Uisheon Kim

Design of a dipole tag antenna enclosed by a short-stub for UHF RFID application

Radio frequency identification (RFID) systems have been rapidly developing in the ultra high frequency (UHF) band due to the advantage of long recognition distance. To reduce the production cost, a tag antenna should be directly matched to a tag IC including a charge capacitor which compensates the large conductive reactance of a tag IC. In addition, the power from an antenna can be maximally delivered to a tag IC when an antenna impedance is conjugately matched with that of tag IC. However, folded dipole antennas, slot antennas, and meander antennas, which are commonly used for RFID tags in UHF band, do not have enough large inductive reactance for conjugate matching to a tag IC. Thus, new type of RFID tag antenna having large inductive reactance is necessary. In this paper, a UHF band RFID tag dipole antenna enclosed by a short-stub is proposed. The proposed antenna has a compact size (64.1 mm times 17.8 mm) and large inductive reactance.

The Design of an UWB Antenna with Notch Characteristic

Four types of novel and compact ultra-wideband (UWB) microstrip-fed monopole antennas having frequency band-stop function are presented. To generate the band-stop perfor- mance, modifled planar monopoles with inverted U-slot, U-slot, small strip bar and ‚=4 C-shaped slot are used. The designed antennas satisfy the i10dB return loss requirement in the frequency band between 3 and 11GHz, while showing the band-stop characteristic in the frequency band of 5.0 to 5.9GHz. DOI: 10.2529/PIERS061007113522

Design of an implantable antenna for WBAN applications

In this paper, an implantable planar inverted-F antenna (PIFA) for an artificial cardiac pacemaker is proposed. The antenna has a simple structure with a low profile and is placed on the top side of the pacemaker. The dimension of the pacemaker system, including the antenna element, is 42 mm × 43.6 mm × 11 mm. When the antenna is embedded in pig tissue, -10 dB impedance bandwidth of the antenna is 6 MHz (399 ~ 406 MHz). The proposed PIFA in tissue has a peak gain of -20.19 dBi and a radiation efficiency of 1.12 % at 403 MHz. When the proposed antenna is placed in a liquid flat phantom, its specific absorption ratio (SAR) value is 0.038 W/Kg (1 g tissue). Performances of the proposed PIFA is sufficient to operate at the MICS band (402 ~ 405 MHz).

An Implantable Antenna for Wireless Body Area Network Application

In this paper, an implantable planar inverted-F antenna (PIFA) for an artificial cardiac pacemaker is proposed. The antenna has a simple structure with a low profile and is placed on the top side of the pacemaker. The dimensions of the pacemaker system, including the antenna element, are 42×43.6×11 mm. When the antenna is embedded in pig tissue, its S11 value is 10.94 dB at 403 MHz and the 10 dB impedance bandwidth of the antenna is 6 MHz (399 406 MHz). The proposed PIFA in tissue has a peak gain of 20.19 dBi and a radiation efficiency of 1.12 % at 403 MHz. When the proposed antenna is placed in a flat phantom, its specific absorption ratio (SAR) value is 0.038 W/kg (1 g tissue). Performances of the proposed PIFA is sufficient to operate at the MICS band (402 ~ 405 MHz).

Design of an UHF RFID tag antenna for paper money management system

In this paper, an UHF dipole tag antenna with a short stub and meander lines is proposed for RFID-based paper money management system. The short stub and meander lines in tag antenna are used to improve the impedance matching between tag antenna and tag IC. The proposed RFID tag antenna can be used effectively to band wads of paper money at banks and financial agencies for security purpose.

Design of Antennas for the UHF RFID System

In this paper, a dual-band circularly polarized antenna is designed for the UHF band (860 MHz ~ 960 MHz) and ISM band (2.4 GHz ~ 2.48 GHz) RFID reader applications and novel microstrip patch RFID tag antennas for the UHF RFID band (908 MHz -914 MHz) in Korea are proposed. They have less sensitive characteristic against the size of metallic object, wide impedance bandwidth and a long reading distance.

Design of RFID reader antennas for UHF RFID handheld systems

Two types of compact wideband UHF reader antennas for handheld applications are proposed. To overcome the narrow bandwidth of a compact patch antenna, an aperture-coupled feeding technique and artificial magneto-dielectric structure are utilized. The proposed antennas have compact sizes of 100 mm × 100 mm × 9.6 mm and 100 mm × 100 mm × 3.2 mm, respectively. In spite of small size, proposed antennas yield the wideband impedance and good axial ratio characteristics. Due to the compact size and wide bandwidth, the proposed antennas are suitable candidates for a handheld RFID reader.

Design of a loop antenna with stubs for RFID tag

In this paper, a loop antenna with stubs was investigated for UHF RFID tag application. For reactive impedance matching of a loop, open and short stubs were used. Two types of stubs were designed symmetrically with respect to the feed point of a loop. The impedance of proposed tag antenna can be easily matched to that of tag IC by optimizing the dimensions of stubs. The antenna was fabricated by etching on a thin flexible PCB (Material: Polyimide, epsivr=3.4, thickness=1mil). Furthermore, the proposed tag antenna could be designed on thin film or paper using inkjet printing method for simple, fast and low cost fabrication.

Design of a UHF band RFID tag antenna for library management system application

In this paper, a loop antenna is designed for UHF band RFID tag which is used for a library management system. To achieve the wide-band characteristic, both vertical sides of a loop antenna are widened. The proposed antenna had impressively broad impedance bandwidth of about 270 MHz (756 MHz ~ 1028 MHz) for S11 less than -10 dB. The average measured reading distance of fabricated antennas inserted in a book is about 5 m.

Design of an enhanced bandwidth PIFA with modified shorting strip

In this paper, a novel compact internal wide-band planar inverted F-antenna (PIFA) is presented. The proposed antenna consists of a main patch with stubs and folded plate and occupies a total volume of 36 times 16 times 6 mm3. The dual bands characteristic can be achieved by changing the length of a main patch. A wide impedance bandwidth characteristic was obtained by optimizing the length of folded patch, stubs and shorting strip. The measured impedance bandwidth, determined by 6 dB return loss, of the operating bands reach 10.85% at 922.5 MHz and 58% at 2115 MHz, respectively. The maximum gains at the frequencies of 915, 1576, 1785, 2170, 2400 and 2630 MHz were 1.0, 2.7, 5.43, 4.65 and 1.52, 2.95 dBi, respectively. The overall shapes of the radiation patterns are suitable for mobile communication application.