This work proposes a polarization-reconfigurable antenna composed of two independent, co-located, and orthogonal ('crossed') narrow microstrip patch antennas with a novel pressure-driven fluidic loading network. Repeating and alternating high-low dielectric constant fluids in the network excite the two patches independently through capacitive coupling. A second iteration of this design with RF PIN diodes allows for a comparison between the fluidic reconfiguration mechanism and current state-of-the-art approaches. Circuit models for the antenna with each reconfiguration mechanism are developed to better understand the impacts on antenna performance. Furthermore, these models show good agreement with full-wave simulations and measured results taken from the two fabricated prototype antennas. Pattern data shows good linear polarization switching with both designs. The two mechanisms are compared based on the impact to electrical size, radiation patterns, efficiency, and switching speed. \ 2014 IEEE.