Every time someone picks up a call, the phone does a quiet bit of translation. Incoming radio signals are converted into tiny sound waves that ripple across chips before being turned back into data.

“Those waves are useful but unruly,” says physicist A.T. Charlie Johnson of the School of Arts and Sciences. Imperfections in the material, he explains, can bounce waves backward or send them off course, and every stray reflection hampers the signal.

Now, researchers led by Johnson with collaborators at the University of Texas at Austin have developed a device that keeps those waves on track. Their findings are published in Physical Review Applied.