Abstract: Provided is an electromagnetic bandgap (EBG) structure, and particularly, an overlay EBG structure in which a plurality of vias and a plurality of plates are formed at intervals on a central signal line in such a manner that the vias and plates extend vertically from a substrate in order to reduce leakage loss of an electromagnetic wave through the substrate. Therefore, it is possible to prevent an electromagnetic wave passing through a transmission line from being lost through the substrate, to obtain desired frequency characteristics by adjusting the dimensions of the vias and plates, and to manufacture the overlay EBG structure using an existing CMOS process without having to perform any additional process.

Abstract: Provided is a switched beam-forming apparatus which includes a beam-forming unit forming a plurality of beams using an array antenna, a beam selection adjusting unit measuring Quality of Service (QoS) values of each of a plurality of signals received through the plurality of beams, a beam selecting unit selecting at least two beams with high QoS from among the plurality of beams according to the results of the QoS measuring, and a beam combining unit combining the at least two beams selected by the beam selecting unit.

Abstract: A waveguide of a multi-layer metal structure and a manufacturing method thereof are provided, the method including applying a plurality of metal layers on a substrate and a plurality of insulating layers respectively between the respective metal layers. Accordingly, it is possible to minimize conductive loss by dispersing current uniformly through wide regions between a signal line and ground lines.

Abstract: A multilayered coplanar waveguide (CPW) filter unit and a method of manufacturing the same are provided. A plate having a capacitance element is formed on or below a CPW layer including a signal line for transmitting a signal and a ground plane. As the filter unit has a multilayered structure, characteristic impedance may be reduced without increasing the width of the signal line. Where an inductor line is inserted between the signal line and the plate, a clear frequency response curve may be obtained without performing an additional process or increasing the area of the filter unit.

Abstract: Disclosed are a beamformer and a beamforming method. The beamformer includes a plurality of dividers, each of which divides an input signal along a plurality of paths, an input switch which selects one of the dividers such that the input signal is input to the selected divider, a phase shifter which shifts phases of respective output signals from the divider, and an output switch which transmits the output signals from the phase shifter to an antenna.

Abstract: Provided is an Electromagnetic Bandgap (EBG) structure, particularly, a resonator and a bandpass filter having an overlay EBG structure, and a method of manufacturing the resonator. The resonator is manufactured by forming a transmission line and ground plates on a substrate, arranging a plurality of reflector units at regular intervals along the longitudinal direction of the transmission line, and removing at least one reflector among the plurality of reflectors, thus forming a common resonating mode. Therefore, since reflector units constructing capacitance components are separated from a substrate, it is possible to prevent electromagnetic waves from leaking out of the substrate and ensure a high Q characteristic in a high frequency environment due to a resonating unit formed between the reflector units.

Abstract: Provided is a switched beam-forming apparatus which includes a beam-forming unit forming a plurality of beams using an array antenna, a beam selection adjusting unit measuring Quality of Service (QoS) values of each of a plurality of signals received through the plurality of beams, a beam selecting unit selecting at least two beams with high QoS from among the plurality of beams according to the results of the QoS measuring, and a beam combining unit combining the at least two beams selected by the beam selecting unit.

Abstract: A broadband microstrip balun and a method of manufacturing the same are provided. In the balun, transmission lines formed at different layers partially overlap in parallel with each other, and a common ground having a predetermined opening is inserted between the transmission lines. Thus, an unbalanced signal may be converted into a balanced signal in a broad frequency band using resonance of a common ground plate with the opening and a Bethe hall effect. Also, impedance matching is readily enabled, thereby reducing a parasitic element.

Abstract: A multilayered coplanar waveguide (CPW) filter unit and a method of manufacturing the same are provided. A plate having a capacitance element is formed on or below a CPW layer including a signal line for transmitting a signal and a ground plane. As the filter unit has a multilayered structure, characteristic impedance may be reduced without increasing the width of the signal line. Where an inductor line is inserted between the signal line and the plate, a clear frequency response curve may be obtained without performing an additional process or increasing the area of the filter unit.

Abstract: Provided is an electromagnetic bandgap (EBG) structure, and particularly, an overlay EBG structure in which a plurality of vias and a plurality of plates are formed at intervals on a central signal line in such a manner that the vias and plates extend vertically from a substrate in order to reduce leakage loss of an electromagnetic wave through the substrate. Therefore, it is possible to prevent an electromagnetic wave passing through a transmission line from being lost through the substrate, to obtain desired frequency characteristics by adjusting the dimensions of the vias and plates, and to manufacture the overlay EBG structure using an existing CMOS process without having to perform any additional process.

Abstract: A semiconductor element for macro and micro frequency tuning, and an antenna and a frequency tuning circuit having the semiconductor element, are provided. The semiconductor element includes first and second semiconductors which have a same polarity, a third semiconductor which has a polarity opposite to the polarity of the first and second semiconductors and is interposed between the first and the second semiconductors, a first intrinsic semiconductor which is interposed between the first and the third semiconductors, and a second intrinsic semiconductor which is interposed between the third and the second semiconductors.

Abstract: A high frequency signal switching apparatus includes a bias unit which transmits a bias power source; a control signal transmitter, which provides a control signal received from outside; and a switching unit, so that the input signal input through the input terminal by switching one or more diodes according to the control signal driven by the bias power source is output selectively on the output terminal.

Abstract: A downward type micro electro mechanical system (EMS) switch and a method of fabricating the same is provided. The downward type MEMS switch includes first and second cavities formed in a substrate, first and second actuators formed on upper portions of the first and second cavities, first and second fixing lines formed on an upper surface of the substrate and not overlapped with the first and second cavities, and a contact pad which is spaced apart at a predetermined distance from surfaces of the first fixing line and the second fixing line but which can be contacted with the first fixing line and the second fixing line when the first actuator and the second actuator are driven. The contact pad, which is actuated downward by piezoelectricity, is fabricated as it shares a layer with a RF signal line, after the RF signal line is fabricated.

Abstract: A signal transformation apparatus capable of performing stable transformation of a signal using a Mechanical switch includes a signal generator which generates a reserve pulse signal in response to an applied sync signal, a signal controller which outputs control signals to change and transform the reserve pulse signal to pulse signals having a predetermined pulse width, and a signal modulator which transforms the reserve pulse signal to the pulse signals having different pulse widths in response to the control signals. The signal modulator includes a switch bank in which a plurality of mechanical switches are connected in parallel, and a transmission line between nodes where the mechanical switches are formed.