This paper presents the design and analysis of a D-band microstrip patch antenna array for communication and radar applications operating at 150 GHz. The proposed 2×2 array achieves a broadside gain of 10.8 dB in free space. A polycarbonate dielectric cover is introduced to evaluate its impact on antenna performance, simulating the effects of radome structures or mobile device bezels. An equivalent model is developed to optimize the slab thickness, ensuring minimal reflection and efficient wave transmission. The proposed approach supports the possibility of assembling sub-THz telecommunication modules with protective dielectric structures while preserving radiation performance, making them suitable for next-generation wireless applications.
