Abstract: A planar antenna includes a dielectric layer including a first surface and a second surface on a side opposite from the first surface, an antenna conductor provided on the first surface, a ground conductor provided on the first surface or the second surface, or provided on both of the first surface and the second surface, and a transmission line including a signal line that is connected to the antenna conductor or provided in proximity to the antenna conductor, wherein a dielectric portion of the dielectric layer that is in contact with the signal line has a loss tangent of 0.007 or less at 28 GHz.

Abstract: A system includes an earphone having an earplug, a processor, a wireless interface, a battery, a memory, and a speaker, and an electronic device separate from the earphone and in communication with the earphone via the wireless interface. The electronic device transmits audio to the earphone for storage in the memory. The processor of the earphone cause the speakers to play the audio stored in the memory in a loop. The electronic device and the processor of the earphone do not operate the wireless interface continuously after the audio is stored in the memory.