Korea Advanced Institute of Science and Technology

Electronics and Telecommunications Research Institute

Samsung Electronics Co., Ltd.

Korea Institute of Science and Technology

Korea Basic Science Institute

Chulsoon Park

InnYeal Oh

Jinhee Lee

Kyuhwan Shim

Sungjae Maeng

Dojin Kim

Youngkyu Choi

Kyungho Lee

Jinyeong Kang

Jeonwook Yang

Hojung Kim

Taehwan Jang

SeungYoung Park

JooYoung Jang

SeungHun Kim

MinChul Shin

HaeJin Lee

ByoungChul Min

Honghyun Bae

Hongyi Kim

SukHee Han

Inn Yeal Oh

Joongho Lee

SeongJun Cho

HyukSu Son

WooYoung Kim

A dual-polarized antenna with high isolation is disclosed. A first differential signal feeding unit extends from a first input port toward one side of a patch radiator through a dielectric substrate, and is branched into a balun structure to provide first and second feeding probes for differentially feeding vertically polarized signals to opposite first and second portions of the patch radiator. A second differential signal feeding unit extends from a second input port toward another side of the patch radiator through the dielectric substrate, and is branched into the balun structure to provide third and fourth feeding probes for differentially feeding horizontally polarized signals to opposite third and fourth portions of the patch radiator. When feeding the vertically polarized signals through the first and second feeding probes, a virtual ground region in which there is little electric field is formed in the center portion of the patch radiator. The cross-sectional polarization components of the third and fourth probes are also greatly reduced, so that they hardly exist. A soft surface structure surrounding the patch radiator and the first to fourth probes can improve the radiation pattern deterioration caused by diffraction of surface waves.

Dual polarization antenna with high isolation

A wideband variable gain amplifier (VGA) having a low phase change is disclosed. The first VGA amplifies an input signal by a current steering manner so that an amplification gain is variable. The larger a variable gain amount of the first output signal amplified by the first VGA is, the more a relative phase change amount gradually increases in either positive direction or negative direction. The second VGA further amplifies the first amplified output signal in the current steering manner so as to vary the amplification gain. As a variable gain amount of a second output signal amplified by the second VGA becomes larger, a relative phase change amount gradually increases in a direction opposite to the phase change direction of the first VGA. This opposing phase changes of the first and second VGAs are canceled against each other to provide a variable amplification gain over the wideband frequency range with a low phase change.

Wideband variable gain amplifier with low phase variation

Provided are chip antennas for near field communication and methods of manufacturing the chip antennas. A chip antenna for near field communication includes a substrate; a first antenna element on the substrate; and a second antenna element on the first antenna element. The substrate, the first antenna element, and the second antenna element are included in a single chip. The first and second antenna elements are formed outside the chip. The substrate is a lower layer including a plurality of devices. The first antenna element is a metal structure having a fish bone shape. The second antenna element is a dipole antenna.

Chip antenna for near field communication and method of manufacturing the same

A spintronic wireless communication system for simultaneously modulating multiband frequencies and amplitudes includes a plurality of spin-torque transfer devices which have different frequency characteristics from each other, and OOK modulate or multi-level ASK modulate input data to thereby output a multiband OOK modulation signal or a multiband, multi-level ASK modulation signal; a plurality of matching networks which match individual impedances of the plurality of spin-torque transfer devices; and a broadband antenna which receives the multiband OOK modulation signal or the multiband, multi-level ASK modulation signal from ends of the plurality of matching networks and simultaneously transmits the signals to the outside.

Spintronic wireless communication system for simultaneously modulating multi-band frequency and amplitude

A spin modulator with phase tuning means which comprises, a spin array which consists of m&#xd7;n matrix spin-transfer torque oscillators, a selection control means which selectively operates the spin-transfer torque oscillators according to an operation condition of the spin array, and a phase tuning array which includes m&#xd7;n matrix phase tuning means, wherein the m&#xd7;n matrix phase tuning means tune a phase synchronization operation of the spin-transfer torque oscillators according to the operation condition.

Spin modulator and spin-transfer torque oscillators having phase tuning means and modulation method thereof

The present invention provides a spin-transfer torque type injection locking oscillator which improves both power and noise performance by using pair of spin-transfer torque devices. One is optimized for high power and the other is optimized for low noise characteristics. The output signal of the low noise spin-transfer torque device is injected into the high output power spin-transfer torque for phase locking. The present invention has several advantages such as the miniaturization, the high quality and low cost, and the mass production of integrated chips by the nanoscale.

Spin-transfer torque type injection locking oscillator and design method thereof

Provided is a display apparatus for receiving millimeter waves or terahertz waves from a transmitter under a non-line-of-sight condition, the apparatus including: a plurality of diversity boards that are installed in a bezel of the display apparatus, receive millimeter waves or terahertz waves having different paths, convert the received waves into a plurality of baseband signals, and sense output powers of the plurality of baseband signals; a controller to output a control signal for selecting a diversity board of a maximum output power from the output powers sensed by the plurality of diversity boards; a selector to connect the diversity board of the maximum output power among the plurality of diversity boards to an image converter by the control signal; and the image converter to convert an output of the selector into image data for displaying.

Display apparatus of receiving millimeter wave or terahertz wave under non-line-of-sight conditions and displaying method thereof

This invention is related to a wireless communication system for giga bit data rate and low power consumption, comprising a mobile communication terminal that transmits massive data to a display apparatus using a millimeter wave or terahertz wave band, a display apparatus that plays received massive data and a low speed wireless controller that controls the operation of the mobile communication terminal and the transmission of massive data from the mobile communication terminal into the display apparatus.

Wireless communication system for giga bit data rate and low power consumption

Provided is a hybrid envelope amplifier having improved efficiency, and more particularly, to an envelope amplifier using a dual switching amplifier and having improved efficiency in which power consumption is reduced by controlling a switching current of a switching region according to a magnitude of an envelope input signal, thereby improving efficiency compared to a conventional hybrid envelope amplifier. The envelope amplifier using a dual switching amplifier and having improved efficiency comprises a linear amplifier and a switching amplifier, wherein the switching amplifier includes two or more switching stages that are selectively operated according to a magnitude of an input signal.

Efficiency improved envelope amplifier using dual switching amplifiers

A manufacturing method of GaAs metal semiconductor FET is disclosed. The method comprises the steps of: preparing a GaAs substrate; depositing a silicon layer on the GaAs substrate; forming a first photoresist pattern on the silicon layer by means of well-known image reversal process; etching the silicon layer by means of photolithographic process using the first photoresist pattern as a mask to define ohmic contact regions of source/drain electrodes; forming a second photoresist pattern on the GaAs substrate after removal of the first photoresist pattern to define a channel region; injecting a predetermined quantity of silicon ions into the GaAs substrate to form the channel region; depositing a protective layer around the GaAs substrate after removal of the second photoresist pattern; annealing the substrate deposited with the protective layer to activate silicon ions of the remaining silicon layer and thus diffusing the activating silicon ions into the depth direction of the substrate; forming ohmic contacts on the substrate using an ohmic contact mask after removal of the protective layer and the remaining silicon layer; and forming a gate electrode by using a gate mask.

Manufacturing method of GaAs metal semiconductor FET

There is disclosed a manufacturing method of self-aligned GaAs FET using refractory gate with dual structure, the manufacturing method of the invention comprising the steps of: forming first photoresist pattern on a GaAs substrate to define an active region and ion-implanting n type impurity in the active region of the GaAs substrate; sequentially depositing a nitrogen-containing silicon layer and a metal layer on the substrate after removal of the first photoresist pattern; forming second photoresist pattern on the metal layer to define a gate; removing the silicon and metal layers using the second photoresist pattern as a gate mask to form the gate with dual structure of the silicon and metal layers; forming third photoresist pattern on the substrate to define source/drain regions after removal of the second photoresist pattern, and ion-implanting high-density impurity in the source/drain regions using the third photoresist pattern and the gate as a source/drain mask; annealing the substrate to make the silicon layer as upper side of the gate into metal-silicon-nitride material, and to make bottom portion of the metal layer as lower side of the gate into metal-silicon-nitride material; and forming ohmic contacts on the source/drain regions, respectively. A GaAs FET according to the invention is provided with a gate having low-resistance and improved schottky characteristics.

Growing community of inventors

Daejeon, South Korea

Chulsoon Park