation further validated by measurement result.

Design of Hexagon Shape Bow-Tie Patch Antenna for Implantable Bio-Medical Application

In this paper presents the patch antenna in the shape of hexagon bow-tie antenna for implantable bio-medical application in the frequency range of 2.4–2.48GHz ISM (industrial, scientific and medical) band. The patch antenna designed with CPW feed for high frequency response. The proposed system is designed with the material of Alumina ceramic substrate (Al2O3), the value of dielectric constant is 9.8 with thickness of 1mm. The total size of the antenna is 10*10*1 mm. The main advantage of proposed system is it consumes very low size and the accuracy of the system is increased. The designed antenna is analyzed with human tissues like skin, fat and muscle and the parameters of the antenna like return loss, VSWR, radiation pattern and gain etc, are measured. The return loss of proposed antenna is-29dB achieved. So the proposed hexagon shape bow-tie antenna is used for several implantable applications.

TelG Mote: a green wireless sensor node platform for smart home and ambient assisted living

The wireless sensor network (WSN) consists of sensor nodes that interact with each other to collectively monitor environmental or physical conditions at different locations for the intended users. One of its potential deployments is in the form of smart home and ambient assisted living (SHAAL) to measure patients or elderly physiological signals, control home appliances, and monitor home. This paper focuses on the development of a wireless sensor node platform for SHAAL application over WSN which complies with the IEEE 802.15.4 standard and operates in 2.4 GHz ISM (industrial, scientific, and medical) band. The initial stage of SHAAL application development is the design of the wireless sensor node named TelG mote. The main features of TelG mote contributing to the green communications include low power consumption, wearable, flexible, user-friendly, and small sizes. It is then embedded with a self-built operating system named WiseOS to support customized operation. The node can achieve a packet reception rate (PRR) above 80 for a distance of up to 8 m. The designed TelG mote is also comparable with the existing wireless sensor nodes available in the market.

Dual‐band dual‐mode patch antenna for on–on–off WBAN applications

A dual-band dual-mode patch antenna for on–on–off wireless body area network (WBAN) applications is proposed. The antenna consists of a half-circular patch with two shorting posts to generate a TM41 higher-order resonant mode and a bottom ground slot to generate additional resonance. To reduce the antenna size without seriously affecting the radiation pattern, the antenna is cut in half and operates in half-mode. The antenna has a vertical monopole-like radiation pattern in the 2.45 GHz industrial, scientific and medical (ISM) band and a horizontal monopole-like radiation pattern in the 5.8 GHz ISM band. To evaluate the body effect, both 2.45 and 5.8 GHz muscle-equivalent phantoms were used. The overall dimensions of the proposed antenna is 30.5 × 62 × 3.15 mm.

Design and Analysis of a Multiple-Input Receiver for Mimo Wireless Applications

In this article, we present multiple-input receiver architecture for MIMO (Multiple-Input Multiple-Output) wireless communication applications. The proposed implementation is provided by a defined number of identical receiver units that are fed by a RF modulated signal on specific carrier frequency, power strength and initial phase. These units carry out the corresponding amplification, filtering and demodulation procedures. Details on design and implementation of this Printed-Circuit-Board are introduced and further discussed. Experimental results are also presented, allowing the validation of investigation on the performance of the current receiver architecture. Besides, these measurements indicate that the proposed device, combining with a suitable antenna array, provides a versatile receiver platform for baseband signal processing. The incoming RF modulated signals have frequencies on the range of 2.4 GHz, several phases, magnitudes and modulation modes. From these, it seems that the proposed receiver implementation supports MIMO communication and multiple port channel characterization applications at 2.4 GHz ISM (Industrial, Scientific and Medical) band.

Conformable Patch Antenna Array for Energy Harvesting

AbstractCarbon nanotube (CNT) has emerged as potential candidate for replacement of conventional metal patch in antenna application. The principal objective of our research is to develop nanostructured flexible patch antenna array for multi- frequency operation in industrial, scientific and medical (ISM) band. Patch antenna design using CNT on flexible cotton sheets has been simulated with cotton as a substrate and CNT as conductive patch and ground plane. Due to high conformability and conductivity of CNT all antenna parameters like VSWR, return loss, gain and radiation pattern obtained using FEKO EMSS software meet design criteria. Our simulated antenna design shows a return loss less than -10 dB and VSWR less than 2 at 2.06 GHz, 2.38 GHz and 2.49 GHz. We have also simulated a versatile and conformable antenna design where the whole geometry is rolled up like patch array on cylindrical surface. Conformability to curved surfaces and integration with the structure brings about a unique antenna design. An inset fed square patch array is also proposed for RF energy harvesting operating in the 2.45 GHz ISM band that can harvest and store energy from the surrounding environment. Simulation result shows that dc voltage of 0.215 V can be achieved at -6 dbm received energy level at 2.45 GHz IEEE 802.11b band. This would correspond to potential working distance of 10m.

Topology bandpass filters in coplanar strip lines

We report a new bandpass filter on coplanar strip (CPS) lines for RF and microwave applications. The filter is implemented as electrode topology on the CPS electrodes. The topology consists of basic electrode patterns that emulate inductors and capacitors in a two-port filter section. In the design process, equivalent circuit model is used to identify the initial topology, which is then fine tuned using full wave analysis. The bandpass filter is very compact in size and planar in structure. It does not use quarter-wavelength sections, vias, or bonding wires. It can be fabricated without incurring additional cost. Bandpass filters for the 2.4 GHz ISM (Industrial, Scientific, and Medical) band were designed, fabricated, and measured. The measurement responses agree well with the full-wave simulation results. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.

Outage performance of a hybrid DS/FH spread‐spectrum signal in an ISM band

AbstractThis paper develops an analytical model for characterizing the coexistence interference in the unlicensed industrial, scientific and medical (ISM) bands, based on radio frequency measurement results in the 2.4 GHz ISM band. The modeling approach presented here offers a simple methodology for profiling the interference from devices occupying a common spectrum. Outage performance using the interference model is exemplified through the analysis for a hybrid direct‐sequence frequency‐hopping spread‐spectrum signal. The work presented in this paper looks to provide insight by means of quantitative evaluation of signal outage in a coexistence environment that can be used for engineering design of applications for unlicensed bands as well as function as a tool in the development process for future spectrum management policy models. Copyright © 2006 John Wiley &amp; Sons, Ltd.