A spiral antenna apparatus, which may comprise an antenna element disposed in two spiral arms in a vertical zigzag pattern. The apparatus may comprise an electromagnetic band gap cavity comprising: a ground plane, one or more layers of conductive patches, at least one pillar extending between the ground plane and a top layer of the one or more layers, and low dielectric foam disposed to fill gaps between the ground plane and the one or more layers and to fill gaps between the one or more layers. The apparatus may comprise a corrugated radio frequency choke disposed within the electromagnetic band gap cavity. At least one of the antenna element, the balun element, the electromagnetic band gap cavity, and the radio frequency choke may be fabricated using additive manufacturing.

A microwave device is based on gap waveguide technology, and comprises two conducting layers (101, 102) arranged with a gap there between, and protruding elements (103, 104) arranged in a periodically or quasi-periodically pattern and fixedly connected to at least one of said conducting layers, thereby forming a texture to stop wave propagation in a frequency band of operation in other directions than along intended waveguiding paths. Sets of complementary protruding elements are either each formed in said pattern and arranged in alignment and overlying each other, the complementary protruding elements of each set forming part of the full length of each protruding element of the pattern, or the sets of complementary protruding elements are arranged in an offset complementary arrangement, the protruding elements of one set thereby being arranged in between the protruding elements of the other set.

A tunable antenna isolator includes a first wall, a second wall, and an electromagnetic band-gap (EBG) structure located between the first wall and the second wall. The first wall may be a metallic wall or an EBG structure, and the second wall may be a metallic wall or an EBG structure.

A method and apparatus for attenuating crosstalk between dielectric waveguides is provided. A first dielectric waveguide is formed to carry a first frequency band. A first filter is embedded within the first dielectric waveguide to attenuate transmission of a second frequency band through the first dielectric waveguide. The filter comprises alternating sections of a first dielectric material and a second dielectric material having different dielectric constants. The length of each section of the first and second dielectric materials is equal to a quarter of the wavelength of the central frequency of the second frequency band. A second waveguide is formed to carry the second frequency band. A second filter is embedded in the second dielectric waveguide to attenuate transmission of the first frequency band through the second dielectric waveguide. A cladding is disposed between the first and second waveguides.

An electromagnetic field band-stop filter includes a plurality of unit structures that have reflection characteristics on an electromagnetic wave of a predetermined frequency. Each of the plurality of unit structures includes: a plurality of electrode parts each of which is disposed along a side of a polygon in a non-contact manner with another electrode part; and a plurality of conductor parts which are provided for the plurality of electrode parts on a one-to-one basis and each of which has at least one bent portion between one end and other end, the one ends of the plurality of conductor parts being connected to the electrode parts on a one-to-one basis and the other ends of the plurality of conductor parts being connected at one point on an inner side of the electrode parts in the individual unit structure. The plurality of unit structures are regularly and two-dimensionally disposed by disposing electrode parts of the plurality of unit structures to be adjacent to each other with a spacing that reflects the predetermined frequency.

A film includes a substrate having a planar surface attachable to a surface that transmits electromagnetic energy; and a photonic crystal structure formed in the planar substrate that alters the transmitted electromagnetic energy.

A 3D electromagnetic bandgap circuit includes: a dielectric layer having a first surface and an opposing second surface; a spiral element positioned on the first surface; a first surrounding element positioned on the first surface and surrounding the spiral element, but does not touch with the spiral element; a plane element positioned on the second surface and including a notch; a second surrounding element positioned on the second surface and surrounding the plane element, but does not touch with the plane element, wherein the second surrounding element further includes a protruding portion extending toward the notch; a first via passing through the dielectric layer, the spiral element, and the protruding portion; a second via passing through the dielectric layer, the plane element, and the first surrounding element; and a third via passing through the dielectric layer, the plane element, and the first surrounding element.

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 microwave oven comprising a cavity in which a material can be placed for heating and a magnetron for generating a microwave. The microwave oven further comprises an electromagnetic element adapted to interact with microwaves into the cavity and a control unit that provides a control signal to the electromagnetic element for modifying an impedance of the electromagnetic element during time of heating.

An electromagnetically reflective plate for a miniature antenna device includes: etched conductive elements on a first dielectric substrate layer; an apertured ground plane placed between the first substrate layer and a second dielectric substrate layer; a set of metal through-vias formed in the thickness of the two substrate layers, each including an upper end making contact with one of the conductive elements, a lower end reaching a lower face of the second substrate layer, and passing through the ground plane without electrical contact in one of its apertures. Each conductive element makes contact with a plurality of vias and each via of each conductive element is connectable to another via of a neighboring conductive element using a corresponding electrical connection making contact with the lower end of this via. At least some of the electrical connections include one or more meanders.