In the present-day scenario, the wireless/broadband communication is growing at a rapid pace with the days progressing. Presently, in the existing 4G there are several shortcomings such as the high communication setup cost, large number of devices not being able to establish connection and low data rates. So, 5G Technology – "New Radio" is the key solution to it. The 5G technology portrays 5 different network protocol stack layers that are derived from the 7 layers of the OSI model. The focus in this paper would be on the designing of 1st layer of the 5G network protocol stack architecture i.e. Physical Layer. The implementation of this layer in technical terms is known as PHY. The PHY layer Downlink Channel comprises of (i)Physical Broadcast Channel [PBCH], (ii)Physical Downlink Shared Channel [PDSCH] and (iii)Physical Downlink Control Channel [PDCCH] which are being designed. The approach for the designing of the Downlink channels of PHY layer uses Polar Coding, Low Density-Parity Check [LDPC] coding which is accomplished using MATLAB® and Simulink tool. The approach is focused to accomplish increased data rates and reduced error rate. Further the testing of the modules are done in order to verify the designed approach and its functioning. The design further involves using mmWave by providing different ranges of Bandwidth for the operation. It was observed that Polar Coding as well as LDPC coding-based design modules showed better Block Error Rate (BER) i.e.0.064815 for Downlink CRC attachment of 24-bits. The other case for the 11-bit CRC attachment was found to be BER of 0.1152. Further, the throughput vs SNR was obtained for 1000 subframes and observed that as signal strength increased the throughput. Hence, the enhancement was established by using subcarrier spacing and concluded by using mmWave Technology for exploiting the spectrum of bandwidth.