• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.10A
• /
• pp.1015-1022
• /
• 2007

In this paper, dual-band digital codec for UHF(Ultra High Frequency) and MW(Micro Wave) is proposed for an RFID reader system. Most RFID systems have been supported only one protocol. But, There are many protocols of each bandwidth. Especially, UHF bandwidth which is widely used on the globe consists of A,B,C type, and more standards will be established. Recently, Since an interest about mobile RFID system is increasing, the RFID system with more than one protocol will be need. Therefore, this paper suggests a dual-band digital codec with UHF and MW bands for an RFID reader system. Standards used in this system are 18000-6C and 18000-4 standards. The digital codec is synthesize by the Quartus II compiler. Target device is EPC20Q240C8 which is family of CycloneII. Main Clock is 19.2MHz and elements of FPGA which is used for the system is 18,752.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.12
• /
• pp.78-83
• /
• 2010

In this paper, a novel dual-band power amplifier using metamaterials has been realized with one RF GaN HEMT diffusion metal-oxide-semiconductor field effect transistor. The CRLH TL can lead to metamaterial transmission line with the dual-band tuning capability. The dual-band operation of the CRLH TL is achieved by the frequency offset and the nonlinear phase slope of the CRLH TL for the matching network of the power amplifier. We have managed only the second- and third-harmonics to obtain the high efficiency with the CRLH TL in dual-band. Also, the proposed power amplifier has been realized by using the harmonic control circuit for not only the output matching network, but also the input matching network for better efficiency. Two operating frequencies are chosen at 900 MHz and 2140 MHz in this work. The measured results show that the output power of 39.83 dBm and 35.17 dBm was obtained at 900 MHz and 2140 MHz, respectively. At this point, we have obtained the power-added efficiency (PAE) and IMD of 60.2 %, -23.17dBc and 67.3 %, -25.67dBc at two operation frequencies, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.8
• /
• pp.1352-1358
• /
• 2006

In this paper, we have fabricated and tested a broad band bow-tie slot antenna with dual reflector. If we put 1/2 length thin and long slot on a wide metal plate, the slot antenna radiates efficient and strong radio wave as same as 1/2 dipole antenna does. we made with bow-tie form slot which has wider broad band than normal rectangular slot. At first, we made and test a single reflector slot antenna. To enlarge the broad band, we inserted another reflection plate between the slot antenna and reflection plate. After the test, we could have known that the low band(VSWR<2.0) has about $22%(793MHz\sim992MHz)$, high band(VSWR<2.0) has about 61% (1626MHz\sim3064MHz).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.4
• /
• pp.343-348
• /
• 2019

In this paper, a dual-band antenna is proposed for the autonomous vehicle as well as omni-directional. The proposed antenna operates in the 4G/LTE band (1,710~2,170MHz) and 5G/NR band (3,400~3,700MHz). In order to obtain the dual-band operation, the planar monopole antenna is proposed as the novel structure with single port of the 50ohm. To give the properties of dual-band, an additional antenna element with slit was added to the planar monopole antenna, and then a structural adjustment parameter was optimized for achieving the target performance in bands. The planar monopole antenna in the LTE band acts as the coupled feed for the added parasitic radiator in the 5G NR band. The proposed antenna has $38.5{\times}36.0{\times}1.0[mm^3]$ on a ground with diameter of 96mm. From the fabrication and measurement results, the impedance bandwidth (VSWR<2) of the proposed antenna covers 1,480~2,260MHz (LTE band: 1,710~2,170MHz) and 3,310~3,930MHz (5G NR band: 3,400~3,700MHz). The proposed planar monopole antenna also obtained the measured gain and radiation pattern of omni-directional radiation pattern in the anechoic chamber.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.11
• /
• pp.32-36
• /
• 2008

In this paper, we investigate the capacity of CDMA/TDD in the inner zone of multimode scenario with dual-band operation where high frequency band is used for TDD in the inner zone and lower frequency band is utilized for FDD in the outer zone. The effects of various system parameters such as cell radius, date rate, and time slot allocation are analyzed.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2005.11a
• /
• pp.235-240
• /
• 2005

This paper presents a dual band circularly polarized microstrip patch antenna. The antenna consists of two corner truncated patches implemented in one plane and single feed point. The input signal is directly excited to the patch 2 and the patch 1 is fed from patch 2 by coupling between two patches. The antenna is operated at 900 MHz and 2.45 GHz bands and has the right hand circularly polarized radiation pattern at all. The measured gains of the antenna are 2.95 dBic at 900 MHz band and 4.6 dBic at 2.45 GHz band.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.12
• /
• pp.1719-1724
• /
• 2013

In this paper, a size-reduction technique is presented for the RFID reader antenna working at two UHF bands. To tackle the problem of size increase in multi-band applications, two resonance paths are made to occur in one geometry with a single feed. While one resonance path is combined with the other, the entire geometry is determined to guarantee the resonance at the target frequencies through the dual-band input impedance matching. The antenna performance is predicted by the full-wave simulation, and the design method is verified by observing the good agreement between the simulated and measured results. At the two frequencies, the satisfactory return loss as well as the antenna efficiency and peak gain of the far-field pattern is obtained.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.2
• /
• pp.130-135
• /
• 2005

In this papers, we made study for plastic chip antenna, the plastic is Foamex with the circle of PVC and its electric characteristics are dielectric constant 1.9, insulation intensity 112 KV/cm. The proposed antenna is same as the conventional antennas are usually constructed with ceramic chip, which are not fragile in nature and don't tend to break easily. Therefore the proposed antenna with its advantage is attractive for application in mobile antenna. In order to valid the proposed papers, it is implemented the antennas of four types and experimented. From the results, we conformed that the antennas are operated at the dual band which is cellular band and Korea-PCS band. And the gain of the antennas has about above -2 dB and the pattern is same as conventional antennas. From this papers, the realized antennas using Foamex material will be application for mobile phone antenna.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.9
• /
• pp.841-848
• /
• 2016

In this paper, a microstrip-fed dual-band monopole antenna with DGS(: Defected Ground System) for WLAN(: Wireless Local Area Networks) applications was designed, fabricated and measured. The proposed antenna is based on a microstrip-fed structure, and composed of two strip lines and DGS structure and then designed in order to get dual band characteristics. We used the simulator, Ansoft's High Frequency Structure Simulator(: HFSS) and carried out simulation about parameters W2, L10, W3, and DGS to get the optimized parameters. The proposed antenna is made of $21.0{\times}36.0{\times}1.6mm3$ and is fabricated on the permittivity 4.4 FR-4 substrate. The experiment results are shown that the proposed antenna obtained the -10 dB impedance bandwidth 700 MHz(2.10~2.80 GHz) and 1,780 MHz(5.02~6.80 GHz) covering the WLAN bands. Also, the measured gain and radiation patterns characteristics of the proposed antenna are presented at required dual-band(2.4GHz band/5.0GHz band), respectively.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.3 no.2
• /
• pp.53-57
• /
• 2008

This paper designed and fabricated the printed dual monopole antenna with CPW feeder for PCS and UWB(Ultra-Wide Band) band. In this paper, modified dual monopole antenna is proposed transform conventional monopole antenna to get dual band frequency. The dual monopole antennas have dual band, broad bandwidth and omni-directional radiation patterns, as it is the conventional monopole antenna. As one monopole operated a stub to match feed line with antenna, we are obtained easy an ideal impedance matching. It is increased band width of impedance. The antenna bandwidth is about 1350MHz (1.69~2.04[GHz]z]) at 1st resonance frequency, 2,670MHz (4.33~6[GHz]) at 2nd, resonance frequency, and, 3,980MHz (6.1~10.08[GHz]) at 3th resonance frequency on VSWR$$\leq_-$$2, and then we can be got not only 1.75~1.87 [GHz] PCS band but also, UWB band.