Side Lobes

• The transmitted beam for typical meterological radars is not perfect - it is not a pencil beam like a laser is.
• if antenna is much larger than the wavelength of the transmitted radiation, the beam is much more focussed, like a laser.
• If this is not the case, you end up with Side Lobes.

Laser:

Radar: q is the 1/2 power beam width At 1/2 P0, the power drops off by 3 dB q = 0.95° for the 88D here is a 3-dimensional view of a real beam pattern