ANALYSIS OF MICROSTRIP ANTENNAS ON A CURVED SURFACE USING THE CONFORMAL GRIDS FD-TD METHOD

The need for small, portable antennas for mobile communications has recently spurred the study of microstrip antennas (MSA). MSA are quite flexible and have been used as conformal antennas on arbitrary curved surfaces. The characteristics of conformal MSA can be expected to differ from those of planar models. Dependable numerical analyses will obviate many of the costs and other inconveniences associated with experiments, but as antennas may be mounted on surfaces of arbitrary topological complexity, analysis methods must have as general applicability as possible. The curvilinear finite-difference time-domain (FD-TD) method has shown excellent versatility. In this paper, the curvilinear FD-TD method is applied to analyze microstrip antennas mounted on curved surfaces. The numerical predictions are compared with the experimental values. The results confirm the predictions within acceptable limits and appear to confirm the validity of the method. As a result, it was confirmed that the input impedance and directivity of MSA on curved surfaces are different from the flat MSA.