This paper proposes a design of folded substrate integrated waveguide (SIW) cavity-fed miniaturized microstrip patch filtering antenna. The presented antenna consists primarily of a folded SIW cavity, a rectangular coupling aperture, and a stacked patch resonant radiator. Energy is fed into antenna through the folded SIW cavity on the bottom layer, coupled to the patch radiator on the upper layer, and then radiated. The multilayered design, along with the folded SIW cavity, allows for a compact antenna configuration. A prototype is designed and simulated. The results show a -10 dB impedance bandwidth of 4.75% (4.11 GHz to 4.31 GHz), a peak realized gain of 7.8 dBi, and a cross-polarization level better than 35 dB.