Design and simulation of a tunable dual-band bandpass filter for detection and measurement of Wi-Fi waves exposure

In this paper, a novel dual-band bandpass filter for the measurement and optimization of Wi-Fi waves exposure in the non-ionizing frequency range of 2.4 and 5 gigahertz, has been designed and simulated. In the novel proposed method for detection, initially the Wi-Fi waves have been filtered and then converted to the direct current signal in the detector. This filter consists of a complementary split ring resonator metamaterial and an interdigital capacitor which has been printed on a 50 ohms coplanar waveguide with the Rogers 3003 dielectric. In the equivalent circuit model of the bandpass filter, the complementary split ring resonator has been represented by a tank circuit which is in parallel with the coplanar waveguide. The interdigital coupling capacitor is in series with the waveguide. By adjusting the complementary split ring resonator radius and the interdigital capacitor length, the frequency of transmission poles of the filter can be tuned. The electromagnetic coupling mechanism in the components has been discussed. According to the results of the scattering parameters curve, the return loss at the transmission poles is more than 40 dB while the insertion loss in passbands is less than 0.3 dB.