<p>This paper presents a study of a new dual-band monopole antenna fed by a Coplanar Waveguide (CPW) line suitable for Radio Frequency Identification (RFID) applications especially designed for RFID readers and covering free ISM bands of 2.45GHz and 5.8GHz. The proposed antenna benefits from the advantages of the CPW line to simplify the structure of the antenna into a single metallic level, by consequent making it easier for integration with microwave integrated circuits. The simulation of the antenna was carried out using ADS from Agilent technologies and CST Microwave Studio electromagnetic solvers. A good impedance bandwidth of 500MHz is achieved in measurement (from 2.1GHz to 2.6GHz for the lower band), while the upper band covers 800MHz (from 5.2GHz to 6GHz). Details of the proposed antenna design and both simulated and experimental results are described and discussed.<strong><em></em></strong></p>

A new dual-band monopole microstrip antenna with modified ground structure designed for Radio Frequency Identification (RFID) readers is proposed. The rectangular slots inserted in the ground plan permit to achieve dual frequencies and also provide a broadband operation at high frequency. The entire area of the proposed antenna is 33×35 mm 2 and mounted on an FR4 substrate with dielectric permittivity constant 4.4, thickness of 1.6 mm and loss tangent of 0.025 and fed by a 50 Ohm microstrip line. This antenna has been analyzed and simulated to cover the RFID at 2.45/5.8 GHz. The simulation has been carried out by using two electromagnetic solvers ADS and CST Microwave Studio. By fabricating and measuring the performances of the prototype of the proposed optimal antenna, experimental results show that the dual operating bands excited with-10dB return-loss bandwidths of about 70 MHz centered at 2.45 GHz and of about 490 MHz centered at 5.8 GHz were obtained.

This paper presents a new dual-band microstrip antenna with embedded slots on a rectangular radiator. It is capable of operating in the two radio frequency identification (RFID) frequency bands simultaneously (UHF and microwave) and has a miniaturized size designed to be easily integrated into portable RFID readers. The simulation results, carried out using the two commercial software packages CST Microwave Studio electromagnetic and ADS, show stable radiation pattern performances and good matching input impedance at the desired operating frequencies. The proposed antenna has overall dimensions of 47×46 mm 2 and is mounted on an FR4 substrate with dielectric permittivity constant 4.4, thickness 1.6 mm and loss tangent 0.025. The creation of a prototype of the proposed optimal antenna allowed validation of the dual operating bands with-10 dB return-loss bandwidths of approx. 28 MHz centred at 0.868 GHz and of approx. 90 MHz centred at 2.45 GHz, which shows that the proposed antenna is a good candidate for implementation in handheld RFID readers.

In this chapter, new microstrip antennas for RFID system are presented. The chapter is split into two sections. The first section deals with the design of two dual-band antennas for handheld RFID readers, and the second section is dedicated to antennas for RFID tag. In the first section, the authors describe theory and principle characteristics of microstrip antenna and the fundamentals of multiband behavior. The two proposed antennas are designed to operate in the ISM (industrial, scientific, and medical) band at 2.45 and 5.8 GHz bands. In the second section, the authors present the principles of matching techniques for tag antenna design. Then, they present two examples of tag antenna. The first one is a flexible antenna mounted on paper substrate, and the second one is designed for the identification of metallic object.