Characteristics of a microstrip-fed miniature printed Hilbert slot antenna

The resonant frequencies and input impedance of a microstrip-fed third order Hilbert slot antenna are studied as function of antenna and substrate parameters. A distinct dual-band characteristic is observed. Findings from HFSS simulation are validated by prototype fabrication and experimental measurement. The two resonant frequencies maintain a ratio of approximately 1.4 for narrow slots. A design parameter, Lax is identified which needs to be about 0.80 lambda(g) at the lowest operating frequency. The Hilbert slot provides a unidirectional pattern when operated against a metallic ground plane while maintaining dual-band characteristics.