Electronics and Telecommunications Research Institute

Korea Advanced Institute of Science and Technology

Won-Kyu Choi

Cheol-Sig Pyo

Hae-Won Son

Jong-Suk Chae

Gil-Young Choi

Chan-Soo Shin

Nak-Seon Seong

Chang-Joo Kim

Je-Hoon Yun

Ji-Hoon Bae

Soon-Ik Jeon

Byung-Je Lee

Yong-Heui Cho

Jong-Moon Lee

Han-Phil Rhyu

Noh-Hoon Myung

Sung-Jun Heo

Jung-Hyung Ha

Provided is an antenna system with high isolation. The high-isolation antenna has transmission ports of a transmission antenna and reception ports of a reception antenna highly isolated from each other by using quadrature hybrid couplers. The antenna system includes: a transmission antenna having two feed points for transmitting signals; a reception antenna having two feed points for receiving signals; a transmission hybrid coupler which is connected to the two feed points of the transmission antenna and transmits transmission signals which have a phase difference of 90&#xb0; with each other; and a reception hybrid coupler which is connected to the two feed points of the reception antenna and receives reception signals which have a phase difference of 90&#xb0; with each other. The signals leaking from the two feed points of the transmission antenna to the two feed points of the reception antenna are offset.

Transmit/receive antenna system having offset feed points for high isolation

An open-ended two-strip meander line antenna, an RFID tag using the same and an antenna impedance matching method thereof are provided. The antenna includes: a radiating strip line for deciding a resonant frequency of the antenna; and a feeding strip line for providing a radio frequency (RF) signal to an element connected to the antenna, wherein ends of the radiating strip line and the feeding strip line are open.

Open-ended two-strip meander line antenna, RFID tag using the antenna, and antenna impedance matching method thereof

A cable to waveguide transition apparatus having a signal accumulation form of a backshort is disclosed. The cable to waveguide transition apparatus having a signal accumulation form of a backshort, includes: a waveguide; a RF probe for transferring a radio frequency (RF) signal to the waveguide; and a backshort having the signal accumulation form for reflecting the RF signal excited from the RF probe, wherein the backshort reflects a first fundamental frequency signal excited from the RF probe to have a phase identical to a phase of a second fundamental frequency signal excited from the RF probe to an aperture of the waveguide, and reflects a first 2-order harmonic frequency signal excited from the RF probe to have a phase reverse to a phase of a second 2-order harmonic frequency signal excited to an aperture of the waveguide in order to eliminate the 2-order harmonic frequency signal.

Cable to waveguide transition apparatus having signal accumulation form of backshort and active phase shifting using the same

Provided are a method and apparatus for sharing a portable terminal in a Code Division Multiple Access (CDMA) and a mobile Radio Frequency Identification (RFID) system. The portable terminal includes: a CDMA mobile station system for performing CDMA communication; a mobile RFID system for performing a passive RFID reader function; a switching unit for switching an antenna to any one between the CDMA mobile station system and the mobile RFID system; and a control unit for controlling the switching unit to connect the antenna to the CDMA mobile station system when the portable terminal transmits/receives a signal to/from the base station, or connect the antenna to the mobile RFID system when the portable terminal transmits/receives a signal to/from an RFID tag.

Method and apparatus for sharing portable terminal in CDMA system and mobile RFID system

An antenna and a radio frequency identification (RFID) tag using the same are disclosed. The antenna includes: a radiating unit having a helical structure; and a feeding unit having a loop structure on which a terminal connected to an element connected to the antenna is formed, wherein the feeding unit is electromagnetically induced and coupled with the radiating unit to be apart from each other.

Antenna having loop and helical structure and RFID tag using the same

An antenna, a RFID tag using the same, and an antenna impedance matching method thereof are provided. The antenna includes: a radiation patch for deciding a resonant frequency of the antenna; a ground plate disposed in parallel to the radiation patch; and a feeder disposed between the radiation patch and the ground plate in parallel for providing a RF signal to an element connected to the antenna, wherein the feeder includes a microstrip feed line proximately coupled to the radiation patch by being formed perpendicularly to the resonant length direction of the radiation patch.

Antenna using proximity-coupled feed method, RFID tag having the same, and antenna impedance matching method thereof

Provided are an antenna using an inductively coupled feeding method, a Radio Frequency Identification (RFID) tag thereof, and an antenna impedance matching method thereof. The antenna includes a resonator for determining a resonance frequency of the antenna and a feeder for providing an RF signal to an element connected to the antenna. An RFID tag includes an antenna which receives an RF signal from the RFID reader, an RF front-end which rectifies and detects the RF signal, and a signal processor which is connected to the RF front-end. Particularly, the antenna includes a resonator for determining a resonance frequency of an antenna and a feeder for providing the RF signal to the RF front-end, wherein mutual inductive coupling between the resonator and the feeder is performed.

Antenna using inductively coupled feeding method, RFID tag using the same and antenna impedance matching method thereof

Provided is an antenna for a Radio Frequency Identification (RFID) reader using an electrical loop. It includes an upper metal plate which functions as a radiator; a lower metal plate which is disposed apart from the upper metal plate by a predetermined distance and functions as a radiator; a ground plate disposed apart from the lower metal plate by a predetermined distance; and a feeding probe disposed at the center of the upper and lower metal plates. The antenna can perform radiation parallel to the earth's surface including other directions. Therefore, it is suitable for an RFID reader which recognizes an RFID tag attached in parallel to the earth's surface. The electrical loop antenna can control impedance matching, resonance frequency, antenna gain, and radiation pattern according to the distance between metal plates, size of the metal plates, thickness of a feeding probe, and how the metal plates are arranged.

Electrical loop antenna with unidirectional and uniform current radiation source

Provided is a planar inverted-F antenna (PIFA) which has a Co-Planar Waveguide (CPW) feeding structure and can be attached to a metal surface, and an RFID tag using the same. The PIFA includes a radiation patch layer; a Co-Planar Waveguide (CPW) feeding layer; a feeding probe; and a short-circuit. The CPW feeding layer includes a feeding means and a ground surface. The feeding probe electrically connects the radiation patch layer and the feeding means and provides a Radio Frequency (RF) signal to be radiated to the radiation patch layer. The short-circuiting means short-circuits the radiation patch layer and the ground surface through the dielectric layer. The PIFA can be applied to a passive RFID tag. Impedance matching between the antenna and the RFID chip is possible. Also, the PIFA can easily control resonant frequency of the antenna and reactance.

PIFA and RFID tag using the same

Provided is a dual polarization antenna realized by using four inverted F-type radiators and a Radio Frequency Identification (RFID) reader employing the dual polarization antenna. The dual polarization antenna includes a ground plate and four inverted F-type radiators set up on the ground plate. Currents of the same phase are fed to the first and second inverted F-type radiators each other. Currents of an inverted phase are fed to the third and fourth inverted F-type radiators each other. The four inverted F-type radiators form an angle of 90&#xb0; with one another. The first and second inverted F-type radiators radiate electric wave of vertical polarization and the third and fourth inverted F-type radiators radiate electric wave of horizontal polarization. Since the dual polarization antenna has excellent orthogonal and isolation characteristics, the antenna can extend a transmission distance between the reader and the tag and improve a communication quality.

Dual polarization antenna and RFID reader employing the same

Provided are a Planar Inverted-F Antenna (PIFA), a Radio Frequency Identification (RFID) tag using the PIFA. The present invention miniaturizes the antenna by using a meander line extended from a radiating edge of a radiation antenna and adjusting a resonant frequency of the antenna, and it performs impedance matching by adjusting capacitive reactance of the antenna. Also, it can perform impedance matching by using a stub having a slot formed therein and adjusting inductive reactance and capacitive reactance of the antenna. The present invention miniaturizes the antenna by using a plurality of shorting plates for shorting the radiation patch from a grounding surface and adjusting the resonant frequency of the antenna. The present invention also provides an inexpensive PIFA antenna with an excellent radiation efficiency by forming the radiation patch in the form of metal sheet in the antenna and floating the radiation patch in the air.

PIFA, RFID tag using the same and antenna impedance adjusting method thereof

A microstrip patch antenna formed by using a microelectro-mechanical system technology is included. The microstrip patch antenna includes: a substrate provided with a ground formed on a bottom surface of the substrate; a feeding line formed on a top surface of the substrate for feeding an electric power; a coupling stub formed on the top surface of the substrate and electrically connected to the feeding line; a plurality of supporting posts erected on the top surface of the substrate; and a radiating patch formed on the supporting posts, thereby forming an area of air between the radiating patch and the top surface of the substrate.

Growing community of inventors

Gyeonggi-do, South Korea

Won-Kyu Choi