A series feed E-shaped microstrip antenna with high gain

A series feed E-shaped microstrip antenna is proposed in this paper with high gain. Double E-shaped elements with high gain are series-fed for gain enhancing, while elements space is adjusted for radiation efficiency enhancing. With optimized design of the proposed antenna, the measured bandwidth of VSWR<;1.5 is from 2.33~2.54GHz with the relative bandwith of 8.6%. At the covering frequency band of 2.4~2.5GHz for WLAN, the proposed antenna achieves the gain of larger than 12dBi with steady bandwidth of both E plane and H plane. As a series-fed array, the proposed antenna has the advantage of easy fabrication, but suffers from the beam direction offset with the frequency shifts at E-plane. With the optimal design, the beam direction offset angle controlled within ±1°.