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.