Patent ID: 7352326

Claim:
A multiband planar antenna having at least a lowest operating band and a second operating band and comprising a ground plane ( 310 , 410 ) and a radiating plane ( 320 ; 420 ; 520 ), which is at a feeding point (FP) connected to an antenna port of the radio device and at a short-circuit point (SP) to the ground plane, which radiating plane comprises a first conductor branch and a second part such that the first conductor branch ( 321 ; 421 ; 521 ) together with the surrounding antenna parts forms a quarter-wave resonator shorted at the short-circuit point, a natural frequency of which resonator is located on the lowest operating band, and the second part ( 322 , 422 , 525 ) together with the surrounding antenna parts forms a resonator, a natural frequency of which is located on the second operating band, characterized in that the radiating plane further comprises a conductor loop ( 323 , 423 , 523 ) starting from the feeding point (FP), joining the rest of the radiating plane close to the short-circuit point and ending at the short-circuit point (SP) for forming a loop radiator and for improving antenna matching on the lowest operating band, and a part of the first conductor branch of the radiating plane is located between the conductor loop and said second part.