In acoustics and wireless communications, a lobe pertains to a pattern of transmission (in wireless systems and speakers) or pickup (microphones) that is not spherical, or omnidirectional. Essentially the lobe is the portion of a directional pattern bounded by one or two cones of nulls where there is little or no pickup or transmission. For example, a microphone with a figure 8 pickup pattern has two lobes in its pattern, one on each side of the mic. A hypercardioid mic also has two lobes, it’s just that the front (desired) one is much more pronounced than the rear. A cardioid mic generally has one big lobe. As soon as you concentrate the energy of any transmission in a particular direction you create one or more lobes by definition. Wireless systems that use directional antennas also have this type of lobing, and so do loudspeaker systems. The characteristics of most lobes will vary by the wavelength of the sound or electromagnetic energy being radiated.