New excited mechanism on planar inverted-L antenna for mobile handsets

In this paper, we present a novel compact multiband planar inverted-L antenna (PILA) with an occupied volume of 40x20x5.7 mm3 in the mobile phone to operate GSM (890-960 MHz), DCS (1710-1880 MHz), PCS (1850-1990 MHz), and UMTS (1920-2170 MHz) bands. The proposed PILA comprises two resonant paths close to each other and a dielectric resonant coupling feed is used, which is different from the use of a direct feed of the conventional PIFAs. The position of feeding point and shorting pin in the conventional PIFA affect significantly the impedance matching, which increase the complexity of tuning mechanism in the antenna. But with the dielectric resonant coupling feed in the proposed antenna, the multimode can be easy generated by the dielectric resonant coupling to cover the desired multiband operation. This coupling feed is different from the external matching elements on the radiator of the antenna, which will occupy some valuable board space on the system circuit board of the mobile phone and increase some insertion loss also. Detailed design considerations of the proposed PILA are described in the article.