This research work adopts an open-circuited-series stub-tuning in sequence with unmatched antenna radiator to bring out a small form factor. Thereby, the effective antenna radiator size has been shrunk up to 0.2λ, where similar efficiency and beam pattern has been maintained. The antenna is conceptualized with symmetrical slots, which indicates a multi-ring structure to contribute multiband miniaturization. This consists a loop based rectangular-ring connected with an E-shaped patch, which is excited through a microstrip stepper impedance transmission line followed by an equally distributed strip-line. It enables enhanced impedance-matching at 2.76 GHz and 6.34 GHz by a stepper impedance transmission line with stub-loading technique. The antenna aperture area miniaturization of 56% has been achieved by introducing slots on the radiator patch. Moreover, this miniaturized patch exhibits improved gain response of 4.43 dBi and 5.37 dBi in the broadside direction. The proposed design occupies a dimension of (0.22λ × 0.26λ) mm 2 .