pplied bias voltage, V,(t) is the radiating voltage, V (t) is the screening voltage. The screening voltage can be calculated as Equation 12.10 [Prajapati et al. (2017)], [Khiabani et al. (2013)], Vg(t)=B(t)V(t) (12.10) where, B(t) is the screening voltage coefficient [Khiabani et al. (2013)]. The radiated voltage can be calculated by using Equation 12.11 (12.11) where, Z is the antenna impedance, I is the time dependent capacitance current. The capacitor current is given in Equation 12.12 (12.12) where, At is the time step. The total current flowing through the circuit can be written as Equation 12.13 (12.13) Terahertz Antenna in Future Healthcare Informatics where, 110tal(t) is the total current, R is the dark resistance. The THz photocurrent generated by the laser illumination on the semiconductor material is calculated numer- ically by solving Equation 12.13. The terahertz radiated power can be calculated in Equation 12.14 (12.14) There are three types of efficiencies for PCA, such as, optical to electrical conver- sion efficiency Ne, THz radiation efficiency N, and matching efficiency Nm. The overall efficiency is expressed in Equation 12.15 (12.15) where, Popt is the optical input power and PTH2 THz (peak) is the peak terahertz radiated power. This total efficiency can be increased by increasing the Ne, as it is the ratio of electrical power to optical power. The normalized electric field for the interdigitated photoconductive antenna design is obtained by increasing the number of interdigitated elements. Figure 12.16(a) shows the simulated results for the IPCA structure given in Figure 12.6. The frequency roll-off and ripples increase based on the number 2 elements 5 elements 13 elements Time (ps) 2 elements 5 elements 13 elements Frequency (THz) FIGURE 12.16 (a) Simulated E-field for the IPCA and (b) Gain for the different elements of IPCA. 5G Wireless Communication System in Healthcare Informatics of elements. Figure 12.16(b) depicts the frequency spectrum which clearly shows the ripples for the 2-interdi