Impedance modeling for a unit cell of the square loop frequency selective surface at 2.4 GHz

Equivalent Circuit (EC) method gives a simple alternative method in Frequency Selective Surface (FSS) analyses which are useful for quickly predicting the characteristic of FSS. An impedance modeling of the Equivalent Circuit (EC) for a unit cell of the square loop FSS structure is presented in this paper. The unit cell of the square loop FSS is designed and simulated using the CST Microwave Studio software at 2.4 GHz based on industrial, scientific and medical bands (ISM) standard. The square loop FSS is simulated without FSS, with square FSS and square FSS with slot. The investigation has been done on the length of substrate (s), width of substrate (w), length of square FSS (a), length of square FSS with slot (b) and the number of slots (n). Real (Re) and Imaginary (Im) component of EC or known as resistance and reactance has been modeled based on physical parameters of the design structure of the FSS. The resistance and reactance of the impedance are depending on the geometry of the unit cell of FSS. This impedance modelling can be used to design the advance FSS for the similar ISM band. EC gives a simple alternative method in FSS analyses which are useful for quickly predicting the performance of FSS. The 7^th and 8^th degree polynomial type has been used to model the component of EC.