We　present　the　first　CMOS　integrated　circuit　implementation　of　the　spatio-temporal　modulated　millimeter　wave　transmitter　array　architecture　across　71-　76　GHz.　We　demonstrate　physical　layer　security　wherein,　we　preserve　the　signal　fidelity　in　an　intended　secure　cone　and　scramble　the　digital　data　stream　elsewhere.　The　physical　layer　security　using　space-time　modulation　principle　is　demonstrated　for　both　2-element　and　4-element　series-fed　patch　antenna　array.　©　2020　IEEE.