Abstract: A waveguide for use with a dual polarization waveguide probe system is described which provides an improved frequency response across a desired frequency range (10.7 to 12.75 GHz) and particularly at the band edges. This is achieved by providing a waveguide with a rotator that incorporates a reflector plate in combination with a differential phase shifter in the form of a waveguide of slightly asymmetrical cross section so that orthogonal signals which travel through this portion have a different cut-off wavelength. This results in a rotator which achieves 180° of phase shift between two orthogonal components across the frequency range of signals received by the waveguide. The reflector plate and the differential phase shifter have inverse frequency characteristics so that the combined phase shift characteristic of the rotator has a flatter frequency characteristic.

Abstract: There is disclosed herein a waveguide rotator for use with a dual polarization waveguide probe system. The waveguide has an internal structure that protrudes into the waveguide such that a first orthogonal component of the incident polarized signal propagates to the end of the waveguide and is reflected therefrom and the second orthogonally polarized component is cut-off by the protruding structure which narrows the waveguide, at a distance from a short circuit at the end of the waveguide, and is reflected substantially at the cut-off point, the cut-off point being frequency dependant. At some predetermined distance from the reflecting means and the cut-off point, the first component and the second component are recombined such that the polarization of the recombined structure is rotated 90° from the incident polarization. The protruding interior surface creates a pocket or cavity behind the waveguide into which components from a circuit board can be inserted.

Abstract: A low nosie block (LNB) system is described which facilitates the mount of printed circuit board (PCBs) with probes attached to an LNB housing. The LNB housing has, in a preferred arrangement, two keyhole-shaped apertures located in the back wall of the waveguide for receiving the probes already mounted to the PCB. The apertures are dimensioned and proportioned to lie on either side of a waveguide septum and to allow probes, when coupled to a printed circuit board, to be inserted through the respective apertures for correct orientation within the waveguide once the printed circuit board is secured to the housing and to allow minimal transmission of electromagnetic radiation through the apertures other than by a transmission line formed by the probes.

Abstract: A dual circular polarization waveguide (24) is described which has a septum (36) which divides the waveguide (24) into two separate compartments (38, 40) each with a probe (30A, 30B) passing through the end wall (32) of the waveguide (24) into the compartment (38, 40) to detect respective signals in each of the compartments (38, 40). The septum (36) is proportioned and dimensioned to convert the left and right circularly polarized signals, into substantially linearly polarized signals as the signals pass along the waveguide (24) past the septum (36) so as by the time the signals reach the probes (30A, 30B) they are linearly polarized. The probes (30A, 30B) which pass through the rear wall (32) of the waveguide (24) are oriented such that they couple into the magnetic field of the primary or fundamental waveguide mode.

Abstract: A waveguide for use with a dual polarization waveguide probe system is described which provides an improved frequency response across a desired frequency range (10.7 to 12.75 GHz) and particularly at the band edges. This is achieved by providing a waveguide with a rotator that incorporates a reflecting plane in combination with a differential phase shift portion in the form of a waveguide of slightly asymmetrical cross section so that orthogonal signals which travel through this portion have a different cut-off wavelength. This results in a rotator which achieves 180° of phase shift between two orthogonal components across the frequency range of signals received by the waveguide. The reflecting plate and the differential phase shift portion have inverse frequency characteristics so that the combined phase shift characteristic of the rotator has a flatter frequency characteristic.

Abstract: There is disclosed herein a waveguide rotator for use with a dual polarization waveguide probe system. The waveguide has an internal structure that protrudes into the waveguide such that a first orthogonal component of the incident polarized signal propagates to the end of the waveguide and is reflected therefrom and the second orthogonally polarized component is cut-off by the protruding structure which narrows the waveguide, at a distance from a short circuit at the end of the waveguide, and is reflected substantially at the cut-off point, the cut-off point being frequency dependant. At some predetermined distance from the reflecting means and the cut-off point, the first component and the second component are recombined such that the polarization of the recombined structure is rotated 90° from the incident polarization. The protruding interior surface creates a pocket or cavity behind the waveguide into which components from a circuit board can be inserted.

Abstract: A multi-frequency antenna feed for incorporation into a single unit which combines at least two waveguides to provide simultaneous reception and/or transmission of signals in at least two separate frequency bands is described. This is achieved by creating a waveguide system of at least two waveguides sharing the same central axis; a central conventional waveguide which also acts as a center conductor for an outer coaxial waveguide and feeding the outer coaxial waveguide from a non-circular side feed, orthogonal to the waveguide axis, to set up a uniform field in the outer coaxial waveguide. The feeds are adjusted so that the phase center for each frequency band is at the same point in the feed for the same dish. Various embodiments of the invention are described.

Abstract: A low nosie block (LNB) system is described which facilitates the mount of printed circuit board (PCBs) with probes attached to an LNB housing. The LNB housing has, in a preferred arrangement, two keyhole-shaped apertures located in the back wall of the waveguide for receiving the probes already mounted to the PCB. The apertures are dimensioned and proportioned to lie on either side of a waveguide septum and to allow probes, when coupled to a printed circuit board, to be inserted through the respective apertures for correct orientation within the waveguide once the printed circuit board is secured to the housing and to allow minimal transmission of electromagnetic radiation through the apertures other than by a transmission line formed by the probes.

Abstract: A waveguide for use with a dual polarisation waveguide probe system is described which provides an improved frequency response across a desired frequency range (10.7 to 12.75 GHz) and particularly at the band edges. This is achieved by providing a waveguide with a rotator which incorporates a reflecting plane in combination with a differential phase shift portion in the form of a waveguide of slightly asymmetrical cross section so that orthogonal signals which travel through this portion have a different cut-off wavelength. This results in a rotator which achieves 180° of phase shift between two orthogonal components across the frequency range of signals received by the waveguide. The reflecting plate and the differential phase shift portion have inverse frequency characteristics so that the combined phase shift characteristic of the rotator has a flatter frequency characteristic.

Abstract: An RF waveguide signal transition apparatus for minimizing leakage at RF frequency is described which consists of providing a plurality of plated through-holes (16) of blind holes in a circuit board (10). The plated holes (16) are disposed on the circumference of a circle around the RF waveguide to microstrip transition of probe (14) and each of the plated holes (16) is connected to a ground plane (24). The size of distribution of the plated holes provides a barrier to signal leakage at RF frequencies in the range 10.95-11.7 GHz and they also provide a transition impedance similar to the 50 ohm characteristic impedance providing satisfactory matching and minimizing leakage into the board. The apparatus can also be used to minimise leakage from microstrip to microstrip transitions passing through the circuit board.

Abstract: A waveguide includes a waveguide body, a twist plate, and a first and second probes. The waveguide body defines a waveguide cavity therein wherein the waveguide cavity has an aperture at a first end thereof, and wherein the waveguide cavity has a waveguide axis therethrough extending from the first end to a second end. The twist plate is in the waveguide cavity at the second end of the waveguide cavity wherein the twist plate is parallel to the waveguide axis, wherein the twist plate includes a leading edge facing the aperture, and wherein the leading edge includes first and second portions with the second portion being more distant from the aperture than the first portion. The first probe is in the waveguide cavity between the aperture and the leading edge of the twist plate for receiving a first signal having a first polarization entering the aperture.

Abstract: An RF waveguide signal transition apparatus for minimizing leakage at RF frequency is described which consists of providing a plurality of plated through-holes (16) of blind holes in a circuit board (10). The plated holes (16) are disposed on the circumference of a circle around the RF waveguide to microstrip transition of probe (14) and each of the plated holes (16) is connected to a ground plane (24). The size of distribution of the plated holes provides a barrier to signal leakage at RF frequencies in the range 10.95-11.7 GHz and they also provide a transition impedance similar to the 50 ohm characteristic impedance providing satisfactory matching and minimizing leakage into the board. The apparatus can also be used to minimise leakage from microstrip to microstrip transitions passing through the circuit board.