Strain-Insensitive Hierarchically Structured Stretchable Microstrip Antennas for Robust Wireless Communication

As the key component of wireless data transmission and powering,stretchable antennas play an indispensable role in flexible/stretchable electronics.However,they often suffer from frequency detuning upon mechanical deformations;thus,their applications are limited to wireless sensing with wireless transmission capabilities remaining elusive.Here,a hierarchically structured stretchable microstrip antenna with meshed patterns arranged in an arched shape showcases tunable resonance frequency upon deformations with improved overall stretchability.The almost unchanged resonance frequency during deformations enables robust on-body wireless communication and RF energy harvesting,whereas the rapid changing resonance frequency with deformations allows for wireless sensing.The proposed stretchable microstrip antenna was demonstrated to communicate wirelessly with a transmitter(input power of−3 dBm)efficiently(i.e.,the receiving power higher than−100 dBm over a distance of 100 m)on human bodies even upon 25%stretching.The flexibility in structural engineering combined with the coupled mechanical-electromagnetic simulations,provides a versatile engineering toolkit to design stretchable microstrip antennas and other potential wireless devices for stretchable electronics.

Create Your Own Data and Energy Integrated Communication Network:A Brief Tutorial and a Prototype System

In order to satisfy the ever-increasing energy appetite of the massive battery-powered and batteryless communication devices,radio frequency(RF)signals have been relied upon for transferring wireless power to them.The joint coordination of wireless power transfer(WPT)and wireless information transfer(WIT)yields simultaneous wireless information and power transfer(SWIPT)as well as data and energy integrated communication network(DEIN).However,as a promising technique,few efforts are invested in the hardware implementation of DEIN.In order to make DEIN a reality,this paper focuses on hardware implementation of a DEIN.It firstly provides a brief tutorial on SWIPT,while summarising the latest hardware design of WPT transceiver and the existing commercial solutions.Then,a prototype design in DEIN with full protocol stack is elaborated,followed by its performance evaluation.

Wireless sensing system for environmental humidity and temperature monitoring

Aiming at the actual demand for monitoring environmental information,a wireless sensing system for temperature and relative humidity(RH)monitoring based on radio frequency(RF)technology and mobile network was designed.This paper introduces the architecture of the system.The system uses AVR micro controller unit(MCU),KYL-1020U RF module and SHT71 to complete real-time temperature and humidity monitoring,and uses SIM900A module to realize remote alarming and monitoring with short message system(SMS)through global system for mobile communication(GSM).Experimental results show that the designed system has good stability of measurement and real-time performance,and it can be used in some small temperature and humidity monitoring occasions.

An efficient technique to retrieve information from a damaged near-field communication tag

Purpose-The purpose of this paper is to discuss a technique of restoring data from a broken/damaged near-field communication(NFC)tag whose coil is damaged and seems unrecoverable.Design/methodology/approach-This paper discusses a method to restore data from damaged NFC tags by designing a coil that matches the technical specification of NFC for restoring information.In this paper,an NFC tag with a broken antenna coil and its operational NFC chip is used for restoring data by making an external loop antenna for the same chip.Findings-If the NFC tag is damaged,the information stored on the tag can be lost and can cause serious inconvenience.This research provides an excellent mechanism for retrieving all the information accurately from a damaged NFC tag provided the NFC chip is not damaged.Research limitations/implications-One of the major limitations of this research is that the NFC chip remains intact without any damages.Data can only be recoverable if just the antenna of the NFC tag is damaged;any damage to the NFC chip would make it impossible for the data to be recoverable.Practical implications-The research is carried out with limited resources in an academic institute and hence cannot be compared to antenna designs of the industry.Furthermore,industry vendors are using aluminum to design the coil;however,in this study a copper coil is used for coil design since it is far less expensive than aluminum coil.Originality/value-NFC is a rather new short-range wireless technology and not much work is done in this field as far as antenna study is concerned.This study brings a technique to design a coil antenna for a damaged NFC tag to retrieve all the information without losing even a single bit of sensitive information.

Design of an L1 band low noise single-chip GPS receiver in 0.18 μm CMOS technology

This article presents an L1 band low noise integrated global positioning system （GPS） receiver chip using 0.18 μm CMOS technology. Dual-conversion with a low-IF architecture was used for this GPS receiver. The receiver is composed of low noise amplifier （LNA）, down-conversion mixers, band pass filter, received signal strength indicator, variable gain amplifier, programmable gain amplifier, ADC, PLL frequency synthesizer and other key blocks. The receiver achieves a maximum gain of 105 dB and noise figure less than 6 dB. The variable gain amplifier （VGA） and programmable gain amplifier （PGA） provide gain control dynamic range over 50 dB. The receiver consumes less than 160 mW from a 1.8 V supply while occupying a 2.9 mm2 chip area including the ESD I/O pads.