Transparent Ultrawideband Halved Coplanar Vivaldi Antenna With Metal Mesh Film

In this letter, a transparent ultrawideband (UWB) halved coplanar Vivaldi antenna (HCVA) with metal mesh film (MMF) is proposed. Based on the equivalence principle, the halved type antenna is achieved by replacing a radiation fin with the ground plane. The proposed HCVA has the advantages of UWB impedance matching, miniaturized aperture size, high directivity, and simple feed structure. By employing MMF with a low sheet resistance of 0.35 Ω/sq and high optical transmittance above 72% in the radiation fin and ground plane, the antenna is entirely transparent. An example transparent HCVA is fabricated and measured. According to the simulated and measured results, most of the reflection coefficient is below –10 dB from 0.78 to 20 GHz. Moreover, the peak realized gain reaches 10.4 dBi with the compact size of 0.32×0.47×0.052 λ_L ³ , where λ_L is the wavelength at the lowest operating frequency.