Analysis, Design, and Implementation of a New Extremely Ultrathin 2-D-Isotropic Flexible Energy Harvester Using Symmetric Patch FSS

Polarization Insensitive and Transparent Frequency Selective Surface for Dual Band GSM Shielding

“…To obtain the values of each component in the ECM, we have used the curve-fitting optimization with the help of transmission poles and zeros [38] in the Advanced Design System (ADS) simulator from Keysight Technologies [39]. To accommodate for the loss of the conductor, a series resistance has been introduced in the inductor model.…”

An ultra-thin double-functional metasurface patch antenna for UHF RFID applications

“…A perfect metasurface absorber, assessed by the balance between the internal losses and the external coupling, prevents re-radiation by canceling out the amount of transmission and reflection power coefficinets 29 . Since the backside of the structure is completely covered by copper, transmission coefficient is zero, and hence, the absorptivity (A) can be calculated by A( , where and are the angular frequency and reflection coefficient, respectively 41 .…”

“…In ultra-thin metasurface absorbers where the perfect absorption is achieved by additional internal losses, the periodicity of the cell ( P ), which greatly affects the absorption frequency, can be approximately calculated as in ( 2 ) 41 where , , c , and f are the guided wavelength, substrate permittivity, velocity of light, and the resonance frequency, respectively. Although the critical coupling condition to attain perfect absorption was satisfied here by adjusting the external coupling rather than the internal losses, the above formulation can be used provided that the increase of the length of the current path due to the addition of the slits into the unit-cell design is considered.…”

“…In order to have an insight on the role and effects of the slits introduced in the unit-cell on the absorption mechanism from the circuit point of view, a simplified equivalent circuit model was designed and developed. The unit-cell dielectric can be modeled as a combination of parallel resistor and capacitor representing the dielectric losses and its capacitance, whereas the conductive ground plane can be simply an inductor neglecting the ohmic losses 41 . The unit-cell metal patch can be described using inductors and the addition of the slits calls for extra parallel combination of equivalent resistors and capacitors.…”

“…Since the considered artificial ground is a metasurface absorber rather than a high-impedance surface, it is necessary to understand its physical behavior to be able to figure out how it would contribute to the antenna radiating properties. In order to explain that, the loss of the artificial ground (including the substrate and copper layers) in the MPA structure was removed to convert it to a HIS 41 , 47 (Fig. 4 ).…”