The radiation characteristics of a monopole antenna that consists of one-half of a bow-tie dipole antenna, made of optically transparent conductive thin film and mounted above a ground plane, are investigated. The antenna's performance is measured for several films with different sheet resistivities. It is found that the gain lowering of the antenna caused by material resistance decreases from 4.4 dB to 0.2 dB at 2.4 GHz and the efficiency of the antenna increases from 46% to 93% at the same frequency, as the sheet resistivity decreases from 19.8 Ω/ to 1.3 Ω/. The antenna is analyzed by the moment method. A wire-grid model with resistance loading on every discretized wire is applied. The analyzed results agree with the experimental values very well.