Advanced Chipless RFID

CHAPTER 5SYSTEM TECHNICAL ASPECTS

5.1 INTRODUCTION

It was already shown that suggested structures of strip lines and meander lines as effective EM polarizers are suitable as the data encoding elements of the spatial-based system. The salient attributes of the polarizers were also discussed. Reaching to millimeter image resolution at a reading range of less than 50 cm mandates the 60 GHz band and above. This chapter looks at this new industrial, scientific, and mathematical (ISM) band and explores its technical and regulatory limitations.

In the second part of this chapter, the reader antenna is described. First, the technical and operational necessities of the reader antenna are discussed. Then, the available or proposed antennas at the 60 GHz band are reviewed to confirm that “off-the-shelf” products are not suitable for the demanded reader antenna specifications in the proposed approach. Finally, the suitable antenna candidate is suggested along with its design and measurement procedure.

5.2 THE MM-BAND OF 60 GHZ

5.2.1 Highest Attenuation, Lowest Regulatory Limitations

The frequency band 60 GHz is a bold region in the frequency spectrum as it has one of the highest attenuations due to the oxygen absorption. While 0.1–0.5 dB/km loss occurs from oxygen absorption in the frequency spectrum below 100 GHz, the region around 60 GHz experiences 15–20 dB/km loss [1] (Figure 5.1). Moreover to this unusual loss, the high frequency nature also suggests a higher free space attenuation ...