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　1λ.　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　3.2λ　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.　©　2024　De　Gruyter.　All　rights　reserved.