A miniaturized in size linear multiple-input multiple-output (MIMO) antenna array operating on demand at 28 GHz and 24.8 GHz for 5G applications is presented and investigated in this research work. The antenna array has the capability to switch and operate efficiently from 28 GHz to 24.8 GHz with more than 15 dB gain at each frequency, having 2.1 GHz and 1.9 GHz bandwidth, respectively. The unit cell of the proposed antenna array consists of a transmission line (TL) fed circular patch connected with horizontal and vertical stubs. The vertical stubs are used to switch the operating frequency and mitigate the unwanted interaction between the adjacent elements of the antenna array to miniaturize the overall dimension of the array. The proposed antenna array is compared with the recent works published in the literature for 5G applications to demonstrate the features of miniaturization and high gain. The proposed array is a potential candidate for 5G sensors applications like cellular devices, drones, biotelemetry sensors, etc.