<p>This paper presents a numerically investigated tunable terahertz (THz) biosensor for Avian Influenza virus identification based on a hybrid InSb–graphene structure and analyzed using the wave concept iterative process (WCIP) method. The proposed sensor consists of a rectangular patch antenna incorporating a split ring resonator (SRR), where InSb and graphene are employed in order to achieve dual tunability. Frequency reconfigurability is realized by adjusting either the temperature of the InSb semiconductor or the chemical potential of graphene. The resonance frequency can be tuned from 2.64 to 3.24 THz by increasing the InSb temperature from 300 K to 700 K, and from 2.64 to 2.94 THz by varying the graphene chemical potential from 0.1 to 0.4 eV. The sensing performance of the device is evaluated by analyzing its response to variations in the real and imaginary parts of the complex refractive index of Avian Influenza viruses. Numerical results demonstrate that changes in the complex refractive index of the sample induce resonance frequency shifts with a variation of the reflection amplitude. Based on these electromagnetic response, the proposed sensor is capable of distinguishing different Avian Influenza sub-types. In particular, resonance frequency shifts from 2.64 THz to 2.73 THz, 2.76 THz, and 3.13 THz are obtained for H1N1, H5N2, and H9N2 sub-types, respectively, accompanied by distinct sensing parameters variations. These results confirm the potential of the proposed InSb–graphene based THz sensor as a promising platform for virus identification and classification.</p>