An apparatus may include a substrate assembly having a first side and a second side. The apparatus may further include a waveguide antenna element positioned on the first side of the substrate assembly. The apparatus may also include a first reference ground plane positioned on the first side of the substrate assembly and enclosing the waveguide antenna. The apparatus may include a stripline positioned within the substrate assembly. The apparatus may further include a second reference ground plane positioned on the second side of the substrate assembly.

An apparatus may include a substrate assembly having a first side and a second side. The apparatus may further include a waveguide antenna element positioned on the first side of the substrate assembly. The apparatus may also include a first reference ground plane positioned on the first side of the substrate assembly and enclosing the waveguide antenna. The apparatus may include a stripline positioned within the substrate assembly. The apparatus may further include a second reference ground plane positioned on the second side of the substrate assembly.

An illustrative example embodiment of an antenna device includes a substrate, a plurality of antenna elements supported on the substrate, an integrated circuit supported on one side of the substrate, and a metallic waveguide antenna situated against the substrate. The metallic waveguide antenna includes a heat dissipation portion in a thermally conductive relationship with the integrated circuit. The heat dissipation portion is configured to reduce a temperature of the integrated circuit.

An illustrative example embodiment of an antenna device includes a substrate, a plurality of antenna elements supported on the substrate, an integrated circuit supported on one side of the substrate, and a metallic waveguide antenna situated against the substrate. The metallic waveguide antenna includes a heat dissipation portion in a thermally conductive relationship with the integrated circuit. The heat dissipation portion is configured to reduce a temperature of the integrated circuit.

An antenna may include a reflector and a multi-band feed assembly. A support member may be coupled to the multi-band feed assembly to orient the multi-band feed assembly for direct illumination of the reflector. The multi-band feed assembly may include first and second feeds, each having a respective septum polarizer coupled between a respective common waveguide and a respective pair of waveguides. A housing of the support member may contain the respective septum polarizers and the respective pairs of waveguides.

A system for a Rydberg atom based quantum communications transceiver is provided. The system may include a laser source for generating a photon. The system may also include one or more optical elements to create a pair of entangled photons from a generated photon, wherein the pair of entangled photons comprises a first entangled photon and a second entangled photon. The system may further include a radio-frequency (RF) based element to generate a quantum communication path from the pair of entangled photons by creating two Rydberg atom vapor cells (RAVC) that are entangled such that entangled photons may transfer or communicate their entangled state to Rydberg atoms within the Rydberg atom vapor cells (RAVCs) and form at least one entangled link with the other, the communication path comprising the least one entangled link. The system may also include one or more photon receivers, which may use at least one translation technique, to translate entangled state of each of the Rydberg atom vapor cells (RAVC).

A system for a Rydberg atom based quantum communications transceiver is provided. The system may include a laser source for generating a photon. The system may also include one or more optical elements to create a pair of entangled photons from a generated photon, wherein the pair of entangled photons comprises a first entangled photon and a second entangled photon. The system may further include a radio-frequency (RF) based element to generate a quantum communication path from the pair of entangled photons by creating two Rydberg atom vapor cells (RAVC) that are entangled such that entangled photons may transfer or communicate their entangled state to Rydberg atoms within the Rydberg atom vapor cells (RAVCs) and form at least one entangled link with the other, the communication path comprising the least one entangled link. The system may also include one or more photon receivers, which may use at least one translation technique, to translate entangled state of each of the Rydberg atom vapor cells (RAVC).

A terahertz carrier sending apparatus and a terahertz carrier receiving apparatus include a feed transmission line configured to receive an electrical signal sent by a radio frequency sending circuit. A mode excitation structure is configured to excite a terahertz signal. A mode conversion structure includes an inner cavity whose inner wall is metal. A circuit board is configured to fasten the feed transmission line and the mode excitation structure. The mode conversion structure further includes a positioning slot. A part of the circuit board and the mode excitation structure are inserted into the inner cavity of the mode conversion structure. A plurality of metal through holes are distributed on both sides of the mode excitation structure. A boundary of the positioning slot is metal and press-fitted on the metal through holes on the both sides of the mode excitation structure.

A waveguide microstrip line converter includes a waveguide, a dielectric substrate, a ground conductor including a slot, and a line conductor. The line conductor includes a first section that is a microstrip line having a first line width, a conversion unit that is a second section positioned immediately above the slot and having a second line width greater than the first line width, and a third section extending from the second section in a first direction and performing impedance matching between the first section and the second section. One of the opposite ends of the third section in the first direction is connected to the second section. The first section extends in a second direction perpendicular to the first direction continuously from the other end of the opposite ends of the third section.

A hybrid coupler for dividing an input electrical signal to produce first and second output electrical signals which are substantially out of phase, the hybrid coupler including an input port for receiving the input electrical signal, and an input line for coupling the input electrical signal to a slotline. The hybrid coupler further includes an output line for coupling the first and second output electrical signals to a first output port and a second output port, respectively. The output line has a junction with the slotline. The hybrid coupler further includes a co-planar waveguide electrically connected to said output line and having a first end and an opposing second end, and defining, at the second end, a sum port configured to divert common mode signals received at said first and second output ports to said second end. The slotline transitions into the first end of the co-planar waveguide.