device converting electric signals to electromagnetic (radio) waves and back
transmitting antenna: accelerates electrons, radiating energy into space
receiving antenna: electromagnetic waves induce current in conductor
types: dipole, monopole, parabolic dish, phased array, patch, loop, Yagi-Uda
parameters: gain, bandwidth, radiation pattern, polarization, impedance
parabolic dish focuses signals for telescope and satellite communication
phased array steers beam electronically using semiconductor control
communication infrastructure: radio, television, cellular, Wi-Fi, deep space
energy harvesting antennas (rectennas) convert ambient RF to DC power
meshes of antennas form the physical layer of cyberia network connectivity