• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.11 no.4
• /
• pp.80-85
• /
• 2012

In this paper, a new planar folded UHF band RFID reader antenna is suggested. For the antenna suggested in this paper, 4 PIFA (Planar Inverted F Antenna) micro-strip structures are adopted. The size is $50mm{\times}50mm{\times}6.2mm$. The gain of the antenna is 1.1 dBi, the VSWR is 1.2:1, and the efficiency is 63.3 %. The radiation pattern is designed as upper direction. Identification distance for the RFID tags is improved by minimizing hand effects with properly integrating 4 PIFAs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.2 s.105
• /
• pp.178-183
• /
• 2006

The proposed triple-band compact chip antenna using coupled meander line and stacked meander structure for mobile RFID/PCS/WiBro. The proposed antenna is designed to operate at 900, 1,800, and 2,350 MHz, and is realized by parasitic coupled and stacked a meander line. Meander lines are using extend length of effective current path more than monopole and contribute miniaturization. The coupled meander line controls the excitations of the mobile RFID and PCS, stacked meander line controls the excitation of the WiBro. The fabricated antenna size is $10.98{\times}22.3{\times}0.98\;mm$. The resonance frequencies are 905 MHz, 1.77 GHz and 2.32 GHz. The impedance bandwidths are 24 MHz, 140 MHz and 92 MHz. The maximum gains of antenna are 0.34 dBi, 2.58 dBi and 0.4 dBi at resonance frequencies.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.7
• /
• pp.67-74
• /
• 2010

TIn this paper, it is designed the polarization selective antenna for UHF RFID system. The proposed antenna is consist of microstrip patch antenna with dual feeding and two SPDT switches and a SP4T switch and 3dB hybrid coupler. Through control of voltage of switches, the proposed reader antenna can select horizontally linear polarization, vertically linear polarization, left-hand circular polarization (LHCP) and right hand circular polarization (RHCP). The proposed reader antenna satisfied 2:1 VSWR at 902MHz~928MHz. and it has under 3dB AR(axial ratio). Peak gain of antenna is 7.71dBi, 7.55dBi with linear polarization and 7.31dBic, 7.81dBic with circular polarization at x-y plane. Also Axial ratio of antenna is 2.01~2.83dB and 2.02~2.60dB respectively. It is satisfied 3dB axial ratio.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.2
• /
• pp.45-49
• /
• 2009

In this paper, a direct down conversion LNA/Mixer has been designed and tested for 900Mhz UHF RFID application. The designed circuit has been implemented in 0.18um CMOS technology with 3.3V operation. In this work, a common gate input architecture has been used to cope with the higher input self jamming level. This LNA/Mixer is designed to support two operating modes of high gain mode and low gain mode according to the input jamming levels. The measured results show that the input referred P1dBs are 4dBm of high gain mode and 11dBm of low gain mode, and the conversion gains are 12dB and 3dB in high and low gain mode respectively The power consumptions are 60mW for high gain mode and 79mW for low gain mode. The noise figures are 16dB and 20dB in high gain mode and low gain mode respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.12 no.5
• /
• pp.46-51
• /
• 2013

In this paper, a dual-band antenna is proposed for the RF power harvester system as well as RFID tag. The proposed antenna operates as the passive and active RFID tag antenna in the UHF and microwave band, respectively. In addition, to charge the battery of an active RFID tag in the microwave band, it harvest the RF signal for tagging from the passive RFID tag antenna in the UHF band. The proposed antenna operates in the UHF band (917~923.5 MHz) and microwave band (2.4~2.45 GHz). In order to obtain the dual-band operation, the dipole structure and meander parasitic elements are proposed as the ${\lambda}/2$ and $1{\lambda}$ dipole antenna, respectively. The radiating dipole structure in the microwave band acts as the coupled feed for the meander parasitic elements in the UHF band. The impedance bandwidth (VSWR < 2) of the proposed antenna covers 917~923.5 MHz (UHF band) and 2.4~2.45 GHz (Microwave band). Measured total efficiencies are over 45 % in the UHF band and over 70 % in the microwave band. Peak gains are over 0.18 dBi and 2.8 dBi in the UHF and microwave band with an omni-directional radiation pattern, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.8 s.99
• /
• pp.797-802
• /
• 2005

In this paper, we design a UHF band RFID tag antenna which is conjugate matched to an impedance of a chip and also mountable on conductive materials. The proposed tag antenna is very compact($50{\times}30{\times}4mm$) with a modified PIFA shape. The proposed tag antenna has an advantage of easy matching to various chip input impedances. The performance of the antenna is evaluated by monitoring RCS in the reader direction. The RCS of the designed tag is $-10.2\;dBm^2$ when the chip is shorted and is $-21\;dBm^2$ when the chip impedance is a complex conjugate of the antenna impedance.

• Tunnel and Underground Space
• /
• v.26 no.4
• /
• pp.253-265
• /
• 2016

In this study, travel time data collection of mine equipments was conducted in an underground mine using a reverse Radio Frequency IDentification (RFID) system. In the reverse RFID system, RFID readers and antennas are mounted on mine equipments, and RFID tags are attached to the underground mine gallery. Indoor experiments were performed to analyze how RFID reader transmission power levels affect tag readable area and tag recognition rates. The results showed that travel time measurement become precise when the reader transmission power was reduced, however tag recognition rates were reduced. The field experiments indicated that setting the reader transmission power to 28 dBm maintained the tag recognition rate while minimizing the tracking location error. In addition, the results revealed that the reverse RFID system can be used successfully in an underground mine to collect the travel time data of haulage trucks.

• Journal of Advanced Navigation Technology
• /
• v.8 no.2
• /
• pp.184-190
• /
• 2004

A feedforward linear power amplifier (FLPA) has been developed for UHF-band RFID reader applications. The main and error amplifiers are composed of a 2 stage so that linearity of the FLPA can be improved. The FLPA has been implemented on an FR-4 substrate (Er=4.7 and thickness=0.8 mm) with 3-dB and 10-dB hybrid couplers for input/output power divider and combiner. For 2-tone measurement (input level=-11 dBm at $f_1$=915 MHz and $f_2$=916 MHz), the FLPA exhibits a -18.52 dBm of $IMD_3$, which indicates that $IMD_3$ cancellation with feedforward loop is more than 27 dB. From 890 to 960 MHz, 1-dB gain compression output power and power gain of the FLPA are higher than 30 dBm and 40 dB, respectively.

• Journal of the Korea Convergence Society
• /
• v.6 no.1
• /
• pp.109-114
• /
• 2015

A circularly polarized small UHF RFID reader antenna is presented. The antenna is composed of four elements and printed on the plastic substrate(${\varepsilon}_r=2.2$, t=5mm). Each element is fed by a probe which is sequentially connected to the feed line. The feed line is manufactured on the FR-4 substrate(t=1.0mm, ${\varepsilon}_r=4.7$). The simulation results shows that the antenna can be achieved a return loss of 12dB, gain of 3.46dBic over the UHF band of 902-928MHz. According to our simulation results, two prototype antennas are manufactured and measured. The obtained antennas operate in UHF RFID bands and can be adapted for various portable applications. In addition, a parametric study is conducted to facilitate the design and optimization processes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.2
• /
• pp.174-182
• /
• 2009

In this paper, we propose a novel hybrid reader antenna using a triangular and rectangular sub-patch for near- and far-field RFID reader in UHF band. The antenna operates at 912 MHz, and the low-cost mass-production is available, since the antenna can be built by printing on a FR-4 substrate. The triangular patch is designed to produce a circularly polarized radiation along the bore-sight direction and the rectangular sub-patch is designed to generate a strong magnetic field over the antenna aperture. The measurement shows Hz field greater than -25 dBA/m(3 cm above the antenna aperture), and exhibits circularly polarized radiation(AR<3 dB) with a radiation gain of 6 dBi.