1.Radiation Mechanism（辐射机理 "to create radiation,there must be a time-varying current or an acceleration(or deceleration)of charge" 1.Single wire If a charge is not moving,current is not created and there is no radiation. If charge is moving with a uniform velocity: a.There is no radiation if the wire is straight,and infinite in extent. b.There is radiation if the wire is curved,bent,discontinuous,terminated,or truncated If charge is oscillating in a time-motion,it radiates even if the wire is straight. 乡 (c)Discontinuous 纱 (a)Curved 乡 (d)Terminated Ground (b)Bent 奇 乡 (e)Truncated1. Radiation Mechanism（辐射机理） “to create radiation, there must be a time-varying current or an acceleration (or deceleration) of charge”  If a charge is not moving, current is not created and there is no radiation.  If charge is moving with a uniform velocity: a. There is no radiation if the wire is straight, and infinite in extent. b. There is radiation if the wire is curved, bent, discontinuous, terminated, or truncated  If charge is oscillating in a time-motion, it radiates even if the wire is straight. 1. Single wire