LOW-COST AND COMPACT RF-MIMO TRANSCEIVERS
In the last decade, multiple-input multiple-output (MIMO) wireless technology has gained considerable attention due to its potential to significantly increase spectral efficiency and/or reliability compared to traditional single-input single-output (SISO) systems [1–3]. A full-rank n × n MIMO channel is equivalent to n orthogonal SISO channels ; therefore, to exploit all the benefits of the MIMO channel (diversity or multiplexing gain), n parallel antenna paths must be independently acquired and processed at baseband. Consequently, the hardware costs, size, and power consumption are multiplied by a factor of n as well. Despite the numerous advantages of MIMO systems, these higher costs have delayed the wide-scale commercial deployment of multiple-antenna wireless transceivers mainly in handsets or low-cost terminals. The demand of low-cost, low-power-consumpting and compact wireless transceivers is even more important for radio-frequency identification (RFID) applications, which explains why conventional MIMO technologies have not found widespread application in RFID systems .
In this chapter, we describe a novel MIMO architecture ...