In　this　paper,　we　introduce　a　novel　design　for　a　high-gain,　low-profile　quad-feed　folded　transmitarray　antenna　(FTA)　to　enable　a　more　compact　system.　The　proposed　antenna　system　consists　of　a　transmitarray,　a　reflectarray,　and　four　identical　planar　microstrip　U-slot　patch　antennas　placed　on　the　same　surface　of　the　reflectarray　with　an　adjacent　distance　greater　than　1　lambda.　To　compare　the　effectiveness　of　our　design,　we　developed　three　different　antenna　array　systems　with　the　same　aperture　size:　a　single-feed　transmitarray　antenna　(TA)　system,　the　proposed　quad-feed　FTA　system,　and　a　single-feed　FTA　system.　Our　experimental　results　demonstrate　that　employing　four　symmetrical　feeders　with　an　adjacent　distance　of　3.2　lambda　effectively　reduces　the　height　by　about　76.7　%　in　comparison　to　the　height　of　a　single-feed　TA,　and　by　30　%　when　compared　to　the　height　of　a　single-feed　FTA.　We　also　present　the　design,　fabrication,　and　testing　of　a　prototype　of　the　proposed　quad-feed　FTA　operating　in　the　Ku-band.　The　measured　results　of　the　prototype　confirm　the　effectiveness　of　our　design.