Internal laptop antenna with a wideband coupled ring for WLAN/WiMAX operation

The proposed antenna with a wideband coupled ring for the WLAN/WiMAX operation in this study is very promising for the practical application. A coupling-T strip fed by a 50-Ω coaxial mini-cable excites a higher resonant mode at about 5.5 GHz. A wide operating bandwidth with multi-resonance excitations near the frequencies at about 2.5 and 3.5 GHz is obtained by coupling the energy to the wideband coupled ring. The antenna size of 28 x 8 mm only occupies a small area at the top edge of the supporting metal frame of the laptop display and can be easily printed on the PCB with low profile characteristic as an internal antenna in the laptop. The constructed prototype is fabricated and tested in the study. Detailed results are analyzed and discussed in the paper.