A Study of substrate permittivity effects on the gain of planar inverted-F antennas

Abstract

A planar inverted-F antenna (PIFA) of fixed dimensions, with a 4.92 cm x 2.13 cm radiating element 4.4 mm high above the ground plane is evaluated with different substrates. The resonance frequency, the bandwidth and the gain are studied in relation to the relative dielectric constant of the perfect and lossy substrates. The results reveal that the normalized resonance frequency (Deltaf/f) decreases logarithmically and the gain drops linearly with a slope of 2 dB per decade.