Design of multi-band monopole antenna for mobile phone

In this paper, we propose a multi-band monopole antenna design which modifies the reduced-size planar monopole antenna [3], shown in Fig. 1(a), by inserting a new L-shaped slit and widening the width of the outer subpatch and gap distance between the outer subpatch and ground and let it excite a new 2.4 GHz band for ISM applications. The proposed design is described in detail in the following, and experimental results of the constructed prototype are presented and discussed.