Nanotechnology in Wireless Devices

By Will Soutter

Topics Covered

Introduction
The Wireless Revolution
Nanotechnology-enabled Wireless Devices
     Tuneable Radio Components
     High Frequency Electronics
     Wireless Sensors
Recent Developments
Conclusion
References

Introduction

Devices that use wireless communication range from RFID tags to TV receivers, and satellites to mobile phones. The availability of internet access from tablets and mobile phones is growing at an exponential rate, causing increasing demands on the performance of wireless networks and mobile devices.

Some passive components necessary in wireless devices, such as inductors and capacitors, cannot be minimized as quickly as transistors and integrated circuits. This imbalance makes it likely that the performance requirements of mobile handsets will exceed the capabilities of current RF technologies within the next 10 to 15 years.

As well as the global growth in mobile internet access via tablets and smartphones, wireless sensors, health monitoring systems, and other devices dependent on wireless communication are becoming more and more prevalent.

Developing more compact, more efficient, and less expensive wireless communication devices will have significant impact on these areas and enable new solutions for healthcare services, logistics and environmental monitoring.

The rise in popularity of mobile devices is causing rapid increases in the amount of internet traffic through wireless connections. Image credit: Photos.com

The Wireless Revolution

According to a report by Cisco, global internet traffic from wireless devices (both Wi-Fi and mobile) will exceed that from wired devices by 2015. The convenience, sophistication and flexibility of wireless technology for consumers is very high, which is driving the increasing adoption of wireless internet access over wired access.

The type of activities that consumers engage in over wireless connections is also changing. Even laptop computers and desktop workstations are now often connected via Wi-Fi, as it is perceived as easier to set up for the end-user.

As mobile devices become more and more capable, the limitations on online activities are receding, and the differences in types of traffic between mobile and desktop use are diminishing.

So far, wireless technology is keeping up - LTE networks and other 4G technologies are fast enough to support streaming of video - but if this is to continue, considerable advances in wireless communication technology will be needed.

Nanotechnology-Enabled Wireless Devices

Tuneable Radio Components

Recently, it has been suggested that graphene nanoelectromechanical (NEMS) resonators could be used as tuneable resonators for radio circuits. It is possible for a graphene strip to withstand extremely high strains, making it possible to tune the resonator’s operating frequency over a broad bandwidth by electrical straining.

High Frequency Electronics

According to experts, additional frequency bands will also be required to support the increasing quantity of mobile internet traffic. Presently, there are standardization efforts to introduce new frequencies for mobile data traffic in the high frequency range around 2-5 GHz and up to 60GHz. It is anticipated that devices operating at 60 – 100 GHz will be required in the not too distant future.

These very high frequencies cannot be achieved by silicon-based transistor technologies. Novel solutions are required for electronics that can operate at high frequencies. RF transistors made of graphene are promising alternatives.

Wireless Sensors

the modern world is gradually becoming an intelligent, interactive environment, with novel autonomous sensors with wireless communication links incorporated into everyday objects. For this to become reality, these devices must be compact, cheap, and operated on a small battery or on electricity harvested from light, thermal energy or radio waves.

Innovative nano-enabled sensors integrated with small RF transceivers can be utilized for monitoring soil, air quality or water pollution. RFID tags are simple, passive devices that can be read with a radio frequency transceiver. Fabrication by printing can bring down the cost of wireless sensors and the use of nanoparticle inks will largely improve the performance of the printed devices.

Recent Developments

In 2011, IBM research scientists announced that they successfully created a building block for future wireless devices. In a paper published in Science, IBM researchers announced the fabrication of the first IC from wafer-size graphene, and showed a broadband frequency mixer operating at frequencies up to 10 GHz (10 billion cycles/s).

This graphene-based IC was especially developed for wireless communications and can be used for a wide range of applications. At present day conventional frequencies, transceiver and cell phone signals can be improved enabling phones to work where they cannot. At higher frequencies, medical and military personnel can view hidden weapons and perform medical imaging without the radiation exposure dangers of X-rays.

This novel IC includes a graphene transistor and an inductor pair, integrated compactly on a silicon carbide (SiC) wafer. Advances were made in wafer-scale fabrication procedures that maintain graphene quality, and also enable its integration to other components in a complex circuitry.

Here the synthesis of graphene is done by thermal annealing of SiC wafers to form uniform graphene layers on the silicon carbide surface. The fabrication of graphene circuits involves four metal and two oxide layers to form on-chip inductor, graphene transistor and interconnects.

The circuit operates similar to a broadband frequency mixer that produces output signals with mixed frequencies (sum and difference) of the input signals. Mixers are the key components of most electronic communication systems. Frequency mixing up to 10 GHz and excellent thermal stability up to 125°C have been shown with the graphene integrated circuit.

The developed fabrication scheme can be applied to other graphene materials including chemical vapor deposited (CVD) graphene films synthesized on metal films, and also comply with optical lithography for less thought put and cost.

Conclusion

In today’s world, the use of wireless communication is rapidly increasing. The main drivers for the use of nanotechnology in wireless devices are high performance, lower power consumption and compact size and novel features.

Present RF technologies for high data rate communication systems will be capable of meeting the needs of the industry for the next 10 to 15 years, but after that the basic physical limits of radio electronics will begin hindering development.

Nanotechnology-enabled devices will form the core of the next generation of wireless communication technologies, allowing wireless networks to keep up with the performance demands of mobile electronic devices.

References



 

Date Added: Jan 29, 2013 | Updated: Jun 25, 2014
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