Imagine shirts that act as antennas for smartphones or tablets, workout clothes that monitor fitness level or even a flexible fabric cap that senses activity in the brain! All this will soon be possible as the researchers working on wearable electronics have been able to embroider circuits into fabric with super precision -- a key step toward the design of clothes that gather, store or transmit digital information.
"A revolution is happening in the textile industry. We believe that functional textiles are an enabling technology for communications and sensing and one day, even for medical applications like imaging and health monitoring," said lead researcher John Volakis from Ohio State University.
The milestone achieved by the Ohio researchers has the potential to allow integration of electronic components such as sensors and computer memory devices into clothing with 0.1 mm precision.
With further development, the technology could also lead to sports equipment that monitor athletes' performance or a bandage that tells doctors how well the tissue beneath it is healing. Volakis' team created the functional textiles, also called "e-textiles," on a typical tabletop sewing machine.
Like other modern sewing machines, it embroiders thread into fabric automatically based on a pattern loaded via a computer file. The researchers substituted the thread with fine silver metal wires that, once embroidered, feel the same as traditional thread to the touch.
"For the first time, we've achieved the accuracy of printed metal circuit boards, so our new goal is to take advantage of the precision to incorporate receivers and other electronic components," added Volakis in a paper published in the journal IEEE Antennas and Wireless Propagation Letters. The shape of the embroidery determines the frequency of operation of the antenna or circuit.
"Shape determines function. And you never really know what shape you will need from one application to the next. So we wanted to have a technology that could embroider any shape for any application," noted Asimina Kiourti, co-author of the study. She also incorporated some techniques common to microelectronics manufacturing to add parts to embroidered antennas and circuits.