Microwave absorption analysis of reflectarray resonant elements based on non-homogeneous substrate

A planar microwave absorber based on the anisotropic properties of tunable reflectarray has been introduced in this paper. A non-linear liquid crystal material along with polystyrene foam has been designed to analyze X-band microwave absorption performance of three different reflectarray resonant elements. A thorough investigation based on finite integral method has been performed to investigate the reflection loss, dynamic phase distribution performance and frequency tunability characteristics of rectangular, dipole and ring elements. It has been demonstrated that the ring element offers the highest reflection loss of 45.91 dB followed by dipole and rectangular elements which offer maximum reflection loss of 39.41 dB and 6.92 dB respectively. Furthermore ring element is shown to attain a wider dynamic phase range of 192° with minimum frequency tunability of 176 MHz whereas rectangular element is observed to offer a narrower dynamic phase range of 50° with maximum frequency tunability of 188 MHz. The possibility of using different reflectarray resonant elements with non-homogeneous substrate demonstrates a significant effect on the reflection loss and dynamic phase range performance of reflectarrays.