A modular wideband antenna includes a ground plane, first and second antenna elements disposed on a first surface of a substrate, a first portion of a two-layer feed balun disposed on the first surface of the substrate, and electrically coupled to the first and second antenna elements, and to the ground plane, a second portion of the two-layer feed balun disposed on a second surface of the substrate, the second portion of the two-layer feed balun being electrically coupled to a signal feed, and being capacitively coupled to the first portion of the two-layer feed balun, first and second coupling capacitances disposed on the second surface of the substrate, the first coupling capacitance being capacitively coupled to the first antenna element, and the second coupling capacitance being capacitively coupled to the second antenna element, and first and second grounding posts being electrically coupled to the first and second coupling capacitances.

The present disclosure relates to a gradient structure (100) for transmitting and/or reflecting an electromagnetic signal. The gradient structure comprises a plurality of interconnected cells (110). Each cell comprises a through cavity (112) surrounded by walls (111), wherein the walls of each cell have a gradually varying thickness along a longitudinal direction of each cell. The present disclosure also relates to a cover structure (200) comprising the gradient structure (100), a system (300) comprising the cover structure (200), a structure element (400) having integrated therein the system (300) and to a method for optimizing the transmittance and/or reflectance of an electromagnetic signal of a gradient structure.

A gradient permittivity film comprises (a) a first permittivity layer comprising a first continuous matrix of a first material having a first relative permittivity (ε.sub.r1) and a second component having a second relative permittivity (ε.sub.r2) dispersed in the first continuous matrix, the first permittivity layer having a first effective layer relative permittivity (ε.sub.1) and a thickness (T.sub.1); And (b) a second permittivity layer having a second effective layer relative permittivity (ε.sub.2) and a thickness (T.sub.2) disposed on the first permittivity layer. T.sub.1=0.8(t.sub.1) to 1.2(t.sub.1), where

[00001]$t_1=\frac{c}{4f\sqrt{{\epsilon }_1}};T_2=0.8\left(t_2\right)\mathrm{to}1.2\left(t_2\right),\mathrm{where}{t}_2=\frac{c}{4f\sqrt{{\epsilon }_2}}.$

Exemplary embodiments are disclosed of low dielectric, low loss radomes. Also disclosed are materials for radomes according to exemplary embodiments.

A modular wideband antenna includes a ground plane, first and second antenna elements disposed on a first surface of a substrate, a first portion of a two-layer feed balun disposed on the first surface of the substrate, and electrically coupled to the first and second antenna elements, and to the ground plane, a second portion of the two-layer feed balun disposed on a second surface of the substrate, the second portion of the two-layer feed balun being electrically coupled to a signal feed, and being capacitively coupled to the first portion of the two-layer feed balun, first and second coupling capacitances disposed on the second surface of the substrate, the first coupling capacitance being capacitively coupled to the first antenna element, and the second coupling capacitance being capacitively coupled to the second antenna element, and first and second grounding posts being electrically coupled to the first and second coupling capacitances.

A spacer used in an electrical device that sends and receives radio waves comprises a foam that contains a resin composition containing a thermoplastic or thermosetting resin as a base resin. When the foam is not a bead foam, a ratio (B/A) of an average diameter B of central section cells relative to an average diameter A of surface layer cells is not less than 0.3 and less than 3.0. When the foam is a bead foam, a ratio (B′/A′) of an average diameter B′ of center cells relative to an average diameter A′ of outermost layer cells is not less than 0.3 and less than 3.0. Water absorption of the resin composition in a high-temperature and high-humidity environment is 2.2 mass % or less, and (εr).sup.1/2×tan δ (εr: relative permittivity, tan δ: a dielectric dissipation factor) is 0.0120 or less at 28 GHz.

A radome structure for a multilayered broadband radome structure is described. The radome structure may include a central core layer comprising a first dielectric constant, an interior intermediate core layer adjacent to an interior side of the central core layer, comprising a second dielectric constant less than the first dielectric constant, an exterior intermediate core layer adjacent to an exterior side of the central core layer, comprising a third dielectric constant less than the first dielectric constant, and an interior outside core layer adjacent to an interior side of the interior intermediate core layer, comprising a fourth dielectric constant less than the second dielectric constant. In some examples of the radome structure described above may further include an exterior outside core layer adjacent to an exterior side of the exterior intermediate core layer, comprising a low dielectric constant.

Provided is a protective material that protects a wireless communication portion for wireless communication, comprising a substrate formed of a foam synthetic resin and a coating layer of a polyurea resin covering at least a front side surface of the substrate. The wireless communication device includes a wireless communication portion for wireless communication and a protective material.

A millimeter-wave active antenna unit and an interconnection structure between PCBs is provided. The interconnection structure between PCBs comprises a mainboard and an AIP antenna module. The mainboard is a first multilayer PCB on which a signal transmission line and a first pad electrically connected to the signal transmission line are provided. The AIP antenna module is a second multilayer PCB on which a second pad, an impedance matching transformation branch, an impedance line and a signal processing circuit are provided. The mainboard and the AIP antenna module are interconnected by directly welding multiple PCBs.

A millimeter-wave active antenna unit and an interconnection structure between PCBs is provided. The interconnection structure between PCBs comprises a mainboard and an AIP antenna module. The mainboard is a first multilayer PCB on which a signal transmission line and a first pad electrically connected to the signal transmission line are provided. The AIP antenna module is a second multilayer PCB on which a second pad, an impedance matching transformation branch, an impedance line and a signal processing circuit are provided. The mainboard and the AIP antenna module are interconnected by directly welding multiple PCBs.