asma in the antenna active region. The antenna impedance (Z) is used to determine the power loss during the antenna radiation [Gregory et al. (2003)]. The screening voltage, capacitance voltage, and the conductance of the PCA are time dependent. To improve the performance of PCA and to extract the analytical relation between the time-dependent parameters, researchers are working on the interdigitated PCA structure simulation and its theoretical analysis through the equivalent circuit model. In the IPCA design, the cathode and anode finger-like structures in the gap area are parallel to each other [Godyak, Piejak, & Alexandrovich (1991)]. Hence, the number of parallel combinations of gap capacitance (C(t)) and conductance (G(t)) depends on the number of interdigitated structures. By applying Kirchhoff's law Terahertz Antenna in Future Healthcare Informatics to the equivalent circuit, the time dependent radiation voltage (V,(t)), capacitance voltage (V((t)) and screening voltage (V (t (t)()) can be calculated and analysed using the Drude-Lorentz model (explained in the next section), the energy balanced trans- port model [Emadi, Safian, & Nezhad (2017)], the drift diffusion model [Prajapati, Bharadwaj, Chatterjee, & Bhattacharjee (2017); Boby, Prajapati, Rathinasamy, Rao, & Mondal (2022)], and SO forth. 12.10 NUMERICAL SIMULATIONS OF PCA The simulation of PCAs is always required before an experimental investigation. It can be performed by using commercial software, such as, Silvaco/Sentaurus TCAD, Ansys HFSS, CST Microwave Studio Suite, or COMSOL Multiphysics package. The drift diffusion model is used to determine the density of carriers in the active layer of the substrate. The contribution of holes is not considered in the calculation because of their high mass and less mobility compared to the electrons. The carrier density is directly proportional to the optical generation rate, and it increases with a decrease in the carrier lifetime. The time dependent carrier density is calculated by using the continuity equ