Radiating and balanced mode analysis of PIFA shorting pins

Radiating and balanced mode analysis has been routinely used to study the performance of folded dipole antennas. Here it is applied to the combination of a planar inverted F antenna (PIFA) and its supporting PCB. The original theory, used to analyze closely coupled antenna structures, was developed by Uda and Mushiake (1954) and has subsequently been widely used to analyze the folded monopole and dipole. The theory presented is similar to that used for a folded monopole, but adapted to take account of the effect of the PCB and the planar section of the PIFA.