A transmission line has a first conductor layer extending in a first direction, a second conductor layer disposed on a side of a first surface of the first conductor layer via a first dielectric layer, the second conductor layer extending in the first direction, and a third conductor layer disposed on a side of a second surface of the first conductor layer opposite to the first surface, via a second dielectric layer, the third conductor layer extending in the first direction, wherein a width, in a second direction intersecting the first direction, of each of the second conductor layer and the third conductor layer is different at a plurality of locations in the first direction, and the first conductor layer, the second conductor layer, and the third conductor layer at least partially overlap each other in a plan view from a normal direction of the first surface.

An acoustic resonator includes a wafer and a first phononic crystal disposed on the wafer to define an acoustic waveguide so as to propagate an acoustic wave along a propagation direction. The first phononic crystal includes a first two-dimensional (2D) array of metal stripes having a first period on the propagation direction. The apparatus also includes a second phononic crystal and a third phononic crystal disposed on two sides of the first phononic crystal and having a different period from the first period. The second phononic crystal and the wafer define a first reflector to reflect the acoustic wave. The third phononic crystal and the wafer define a second reflector to reflect the acoustic wave.

An acoustic resonator includes a wafer and a first phononic crystal disposed on the wafer to define an acoustic waveguide so as to propagate an acoustic wave along a propagation direction. The first phononic crystal includes a first two-dimensional (2D) array of metal stripes having a first period on the propagation direction. The apparatus also includes a second phononic crystal and a third phononic crystal disposed on two sides of the first phononic crystal and having a different period from the first period. The second phononic crystal and the wafer define a first reflector to reflect the acoustic wave. The third phononic crystal and the wafer define a second reflector to reflect the acoustic wave.

A board main body includes first and second resin layers contacting each other and including thermoplastic resin, a first signal conductor layer on an upper main surface of the second resin layer, an overlapping region in which the first and second resin layers are present when viewed in an up-down direction, and a non-overlapping region in which the first resin layer is not present and the second resin layer is present when viewed in the up-down direction. The first signal conductor layer includes a first curved portion in which the first signal conductor layer is curved in the up-down direction such that the first signal conductor layer in the first non-overlapping region is above the first signal conductor layer in the overlapping region. The first signal conductor layer is electrically connectable to an element on the board main body in the first non-overlapping region.

A distributed amplifier includes a transmission line configured so as to transmit a signal, a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable, and a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable. The transmission line is configured in such a manner that the inductance is adjustable.

A distributed amplifier includes a transmission line configured so as to transmit a signal, a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable, and a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable. The transmission line is configured in such a manner that the inductance is adjustable.

A phase shifter includes a first substrate; a microstrip formed on the first substrate so as to extend in a first direction; a ground layer disposed with a space on the upper surface of the microstrip and having a defected ground structure (DGS) with a defected pattern formed therein; a second substrate disposed on the ground layer; and a liquid crystal layer disposed in a space between the first substrate and the second substrate, wherein DC voltage is applied between the ground layer and the microstrip.

A phase shifter includes a first substrate; a microstrip formed on the first substrate so as to extend in a first direction; a ground layer disposed with a space on the upper surface of the microstrip and having a defected ground structure (DGS) with a defected pattern formed therein; a second substrate disposed on the ground layer; and a liquid crystal layer disposed in a space between the first substrate and the second substrate, wherein DC voltage is applied between the ground layer and the microstrip.

Disclosed is a radar for a vehicle configured to detect objects around a vehicle using an antenna, and the radar includes a substrate-integrated waveguide (SIW) in which a plurality of bent slots is formed, at least one processor electrically connected to the substrate-integrated waveguide, and a differential line electrically connecting the substrate-integrated waveguide to the at least one processor.

A signal transmission line includes a signal region that includes a signal conductor layer and insulating base material layers, and a first ground region that includes a first ground conductor layer and insulating base material layers and is located above the signal region. The signal region is not fixed to the first ground region in a first section of a base. One or more first spacers are fixed to the signal region and in contact with the first ground region without being fixed thereto, or are in contact with the signal region without being fixed thereto and fixed to the first ground region. The one or more first spacers are in the first section.