Leaky coaxial cable, also known simply as leaky cable or leaky cable, has a structure basically the same as a regular coaxial cable, consisting of an inner conductor, an insulating medium, and an outer conductor with periodically spaced slots. Electromagnetic waves propagate longitudinally within the leaky cable while simultaneously radiating outwards through the slots; external electromagnetic fields can also be induced into the leaky cable through the slots and transmitted to the receiving end.
Based on the different slot structures and operating principles of the outer conductor, leaky cables are mainly divided into two types: radial (RMC) and coupled (CMC). In radial leaky cables, the spacing of the slots on the outer conductor is approximately equal to the wavelength (or half a wavelength), and the slot structure causes signals to superimpose in phase at the slots. In coupled leaky cables, the outer conductor has a long, narrow slot or a group of small holes spaced much smaller than the wavelength, causing electromagnetic waves to be densely distributed around the cable in the form of surface waves.
