Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
home > search

Now showing items 1 - 10 of 10

  • A NOVEL MINIATURE MONOPOLE TAG ANTENNA FOR PASSIVE UHF RFID APPLICATIONS

    Liu, Hsien-Wen   Ku, Chia-Hao   Yang, Chang-Fa   Wang, Te-Shun  

    A novel miniature monopole tag antenna for passive Ultra-High Frequency (UHF) radio frequency identification (RFID) operation is presented. The antenna possesses a two-sided structure that is printed on an FR4 substrate and fed by a 50-Omega microstrip line. Be properly using helical strips and vial, the antenna size can be reduced to a small volume of 10 (L) X 9.5 (W) x 0.8 (H) mm(3) to be easily integrated within various portable devices. A miniaturized quasi-lumped circuit is also designed to attain a good impedance matching between the antenna and the chip. Experimental results demonstrate that the antenna has a suitable operating band about 914-939 MHz and also quite omnidirectional radiation pattern with appreciable gain. Moreover, the proposed compact tag antenna, capable of achieving a maximum readable range of about 5.6 m with an EIRP equal to 4 W, is well suited for RFID applications. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2770-2772, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25596
    Download Collect
  • Compact Monopole Antenna With Band-Notched Characteristic for UWB Applications

    Liu, Hsien-Wen   Ku, Chia-Hao   Wang, Te-Shun   Yang, Chang-Fa  

    A compact planar monopole antenna with standard band-notched characteristic suitable for ultrawideband (UWB) applications is presented. This microstrip-fed antenna, consisting of a square slot patch with a vertical coupling strip, only occupies a small size of 15 (L) x 15 (W) x 1.6 (H) mm(3). By properly designing the strip placed at the center of the patch, good frequency rejection performance of the antenna with a wide operating band from 3.05 to 11.15 GHz can be obtained. Compared to other designs, the antenna has a quite simple structure to make the band-notched property to reduce the effect caused by the frequency interference. Furthermore, fairly good omnidirectional radiation patterns and transmission responses both indicate that the proposed antenna is well suited to be integrated within various portable devices for UWB operation.
    Download Collect
  • Compact Inverted-F Antenna With Meander Shorting Strip for Laptop Computer WLAN Applications

    Liu, Hsien-Wen   Lin, Sheng-Yu   Yang, Chang-Fa  

    In this letter, a novel compact inverted-F antenna with dual-band property for WLAN applications is presented. It comes with a C-shaped radiator and two meander shorting strips, which only occupy a small size of 35 (L) 3 (W) mm(2) to be easily embedded inside a laptop computer as an internal antenna. This design can radiate with two operating bands covering 2.38-2.54 and 4.99-5.96 GHz. By properly forming these two shorting strips, the effects due to the antenna near the external casing can be suitably tackled for actual application. Nearly omnidirectional coverage to enhance the communication quality can be obtained with our design. Therefore, the proposed antenna with a compact size is well suitable for WLAN operation in a laptop computer.
    Download Collect
  • Miniaturized NFC Antenna Design for a Tablet PC With a Narrow Border and Metal Back-Cover

    Chung, Ming-An   Yang, Chang-Fa  

    A novel structure of the near-field communication (NFC) antenna design for a tablet PC is proposed. This tablet PC has a narrow border and full metallic back-cover. A miniaturized loop antenna design is achieved by attaching ferrite sheets on both sides of the loop antenna. The ferrite sheets may reduce eddy currents induced on the adjacent metallic back-cover by the loop antenna to improve the communication range of the NFC. Only the edge of the tablet PC allows the antenna to radiate due to the full metallic back-cover. Thus, the NFC antenna needs to be narrow to be installed on the edge of the tablet PC. Therefore, we propose a miniaturized NFC antenna with the dimensions of 41.5 (L) x 7.5 (W) x 0.45 (T) mm(3) only. Simulated magnetic field distributions are consistent with measured voltage distributions. This design has a good communication rangemore than 6 cm in front of the touchscreen panel and reaches 2 cm over the other side above the metal back-cover.
    Download Collect
  • A new planar artificial transmission line and its applications to a miniaturized butler matrix

    Wang, Chao-Wei   Ma, Tzyh-Ghuang   Yang, Chang-Fa  

    A miniaturized quadrature hybrid coupler, a rat-race coupler, and a 4 x 4 Butler matrix based on a newly proposed planar artificial transmission line are presented in this paper for application in ultra-high-frequency (UHF) radio-frequency identification (RFID) systems. This planar artificial transmission line is composed of microstrip quasi-lumped elements and their discontinuities and is capable of synthesizing microstrip lines with various characteristic impedances and electrical lengths. At the center frequency of the UHF RFID system, the occupied sizes of the proposed quadrature hybrid and rat-race couplers are merely 27% and 9% of those of the conventional designs. The miniaturized couplers demonstrate well-behaved wideband responses with no spurious harmonics up to two octaves. The measured results reveal excellent agreement with the simulations. Additionally, a 4 x 4 Butler matrix, which may occupy a large amount of circuit area in conventional designs has been successfully miniaturized with the help of the proposed artificial transmission line. The circuit size of the Butler matrix is merely 21% of that of a conventional design. The experimental results show that the proposed Butler matrix features good phase control, nearly equal power splitting, and compact size and is therefore applicable to the reader modules in various RFID systems.
    Download Collect
  • A MINIATURE MULTIBRANCH INVERTED-F ANTENNA TO BE EMBEDDED IN THE LAPTOP COMPUTER FOR WWAN APPLICATIONS

    Hu, Chuan-Ling   Liu, Hsien-Wen   Yang, Chang-Fa   Lin, Shun-Tian  

    A novel miniature multibranch inverted-F antenna (IFA) suitable for penta-band Wireless Wide Area Network (MAN) applications is presented. The antenna is fabricated on a direct bond copper substrate and consists of multibranch strips, which occupies a very small size of 83(L)x 7(W) x 0.5(H) mm(3) to be easily embedded inside the laptop computer as an internal antenna. By properly designing the antenna operated as an inverted-F antenna, two frequency bands covering 813-993 and 1703-2196 MHz for the GSM8501900 and DCS/PCS/UMTS operations are achieved with good radiation efficiencies. Compared with other studies, the proposed antenna with a compact size is suitable to be installed in the laptop computer for the WWAN applications. (C) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:547-550. 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25802
    Download Collect
  • Built-in antenna design for 2.4 GHz ISM band and GPS operations in a wrist-worn wireless communication device

    Chung, Ming-An   Yang, Chang-Fa  

    A compact monopole and inverted-F antenna design for 2.4 GHz ISM band (2400-2485 MHz) and 1.575 GHz GPS operations suitable to be embedded within a wrist-worn wireless communication device is presented. Those antennas are fabricated on a polycarbonate and acrylonitrile-butadiene-styrene blend substrate with a three-dimensional etching process for irregular plastic materials. The wrist-worn device with and without a solid hand phantom model is evaluated. The radiation efficiency of the antennas can reach 80% for the ISM band and 63% for the GPS band without the hand phantom model. With the hand phantom model, the radiation efficiency reduces in half for both the ISM and GPS bands due to lossy materials in the phantom model. Good agreements between simulations and measurements are obtained. Moreover, the specific absorption rate of the device for the ISM band is measured and the results are much lower than the limit required by the FCC. This build-in antenna design can be applied in the wearable wireless communication device.
    Download Collect
  • Simulations and measurements of wave propagations in curved road tunnels for signals from GSM base stations

    Wang, Te-Shun   Yang, Chang-Fa  

    This paper presents a ray-tube tracing method to simulate waves propagating in curved road tunnels-from base stations for mobile communications. Ray tubes are traced by including multiple reflections in the curved tunnels and diffractions from wedges of the tunnel structures, together with the direct path. To verify this ray-tube tracing approach, field measurements of 900 MHz signals in two curved road tunnels from GSM base stations were performed for comparisons with the ray-tube tracing simulations. By tracing ray tubes reflected and diffracted from the curved structures of the tunnels, the effects of the curvature on wave propagations in large guiding structures can be evaluated. Good agreement between simulations and measurements has been obtained. A parametric study of the influence of the tunnel geometry and the signal frequency on the path loss is also presented by applying this ray-tube tracing method. Curved tunnels for different radii of curvature in the tunnel cross-section and horizontal plane and also lengths of the curved part are compared, together with rectangular tunnels. Simulations of the field distribution over the cross-section of the curved tunnel away from the transmitting antenna are demonstrated as well. The ray-tube tracing program can be applied to determine the deployment of the base-station antennas for improving signal coverage in tunnels, which may have curved structures.
    Download Collect
  • Miniaturized branch-line coupler with harmonic suppression for RFID applications using artificial transmission lines

    Wang, Chao-Wei   Ma, Tzyh-Ghuang   Yang, Chang-Fa  

    A miniaturized branch-line coupler based on a newly proposed planar artificial transmission line (ATL) is presented in this paper for UHF RFID applications. This planar artificial transmission line consists of quasi-lumped elements and their discontinuities, and can synthesize microstrip lines with a wide variety of characteristic impedances and electrical lengths. The measurement results agree well with the simulation ones. The experiments demonstrate that the proposed hybrid has a compact size of 24.4mm x 25.8mm, or equivalently 0.12 lambda(g) x 0.13 lambda(g) at the operation frequency, 915MHz. This corresponds to a 73% size reduction as compared to that of a conventional branch-line coupler. The wideband response reveals that the proposed hybrid is well-behaved with no spurious harmonics up to 11.1 GHz.
    Download Collect
  • Miniaturized Branch-Line Coupler with Harmonic Suppression for RFID Applications using Artificial Transmission Lines

    Wang, Chao-Wei   Ma, Tzyh-Ghuang   Yang, Chang-Fa  

    A miniaturized branch-line coupler based on a newly proposed planar artificial transmission line (ATL) is presented in this paper for UHF RFID applications. This planar artificial transmission line consists of quasi-lumped elements and their discontinuities; and can synthesize microstrip lines with a wide variety of characteristic impedances and electrical lengths. The measurement results agree well with the simulation ones. The experiments demonstrate that the proposed hybrid has a compact size of 24.4mm 脳 25.8mm; or equivalently 0.12驴g 脳 0.13 驴g at the operation frequency; 915MHz. This corresponds to a 73%size reduction as compared to that of a conventional branch-line coupler. The wideband response reveals that the proposed hybrid is well-behaved with no spurious harmonics up to 11.1 GHz.
    Download Collect
1

Contact

If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

Submit Feedback