An array of meander Travelling Wave Antennas for near-field UHF-RFID readers

An array of Travelling Wave Antennas (TWAs) is presented for near-field RFID applications in the UHF band (865–928 MHz). Since TWAs are not resonating structures, the proposed antenna results to be scalable, allowing for an easy integration in commercial readers. The antenna is realized exploiting the coplanar waveguide technology and it is composed by four in-phase radiating elements, in order to obtain strong and uniform fields within a confined volume above the antenna surface. The overall antenna volume is 275 × 135 ×10 mm
³
. The meander geometry allows exciting all fields components, making the tag detection almost independent on its location and orientation on the antenna surface. In this paper, preliminary simulated results are discussed in terms of reflection coefficient and electric and magnetic field distributions.