Nearly 10 years ago, the 79 GHz band was utilized in automotive radar applications. In difficult conditions, this frequency band improves the ability and accuracy of target detection. This work presents a good design for a key component of the radar sensor. It maintains the performance parameters needed for mm-wave radar and Internet-of-Things applications (IoT). We present a single patch antenna, 1x4 and 1x8 series feed patch antenna array that operates at the 79 GHz band by using an inset-feed line feeding technique that is one of the most popular techniques for perfect matching. The simulated results were obtained by two different software programs CST microwave studio 2020 and Ansys HFSS 2021. These software packages are basically different and used for confirming the results. these results include the return loss, voltage standing wave ratio, Band Width, Gain, Directivity, and Efficiency. A new technique has been used to optimize the bandwidth and overcome one of the most popular weaknesses of the series array microstrip antenna. The proposed design's good results make it appropriate for medium-range and short-range radar in the 77-81 GHz frequency band. The antenna is fabricated, and the simulated results are validated by the experimental measurements.