The rectenna design couples with an AC field to provide a DC output to power devices such as sensors. The design, by researchers at the Printed Electronics Engineering programme of Sunchon National University and the Paru Printed Electronics Research Institute in Sunchon, can even harvest the energy radiated by mobile phones to power devices.

This could allow sensor networks such as RFID tags, price tags, smart logos, signage and sensors could be fully interconnected and driven by DC power of less than 0.3 W.

"What is great about this technique is that we can also print the digital information onto the rectenna, meaning that everything you need for wireless communication is in one place," said Gyoujin Cho, co-author of the study Gyoujin Cho. "Our advantage over current technology is lower cost, since we can produce a roll-to-roll printing process with high throughput in an environmentally friendly manner. Furthermore, we can integrate many extra functions without huge extra cost in the printing process."

The DC power is inductively coupled AC from a 13.56 MHz power transmitter through a rectenna, consisting of an antenna, a diode and a capacitor, which would be cheap to integrate with inexpensive smart electronic devices. To integrate the rectenna with a minimum cost, a roll-to-roll (R2R) gravure printing process has been considered to print the rectenna on plastic foils.

The researchers show that the R2R gravure printing system including printing condition and four different nanoparticle based inks is able to print the rectenna (antenna, diode and capacitor) on plastic foils at a printing speed of 8m per minute and more than 90% device yield for a wireless power transmission of 0.3 W using a standard 13.56 MHz power transmitter. This translates to an antenna cost under 1¢.

paru.co.kr