The present invent ion utilizes the top loading technique and the smooth tapering technique to create the design of a compact and built-in antenna which will provide a planar antenna structure with broad bandwidth and high radiation efficiency.

• 馈入传输线的宽度大致与渐变带段的底边同宽，且顶边与渐变带段的底边密接，而底边藕接至频电路。