Two-dimensional interdigital capacitive small antenna resonating at enhanced left-handed modes

A two-dimensional interdigital capacitive small antenna to resonate at left-handed (LH) modes is presented in this study. Since a LH resonant mode occurs at a lower frequency, the resonant frequencies of the proposed antenna become lower so that the antenna size can be reduced. The antenna size is significantly decreased thanks to interdigital capacitors which are employed to enhance the LH modes. The antenna is implemented with three open-ended composite right/left-handed unit cells and its experimental results are compared with parametric and full-wave simulation results. It is observed to resonate at 2.724 GHz as the second negative mode. At this frequency, the patch size is calculated to be 13.5 × 13.5 mm which is 0.16λ_g × 0.16λ_g in an electrical dimension.