FDTD analysis of rectangular microstrip loop antennas

The characteristics of ordinary loop antennas are well known. This paper explores methods to reduce the physical size of printed rectangular loop antennas by introducing a ground plane into the structure. With the introduction of the ground plane into the antenna structure, the relationship between the dimensions of the modified loop are explored to achieve the design goals. This type of antenna is analyzed using the finite difference time domain (FDTD) method and these results are verified by other numerical simulation packages. Differences between full (unmodified) loop antennas and the modified antennas of the same dimensions are examined. Optimization of bandwidth, gain, directivity, and operational bands are discussed. Reducing the physical size of the antenna allows for more commercial uses in mobile transceiving platforms. By manipulating the dimensions of the modified antenna it is possible to adjust its parameters to achieve maximal operation at a specific band, or within several different bands concurrently. Design examples of this type of antennas for radar applications and personal communication devices are presented.