Quad-Band Internal Mobile Phone Antenna

A novel internal, quad-band antenna placed inside a "foldable" type of mobile phone is presented. Its structure consists of a helical and a monopole element exciting two broad frequency bands. Using a simple matching circuit the proposed antenna covers several frequency bands including the global system for mobile communication (890-960 MHz), digital communication system (1710-1880 MHz), personal communication system (1850-1990 MHz), and universal mobile telecommunication system (1920-2170 MHz). It achieves a voltage standing wave ratio (VSWR) of less than three across all frequency bands with total radiation efficiency of more than 50%. Its novel design and structure occupies only 1.8 cm³ of volume making this antenna very small and very suitable for internal use inside mobile terminals.