Design of miniaturized slot antennas

A procedure for the design of a novel small slot antenna is presented. Using this method enables us to achieve a perfectly matched antenna with a fairly high efficiency for a given arbitrary small size. The miniaturization is achieved by terminating the short slot by an inductor. Inductive loading is realized by coiling the shortened slot line with a length of less than a quarter wavelength. Although the choice of antenna size is optional, it is subject to limitations such as antenna bandwidth and gain/efficiency. However, the directivity of this small dipole-slot antenna, in the limit, is equal to that of the infinitesimal Hertzian dipole, and its gain depends on the substrate material specifications and antenna size. Microstrip line is used to feed the antenna, which provides more stable feeding compared to coaxial feed. Then simulation results for a prototype antenna at 300 MHz as well as the input impedance and radiation pattern of the antenna are presented and compared with measurements.