Masayasu Miyake

New integral equation formulation of the measured equation of invariance and the extension to analyze two-dimensional cylinders with impedance boundary conditions

We have derived a new form of the integral equation formulation of the measured equation of invariance (IE-MEI). The new formulation clarifies the existence of a relationship between scattered electric and magnetic fields at consecutive nodes in the IE-MEI and indicates that the relationship in a problem for a perfect electric conductor (PEC) holds for a problem with arbitrary materials. In a scattering problem of a two-dimensional cylinder with an impedance boundary condition (IBC), every matrix in the IE-MEI is a band-like sparse matrix. That is, the solution process in the IE-MEI with an IBC is the same as that for a PEC. Therefore the IE-MEI with an IBC has the same merits of the IE-MEI for a PEC: The more efficient computation can be achieved with the smaller memory than those of the method of moments (MOM). The IE-MEI with an IBC is validated by numerical examples for a circular cylinder and a square cylinder by comparison with a combined field MOM that satisfies exact boundary conditions. Numerical examples show that the IE-MEI with an IBC is applicable to the case where the generalized skin depth is less than half the width of a scatterer.

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.

On the validity of the integral equation formulation of the MEI and the extension to analyze object with impedance boundary condition

We show the validity of the assumption of the existence of the local sources. That is, from the observation that the electric and magnetic line current sources very close to the perfect electric conductor (PEC) induce the electric and magnetic local currents on the surface, the assumption is shown to be true with a new reaction integral in contrast to the original integral equation-measured equation of invariance (IE-MEI). As a natural extension, the interpretation of the new reaction integral makes it possible to analyze objects with impedance boundary conditions (IBC). The extension has the invariable feature that the procedure to solve the problem with IBC is the same for the PEC except only in the final step to obtain the current, where no noticeable increase of the CPU time is found and no extra memory is needed. As numerical examples, scattering from a circular cylinder with IBC is considered in the cases of a plane wave incidence and electric line sources very close to the cylinder. By comparison with the results of the new IE-MEI method with IBC and exact series solutions, we show the validity of the new method.

Gain improvement for a new built-in antenna system on a handset including the proximity effect of the hand and head

We propose a new built-in antenna system on a handset for PCS and PHS (Japanese digital cordless phone) at 1.9 GHz. The new antenna system consists of a PIFA (planar inverted F antenna), two conducting bodies divided from a body, and a short plate connecting the two bodies. The new antenna system improves the horizontal plane peak gain and average gain about 2 dB in free space, even at the very proximity to the hand and head. The experiments and the calculations confirmed it.