Abstract: A signal line that can be easily bent and significantly reduces loss generated in a high-frequency signal includes a main body including a plurality of insulating sheets made of a flexible material and stacked on each other in a stacking direction. Ground conductors are provided in the main body on the positive z-axis direction side of a signal line. The ground conductors have a slit S formed therein that overlaps the signal line when viewed in plan from the z-axis direction. A ground conductor is provided in the main body on the negative z-axis direction side of the signal line, and is overlapped by the signal line when viewed in plan from the z-axis direction. The ground conductors and the signal line define a strip line structure. A distance between the ground electrodes and the signal line is smaller than a distance between the ground electrode and the signal line.

Abstract: The invention is related to a microstrip line structure, which comprises: a first microstrip line and a second microstrip line, paralleled with the first microstrip line for transferring a transmission signal, and a plurality of grooves periodically arranged on both sides of the second microstrip line by using subwavelength, and each period length in the plurality of grooves is smaller than the wavelength of the transmission signal.

Abstract: Two transmission lines are formed adjacent to each other at spacing on an upper surface of a base insulating layer, and a ground conductor layer is formed on a lower surface of the base insulating layer. The ground conductor layer is arranged to be opposite to at least part of one transmission line and at least part of the other transmission line in a width direction of the two transmission lines. When a width of one transmission line, a width of the other transmission line, a spacing between the two transmission lines and a width of the ground conductor layer in an arbitrary cross section perpendicular to the two transmission lines are referred to as W1, W2, S, Wg, respectively, the width Wg of the ground conductor layer is set to satisfy relationship of Wg<(W1+W2+S) and S?0.8 Wg.

Abstract: In one embodiment, the present invention includes a transformer formed on a semiconductor die. Such transformer may have multiple coils, including first and second coils. Each coil may have segments that in turn are formed on a corresponding metal layer of the semiconductor die. The segments of a given coil are coupled to each other, and the first and second coils can be interdigitated with each other.

Abstract: An electronic product includes a case; a first board placed inside the case; and a second board having an Electromagnetic Band Gap (EBG) structure inserted therein. The second board is coupled to an inside of the case facing the first board so as to shield a noise radiated from the first board.

Abstract: A device is provided for use with a signal, wherein the device includes a substrate, a first signal trace and a second signal trace. The first signal trace is disposed within the substrate at a first plane from the top surface by a distance d1. The second signal trace is disposed within the substrate at a second plane from the top surface by a distance d2, wherein d2<d1<t. The first signal trace includes a first portion, whereas the second signal trace includes a second portion. The first portion is parallel to the second portion. The first signal trace and the second signal trace form a differential pair. The first signal trace is operable to conduct a positive portion of the signal, whereas the second signal trace is operable to conduct a negative portion of the signal.

Abstract: A high-frequency signal transmission line includes a flexible body including a plurality of insulating layers. A linear signal line is located in or on the body. A first ground conductor is located opposite to the signal line via at least one of the insulating layers. A second ground conductor extends along the signal line. An interlayer connection portion that connects the first ground conductor and the second ground conductor includes a plurality of interlayer connection conductors individually pierced in some of the insulating layers and connected to each other. The plurality of interlayer connection conductors includes two interlayer connection conductors that are pierced in adjacent ones of the insulating layers with respect to a layer-stacking direction and that have central axes located in different positions when viewed from the layer-stacking direction.

Abstract: A high-frequency signal line includes an element assembly including a plurality of insulator layers, a linear signal line provided in or on the element assembly, a first ground conductor provided in or on the element assembly and extending along the signal line, and a plurality of floating conductors provided in or on the element assembly on a first side in a direction of lamination relative to the signal line and the first ground conductor, so as to be arranged along the signal line in an orientation crossing the signal line when viewed in a plan view in the direction of lamination. The floating conductors are opposite to the signal line and the first ground conductor with at least one of the insulator layers positioned therebetween, the floating conductors being connected to neither the signal line nor the first ground conductor.

Abstract: A high-frequency signal line includes an element assembly including a plurality of flexible insulator layers. a linear signal line provided in or on the element assembly, a first ground conductor provided in or on the element assembly and extending along the signal line, a plurality of second ground conductors provided in or on the element assembly and arranged at predetermined intervals in a direction in which the signal line extends, on a first side in a direction of lamination relative to the signal line, the second ground conductors being opposite to the signal line with at least one of the insulator layers positioned therebetween, and a plurality of first via-hole conductors extending through at least one of the insulator layers so as to connect the first and second ground conductors.

Abstract: A dielectric element assembly includes a plurality of stacked dielectric sheets. A signal line is provided in or on the dielectric element assembly. A ground conductor is provided in or on the dielectric element assembly on the negative direction side of a z-axis direction relative to the signal line and is arranged so as to oppose the signal line via the dielectric sheets. The ground conductor includes a main body portion and protruding portions. The main body portion extends along the signal line on one side of a direction perpendicular or substantially perpendicular to the signal line relative to the signal line when viewed in plan from the z-axis direction. The protruding portions protrude from the main body portion toward the signal line and overlap the signal line when viewed in plan from the z-axis direction.

Abstract: On-chip high performance slow-wave coplanar waveguide structures, method of manufacture and design structures for integrated circuits are provided herein. The structure includes at least one ground and a signal layer provided in a same plane as the at least one ground. The signal layer has at least one alternating wide portion and narrow portion. The wide portion extends toward the at least one ground.

Abstract: On-chip high performance slow-wave microstrip line structures, methods of manufacture and design structures for integrated circuits are provided herein. The structure includes at least one ground and a signal layer provided in a different plane than the at least one ground. The signal layer has at least one alternating wide portion and narrow portion with an alternating thickness such that a height of the wide portion is different than a height of the narrow portion with respect to the at least one ground.

Abstract: A high-frequency signal line includes an element assembly including a plurality of flexible insulator layers, a linear signal line provided in or on the element assembly, a first ground conductor arranged in or on the element assembly so as to be opposed to the signal line not in a first section including a portion of the signal line but in a second section adjacent to the first section, and a second ground conductor provided along the signal line in the first section on the insulator layer on which the signal line is provided. The second ground conductor is not opposed at least in part to the first ground conductor in the first section.

Abstract: A high-frequency signal line includes a dielectric element body including regions and a plurality of flexible dielectric sheets. A signal conductive layer is provided in or on the dielectric element body. Ground conductive layers are provided in or on the dielectric element body and face the signal conductive layer. A distance between the ground conductive layer and the signal conductive layer in the region is smaller than a distance between the ground conductive layer and the signal conductive layer in the regions. The dielectric element body is bent in the region.

Abstract: In a circuit module, even if a transmission signal output from a transmission electrode of a mounting substrate to a transmission terminal of a splitter leaks into a ground electrode, the transmission signal that has leaked into the ground electrode is mainly transmitted along an edge of the ground electrode and the transmission signal that has leaked into the ground electrode flows into a plurality of via conductors arranged with end surfaces superposed with the edge of the ground electrode when viewed in plan. Therefore, a transmission signal that has been output from the transmission electrode and leaked into the ground electrode is prevented from traveling along the edge of the ground electrode toward the reception electrode side. As a result, isolation characteristics of the transmission electrode and the reception electrode from each other are improved.

Abstract: A high-frequency signal transmission line includes a dielectric body including a stack of a plurality of dielectric layers, a linear signal line located in the dielectric body, a first ground conductor located at a first side of the signal line in a stacking direction and including a plurality of first openings arranged along the signal line, and a plurality of floating conductors located at the first side of the signal line in the stacking direction to overlap with the first openings, when viewed from the stacking direction, each of the floating conductors being not connected to any other conductors.

Abstract: A high-frequency signal transmission line includes a dielectric body including a plurality of dielectric sheets. A signal line is provided in the dielectric body. A connector is mounted on a first main surface of the dielectric body and electrically connected to the signal line. A ground conductor is provided on a second main surface side of the dielectric body, compared with the signal line, and faces the signal line across the dielectric sheet. In the ground conductor, conductor-missing portions are provided in which no conductors are provided in at least portions of regions overlapping with the signal line in planar in connection portions. Adjustment conductors are provided in the second main surface of the dielectric body, and overlap with at least portions of the conductor-missing portions in the planar view.

Abstract: On-chip high performance slow-wave coplanar waveguide structures, method of manufacture and design structures for integrated circuits are provided herein. The structure includes at least one ground and signal layer provided in a same plane as the at least one ground. The signal layer has at least one alternating wide portion and narrow portion with an alternating thickness. The wide portion extends toward the at least one ground.

Abstract: The present invention provides a space saving and simply implementable planar integrated switching device comprising at least two CPW-slotline transition units each including an access for inputting and/or outputting a transmission signal, a slotline connecting said at least two CPW-slotline transition units, and a switching element arranged on said slotline between said at least two CPW-slotline transition units for switching the transmission signal over said slotline on and off under control of a switch control signal.

Abstract: External electrodes are provided on a bottom surface of a laminate, and are connected to both ends of a main line and both ends of a sub-line, respectively. A warpage prevention conductor is provided on an insulating material layer that is provided on a top surface side of the laminate with respect to insulating material layers to which the main line is provided and with respect to insulating material layers to which the sub-line is provided. The warpage prevention conductor overlaps with the external electrodes when seen from a z-axis direction in a plan view. A conductor layer that is not connected to the main line or the sub-line is not provided on any of the insulating material layers provided on a bottom surface side of the laminate with respect to the insulating material layer on which the warpage prevention conductor is provided.

Abstract: An antenna includes a first conductive plane, a second conductive plane disposed in parallel with the first conductive plane, a power-supply unit applying a high frequency signal between the first conductive plane and the second conductive plane, and at least one shunt which is aligned in the second conductive plane and includes a transmission line including an open end aligned in a plane above or below the second conductive plane and a conductive via electrically connecting another end of the transmission line to the first conductive plane. A distance between a bottom surface of the transmission line and the second conductive plane is less than a distance between the bottom surface of the transmission line and the first conductive plane. The transmission line is formed on a plane positioned to face the second conductive plane outside a region circumscribed between the first conductive plane and the second conductive plane.

Abstract: The present invention provides a capacitively coupled stripline to microstrip transition which comprises a stripline, a microstrip, an upper conductive ground plane, a lower conductive ground plane, an insulating layer and an insulating fixing component. The stripline is positioned between the upper conductive ground plane and the lower conductive ground plane, and has a stripline overlap section. The microstrip is mounted on the upper conductive ground plane, and has a microstrip overlap section which penetrates the upper conductive ground plane. Wherein the microstrip overlap section, the insulating layer and the stripline overlap section are attached uniformly and tightly in sequence and fixed together by the insulating fixing component. The present invention further provides an antenna comprising this transition.

Abstract: The invention is related to a microstrip line structure, which comprises: a first microstrip line and a second microstrip line, paralleled with the first mircostrip line for transferring a transmission signal, and a plurality of grooves periodically arranged on both sides of the second microstrip line by using subwavelength, and each period length in the plurality of grooves is smaller than the wavelength of the transmission signal.

Abstract: An easily bendable high-frequency signal transmission line includes a dielectric body including a protection layer and dielectric sheets laminated on each other, a surface and an undersurface. A signal line is a linear conductor disposed in the dielectric body. A ground conductor is disposed in the dielectric body, faces the signal line via the dielectric sheet, and continuously extends along the signal line. A ground conductor is disposed in the dielectric body, faces the ground conductor via the signal line sandwiched therebetween, and includes a plurality of openings arranged along the signal line. The surface of the dielectric body on the side of the ground conductor with respect to the signal line is in contact with a battery pack.

Abstract: An easily bendable high-frequency signal transmission line includes a dielectric body including a protection layer and dielectric sheets laminated on each other, a surface and an undersurface. A signal line is a linear conductor disposed in the dielectric body. A ground conductor is disposed in the dielectric body, faces the signal line via the dielectric sheet, and continuously extends along the signal line. A ground conductor is disposed in the dielectric body, faces the ground conductor via the signal line sandwiched therebetween, and includes a plurality of openings arranged along the signal line. The surface of the dielectric body on the side of the ground conductor with respect to the signal line is in contact with a battery pack.

Abstract: Provided is a transmission line used to transmit high-frequency electrical signals which can remove a dip-shaped (S21) loss of transmission characteristics due to wall surface resonance, furthermore, can further decrease the size, and can suppress the manufacturing cost at a low level. The transmission line used to transmit high-frequency electrical signals (1) is made up of a signal line (3) used to transmit high-frequency electrical signals which is formed on a front surface (2a) of a dielectric substrate (2), GND electrodes (4) formed outside the signal line (3) and in vicinities of end portions of the front surface (2a), a GND electrode (6) that is electrically connected to the GND electrodes (4) through via holes (5) formed across an entire rear surface (2b) of the dielectric substrate (2), and band-shaped resistors (7) that are formed outside the GND electrodes (4) and in the end portions of the surface (2a) and are electrically connected to the GND electrodes (4).

Abstract: Unwanted radiation is reduced in a high-frequency signal transmission line that includes a ground conductor provided with an opening that overlaps a signal line. A dielectric element assembly has a relative dielectric constant ?1 and has a first principal surface and a second principal surface. A signal line is provided in the dielectric element assembly. A ground conductor is provided in the dielectric element assembly and on the first principal surface side with respect to the signal line, faces the signal line, and is provided with an opening that overlaps the signal line. A high dielectric constant layer has a relative dielectric constant ?2 higher than the relative dielectric constant ?1 and is provided on the first principal surface so as to overlap the opening.

Abstract: Transmission lines for electronic devices such as microstrip and stripline transmission lines may be provided that include patterned conductive lines and a conductive paint in the patterned conductive lines. The transmission lines may include one or more planar ground conductors. The ground conductors may include conductive lines arranged in a crosshatch pattern with spaces between the conductive lines. The ground conductors may also include conductive paint in spaces within the crosshatched pattern. The ground conductors may form one or more ground planes for the transmission lines.

Abstract: A waveguide for transmission of data signals therealong. Data signals are typically received from and/or transmitted to a remote location and subsequently passed to or emitted from the apparatus which allows the data to be processed. The waveguide includes a channel which has a cross-sectional shape, the angular orientation of which is changed at least one point along the length of the same so as to provide a waveguide which is less sensitive to interferences. The waveguide, in one embodiment, can also include recessed portions and/or ridges along the length of the channel which ensures that the waveguide can be formed in a more reliable and controlled manner.

Abstract: An exemplary transmission line system is provided. The system includes a first transmission line partially arranged on a first layer of a PCB including first structure units and partially arranged on a third layer of the PCB including second structure units, and a second transmission line arranged on a second layer of the PCB. Each first structure unit and each second structure respectively include a first connection line, a second connection line, and a first curved line; and a third connection line, a fourth connection line, and a second curved line. A second end of the first connection line and the second connection line of each of the first structure units are respectively connected to a second end of the third connection line and the fourth connection line of the adjacent second structure unit through vias.

Abstract: A flexible high-frequency signal transmission line includes a dielectric body including laminated flexible dielectric layers. A signal line is provided in the dielectric body. A grounding conductor is arranged in the dielectric body to be opposed to the signal line via one of the dielectric layers. The grounding conductor is of a ladder structure including a plurality of openings and a plurality of bridges arranged alternately along the signal line. A characteristic impedance of the signal line changes between two adjacent ones of the plurality of bridges such that the characteristic impedance of the signal line rises from a minimum value to an intermediate value and to a maximum value and falls from the maximum value to the intermediate value and to the minimum value in this order.

Abstract: A printed circuit board having a micro strip line, a printed circuit board having a strip line and a method of manufacturing thereof are disclosed. The printed circuit board having a micro strip line in accordance with an embodiment of the present invention includes a first insulation layer, a signal line buried in one surface of the first insulation layer, a plurality of conductors penetrating through the first insulation layer and being disposed on both sides of the signal line in parallel with the signal line, and a ground layer formed to be electrically connected to the conductor on the other surface of the first insulation layer.

Abstract: A differential transmission circuit includes a grounded conductive layer, a pair of transmission line conductors, a conductive film and a via hole which connects the grounded conductive layer to the conductive film. The differential transmission circuit further includes a straight-line region which is present in the differential transmission circuit through which a differential transmission signal output by a driving circuit is transmitted and in which the pair of transmission line conductors extends parallel so as to have a first width, and a band rejection filter region in which the pair of transmission line conductors planarly overlaps the conductive film and extends parallel so as to have a second width narrower than the first width and a common mode of the differential transmission signal is attenuated at one of the frequencies which are natural number multiples of a frequency corresponding to the predetermined bit rate.

Abstract: Methods and devices for phase shifting an RF signal for a base station antenna are provided. The device includes a transmission line that has a stationary ground plane coupled to the top of a substrate and a signal line on the bottom of the substrate. The signal line has an input port and an output port. The input port receives the RF signal with a certain phase and travels across the bottom of the substrate to the output port. The RF signal has a different phase at the output port because defected ground structures etched on the stationary ground plane shift the phase of the RF signal. In addition, the device includes a movable ground plane that may cover a portion of the defected ground structures, the substrate, and the stationary ground plane such that the moveable ground plane further adjusts the phase of the RF signal.

Abstract: An easily bendable high-frequency signal transmission line includes a dielectric body including a protection layer and dielectric sheets laminated on each other, a surface and an undersurface. A signal line is a linear conductor disposed in the dielectric body. A ground conductor is disposed in the dielectric body, faces the signal line via the dielectric sheet, and continuously extends along the signal line. A ground conductor is disposed in the dielectric body, faces the ground conductor via the signal line sandwiched therebetween, and includes a plurality of openings arranged along the signal line. The surface of the dielectric body on the side of the ground conductor with respect to the signal line is in contact with a battery pack.

Abstract: Provided is a wiring board including: a board; a differential transmission line constituted by two wirings disposed on the board in parallel; an insulation resin layer which is formed on part of a face of the board. A stepped portion constituted by a lateral face of the insulation resin layer is formed at a boundary between the face of the board and a top face of the insulation resin layer. The two wirings extend from the face of the board to the top face of the insulation resin layer so as to traverse the stepped portion. The extending direction of the wirings traversing the stepped portion and the direction of a periphery are perpendicular to each other in a plan view of the board, the periphery being defined by a boundary between the top face of the insulation resin layer and the lateral face of the insulation resin layer.

Abstract: An easily bendable high-frequency signal transmission line includes a dielectric body including a protection layer and dielectric sheets laminated on each other, a surface and an undersurface. A signal line is a linear conductor disposed in the dielectric body. A ground conductor is disposed in the dielectric body, faces the signal line via the dielectric sheet, and continuously extends along the signal line. A ground conductor is disposed in the dielectric body, faces the ground conductor via the signal line sandwiched therebetween, and includes a plurality of openings arranged along the signal line. The surface of the dielectric body on the side of the ground conductor with respect to the signal line is in contact with a battery pack.

Abstract: A thin film balun of the present invention comprises: an unbalanced transmission line UL including a first line portion L1 and a second line portion L2; a balanced transmission line BL including a third line portion L3 and a fourth line portion L4 that are positioned facing the first line portion L1 and the second line portion L2 and electromagnetically coupled to the first line portion L1 and the second line portion L2, respectively; an unbalanced terminal UT connected to an end of the first line portion L1; a first balanced terminal BT1 connected to the third line portion L3; a second balanced terminal BT2 connected to the fourth line portion L4; and a ground terminal G connected to the third line portion L3 and the fourth line portion L4, wherein the ground terminal G has an extension that extends from the ground terminal G to an area at the unbalanced terminal UT side.

Abstract: Disclosed is a structure for precision control of electrical impedance of signal transmission circuit board. A substrate forms thereon a plurality of first signal transmission lines, and a first covering insulation layer is formed on a first surface of the substrate to cover a surface of each first signal transmission lines and each spacing section formed between adjacent first signal transmission lines. Each first signal transmission lines can transmit a differential mode signal or a common mode signal.

Abstract: A thin film balun that can be made smaller and thinner while maintaining required balun characteristics is provided. A thin film balun 1 includes: an unbalanced transmission line UL including a first coil portion C1 and a second coil portion C2; a balanced transmission line BL including a third coil portion C3 and a fourth coil portion C4 that are positioned facing and magnetically coupled to the first coil portion C1 and the second coil portion C2 respectively; an unbalanced terminal UT connected to the first coil portion C1; a ground terminal G connected to the second coil portion C2 via a C component D; and an electrode D2 connected to the ground terminal G and facing a part of the second coil portion C2. The C component D is formed by the electrode D2 and the part D1 of the second coil portion C2.

Abstract: A Guanella type balun with a conductive enclosure (for example, a re-entrant box) between its coupled lines and the magnetic material enclosing its coupled lines. Some embodiments use coupled strip lines. Some embodiments have dielectric material, such as printed circuit board material inside the re-entrant box along with the coupled strip lines. Preferably, the magnetic material is ferrimagnetic. Some preferred magnetic materials are non-conductive.

Abstract: Some embodiments relate to a contactless RF coupling device that includes a first substrate and a second substrate. The RF coupling device may provide a broadband, low loss electrical connection without mechanical contact as would a conventional mechanical connector. The first substrate includes a first ground plane on one side and a first transmission line on an opposing side. The first transmission line includes an enlarged first coupling member at an end of the first transmission line. The second substrate includes a second ground plane on one side and a second transmission line on an opposing side. The second transmission line includes an enlarged second coupling member at an end of the second transmission line. The first ground plane may not extend under the first coupling member and the second ground plane may include an opening that is aligned with the second coupling member.

Abstract: A differential transmission circuit includes a pair of transmission line conductors and a ground conductor layer, wherein the pair of transmission line conductors include a first straight line region where both the pair of transmission line conductors extend in parallel to each other in a first direction with a first width in a first layer, a first cross region where one of the pair of transmission line conductors is formed in the first layer, the other thereof is formed in a second layer, and the pair of transmission line conductors cross the each other in a three-dimensional manner, the first cross region being disposed on the front side of the first straight line region, and wherein each of the widths of the pair of transmission line conductors in the first cross region is smaller than the first width.

Abstract: A device that includes a coplanar waveguide structure is disclosed. In an example, a device includes a coplanar waveguide structure that is oriented in a first direction, and a slot-type floating shield structure oriented proximate to the coplanar waveguide structure. The slot-type floating shield structure includes a first portion that extends transversely to the coplanar waveguide structure in a second direction and a second portion that extends from the first portion in a third direction that is perpendicular to the first direction and the second direction.

Abstract: Unwanted radiation is reduced in a high-frequency signal transmission line that includes a ground conductor provided with an opening that overlaps a signal line. A dielectric element assembly has a relative dielectric constant ?1 and has a first principal surface and a second principal surface. A signal line is provided in the dielectric element assembly. A ground conductor is provided in the dielectric element assembly and on the first principal surface side with respect to the signal line, faces the signal line, and is provided with an opening that overlaps the signal line. A high dielectric constant layer has a relative dielectric constant ?2 higher than the relative dielectric constant ?1 and is provided on the first principal surface so as to overlap the opening.

Abstract: Provided are assemblies and processes for efficiently coupling wideband differential signals between balanced and unbalanced circuits. The assemblies include a broadband balun having an unbalanced transmission line portion, a balanced transmission line portion, and a transition region disposed between the unbalanced and balanced transmission line portions. The unbalanced transmission line portion includes at least one ground and a pair of conductive signal traces, each isolated from ground. The balanced portion does not include an analog ground. The transition region effectively terminates the analog ground, while also smoothly transitioning or otherwise shaping transverse electric field distributions between the balanced and unbalanced portions. Beneficially, the balun is free from resonant features that would otherwise limit operating bandwidth, allowing it to operate over a wide bandwidth of 10:1 or greater.

Abstract: A flexible high-frequency signal transmission line includes a dielectric body including laminated flexible dielectric layers. A signal line is provided in the dielectric body. A grounding conductor is arranged in the dielectric body to be opposed to the signal line via one of the dielectric layers. The grounding conductor is of a ladder structure including a plurality of openings and a plurality of bridges arranged alternately along the signal line. A characteristic impedance of the signal line changes between two adjacent ones of the plurality of bridges such that the characteristic impedance of the signal line rises from a minimum value to an intermediate value and to a maximum value and falls from the maximum value to the intermediate value and to the minimum value in this order.

Abstract: This disclosure relates to a flexible triplate stripline that can operate in temperatures of 150 C-250 C, flexible to move up/down with the top of a plasma reactor, and prevent plasma generation near the power transmission line in the stripline. The transmission line may be exposed to ambient conditions. The risk of generating plasma near the transmission line may be minimized by optimizing the height and width of the air gap adjacent to the transmission line and decreasing the voltage in a portion of the stripline by widening the transmission line.

Abstract: A signal carrier for carrying a signal in a direction within the X-Y plane of a multilayer composite electronic structure comprising a plurality of dielectric layers extending in an X-Y plane, the signal carrier comprising a first transmission line comprising a lower continuous metallic layer and further comprising a row of metallic via posts coupled to the continuous metal layer, wherein the transmission line is separated by a dielectric material from an underlying reference plane.

Abstract: A flexible circuit board includes: an insulative substrate having a first surface and a second surface opposite to the first surface; a microstrip line having a first signal line formed on the first surface and a first ground pattern formed on the second surface and located in an area opposite to the first signal line; a coplanar line having a second signal line formed on the first surface, and second ground patterns that are formed on the first surface and are spaced apart from both sides of the second signal line; a connection line that is formed on the first surface and connects the first signal line and the second signal line together, the connection line having an opening; and third ground patterns formed on the second surface and arranged in areas located at both sides of an area opposite to the connection line including the opening.