A directional waveguide coupler (20) has four input ports and four output ports. Each input port is coupled to each of the output ports. The directional coupler (20) includes a first coupler having two waveguides (W1, W2) coupled to each other by a first slot array (S1), defined in a first wall (21) common to the two waveguides (W1, W2) of the first coupler. A second coupler has two waveguides (W3, W4), coupled to each other by a second slot array (S2), defined in a second wall (22) common to the two waveguides (W3, W4) of the second coupler. The first and second slot arrays (S1, S2) lie on a first common plane. The first and second couplers are coupled to each other by a third slot array (S3) and a fourth slot array (S4), which lie on a second common plane perpendicular to the first common plane.

The radar system includes a split-block assembly comprising a first portion and a second portion. The first portion and the second portion form a seam, where the first portion has a top side opposite the seam and the second portion has a bottom side opposite the seam. The system includes at least one port located on a bottom side of the second portion. Additionally, the system includes radiating elements located on the top side of the first portion, wherein the radiating elements are arranged in a plurality of arrays. Yet further, the system includes a set of waveguides in the split-block assembly configured to couple each array to at least one port. Furthermore, the split-block assembly is made from a polymer and where at least the set of waveguides, the at least one port, and the plurality of radiating elements include metal on a surface of the polymer.

According to one aspect of the invention, there is provided a connector for connecting a waveguide and a board, comprising: a first opening part formed in a direction perpendicular to one side of a board and coupled to the one side of the board; a second opening part formed in a direction parallel to a longitudinal direction of a waveguide for signal transmission, wherein the waveguide is capable of being coupled to the second opening part; and a signal guide part connecting the first and second opening parts and including a hollowness surrounded by a conductive layer therein.

A radar system includes a split-block assembly unit comprising a first portion and second portion, where the first portion and the second portion form a seam. The radar system further includes a plurality of ports located on a bottom side of the second portion opposite the seam. Additionally, the radar system includes a plurality of radiating elements located on a top side of the first portion opposite the seam. The plurality of radiating elements is arranged in a plurality of arrays. The plurality of arrays includes a set of multiple-input multiple-output (MIMO) transmission arrays, a set of synthetic aperture radar (SAR) transmission arrays, and at least one reception array. Further, the radar system includes a set of waveguides configured to couple each array to a port.

The radar system includes a split-block assembly comprising a first portion and a second portion. The first portion and the second portion form a seam, where the first portion has a top side opposite the seam and the second portion has a bottom side opposite the seam. The system includes at least one port located on a bottom side of the second portion. Additionally, the system includes radiating elements located on the top side of the first portion, wherein the radiating elements are arranged in a plurality of arrays. Yet further, the system includes a set of waveguides in the split-block assembly configured to couple each array to at least one port. Furthermore, the split-block assembly is made from a polymer and where at least the set of waveguides, the at least one port, and the plurality of radiating elements include metal on a surface of the polymer.

The present invention features a waveguide transition. A waveguide transition is used to join two dissimilar segments of waveguide, in this case coplanar waveguide to rectangular waveguide, and vice-versa. Care taken during the design of the waveguide transition ensures that the reflection of electromagnetic waves, which may be traveling along the coplanar waveguide segment and toward the waveguide transition and subsequent rectangular waveguide segment, is minimized.

A power coupler includes an input port, first and second output ports and an antenna element that is electrically coupled between the first output port and the second output port or that is electrically coupled to an isolation port of the power coupler. The power coupler is configured to split a radio frequency signal incident at the input port and/or to combine radio signals incident at the respective first and second output ports.

A clock apparatus includes: (a) a gas cell, including a continuous path cavity including a sealed interior for providing a signal waveguide; (b) an apparatus for providing an electromagnetic wave to travel along the continuous path cavity and for circulating around the continuous path cavity back toward and past a point of entry of the electromagnetic wave in the continuous path cavity; (c) a dipolar gas inside the sealed interior of the cavity; and (d) receiving apparatus for detecting an amount of energy in the electromagnetic wave, wherein the amount of energy is responsive to an amount of absorption of the electromagnetic wave as the electromagnetic wave passes through the dipolar gas.

A parallel-plate diplexer includes a first parallel-plate transmission line and a second parallel-plate transmission line, a first end of the second parallel-plate transmission line including a first port and a second end of the second parallel-plate transmission line including a second port, and a first end of the first parallel-plate transmission line including a third port and a second end of the first parallel-plate transmission line being coupled to the second parallel-plate transmission line at a T-junction between the first port and the second port. The second parallel-plate transmission line includes a first parallel-plate transmission line tuning network located between the T-junction and the first port, and a second parallel-plate transmission line tuning network located between the T-junction and the second port.

The present invention discloses an accurate and efficient modeling method for the terahertz branch waveguide directional coupler, which uses mode matching method (MMM) to take into account the effects on the coupler field distribution caused by the branch structure discontinuity, combines odd and even mode analysis method to further simplify the derivation process, and finally obtains a simplified and accurate calculation formula of the coupling degree, which the latter produces a new conclusion that when the work frequency of the branch waveguide directional coupler is determined, the coupling degree thereof is determined by the sum of the branch widths. The modeling method of the present invention has the characteristics of simplicity, which can greatly shorten the modeling time and improve the efficiency of the modeling compared with the traditional modeling method. In addition, the modeling method has the characteristics of universality.