A new kind of Wi-Fi

Passive Wi-Fi uses 10,000 times less power



Scientists at the University of Washington have developed a new form of Wi-Fi—one that saves a significant amount of energy. It’s called passive Wi-Fi, and it uses 10,000 times less power than standard Wi-Fi connections and about 1,000 times less power than Bluetooth.


On devices like smartphones, Wi-Fi is a significant source of energy consumption. With passive Wi-Fi, a device’s battery can last significantly longer. Passive Wi-Fi has the potential to be commercialized. As the University of Washington explains, “The technology could enable entirely new types of communication that haven’t been possible because energy demands have outstripped available power supplies. It could also simplify our data-intensive worlds.”

How it works 

A device plugged into an outlet sends analog waves out to specific passive Wi-Fi sensors. The majority of energy is used in this part of the process. The Wi-Fi sensors then reflect the waves with a digital switch. The reflected waves are referred to as “Wi-Fi packets.” These Wi-Fi packets “beam low-energy Internet at bit rates of up to 11 megabits per second to devices like phones, routers, and more.” For comparison, this is about 11 times faster than Bluetooth but still slower than most household broadband connections.

The researchers at the University of Washington said passive Wi-Fi had been successfully tested on campus. They found that phones could receive signals from the sensors up to 100 feet away.

What this means for the future

Passive Wi-Fi would be a helpful, low-energy solution to powering devices. More wearables and smart home accessories can be connected while keeping energy consumption down.

Equipping products for passive Wi-Fi capability may not be as difficult as it seems. Wired says, “Passive Wi-Fi uses only a few simple components, so it would be very cheap and easy to integrate into existing devices like smartphones or tablets. Additionally, it could even reuse the antenna already inside those devices.” Researches will continue to perfect the method, but they say that companies are already contacting them about implementing passive Wi-Fi in future products.

Who knows, down the road, this new technology may be the way everyone stays connected. For now, we will have to wait to see!