The present disclosure relates to a metasurface arrangement including a first metasurface and a second metasurface which run mutually parallel and face each other. Each metasurface includes a corresponding periodic or quasi-periodic structure formed in a respective pattern. The first metasurface is formed in a dielectric material structure and the second metasurface is formed in either a dielectric material structure or in an electrically conducting structure. The periodic or quasi-periodic structure on the first metasurface is configured to yield a first response to an incident electromagnetic wave between the two metasurfaces, and the periodic or quasi-periodic structure on the second metasurface is configured to yield a second response to the incident electromagnetic wave between the two metasurfaces that is equivalent to the first response, thereby rendering the two metasurfaces mutually electromagnetically symmetric.

Embodiments of the invention include waveguide switch rotors, stators, waveguide switch housings and meander clamping mechanisms. In particular, the waveguide switch rotor design employs isolation posts surrounding waveguide ports disposed on the external face of the rotor to achieve an artificial magnetic boundary condition to achieve high isolation with improved gap from rotor to stator.

A transmission line having, for example, a first frequency-selecting surface.

An electromagnetic band-gap (EBG) structure includes an antenna substrate layer, first conductive regions, and second conductive regions. The antenna substrate includes a first planar surface and a second planar surface. The first conductive regions are located on the first planar surface of the antenna substrate and separated from adjacent first conductive regions by a first distance. The second conductive regions are located on the first planar surface of the antenna substrate and are separated from the first conductive regions by a second distance and wherein the second conductive regions at least partially surround the first conductive regions.

Disclosed is a substrate-integrated waveguide slot antenna including a lower substrate having a substrate-integrated waveguide structure, the lower substrate being provided in the upper surface thereof with at least one slot, whereby an electromagnetic wave is guided by the substrate-integrated waveguide structure and is emitted through the slot, and an upper substrate formed on the lower substrate, the upper substrate having a metasurface configured such that a plurality of unit cells is arranged at predetermined intervals, whereby the electromagnetic wave dispatched through the slot is reemitted by the metasurface.

A terahertz (THz) waveguide and method for production allows for THz waveguides to be used in or on a printed circuit board (PCB) such that the propagation of THz waves require less power, result in less signal loss due to radiation or dispersion, and propagate more efficiently. Additionally, the position and/or geometry of a waveguide, as well as any additional antenna or coupling element, may be adjusted on or in the PCB such that the electromagnetic field of the waveguide may more efficiently couple with the electromagnetic field of the PCB.

An electromagnetic band gap structure apparatus includes a first conducting layer having at least one first slot. Each of the at least one slot is arranged with a planar conductor unit, and the each planar conductor unit is coupled to a first via. The electromagnetic band gap structure apparatus further includes a second conducting layer in parallel with the first conducting layer. The second conducting layer has a second slot. The second slot is arranged with at least one planar transmission line unit. The each of the at least one planar transmission line unit is coupled to the first conducting layer through a second via, and the each first via is coupled to the second conducting layer.

A shielded bridge for a coplanar waveguide (CPW) includes a signal bridge extending from a first terminal of the CPW to a second terminal of the CPW. The signal bridge has a raised central portion that extends over a separate signal conductor. The shielded bridge for the CPW also includes a ground bridge extending from a first ground plane on a first side of the separate signal conductor to a second ground plane on a second side of the separate signal conductor. The ground bridge is positioned between the signal bridge and the separate signal conductor.

According to an aspect, there is provided a method of operating a first radio access node in a communication network, the method comprising determining whether a first base key that is used to determine a first encryption key for encrypting communications between a communication device and the first radio access node can be used by a second radio access node for determining a second encryption key for encrypting communications between the communication device and the second radio access node; and if the first base key can be used by the second radio access node, sending the first base key to the second radio access node during handover of the communication device from the first radio access node to the second radio access node.

Antenna systems are described which provide means of mitigating the undesirable transmission line effect(s) by using fractal metamaterials in close proximity to an antenna, with both the antenna and fractal metamaterials being positioned a conductive surface, which may be inside or adjacent to a cavity. The fractal metamaterial can include an array of close spaced (e.g., less than 1/10 wavelength separation) resonant structures of a fractal shape, resonant at or near the intended frequency of use of the antenna. The fractal metamaterial can reverse the phase of the reflected wave so that the metal cavity no longer produces an out of phase current induced by the antenna. Without the cavity being out of phase to the antenna, the transmission line effect is mitigated substantially and the antenna performance can accordingly be enhanced. Further embodiments omit a cavity and locate a fractal metamaterial and antenna(s) adjacent to an underlying conductive surface.