A slot loaded annular sector microstrip antenna having a pentaband operation is presented. The antenna has six resonant frequencies and the fourth band occurs between the fourth and fifth resonance. The radiation pattern is linearly polarized at all the frequencies. The radiation is broadside directed at the first three bands, tilted at the fourth and split at the fifth band. The resonant frequencies are located at 3.543 (Sub-6 GHz 5G band), 5.118 (ISM 5.2 GHz), 5.625 (WiMAX 5.8 GHz), 8.463, 9.534 and 11.25 GHz. Analysis of the structure is done using Multiport Network Modeling which fairly accurately predicts the resonant frequencies of the structure.