Orientation independent compact chipless RFID tag

A design concept of a compact printable orientation independent chipless radio frequency identification tag is presented with near-field and far-field reading techniques. The tag consists of a circular patch loaded with multiple slot ring resonators and it has the advantage to be read from any orientation with the reader due to its symmetric structure. This tag does not have a ground plane and has higher data density and lower cost compared to the most other existing printable chipless tags. Proximity and slot reading techniques are described in details for different applications. This single-sided, compact and orientation independent tag has a great potential to be used in millions both for identification and authentication.