Byunggil Yu

Balanced RFID Tag Antenna Mountable on Metallic Plates

A novel balanced tag antenna for a radio frequency identification (RFID) system is presented. The radiating elements of two planar inverted-F antennas (PIFAs) are inductively coupled by the feed loop with out of phase. The balanced structure provides smaller degradation of performances when an RFID tag is mounted on various sizes of metal plates. The HFSS simulator is employed to analyze the proposed antenna in the design process and to compare with measured results

Multi-band diversity antenna for mobile handset applications

A diversity antenna for a tri-band application is proposed and designed. The proposed diversity antenna consists of two wideband planar inverted-F antennas (PIFAs) and a suspended line between two PIFAs. The measured results show that the proposed antenna has a wide impedance bandwidth (37%) enough to serve a triple band (PCS, UMTS and WiMAX), a high radiation efficiency (> 50%), and a low correlation coefficient (< 0.2).

RFID Tag Antennas Mountable on Metallic Platforms

Auto identification provides information without direct contacts and human intervention errors. Auto identification technology has become very popular in industries, such as the service industry, inventory control, distribution logistics, security systems, transportation and manufacturing process control. So far, the bar code technology leads the auto identification industry, but it has several limitations such as low storage capacity, required line-of-sight contact with the reader, and physical positioning of the scanned objects. Recently, the radio frequency identification (RFID) has been an attractive alternative identification technology to the barcode. The numerous potential applications of the RFID system make ubiquitous identification possible at frequency bands of 125 KHz (LF), 13.56 MHz (HF), and 860-960 MHz (UHF). The RFID system generally consists of two basic components: the reader and the tag, which communicate with each other by electromagnetic waves. The reader can be a read or a read/write device that uses an antenna to send an electromagnetic wave to wake up the tags. The tag is the data carrying device located on the object being identified. In general, the performance of the tag seriously affects the performance of the whole RFID system. The tag consists of the tag antenna and the microchip. Since good connection and power transmission between the tag antenna and the microchip directly impact on the RFID system performance, the tag antenna has to be designed considering its operating environments or platforms. As the use of RFID systems increases, manufacturers are pushing toward higher operating frequencies (UHF band) for long reading range, high reading speed, capable multiple accesses, anti-collision, and small antenna size compared to the LF or HF band RFID system. As the operating frequency of the RFID system becomes higher, the major part of the RFID system that mostly affects the ability to read the tag is the antenna. There are several possible antenna types which can be used for RFID tags in this frequency band. The dipole types of antennas such as folded dipoles and meandered dipoles are used in many applications since they can be printed on a very thin film. However, when they are mounted on the metallic objects, the antenna performance is seriously decreased because of the reactance variation on the antenna impedance. Particularly, the UHF band RFID system is a passive system where a tag does not contain its own power source. Therefore, the reader

Internal antenna for UHF-band mobile RFID system

UHF-band radio frequency identification (RFID) antenna for mobile handset applications is presented. The proposed antenna consists of a radiating element and a parasitic element connected to the ground plane. The radiation pattern of proposed antenna is orthogonal to that of a monopole antenna. The impedance bandwidth (902 MHz ~ 923 MHz) covers a Korea mobile RFID service (908.55 MHz ~ 913.95 MHz). The measured antenna peak gain is -0.37 dBi at 911 MHz.

Multi-band internal antenna including DVB-H band

A multi-band internal antenna including the DVB-H (digital video broadcast for handheld terminals) band is proposed for clamshell types of the mobile handsets. It consists of two radiating elements: a PIFA is for the GSM band, and a monopole covers DVB-H, GPS, DCS, and PCS bands. The measured results show that the proposed antenna has enough isolation between two elements and effectively covers all operating bands.

Crab shaped antenna for RFID tag at UHF band

A crab shaped tag antenna which has a better performance than conventional label type of tag antenna is proposed for UHF band RFID systems. The proposed antenna is a dipole with T-matching network, and parasitic loop is inserted to the T-matching network. The antenna is analyzed by simulator, Ansoft HFSS software, and the measured results based on backscattering method are presented.