Gain improvement of a planar inverted F antenna on a handset by passive loading

In personal communication systems (PCS) and the Japanese Personal Handy Phone System (PHS), the size and the shape of the handset is of great importance with regards to the portability, the tractability, and the design. In these respects, a built-in antenna like the planar inverted F antenna (PIFA) on the handset is desirable. We propose a new built-in antenna system on a handset for the PCS and PHS at 1.9 GHz band. Previously, almost the same structure applied to a /spl lambda//4 monopole antenna system was successful in enhancing the horizontal plane gain and controlling the antenna pattern. The new structure is shown to be also applicable to the PIFA as a built-in antenna. The conclusions are confirmed by the experiments and the calculations using the method of moments.