Internal coupled‐fed loop antenna integrated with notched ground plane for wireless wide area network operation in the mobile handset

An internal wireless wide area network (824–960/1710–2170 MHz) antenna suitable to be disposed at a notched region (size 10 × 40 mm 2 ) of the system ground plane of the handset to achieve compact integration therein is presented.The notched system ground plane, compared to the traditional rectangular system ground plane at which the internal antenna is generally disposed at the entire top or bottom edge of the ground plane, can lead to more compact layout design of the internal antenna and associated electronic elements in the handset. The proposed antenna has a simple structure occupying a small volume of 10 × 40 × 5 mm 3 and comprising a monopole feed and a coupled strip. The latter is coupled‐fed by the monopole feed to provide a 0.25‐wavelength loop path, which generates a 0.25‐wavelength loop mode at about 850 MHz and a higher‐order loop mode at about 1.7 GHz. The monopole feed also contributes a 0.25‐wavelength mode at about 2.1 GHz to combine with the higher‐order loop mode to form the antenna's upper band. The bandwidth enhancement of the 0.25‐wavelength loop mode is obtained by adding an external bandstop circuit, which makes the desired antenna's lower band achieved. The antenna also meets the specific absorption rate and hearing‐aid compatibility requirements for practical applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:553–555, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26620