Biblio

In this work, communication secrecy in the physical layer for various radio frequencies is examined. Frequencies with the highest level of secrecy in 1-1000 GHz range and their level of communication secrecy are derived. The concept of ultimate secrecy in wireless communications is proposed. Attenuation lines and ranges of both detection and ultimate secrecy are calculated for transmitter powers from 1 W to 1000 W. From results, frequencies with the highest potential to apply bandwidth saving method known as frequency reuse are devised. Commonly used secrecy benchmarks for the given conditions are calculated. Frequencies with the highest attenuation are devised and their ranges of both detection and ultimate secrecy are calculated.

Radio Frequency IDentification (RFID) is a technique for speedy and proficient identification system, it has been around for more than 50 years and was initially developed for improving warfare machinery. RFID technology bridges two technologies in the area of Information and Communication Technologies (ICT), namely Product Code (PC) technology and Wireless technology. This broad-based rapidly expanding technology impacts business, environment and society. The operating principle of an RFID system is as follows. The reader starts a communication process by radiating an electromagnetic wave. This wave will be intercepted by the antenna of the RFID tag, placed on the item to be identified. An induced current will be created at the tag and will activate the integrated circuit, enabling it to send back a wave to the reader. The reader redirects information to the host where it will be processed. RFID is used for wide range of applications in almost every field (Health, education, industry, security, management ...). In this review paper, we will focus on agricultural and environmental applications.