A printed inverted-F antenna for circular polarization — Part 2

Authors have proposed a printed inverted-F antenna (PIFA) for circular polarization. In this paper, an approach to improve the bandwidth is investigated. It is shown that the bandwidth can be widened by designing the rectangular element loaded at the feeding line as short as possible. The redesigned PIFA in this paper has approximately twice (210MHz) the bandwidth of the 3dB-axial ratio with a 10dB-return loss than that of the circularly polarized PIFA previously. The antenna area is 0.068λ
_c
²
(λ
_c
: the wavelength at the center frequency). The antenna is small in size.