This paper discusses the miniaturization of microstrip antennas using artificial magneto-dielectric material by inserting a split ring slot on the ground plane. A total of three sample frequencies were taken to determine the characteristics of miniaturization in the Ultra High Frequency (UHF) range, namely at 550 MHz, 1 GHz, and 2.4 GHz. To find out the ratio of miniaturization at each frequency, the sample will be compared into two antennas, a conventional antenna, and antenna with an artificial magneto-dielectric material. Antenna parameters such as Dimension and Impedance Bandwidth will be reviewed to determine how the antenna performs after miniaturization. Based on the results of these comparisons, the largest miniaturization ratio of 60% occurs in sample frequency of 1 GHz with the dimension of 40 x 40 mm and there is an enhancement in impedance bandwidth up to 57.46%.