A window/seal and a satellite ground station antenna using the window/seal. A window/seal for a circular waveguide includes a right-circular cylindrical window having an axis, an annular recess surrounding and coaxial with the cylindrical window, and an annular rib surrounding and coaxial with the annular recess. An outer diameter of the annular rib is configured to fit closely within an inside diameter of the circular waveguide.

A mechanism to connect first and second circular waveguides. A first member includes two or more pins extending radially from a body, the first waveguide coaxial with the body and terminating at a first port at an end face of the body. A second member has a cavity coaxial with the second waveguide and configured to fit over the first member, the second waveguide terminating at a second port within the cavity. Slots disposed around a perimeter of the cavity engage the two or more pins. A cap fits over the second member, the cap including L-shaped slots to engage the two or more pins extending through the slots of the second connecting member. A wave spring between an inside surface of the cap and a shoulder of the second member urges the second port towards the first port when the cap is engaged with the two or more pins.

A radar signal device includes an antenna unit, a transmission circuit and a reception circuit. The antenna unit is used to concurrently transmit a transmission signal and receive a reception signal. The antenna unit includes a metal layer, a first feed structure and a second feed structure. An opening is formed on the metal layer. A first projection of the first feed structure on the metal layer at least partially overlaps with the opening. A second projection of the second feed structure on the metal layer at least partially overlaps with the opening. The antenna unit forms a first radiation pattern used to transmit the transmission signal and a second radiation pattern used to receive the reception signal. An angle between a co-polarized electric field direction of the first radiation pattern and a co-polarized electric field direction of the second radiation pattern is between 45 degrees and 135 degrees.

A wireless node described herein transmits and receives high frequency signals with three or more different polarizations simultaneously thereby increasing network capacity. The different polarizations can be achieved by using polarizer sheets and/or orthomode transducer assemblies or Cassegrain antennas with multiple subreflectors.

A dual polarized waveguide device includes a first waveguide that defines a first linear signal propagation path, a second waveguide that defines a second linear signal propagation path that is parallel to the first linear signal propagation path, and a polarization selective coupling interface coupling the first and second waveguides, the polarization selective coupling interface being configured to enable horizontally polarized signals to pass between the first and second linear propagation paths and prevent vertically polarized signals from passing between the first and second linear propagation paths.

A mechanism to connect first and second circular waveguides. A first member includes two or more pins extending radially from a body, the first waveguide coaxial with the body and terminating at a first port at an end face of the body. A second member has a cavity coaxial with the second waveguide and configured to fit over the first member, the second waveguide terminating at a second port within the cavity. Slots disposed around a perimeter of the cavity engage the two or more pins. A cap fits over the second member, the cap including L-shaped slots to engage the two or more pins extending through the slots of the second connecting member. A wave spring between an inside surface of the cap and a shoulder of the second member urges the second port towards the first port when the cap is engaged with the two or more pins.

In various implementations, a quasi-monostatic STAR antenna system comprises a parabolic reflector antenna for transmission (TX) and a receiving (RX) antenna mounted back-to-back with the reflector feed. The physical size of the RX antenna can be comparable to or smaller than that of the TX feed, in order to prevent additional reflector blockage. To increase the system isolation both the TX feed and the RX antenna are CP. In one implementation, for example, to achieve same TX and RX polarization (i.e. no polarization multiplexing) the TX feed is LHCP and the RX antenna is RHCP. The LHCP fields from the TX feed undergo polarization reversal after bouncing back from the reflector. Thereby, the TX and RX operate in the same polarization, as illustrated in FIG. 1. This approach can also support simultaneous dual polarized operation if appropriate feed and RX antenna are used

A rotary joint including a stator intended to be fastened on a first part of the antenna and defining a transmission surface, and a rotor intended to be fastened on a second part of the antenna and defining a transmission surface, wherein one of the transmission surfaces includes primary means for delimiting electromagnetic signals and the other includes complementary means for delimiting electromagnetic signals; the rotor being mounted rotating relative to the stator such that at least part of the transmission surface of the rotor is positioned across from at least part of the transmission surface of the stator, the facing parts forming at least one transmission path between them for the electromagnetic signals delimited by the primary and complementary delimiting means.

A window/seal and a satellite ground station antenna using the window/seal. A window/seal for a circular waveguide includes a right-circular cylindrical window having an axis, an annular rib surrounding and coaxial with the annular recess, and an annular recess between the cylindrical window and the annular rib. An outer diameter of the annular rib is configured to fit closely within an inside diameter of the circular waveguide.

A dual polarized waveguide device includes a first waveguide that defines a first linear signal propagation path, a second waveguide that defines a second linear signal propagation path that is parallel to the first linear signal propagation path, and a polarization selective coupling interface coupling the first and second waveguides, the polarization selective coupling interface being configured to enable horizontally polarized signals to pass between the first and second linear propagation paths and prevent vertically polarized signals from passing between the first and second linear propagation paths.