Industrial Scientific Medical Band Research Articles

An Investigation Into Relaying of Creeping Waves for Reliable Low-Power Body Sensor Networking

We investigate the use of relaying of creeping waves in the industrial scientific medical frequency bands of 434 MHz, 915 MHz, and 2.4 GHz. The investigation includes generic analysis and experimental setups. For generic analysis, a link budget model is derived based solely on the creeping wave component of the transmitted signal while marginalizing for other effects, such as reflections from the surrounding environment. Closed-form expressions of the gains in network lifetime and energy per bit are derived for a system covering the entire body using relays compared to a reference system offering the same level of reliability without relaying. The experimental setups are used to gather measurements in the 2.4-GHz band with a body sensor network development platform in a nonreflective open-space environment and in a reflective residential environment. The measurements are used to validate the link budget model and evaluate performance of practical systems. Analysis and experimentation demonstrate that relaying of creeping waves offers considerable performance gains in all frequency bands. For example, using a single relay on either side of the body in 2.4 GHz can potentially increase network-lifetime times 40 and decrease energy per bit by 48 dB. Part of this potential is achieved in experimental setups where relaying was shown to increase network lifetime times 13, decrease energy per bit by 13 dB and provide the ability to compensate for a wider fading margin.

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.

Characterization of the indoor/outdoor radio propagationchannel at 2.4 GHz on Qatar University campus

This technical report presents the site-specific signal strength measurement results for path loss, shadowing, and fading in the 2.4GHz band under typical harsh environment (high temperature 40-50 C and humidity 80-90%). We used spectrum analyzer Rohde & Schwarz FSH8 and InSSIDer, free software for wireless local area networks (WLANs). Measurements were taken in indoor and outdoor environments at various locations at different times of the day. An empirical channel model has been derived from these measurements that characterizes the indoor-outdoor wireless channel. This report provides information that would be useful for the design and deployment of wireless mesh network in Qatar University. For a radio communication system, the channel describes how the electromagnetic propagation of a transmitted signal provides that signal at the receiver. In a mobile communication system, the channel changes according to the movement of the communicating entities and other objects that have an effect on the electromagnetic fields at the receiver. In the last decade, most of the indoor wired networks have been replaced by wireless networks. These networks can also provide outdoor connectivity inside the campus areas. WLANs based on IEEE 802.11 are largely deployed to provide users with network connectivity without being tethered to a wired network.Wireless networks can provide nearly the same services and capabilities commonly expected with wired networks. Like their wired counterparts, IEEE 802.11 has been developed to provide large bandwidth to users located in indoor and outdoor campus environments and are being studied as an alternative to the high installation and maintenance costs incurred by traditional additions, deletions, and changes experienced in wired LAN infrastructures. Because of the unlicensed spectrum availability, IEEE 802.11 WLAN devices operate in the ISM (Industrial Scientific Medical) band at 2.4GHz or 5GHz. For an accurate planning of indoor/outdoor radio networks the modeling of the propagation channel is required.

A new method for wireless connectivity in hearing aids

In this era of wireless connectivity, the way we use technology to interact and communicate with each other has changed our perception of the world around us. Happily, hearing aids are no longer an exception, as these devices have become more than just sophisticated signal processors designed to amplify speech. For many patients with hearing loss, a hearing aid is not only a personal communication device, but also a gateway to media connectivity and greater convenience in communication. Today’s digital wireless protocols allow for wireless communication between hearing aids and from hearing aids to numerous forms of media devices. Some of these offerings use frequencies that allow for far-field signal transmission, while others focus on near-field communication. A wide array of frequencies is available for wireless data and audio transmission; the transmission and reception of these signals is performed by small radios embedded in the hearing aids and remote devices. This article will focus on the wireless communication ability of currently available hearing aids, which, at the time of this publication, function in one of three different frequency bands: 3to 15-MHz near-field magnetic induction; 2.4-GHz industrial scientific medical band; and 900-MHz industrial scientific medical band.

Dual Band Hybrid Dielectric Resonator Antenna for Application in ISM and UNII Band

There are many commercial applications, such as mobile radio and wireless communications that use microstrip antennas. Microstrip antennas however have limitations in size, bandwidth, and efficiency. On the other hand, the dielectric resonator (DR) antenna is attractive due to its small-size, high radiation efficient, and ease of excitation.[1-3] Three dielectric properties of materials must be considered for DR antenna used: a high permittivity, a high quality factor, and a near zero temperature coefficient of resonant frequency. The size of the DR antenna decreases with increasing the permittivity of the dielectric resonator. The quality factor is representative of the antenna losses. Typically there are radiation, conduction, dielectric, and surface wave losses. Therefore the total quality factor is influenced by these losses. The DR antenna offers very high radiation efficiency due to its low dielectric loss and it has no metallic loss. A near zero temperature coefficient of resonant frequency are for high temperature stability. In traditionally, the DR with relatively small permittivity around 10 is chosen for DR antenna to enhance the radiation capability.[4-10] However, low profile DR antenna with relatively low resonant frequency can be achieved by using high permittivity. Recently, dual band antenna has been implemented for applications in WLAN (wireless local area network, 2.4–2.484 GHz), ISM (Industrial, Scientific, Medical) and Bluetooth at low band. Additionally, the dual band antenna can be applied at high band, such as HIPERLAN (high-performance radio local area network, 5.15–5.35 GHz) and Unlicensed National Information Infrastructure (UNNI) applied. In this paper, we present the design of a dual band hybrid antenna consists of a rectangular slot and a circular disk high permittivity dielectric resonator for operating at the ISM band and UNNI band. Details of the proposed antenna and experimental results are present. The characteristics of dual band hybrid antenna, such as return loss, input impedance, radiation pattern, and gain, have been measured and discussed.

The Design of a Wireless Data Acquisition and Transmission System

In the field of modern wireless communication, there are mainly some technologies that provide solutions to the wireless data transmission network, such as: GSM, CDMA, 3G, Wi-Fi. These solutions make network work with high efficiency and good quality, but still with high cost. So it was difficulty in popularizing in with low cost and at the circumstance of infrastureless or infrastructure destruction. According to this situation, in this paper, the key components of the Information Terminal and the wireless receiving modules on the data collection and wireless transmission network were designed with the principle of transceiver nRF905 and 51 series of single-chip computer as the core hardware, besides, combining with the current technology on the Wireless Ad Hoc Networks, a short-rang wireless data sampling and transmission network was putting up , which provides a low-powered and high-performance wireless data communication system, works in the ISM (Industrial Scientific Medical )Band. Then, an available solution to the wireless data communications was put forward, and this solution was good at stronger real-time response, higher reliability requirement and smaller data amount. Through software and hardware debugging and actual measuring, this system based on our solution had work well, reached the expected goal and been already successfully applied to Wireless vehicle System.

A low-noise mixer with an image-reject notch filter for 2.4 GHz applications

This paper presents a low noise first down-conversion mixer with a notch filter for the heterodyne receiver. The notch filter connected to the output node of the mixer driver stage plays a role of image rejection at an image frequency, thereby suppressing the sideband image noise and improving the mixer noise performance. Targeted for 2.4GHz industrial–scientific–medical band applications, a simple source-degenerated down-conversion single balanced mixer with the filter is implemented. The measurement results of the proposed down-conversion mixer shows about 3.0dB improvement of single-side band noise figure, about 2.9dB power conversion gain improvement, and 25dB image suppression compared to those without the filter dissipating 4mA from a 2.5V supply voltage.

A 20 dBm Fully-Integrated 60 GHz SiGe Power Amplifier With Automatic Level Control

A + 20 dBm power amplifier (PA) for applications in the 60 GHz industrial scientific medical (ISM) band is presented. The PA is fabricated in a 0.13-mum SiGe BiCMOS process technology and features a fully-integrated on-chip RMS power detector for automatic level control (ALC), built-in self test and voltage standing wave ratio (VSWR) protection. The single-stage push-pull amplifier uses center-tapped microstrips for a highly efficient and compact layout with a core area of 0.075 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The PA can deliver up to 20 dBm, which to date, is the highest reported output power at mm-wave frequencies in silicon without the need for power combining. At 60 GHz it achieves a peak power gain of 18 dB, a 1-dB compression (P1dB) of 13.1 dBm, and a peak power-added efficiency (PAE) of 12.7%. The amplifier is programmable through a three-wire serial digital interface enabeling an adaptive bias control from a 4-V supply.

Mutual interference analysis of IEEE 802.15.4 and IEEE 802.11b

IEEE 802.15.4 and IEEE 802.11b, operating in the 2.4GHz unlicensed industrial scientific medical (ISM) frequency band, may lead to signal interference and result in significant performance degradation when devices are collocated in the same environment. The main goal of this paper is to evaluate the effect of mutual interference on the performance of IEEE 802.15.4 and IEEE 802.11b systems. An analytic model for interference between IEEE 802.15.4 and IEEE 802.11b is suggested. The packet error rate (PER), transmission delay, and throughput are evaluated for IEEE 802.15.4 and IEEE 802.11b. The power spectral density of the IEEE 802.11b is considered in order to determine in-band interference power of the IEEE 802.11b to the IEEE 802.15.4. The simulation results by OPNET are shown to validate the numerical analysis.

Practical channel state aware and cooperative packet scheduling disciplines for coordinating colocated Bluetooth and IEEE 802.11b devices

Attempts to satisfy the demand for ubiquitous communications have resulted in a proliferation of hand-held short range communication devices based on the ISM (Industrial, Scientific, Medical) band technologies, most notably Bluetooth and IEEE 802.11b. However, coexistence between Bluetooth and IEEE 802.11b has become a critical issue that could severely hinder the performance achieved by user devices. In this study we performed a detailed implementation of a Linux based network access point (NAP), in which Bluetooth and IEEE 802.11b interfaces are colocated. Such an NAP is crucial in supporting “hot-spot” systems targeted to serve nomadic users carrying either a Bluetooth or an IEEE 802.11b device. Specifically, the goal of our study is to investigate the efficacy of a software-based interference coordination approach, through a detailed actual implementation so as to identify system issues which are difficult to obtained by simulations. We considered a wide range of common scheduling algorithms as the possible solutions in a Linux environment to estimate the interference effects as viewed from the network layer perspective. Upon our investigation, two wireless scheduling algorithms based on Channel State Independent Fair Queueing (CIFQ) were implemented in Linux to test their empirical performance under this NAP application. Finally, guided by our practical findings, we proposed and implemented two new packet scheduling algorithms in Linux to provide the best trade-offs to colocated Bluetooth and IEEE 802.11b traffics, as well as QoS support for different applications. Our results show that dynamic priorities and cooperative transmissions between Bluetooth and IEEE 802.11b traffic can effectively protect both interfaces from interference. We also compared our proposed scheme with two MAC layer approaches.

Broadband Planar Superstrate Antenna for Integrated Millimeterwave Transceivers

In this paper, a new planar superstrate antenna concept suitable for integration with millimeter wave (mmWave) transceiver integrated circuits (ICs) is presented. The antenna is printed on the bottom of a dielectric superstrate with a ground plane below. The new design provides high bandwidth and high efficiency. Two different examples of the new concept have been designed and manufactured for the 60 GHz industrial scientific medical (ISM) band using folded dipoles. Simulated and measured input impedance matching and far field radiation patterns for both antennas will be shown and discussed. Both designs achieve over 10% bandwidth while maintaining better than 80% efficiency

DESIGN OF AN ACTIVE INTEGRATED ANTENNA FOR A PCMCIA CARD

This paper presents the design and implementation of an Active Integrated Antenna (AIA) using a Voltage Controlled Oscillator (VCO) for applications in the Industrial Scientific Medical band (2.4 ÷ 2.4835 GHz). Surface Mounting Device (SMD) technology has been applied in the realization of the passive and active components, and low cost FR-4 dielectric slabs have been employed for the integration of the antenna and the active/transmissive circuits, residing, respectively, on the opposite faces of a Personal Computer Memory Card International Association (PCMCIA) card. The proposed layout makes use of a properly corrugated ground plane, i.e., a High Impedance Ground Plane (HIGP), to improve the antenna performances and to minimize the coupling between the radiating component and other possible radiating elements and/or electronic circuits residing nearby. The analysis and the design of the radiating element with the HIGP are based on a rigorous full wave Method of Moment (MoM) formulation developed in the Spectral Domain (SD), while the design of the active circuitry is developed through the commercial tool AWR Microwave Office. The final design of the component is obtained hybridizing the 254 Bilotti, Urbani, and Vegni two methods and applying a Genetic Algorithm (GA) optimization tool in order to take advantage of the HIGP, while keeping the geometrical dimensions of the antenna suitable for mounting on a PCMCIA card, and maintaining the antenna performances acceptable. The measured results show the performances of the VCO, an antenna gain of 19.4 dBi and an increased front-to-back radiation ratio compared to the one of the same antenna mounted on a standard Perfect Electric Ground Plane (PEGP). This result, thus, demonstrates the minimization of the interferences between the designed antenna and other possible radiating and transmissive devices residing nearby.

VCO active integrated antenna with reactive impedance surfaces

AbstractIn this paper, we present the design of an active integrated antenna (AIA) using a voltage‐controlled oscillator (VCO) for applications in the Industrial Scientific Medical (ISM) band (2.4 to 2.4835 GHz). The realized active circuit makes use of compact devices in surface‐mounting device (SMD) technology, while the passive radiating element is placed over a reactive‐impedance surface (RIS), properly designed to show an inductive surface impedance within the operative frequency band. The final layout has been optimized in terms of dimensions to achieve the integration of the antenna and the active/transmissive circuits on the opposite faces of a Personal Computer Memory Card International Association (PCMCIA) card. The design is conducted through the employment of a rigorous method of moments (MoM) formulation, used for the design of the antenna, and of a commercial tool for the nonlinear analysis of the active circuitry. Some preliminary experimental results are also presented to illustrate the features of the antenna here proposed. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 82–86, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21088

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.

Interference modeling and performance of bluetooth mac protocol

The emergence of Bluetooth as a default radio interface has allowed handheld electronic devices to be instantly interconnected as ad hoc networks. These short-range ad hoc wireless networks, called piconets, operate in the unlicensed 2.4-GHz ISM (Industrial-Scientific-Medical) band where devices may be used to configure single or overlapping piconets, known as scatternet. As all piconets operate in the same frequency band, the presence of multiple piconets in the vicinity may create interference on signal reception. This paper employs a signal capture model to study the piconet MAC performance, taking inter-piconet interference into consideration. This model leads to several important mathematical relationships for Bluetooth networks, including successful packet transmission probability. Furthermore, our model and anticipated throughput are validated using extensive simulation. These results indicate that Bluetooth throughput is affected by multiple piconet interference. Definitely, our model can be considered to provide a solid foundation for future interference aware Bluetooth protocols.

Low-cost 24 GHz transceiver for unlicensed operation

A low-cost transceiver suitable for point to point communications in the 24 GHz industrial scientific medical (ISM) band, which gives more than 10 Mbit/s full-duplex capacity, is presented. Two complete transceiver systems, including the 24 GHz front-end in microstrip hybrid technology and the intermediate frequency subsystem, have been designed and measured showing excellent performance.

An ultralow-power UHF transceiver integrated in a standard digital CMOS process: transmitter

In the first part of the paper, also in this issue of the JOURNAL, the design of the frequency synthesizer and receiver section of an FSK transceiver was described. It operates in the 434-MHz ISM (Industrial, Scientific, Medical) band and is realized in a standard digital 0.5-/spl mu/m CMOS process. This companion paper focuses on the realization of the transmitter section. It includes a power amplifier, an upconverter, and the circuit generating the baseband quadrature signals with a continuous phase modulation. The overall measured efficiency of the packaged circuit is higher than 38% for a 1.2-V supply and an output power reaching 10 dBm at 433 MHz. The system is designed to still operate at 1-V supply, delivering more than 1 mW with an efficiency higher than 15%.

A direct-conversion receiver for 900 MHz (ISM band) spread-spectrum digital cordless telephone

A single chip direct-conversion receiver for use in the 900 MHz ISM (industrial-scientific-medical) band has been fabricated in a 25 GHz f/sub T/ silicon-bipolar process. The receiver has a maximum gain of 105 dB with more than 80 dB of gain-control range. Integrated quadrature mixers and phase-shift networks are included. The typical phase error of the I/Q outputs is less than 1 degree. A class-AB servo amplifier is used to reduce dc offset while maintaining a turn-on time of 200 /spl mu/s. An integrated filter is included to improve channel selectivity. The integrated circuit operates on a supply voltage range of 2.7 to 5.0 V and draws 50 mA of supply current.