This paper presents 36-bit compact passive chipless RFID tag. The bowtie shape based tag structure is loaded with 36 slots. The tag is capable of yielding high data density. The overall tag dimension is 27mm × 26mm. The tag structure is optimized and analyzed for three different substrates, i.e., FR-4, Taconic TLX-0, and Rogers RT5880. Each loaded slot in tag structure has different length and hence yields resonance at particular frequencies. The response of the tag is observed through radar cross section (RCS) parameter. The 36-bit tag design can tag 236 objects/items. The passive chipless RFID tag produces resonances in the frequency band of 4–13GHz for FR-4 substrate and 5–15.5GHz using Taconic TLX-0 and Rogers RT5880 substrates. The ultimate cost-effective, compact chipless RFID tag can be deployed in various industrial applications. In future, further improvements can be made to integrate the concept of ‘green electronics.’