Multi-frequency printed loop antenna for mobile phone application

The printed loop antenna for multi-frequency operation in the mobile phone application is proposed. The loop antenna consists of an inverted-L shaped strip and a rectangular patch on the front side, while the back side consists of a meander loop antenna and a 100×60 mm² ground plane. The inverted-L shaped strip and the rectangular patch are connected with a 50 Ω microstrip line. The feeding mechanism is coupled-fed method, which excites the loop antenna through the inverted-L strip and the rectangular patch. The loop antenna provides two wide operating bands centered at about 810 and 2175 MHz for LTE700/GSM850/GSM900/DCS/PCS/UMTS/LTE2300/WLAN/LTE2500 bands operation. The proposed antenna also has the advantages of low profile, low cost, ease fabrication, and less affected by changing ground plane size.