## 1 Introduction  
Non-natural metamaterials (MMs) are engineered combinations consisting of subwavelength conducting material (metal) sandwiched with a dielectric medium. These sorts of designs provide some unusual properties which are not naturally present [1]. For these eccentric electromagnetic properties of plentiful metamaterials, namely negative permittivity (ENG), negative permeability (\(\mu\)-negative), negative refractive index (NRI), and cloaking, the structure scheme and practical uses of metamaterials has become an important topic in recent research [2]. The principle characteristic of a perfect EM absorber is that it will not reflect or transmit the incident electromagnetic wave. An absorber highlights the maximizing of losses of scattering of EM fields including reflectivity and transmissivity at expected frequencies. The first metamaterial perfect absorber (MPA) involves three deposits containing two metallic layers and a substrate of dielectric, and exhibits a simulated absorptivity of nearly 99% at 11.48 GHz [3]. Electromagnetic radiation absorber can be classified into two categories- resonant absorber and broadband absorber [4]. When an incidental EM wave interacts with the materials in a resonant setup at a specific frequency it is called a resonant absorber; where the wavelength related to the resonant frequency (\(\omega_{0}\) ); \(\lambda_{0}=\frac{2\pi c}{\omega_{0}}\), and where c is the speed of light. On the other hand, broadband absorbers usually depend on materials whose characteristics are non-dispersive and therefore can absorb radiations over a bulky bandwidth [5]. Consequently, the absorber materials mostly absorb the power of the impacting wave. The enactment of an absorber is influenced by its depth and structural morphology and also the constituents used to manufacture it [6]. Recently, most of the innovative works on MAs have put emphasis on single band and dual band perfect metamaterial absorber (PMA) whereas there are only a few research studies on multi-band perfect metamaterial absorbers [7; 8]. In fact, in refs. [9; 10] a structure containing two or more planar resonant unit were designed and investigated but they did not function for dynamic adjustment. [PERSON] et al. in 2008 designated several metamaterial absorbers that received interest from scientists with perfect absorbers in the millimeter to nanometer wavelength ranges [6], a polarization-insensitive absorber [11], a broadband absorber [12], a multiband absorber, ultra-broadband, and a refractive index sensor. Electric and magnetic resonance occurring in a perfect metamaterial absorber (PMA) are able to unconventionally adapt the effective permittivity and permeability. The perfect metamaterial absorbers have some special advantages compared to the outmoded absorbers including the Salisbury screen [13], ferrite, and wedge tapering [14]. In addition, a thin-film substrate which may attain an atypical condition of absorbance. Furthermore, a highly efficient absorber can be comprehended using tunable gadgets or materials. These functions of metamaterial absorbers make them novel and make them fit to be candidates for different uses in the millimeter wavelength range of the optical band's spectra for example, photodetectors, solar photovoltaic, and thermo-photovoltaic bands [15; 16; 17]. PMAs functioned at the resonant frequency and reveal small absorption due to their intermittent clusters of resonators. Several prior studies on high-absorptivity perfect metamaterial absorbers were designed to describe their absorbance features [18]. For instance, the polarization-independent PMAs conveyed by [PERSON] et al. revealed better performance of absorption properties in the microwave range [19]. An absorber called the Jerusalem Cross of dimensions 24 \(\times\) 24 mm\({}^{2}\) describes absorption above 95% and which resonantes at 14.75 GHz and 16.1 GHz, respectively [20]. [PERSON] et al.