Electric Field Modulation: A New Era in Portable Device Communication

Key things to know:

• Researchers from the University of Sussex propose electric field modulation for wireless communication, potentially reducing energy consumption and enhancing battery life in devices.
• This new method, offering up to 5 times longer battery life than Bluetooth systems, could revolutionise wearable and portable device technology.
• Despite its potential, electric field modulation faces challenges such as limited transmission range and specific technical requirements, making its broader application a subject for ongoing research.

Radio dominates the field of wireless communication, but for all the benefits it provides, the energy penalty associated with its use can make wireless communication in portable devices challenging. Now, researchers believe the future of wireless communication could instead come from modulated electric fields instead of radio transmission. What challenges do radio systems present, how does electric field modulation work, and is it really the future of low-energy wireless communication?

What challenges do radio systems present?

Radio communication dominates the field of wireless communication due to the numerous advantages that it presents. Depending on the frequency chosen, radio waves can be made to travel extraordinary distances, refract around all kinds of obstacles, or be used to encode massive amounts of data.

In fact, radio systems are so advantageous that the majority of consumer electronic devices incorporate some form of radio communication module. But for all the benefits that wireless radio communication presents, there are some drawbacks that can make even the most talented engineers scratch their heads. 

By far, the biggest challenge presented with radio systems is power consumption, especially in portable devices that rely on batteries. As electronic devices become more complex, the expectation for faster data rates and longer connectivity ranges puts mounting pressure on engineers to try and come up with methods for increasing channel bandwidth without increasing energy consumption.

One option for increasing bandwidth without increasing power consumption is to reduce the output power of the radio transmitter, but this results in a reduced range, thereby making it harder to form connections between devices. Other methods involve the use of ultra-wideband modulation, and while this does reduce energy consumption while increasing range, it has a major impact on bandwidth.

Another major challenge faced by radio systems is congestion. In the early days of wireless systems, devices would rarely see issues with congestion due to the small number of devices in active use. 

However, with the introduction of IoT and increased reliance on Internet connectivity, the average home can easily see at least 10 actively connected devices, all requiring internet access. Thus, radio channels are seeing more and more devices requesting connection time, thereby reducing the bandwidth that each device has available to it.

Finally, radio communication systems must be extraordinarily careful with emissions. Most countries in the world have some form of legislation that requires electronic equipment to minimise radio emissions while simultaneously being immune to external radio sources, and depending on the radio band being used, it can also require special licenses. As such, engineers must be meticulous in their design, accounting for stray radio emissions and filtering unexpected sources of noise.

Researchers propose electric field modulation for wireless communication

Recognising the challenges faced with radio communication, researchers from the University of Sussex have outlined a new method that replaced radio with electric field modulation. Unlike radio waves, which consist of oscillations in both electric and magnetic fields, electric field modulation merely varies an electric field via an alternating voltage differential. 

This means that a design utilising such a concept would replace radio transmitters with voltage amplifiers and receivers with voltage detectors. While such a design would have a significantly lower range, the reduction in energy consumption is substantial, with some estimating that low-power devices using such a technology could last as much as 5 times longer compared to Bluetooth systems.

The potential of this technology extends beyond just prolonged battery life. As noted by Daniel Roggen, a professor of wearable technologies at the University of Sussex, the energy savings brought about by this new communication technology could lead to further miniaturization of devices. This opens up new possibilities for tiny wearable devices, such as smart earbuds, smart rings, or even electronics integrated into garments, revolutionizing how we interact with technology on a daily basis.

Furthermore, the use of specialised voltage detectors also eliminates the need for complex matching circuits being tuned to specific frequencies. As only a pair of untuned electrodes are needed, such a communication method works on the principle of capacitive coupling, where power is only consumed when a receiver is in close proximity to a transmitter.

According to the researchers, they were able to demonstrate transmission rates of up to 600kbps, which is more than sufficient for most Bluetooth applications, including audio and data transmission. However, it was noted that the range of the new communication method is significantly lower than Bluetooth, which heavily restricts where it can be used. But it was also noted that such a drawback can also be a benefit, as it becomes significantly more difficult to eavesdrop or interfere with communication.

Moreover, the security implications of this technology are noteworthy. The shorter range of transmission not only reduces power consumption but also minimises the risk of eavesdropping and signal interference. This aspect is particularly crucial in an era where data privacy and security are paramount, especially in applications involving sensitive information.

Is this the future of low-energy communication?

The idea of using capacitive coupling to transmit data wirelessly is certainly interesting, but as pointed out by the researchers, it does come with numerous challenges. The range of such a system would be incredibly small, meaning that most Bluetooth applications would struggle to deploy it, but for devices that don’t expect to be more than a meter away from a transmitter, it could certainly provide some benefits. 

However, with regard to smartphones and other portable devices, technologies such as RFID and NFC are far more practical, and capacitive coupling will unlikely become practical enough for such devices. The other major challenge faced with such a technology is the need for common ground and the large voltages involved. Having portable devices produce potentially hundreds of volts for the sake of reduced energy consumption could incur unacceptable levels of danger to users, and the use of strong insulation could effectively isolate devices, making it hard to transmit signals.

While capacitive coupling presents its own set of challenges, it's essential to recognise the innovative approach it brings to wireless communication. The exploration of alternative methods like electric field modulation is a testament to the ongoing quest for more efficient and safer wireless communication solutions, particularly in the context of the Internet of Things (IoT) and smart devices.

Overall, what the researchers have demonstrated is interesting for sure, but whether or not it could be turned into something practical in the long run is an entirely different conversation.