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.

A wiring substrate includes a first insulating layer with a first opening, a second insulating layer with a second opening, a high-frequency wiring layer, a first wiring layer, a second wiring layer, and a plurality of conductive pillars. The high-frequency wiring layer including a high-frequency trace is sandwiched between the first insulating layer and the second insulating layer. The first opening and the second opening expose two sides of the high-frequency trace respectively. The high-frequency trace has a smooth surface which is not covered by the first insulating layer and the second insulating layer and has the roughness ranging between 0.1 and 2 μm. The first insulating layer and the second insulating layer are all located between the first wiring layer and the second wiring layer. The conductive pillars are disposed in the second insulating layer and connected to the high-frequency trace.

Provided is a rapid over-the-air (OTA) production line test platform, including a device under test (DUT), an antenna array and two reflecting plates. The DUT has a beamforming function. The antenna array is arranged opposite to the DUT, and emits beams with beamforming. Two reflecting plates are disposed opposite to each other, and are arranged between the DUT and the antenna array. The beam OTA test of the DUT is carried out by propagation of the beams between the antenna array, the DUT and the two reflecting plates. Accordingly, the test time can be greatly shortened and the cost of test can be effectively reduced. In addition to the above-mentioned rapid OTA production line test platform, platforms for performing the OTA production line test by using horn antenna arrays together with bending waveguides and using a 3D elliptic curve are also provided.

A circuit board includes a first insulating layer; a first wiring pattern and a second wiring pattern each formed to be side to side with each other on an upper surface of the first insulating layer; a second insulating layer formed on the upper surface of the first insulating layer to cover the first and second wiring patterns; a third wiring pattern formed on an upper surface of the second insulating layer to overlap the first wiring pattern in a vertical direction; a fourth wiring pattern formed on the upper surface of the second insulating layer to overlap the second wiring pattern in the vertical direction; a first via passing through the second insulating layer and connecting the first and fourth wiring patterns; and a second via passing through the second insulating layer and connecting the second and third wiring patterns.

A signal transmission line includes a laminate, a signal conductor, a hollow portion, and a reinforcing conductor. The laminate includes a flexible laminate including resin layers each of which has flexibility. The signal conductor extends in a signal transmission direction of the laminate and is disposed in an intermediate position in a laminating direction of the resin layers. The hollow portion is in the laminate and defined by an opening provided at a portion of the plurality of resin layers. The reinforcing conductor is in the laminate. The hollow portion is disposed at a position overlapping with the signal conductor, in a plan view of the laminate from a surface perpendicular or substantially perpendicular to the laminating direction. The reinforcing conductor is disposed at a position different from the position of the hollow portion in a plan view.

A multilayer board includes a laminated insulating body, signal conductors inside the laminated insulating body and extending in a transmission direction, and ground conductors sandwiching each of the signal conductors in a lamination direction via the insulating base material layers. The multilayer board includes a parallel extending portion in which the signal conductors extend parallel and that includes signal conductors arranged separately from each other in a direction orthogonal to the transmission direction in a planar view in the lamination direction, and a signal conductor overlapping with the signal conductor in a planar view in the lamination direction and arranged separately from the signal conductor in the lamination direction. The parallel extending portion includes first and second regions arranged separately in a direction orthogonal to the transmission direction in a planar view in the lamination direction.

A via-less crossover for use in broadband microwave/mm-wave circuitry, including: a dielectric substrate; a top layer disposed on one side of the substrate and including a microstrip line with an input and an output, two tapered sections placed around the microstrip line along a co-planar waveguide (CPW) central line, one microstrip portion having an input and which connects to one top layer, rectangular stub disposed adjacent to one of the tapered sections, and another microstrip portion having an output and which connects to another top layer, rectangular stub disposed adjacent to the other of the tapered sections; and a ground layer disposed on an opposite side of the substrate and including a bottom layer CPW central line situated in a central cutout and which connects between a bottom layer, rectangular stub on one side and a bottom layer, rectangular stub on the other side situated in ground cutouts, respectively.

A communications apparatus an antenna module include a first substrate on which a first radiation electrode and a first ground electrode are disposed; a second substrate on which a second radiation electrode and a second ground electrode are disposed; a third substrate on which a third ground electrode is disposed; and a first connection member having a flat plate shape and connected between the first substrate and the second substrate, a fourth ground electrode being disposed on the first connection member. A radio frequency signal is transmitted to the first radiation electrode through the first connection member, and a main surface of the first connection member is in contact with a main surface of the third substrate.

An antennas-in-package (AiP) verification board is provided, which includes a carrier board configured for disposing an antenna array or an electronic circuit; and a plurality of SMPM connectors. The plurality of SMPM connectors are arranged in an array on the carrier board and electrically connected with the antenna array or the electronic circuit of the carrier board for testing the characteristics of the antenna array on the carrier board or the characteristics of the electronic circuit on the carrier board. The AiP verification board is fixed on a beamforming test platform. In addition to the aforementioned AiP verification board, an AiP verification board including a plurality of adaptor structures and an AiP verification board including a plurality of connectors and a plurality of adaptor structures are also provided.

In a multilayer board, a transmission line includes layers including a first insulator layer, a first joining material layer in contact with a first surface of the first insulator layer, and a second joining material layer in contact with a second surface of the first insulator layer. A signal conductor of the transmission line is on the first surface of the first insulator layer, a relative permittivity of the second joining material layer is lower than a relative permittivity of the first joining material layer, and an adhesion strength between the first insulator layer and the first joining material layer is higher than an adhesion strength between the first insulator layer and the second joining material layer.