Very compact coupled fed loop antenna for 2.4‐GHz WLAN applications

A novel, coupled fed loop antenna with a small form factor for wireless local area network operation in the 2.4 GHz band is presented.The antenna has a very compact structure with the dimensions 29.75 mm × 5 mm and consists of a half‐wavelength loop and a coupling feed, all printed in a coplanar configuration on a 0.4‐mm thick FR4 substrate. The antenna was easily fed by using a 50‐Ω minicoaxial cable, allowing it to have much flexibility in the placement in a defined location. The results show that good input matching over the 2400–2484 MHz band can be achieved by tuning the coupling‐pad size and the loop width. Good omnidirectional radiation patterns were also observed. Details of a design prototype are described and discussed.