GHz Industrial Scientific Medical Band Research Articles

A dual‐band dual‐polarized omnidirectional patch antenna for on‐body application

AbstractAiming at the 3.5 GHz world interoperability for microwave access band and 5.8 GHz industrial scientific medical band, a dual‐band antenna operating in omnidirectional mode is proposed. The antenna uses a single‐layer dielectric substrate made of FR‐4, which is cheap and easy to process. It uses circular patches and metal branches to generate orthogonal electric fields to achieve circular polarization. At the same time, the upper patch is symmetrically slotted in a T shape, so that the patch produces two resonance frequencies. The measured impedance bandwidth of the antenna in circular polarization on‐body mode and linear polarization on‐body mode is 110 MHz (3.41–3.52 GHz) and 460 MHz (5.42–5.88 GHz), respectively. In addition, the antenna shows good performance under bending conditions and close to human tissue. At the same time, the low specific absorption rate value proves that the antenna is safe to wear on the human body.

Dual‐band circular patch antenna working in TM41 and TM11 mode for on‐/off‐body communications

AbstractA capacitive coupling dual‐band circular patch antenna for on‐/off‐body communications is proposed for 3.5 GHz world interoperability for microwave access band and 5.8 GHz industrial scientific medical band. The antenna has a compact structure with a single substrate made of polydimethylsiloxane which is flexible and easy to wear. To realise off‐body mode, the antenna adopted bias feeding. The on‐body mode is achieved by symmetrically loading four shorting vias on the edge of the patch to stimulate TM41 mode, which tends to bring a high gain of the antenna. The measured operating bandwidths of the antenna for off‐body and on‐body modes are 120 MHz (3.45–3.57 GHz) and 360 MHz (5.54–5.90 GHz) respectively. The peak gains are 5.99 dBi for off‐body mode and 5.46 dBi for on‐body mode. Moreover, the antenna displays robust performances when it is bended or closed to human bodies. Meanwhile, low specific absorption rate values are proving that the antenna is safe to wear on human bodies.

Circular Shape Microstrip Patch Antenna for Body Area Network Application

In wireless communication system antenna plays crucial role. Thus, antenna used every wireless communication system should be low weight, low profile, low cost, smaller in dimension and conformity. A microstrip patch antenna fulfils all these requirements. In this paper a circular shaped microstrip patch antenna for Body Area Network (BAN) application in the 2.45 GHz ISM (Industrial Scientific Medical) band is suggested. To enhance Specific Absorption Rate (SAR). The suggested antenna offers a gain of over 1 dB for the whole 2.45 GHz ISM band application of proposed antenna is in fields of Medical, Military, Sports, Defence etc. Various antenna parameters like return loss, VSWR, directivity, gain etc has been computed and analyzed using HFSS software.

A Novel Patterned Ground Structure With Shunt and Series Lumped Elements for Synthesizing Absorption Common-Mode Filters

To synthesize an absorption common-mode filter (A-CMF) in a two-layer printed circuit board, patterned ground structures (PGSs) have been studied in the past few years. A conventional PGS consists of slotlines and shunt lumped elements across slots. On the contrary, the proposed new PGS uses both shunt and series lumped elements (SSLEs) in a ground plane with a closed-loop asymmetrical coplanar strip. To validate the proposed SSLE PGS, two circuits of bidirectional A-CMFs are developed to absorb common-mode (CM) noise in the 2.4 GHz industrial scientific medical (ISM) band. The one with higher CM noise absorption bandwidth is finally implemented and demonstrated in this article. Besides, nonideal CM return current paths are considered to modify the ideal circuit and reduce the discrepancies between the full-wave and circuit simulations. The measurement results show that the proposed bidirectional A-CMF attains CM noise absorption from 2.29–2.57 GHz for electromagnetic interference suppression in the 2.4 GHz ISM band. Most of all, the proposed work reveals a notable differential-mode −3 dB bandwidth up to 16.3 GHz with an ultracompact size of 0.0143 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _g^2$</tex-math></inline-formula> .

Energy-Efficient UAV-Based IoT Communications With WiFi Suppression in 5 GHz ISM Bands

Unmanned Aerial Vehicle (UAV) based communication is a promising technology for offering wireless communication services. UAVs can typically be adopted as aerial base stations to collect data from ground Internet of Things (IoT) devices. However, the Ground-to-Air link of UAV-based IoT communications is prone to be interfered by surrounding WiFi devices in the Industrial, Scientific, Medical (ISM) band. This paper aims to enable reliable uplink communications for IoT devices in 5 GHz ISM bands, thereby reducing the hover time and energy consumption of the UAV. To this end, we first study and design suppression frames suitable for WiFi devices. Then a suppression method is proposed, which is shown to be effective for all the tested devices, based on emulation performance verification of the frames for multiple commercial off-the-shelf (COTS) WiFi devices. Moreover, by taking the energy consumption of the UAV and multiple transmission parameters of the suppression method into account, we formulate an optimization problem for the desired uplink, which is designed to minimize the energy consumption of the UAV, under the constraints of satisfying the link channel capacity. Given that the optimization problem is non-convex mixed-integer nonlinear programming, this paper proposes an efficient algorithm that takes advantage of the suppression performance of the utilized frames. Numerical simulations demonstrate the performance of the proposed algorithm in terms of the WiFi device density, UAV weight, channel capacity requirement and parameters of the suppression method. The communication quality of the desired Ground-to-Air link is shown to be significantly improved, while the consumed energy is demonstrated to be obviously reduced.

Textile Bandwidth-Enhanced Coupled-Mode Substrate-Integrated Cavity Antenna with Slot

A textile bandwidth-enhanced coupled-mode substrate-integrated cavity antenna with a slot is presented. The original coupled-mode substrate-integrated cavity antenna is of two close resonances for the odd and even coupled modes, and a rectangular slot is added on the top layer to introduce a third resonance. Parameters are optimized to merge the bands of the three resonances to realize a widened −10 dB impedance band to cover the Medical Body Area Network band, 2.45 GHz Industrial Scientific Medical band and Long-Term Evolution Band7. The proposed antenna can operate in a −10 dB impedance band of 2.32–2.69 GHz with a 14.9% fractional bandwidth according to the measurements on a fabricated prototype. Simulation and measurement results illustrate the robustness of the proposed textile antenna in the vicinity of the human body and cylindrical bending conditions. In addition, the simulated specific absorption rate of the antenna radiation in the human body is lower than the IEEE and EN limits.

Dual-Mode Patch Antenna With Capacitive Coupling Structure for On-/Off-Body Applications

A dual-band dual-mode antenna for on-/off-body centric communications is proposed for 2.4 and 5.8 GHz industrial scientific medical bands. Using polydimethylsiloxane as substrate, the proposed antenna has a compact structure and is easy to wear. The on-body mode is realized by a circular patch loaded with four symmetrically distributed metallic vias to generate TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{\mathbf{01}}$</tex-math></inline-formula> mode located on the lower substrate. The off-body mode is achieved by a smaller circular patch on the top of the upper substrate, which generates a directional radiation pattern by exciting its TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{\mathbf{11}}$</tex-math></inline-formula> mode. The measured operating bandwidths of the proposed antenna in two bands are 90 MHz (2.40–2.49 GHz) and 330 MHz (5.63–5.96 GHz), respectively. Average gain for the on-body mode is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 2.38 dBi and for the off-body mode is 6.67 dBi. In addition, the antenna exhibits a robust performance near human tissue and low specific absorption rate values.

A 2.4 GHz ISM Band OOK Transceiver With High Energy Efficiency for Biomedical Implantable Applications.

This article presents a high energy efficiency, high-integrated, and low-power on-off keying transceiver for a 2.4 GHz industrial scientific medical band. The proposed receiver includes an input matching network, a low-noise amplifier, a novel single-to-differential envelope detector, a level shifter, cascaded baseband amplifiers, and a hysteresis comparator. The proposed transmitter includes a bias-stimulating circuit, a current-reused self-mixing voltage controlled oscillator, and a quadruple-transconductance power amplifier. Numerous proposed techniques implemented in the mentioned circuits improve the energy per bit and power efficiency. Therefore, the proposed receiver for short-distanced propagation can achieve a sensitivity of -46 dBm with a carrier frequency of 2.45 GHz and a high data rate of 2 Mbps. The proposed transmitter achieves an output power of -17 dBm with a high data rate of 20 Mbps. This work is fabricated in a TSMC 0.18 μm CMOS process and consumes 160 μW and 0.6 mW in the receiver and transmitter, respectively, from a 1.2 V supply voltage. The energy per bit of 80 pJ/bit in the receiver part and the figure of merit of 9 in the transmitter part are better than those of existing state-of-the-art transceivers.

An Effective Design of Wearable Antenna with Double Flexible Substrates and Defected Ground Structure for Healthcare Monitoring System.

Due to the development of modern wearable mobile devices, the need of antenna with smaller size and internally flexible to fit becomes necessary. Miniaturization of Micro Strip Patch (MSP) antenna increases its employability for communication in different aspects. The use of flexible material for the fabrication of MSP antenna still improves its use for Wireless Body Area Networks (WBAN) which includes devices for monitoring systems in military, surveillance and medical applications. The devices designed specifically in Industrial Scientific Medical (ISM) band are used for communication in these applications. Defected Ground Structure (DGS) is adopted as an emerging technique for improving the various parameters of microwave circuits, that is, narrow bandwidth, cross-polarization, low gain, and so forth. In this paper, the design of compact micro strip patch antenna using different flexible substrate materials with DGS is proposed to resonate the antenna at 2.45GHz ISM band which can be used as biomedical sensors. Felt and Teflon with dielectric constant 1.36 and 2.1respectively are chosen as flexible substrate material among various flexible materials like cotton, rubber, paper, jeans etc. Using CST studio suite software, the designed antenna is simulated and the fabricated antenna is tested with Vector Network Analyzer (VNA). The performance parameters like return loss, gain, directivity and Voltage Standing Wave Ratio (VSWR) of the antenna are analyzed.

Realization of Dual-Band Pattern Diversity With a CRLH-TL-Inspired Reconfigurable Metamaterial

A reconfigurable dual-band antenna with pattern diversity is proposed. By switching the dispersion curve of a composite right-/left-handed transmission-line-inspired structure, the antenna is able to realize both a broadside pattern and an omnidirectional pattern in both the 2.4835–2.5 GHz industrial scientific medical band and the 3.4–3.5 GHz WiMAX band. Despite its complex reconfigurability, only one feeding port is used. A small dual-frequency separation ratio is reached, which makes the antenna suitable for low-frequency range wireless communication systems. A prototype is fabricated and the measured results agree well with the simulated ones.

An ISM 2.4 GHz low power low-IF RF receiver front-end

This paper describes the implementation of an RF receiver front-end for the 2.4 GHz industrial scientific medical band under TSMC 0.13 μm CMOS technology; it comprises a low noise amplifier (LNA) which uses an added gate–source capacitor for low power performance and a dual-converter composed of a single-balanced active RF mixer and double-balanced passive IF mixer. Dual-down-conversion technique is used for reducing power. A 2.4 GHz low power low-IF RF receiver front-end is proposed. An LNA for rejecting image signal, an inductor–capacitor (LC) tank is used in series with source of input-stage transistor of the RF mixer, and combined with the LC load of the LNA, 30-dB image rejection is realized. Fabricated in a 0.13 μm CMOS process, the proposed chip occupies 0.42 mm2 area, achieves 4 dB noise figure, −22 dBm IIP3 and 37 dB voltage gain dissipating only 4.2-mW under 1.2-V supply.

COEXISTENCE OF STANDARDIZED WIRELESS SYSTEMS IN THE 2.4 GHZ-ISM-BAND

Wireless systems continue to rapidly gain popularity. This is extremely true for data networks in the local and personal area, which are called WLAN and WPAN, respectively. However, most of those systems are working in the license-free industrial scientific medical (ISM) frequency bands, where neither resource planning nor bandwidth allocation can be guaranteed. To date, the most widespread systems in the 2.4 GHz ISM band are IEEE802.11 and Bluetooth, with ZigBee and IEEE802.15.4 as upcoming standards for short range wireless networks. In this paper we examine the mutual effects of these different communication standards. Measurements are performed with real-life equipment, in order to quantify coexistence issues.

Design of a Microstrip Patch Antenna with Enhanced F/B for WBAN Applications

This paper proposes a microstrip patch antenna for 2.45GHz Industrial Scientific Medical (ISM) band Wireless Body Area Network (WBAN) applications. To enhance the front-to-back ratio (F/B) and specific absorption rate (SAR), an electrically coupled LC resonator is introduced. The overall dimensions of the proposed antenna are 54mm × 45mm × 2.4mm and it has a gain of over 1dBi for the entire 2.45GHz ISM band. The proposed antenna has an enhanced F/B ratio and specific absorption rate, compared with those of a conventional patch antenna.

SU-FF-T-90: The Use of Bluetooth Technology in Multiple Monitoring of Vital Signs - ECG and Pulse

Purpose: The aim of this work is to evaluate the strengths and demonstrate the benefit of using Bluetooth wireless technology in medical equipment, for close monitoring of multiple patients with heart problems (ECG and vital signs) in recuperatory stage. The main issue discussed and tested is whether Bluetooth technology is ready to be implemented and used to realize an environment were computers would assist the medical staff in offering solutions and real time response, based on the data received from patients, in critical situations. Method and Materials: Our preliminary work consists in a simulation soft (VC++) for monitoring two patients (ECG and pulse), with two Bluetooth equipped devices. Bluetooth is a rather new low-cost radio technology which operates in the free, unlicensed 2.4 – 2.4835 GHz ISM (Industrial, Scientific, Medical) band, and is designed to unite or connect all different types of devices to effectively work as one. The soft created is a server-client based program that interact through information messages interpreted as graphs and action instructions. Results: The server receives instantaneously the data sent by the patients and after a process of comparing, in which if the data for Pulse or ECG is higher or lower than some user-specified values, it builds dynamic charts for the two patients. We assumed the following limits both for ECG and Pulse: lower=50 and upper=130. A counter holds the number of times these values were crossed (under/over), and at 5 or more the application is stopped, and pre-defined messages will appear on the server and patient interfaces. Conclusion: The tests performed presented a very good response of the system — real time — thus giving us a very good reason to think that this technology could be used to perform hard tasks and intervene much more accurate than human personnel can.

Low-power CMOS integrated circuits for radio frequency applications

This paper presents results for a mixer, two voltage-controlled oscillators (VCOs) and a frequency doubler (FD) suitable for low-power CMOS radio frequency (RF) systems. Results are first described for a mixer which uses the body terminal of the transistor as one of the inputs to down-convert a 1.9 GHz RF signal to a 250 MHz intermediate-frequency signal. Next, two VCOs are described. The first VCO is an ultra-low-power oscillator designed to operate in the 2.4 GHz industrial scientific medical band with a supply of 0.4 V. The second VCO described is a fully integrated LC-tank VCO with automatic amplitude control operating at 4 GHz. Frequency tuning for this VCO is performed by accessing the body of cross-coupled transistors of the VCO core. Finally, a wideband, low-power implementation of a frequency doubler is presented. The frequency doubler consists of two identical unbalanced source-coupled pairs with different W/L ratios, whose inputs are connected in parallel and its output taken single-ended. The FD is based on the MOS transistor in saturation. All circuits were designed in a deep n-well 0.18 /spl mu/m technology, allowing application of different potentials to the body of different NMOS transistors.