<p>In this paper, we report a design and analysis of a one-dimensional (1D) quaternary photonic crystal (QPC) with tunable multichannel filtering application in THz (terahertz) region. The chosen QPC contains a nanolayer of silver integrated into the periodic structure containing the layers, SiO₂, Si, and Ge having thicknesses in microns. With the help of the transfer matrix method (TMM), the transmission spectra of the QPC are plotted in four different cases of the parameter variations: incident angle, thickness of silver, damping factor for silver, and number of unit cells, respectively. The three channels of transmission peaks coexist for a chosen value of the number of unit cell N = 4 at normal incidence, and if we increase the angle of incidence, the multichannel peaks shift towards a higher frequency showing blue shift, while the frequency separation between the peaks is almost angle independent. Here, the Quality factor seems to be better at lower angles viz. 30° showing better filtering property that makes it enable to design optical filters at lower angles. Further, the Quality factor increases with increase in the Ag thickness, while the separation between channels decreases as the silver thickness increases and showing blue shift. The damping factor variation doesn’t shift the peak’s position, while the Quality factor and transmittance both decrease when the damping factor increases. Moreover, it is observed that the obtained number of channels is (N-1) and is also angle independent. Based on the above insights, such multichannel filtering features of the chosen QPC, with a good tunability in the channel position and sharpness under optimized varying parameters, can make it a useful candidate for design of THz optical devices and in sensing applications.</p>