A $4 \times 4$ Dual Polarized mm-Wave ACMPA Array for a Universal mm-Wave Chipless RFID Tag Reader

A 4 × 4 dual polarized (DP) aperture-coupled microstrip patch antenna (ACMPA) array for a universal millimeter (mm)-wave chipless RFID tag reader is presented. The mm-wave DP ACMPA array is capable of reading all types of frequency domain-based chipless RFID tags (linearly polarized, orientation insensitive, cross-polarized (CP), and DP) within its operating frequency bandwidth. The developed antenna is operating over the 22-26.5-GHz frequency band with 16-dBi realized gain and over 35-dB isolation. A systematic approach is followed up for designing the mm-wave antenna array where, first, a single antenna element is designed. Then, a 1-32-way corporate feed network for the dual offset feeding of cross slots is designed using multistage power dividers. After that, the 4 × 4 mm-wave DP ACMPA array is designed, optimized, fabricated, assembled, and tested. Simulation and measurement results for different development stages of the array are described in detail. Finally, the assembled antenna is used for measuring 10 orientation insensitive (OI) thermal printed mm-wave chipless RFID tags on a paper substrate to validate its functional accuracy. The developed mm-wave DP ACMPA array with high port-to-port isolation can be used in a universal commercial mm-wave chipless RFID tag reader due to its low cost, high gain, and low-profile structure.