This article provides the design of a dual frequency, dual-polarized microstrip patch antenna using a Single Rectangular Loop (SRL) element. The proposed antenna has a physical footprint of 50 x 40 x 1.2 mm³ and a dielectric constant of 4.2. A single rectangular loop is placed with truncated corners on the inner patch to excite the right-hand circular polarization. The prototype is designed to operate in two modes with frequency and polarization re-configurability. The re-configurable mechanism is controlled by a pair of PIN diodes (BAR64-02V), which connect the inner patch and outer loop. In the ON state, the antenna exhibits right-hand circular polarization (RHCP) as a narrow-band antenna. It is capable of operating at frequencies between 5 GHz and 5.43 GHz. Furthermore, this device provides linear polarization (LP) in the frequency range of 3.75 GHz to 3.86 GHz. It exhibits 110 MHz of bandwidth in 3.8 GHz (S-band) and provides 430 MHz bandwidth in 5.2 GHz WLAN operating frequencies. The suggested antenna provides a maximum gain of 8.56 dBi. The antenna is fabricated and tested to prove its performance parameters. All the simulations are performed using high Frequency Structure(HFSS) software and results are presented with discussions.