Rfid Metal Tag Antenna And Maritime Satellite Antenna Terminal Resistance In The Research And Design

Radio Frequency Identification (RFID) is a new technology. It realized communication without physical touching by microwave, and reached data changing and mutual identification. RFID technology has a very broad application prospects. Its research has gained a worldwide attention. In many applications, it is required that RFID system can work well in metallic backgrounds, such as steel frame, metal container, metal bottle. Antenna is a key component of RFID tags. So researching a RFID tag antenna which could work well on metallic objects is important.Because of the broad application of RFID technology at UHF band, we research RFID tag antennas at UHF band. A new type of tag antenna has been designed for matching the RFID chip named RI-UHF-STRAP-08Gen2produced by TEAXS INSTRUMENTS (TI). This antenna works at860MHZ-960MHZ which covers the most frequency bands distributed for RFID applications in the worldwide. The size of the antenna is84.7mm X44.7mm X1.58mm. Its structure is simple.The measurement of tag antenna is a tough problem nowadays. The impedance of this tag antenna has been calculated by measuring S-parameters. The performance of the antenna on metallic environment has been measured by combining with a reader. The experimental results show that resistance curves agree with the target curves, but reactance curves do not agree with the target curves well. The maximum read range of this antenna in air is0.73m, and1.4m on a piece of metal of size200mm×200mm. A metal background decreases backward radiation and increases the directivity and gain of the antenna. It is proved that this antenna could work well on metallic objects.Inmarsat satellite has been widely used in telegraph, telephone, data transmission, GPS and rescue operations. Inmarsat satellite terminal antenna always operates at L-band, and is required to have characteristics of circular polarization, high gain and directional radiation. To meet the requirements of Inmarsat terminal antennas, a stacked microstrip antenna has been designed, and its performances have been studied. The measured impedance bandwidth of the designed antenna (S11<-10dB) is1.49-1.67GHz (11.3%), simulated Axial ratio (AR) bandwidth is1.525GHZ-1.660GHz (8.5%), simulated gain is above8.4dB along1.52-1.68GHz.