Abstract— We numerically presented and analyzed a new perfect frequency selective surface (FSS) metamaterial absorber (MA) based on resonator with dielectric configuration for terahertz frequency ranges. Proposed FSS MA has features of simple configuration and easy fabrication. Also, it introduces flexibility to adjust its FSS metamaterial (MTM) properties and easily re-scale the model for various other frequencies. Moreover, numerical simulations verify that the FSS MAs could achieve very high absorption at wide different all polarization angles. The proposed FSS MAs and its variations enable myriad potential application areas in defend systems, communication, stealth technologies, and so on. Keywords— absorber; metamaterial; terahertz. I. INTRODUCTION TMs are artificially created electromagnetic (EM) materials have gained great attention of science community. Since, MTMs show specific EM features not ordinarily encountered in nature such as negative refractive index [20, 12, 31, 5, 6]. Also, MTMs are manmade and have many potential application areas for example cloaking [3], absorber [8], super lens [10], sensing [26], antenna [22], and so on [9, 21, 25, 29, 1, 19, 14, 4]. Nowadays, the concept of MA studies has gained attention by the scientists who study on MTMs. There are many MA studies in literature. These studies are commonly realized on microwave regime. However, researchers studied on also ranges of THz and infrared frequency in last few years. Some of these are broadband terahertz absorber [13], multi-band THz MA [11], polarization-independent plasmonic absorber [7], broadband MA [24]. We considered and analyzed on the MA studies in literature. Unlike the others, we presented perfect FSS MA that operates in terahertz frequency ranges and has easy fabrication M.K. acknowledges the support of TUBITAK under the Project Number of 113E290 and partial support of the Turkish Academy of Sciences C. Sabah is with the Department of Electrical and Electronics Engineering, Middle East Technical University - Northern Cyprus Campus, Kalkanli, Guzelyurt, TRNC / Mersin 10, Turkey (e-mail:sabah@metu.edu.tr). F. Dincer is with the Department of Computer Engineering, Mustafa Kemal University, Iskenderun, Hatay, 31200, Turkey M. Karaaslan, E. Unal and O. Akgol are with the Department of Electrical and Electronics Engineering, Mustafa Kemal University, Iskenderun, Hatay, 31200, Turkey. techniques. Also, we are investigated with respect to dependency on polarization angles of the suggested model. Moreover, the proposed FSS MA model has comfortable configuration and can easily be re-scaled for other frequencies. The proposed FSS MA and its variations enable numberless potential applications in medical technologies, sensors, wireless communication, and so on. II. THEORETICAL APPROACH The frequency response of absorption is defined as A(ω)=1- R(ω)-T(ω), where A(ω), R(ω) and T(ω) are the absorption, reflectance and transmittance, respectively. A(ω) comes from minimizing either reflectivity R(ω)=|S 11 | 2 and transmission T(ω)=|S 21 | 2 at an specified frequency range. Reflectivity can be reduced (near-zero) when the effective permittivity ) ( ~ ω ε and permeability ) ( ~ ω µ have the same value. It is possible to absorb both the incident electric and magnetic field t (ω) and ) ( ~ ω µ . They can be manipulated to create high absorption. Absorbers minimize the reflection and transmission coefficients of incident waves at a certain frequency range due to the impedance matching [8]. In the resonance condition, the effective impedance ( ) 2 1 ) ( ~ / ) ( ~ ) ( iz z Z + = = ω ε ω µ ω have to match with the free space impedance Z(ω)=Z 0 (ω) and therefore, the reflection is minimized [16, 5, 23, 24, 18, 9]. III. NUMERICAL STUDY, RESULTS, AND DISCUSSION Proposed FSS MA design is based on square and rectangular-shaped inclusions. The models consist of a resonator, metallic layer and dielectric substrate. Resonator and metallic layer are modelled as silver sheet with electrical conductivity of 6.3x10 7 S/m and thickness of 1 um. Silver is soft, white, lustrous transition metal and also possesses the highest electrical conductivity inside of metals. Also, it has extremely low resistivity. Resonator and metallic plate are separated by the Quartz (Fused)-dielectric substrate and placed parallel to each other. The thickness, loss tangent, relative permittivity and permeability of the Quartz (Fused) are 100 um, 0.0004, 3.75 and 1, respectively. Fig. 1 shows the structure designs with their dimensions. Polarization-Insensitive Perfect FSS Metamaterial Absorber in THz Frequency Range C. Sabah, F. Dincer, M. Karaaslan, E. Unal and O. Akgol M New Developments in Computational Intelligence and Computer Science ISBN: 978-1-61804-286-6 121