Single-conductor strip higher order mode broadband leaky-wave antenna

The leaky modes on various printed-circuit lines, such as microstrip line, slot line, strip line, coplanar waveguide, coplanar strips, have motivated considerable interest because excitation of these leaky modes may result in undesirable spurious performance. Most of these open planar printed-circuit lines exhibit interesting radiation behavior due to the power leakage and are used as leaky-wave antennas based on space-wave leakage of the higher order modes. But, in general, the leaky wave radiation bandwidth for planar printed-circuit transmission lines is about 20% and is limited by the dielectric constant of the substrate and by the bandwidth of the feeding network. For wireless communication applications, broadband leaky-wave antennas, such as tapered microstrip antenna and single-conductor strip antenna, have been proposed. The authors present the higher order space-wave modes of the single-conductor strip structure. The integral equation method in the spectral domain and the method of moments (MoM) are applied to analyze this structure. Finally, a broadband feeding structure is proposed to excite the EH₀₂ space-wave mode. The measured data exhibit the broadband nature of the radiation characteristics of this structure.