Abstract: In this paper, a Tri band linearly-polarized microstrip patch antenna is designed and simulated with Modified Resonating Structures using CADFEKO antenna simulation software from a dual band antenna. Antenna parameters are examined in this which includes resonating frequency, VSWR, impedances and bandwidth of the designed and proposed resonating structure with microstrip feed. The antenna is proposed for GPS/GSM, UMTS and Wi-Fi/WLAN wireless communication applications provided with greater bandwidth. This paper focuses on the designing of miniature microstrip antenna with microstrip feed and analyzes the results like return loss S11, VSWR, impedance and Bandwidth.