When transmitting and receiving electromagnetic signals, there is a need to match the frequencies and the phases of both a received signal and a locally generated signal. In terms of signal to noise ratio (SNR), the alignment of the phases gives the best results for retrieving any data that is modulated on the received signal. Better SNR yields higher...

Orthogonal time frequency space (OTFS) modulation has the potential to enable robust communications in highly mobile scenarios. This is due to multiplexing information-bearing data into nearly-constant channels in the delay-Doppler domain instead of the time-frequency domain, which makes communication more resilient to fast changes in the channel....

Protecting mobile devices from unauthorized access is becoming more than indispensable these days. In particular, mobile devices such as smartphones and tablets are pervasive and store increasingly highly sensitive information about a user (e.g., contacts, usernames, passwords, emails, browser histories, business secrets, health conditions, etc.)....

Background Reflective surfaces, including metasurfaces and reflectarray antennas, are comprised of several subwavelength (< λ/2) passive reflective elements and can steer the reflection of an incident electromagnetic wave in arbitrary directions. Typically, reflective surfaces use one or multiple single-pull-single-through (SPST) switches...