EP3317914B1

EP3317914B1 - Improvements to receiving and/or transmitting apparatus for satellite transmitted data

Info

Publication number: EP3317914B1
Application number: EP16744451.2A
Authority: EP
Inventors: Tao Huang
Original assignee: Global Invacom Ltd
Current assignee: Global Invacom Ltd
Priority date: 2015-06-30
Filing date: 2016-06-30
Publication date: 2023-11-01
Anticipated expiration: 2036-06-30
Also published as: GB201511436D0; WO2017001856A1; EP3317914A1; GB201611420D0; GB2540675A

Description

The invention which is the subject of this application, relates to the provision of improved receiving and transmitting apparatus for use at a location. The apparatus is provided to receive and/or transmit, process data and allow the data to be moved onwardly to a distribution system by which at least some of the received data can be passed to apparatus at one or more user locations. At the user location, processing apparatus can be used to generate video and/or audio and/or other data services such as broadband, which can be provided to a user via a display screen and/or speakers and thereby allow selected television and/or radio programmes and/or other data services to be provided to the user at that location.
The invention relates more specifically to the apparatus which is provided at the receiving location and which apparatus typically includes at least one antenna or dish which is directed and positioned so as to transmit and/or receive data signals which are reflected to the same from a broadcast location, via one or more satellites. The antenna is provided with an arm which extends to the front of the same and at the free or distal end of the arm there is provided a waveguide through which the data signals which are reflected to the same from the antenna, pass. The waveguide is connected to one or more Low Noise Blocks and Block Up Converter (BUC). The Low Noise Block and BUC is provided to allow the passage of data therethrough in selected paths in different polarisations, such as Circular and Linear, and/or in different orthogonal components such as vertical and horizontal. The data signals may also be up or down converted to suit particular frequencies and operating requirements.
The LNB typically also has a number of outputs for the different data signal paths and, in one embodiment, the format of the data may be converted from an RF mode to an optical mode. In either case the data is then carried from the LNB to the one or more user locations using suitable cabling such as coaxial cables or fibre optic cables as appropriate.
The LNB typically comprises the required processing circuitry implemented on one or more printed circuit boards which are located by and within a housing and the data enters the housing from a feed horn which his provided upstream of the LNB to allow data which is reflected from the antenna dish to be collected and passed to the LNB for processing. Typically the feedhorn is provided so as to only collect data signals which are within a predefined frequency range or frequency ranges.
In one example of apparatus of this type it can be required to provide the feedhorn in a manner in which the same is used in conjunction with a VSAT offset antenna which is required to be used for the reception of data signals which allow the provision of co-located Ku and Ka band satellite services simultaneously. The Ka band covers the frequencies in the range of 18.1 to 20.2 GHz (the 20Ghz band) and 27.9 to 30 GHz (the 30 GHz band), while the Ku band covers the frequencies of 10.7-12.75 GHz of the electromagnetic spectrum in the microwave range of frequencies. The services which can be provided include Ku band DBS TV reception and Ka band TV and internet access.
There is an increasing demand for satellite broadcasting in which there can be provided the simultaneous service of receiving TV channels and having internet access with the direct broadcast satellite (DBS) TV services typically provided in the Ku band and the internet services provided in the Ka band.
When the data signals for these services are provided from different satellites at different locations, multiple feed horns are used to produce separate antenna beams pointing to the corresponding satellites independently.
Examples of a conventional dual feed horn is provided in Figures 2a and b which show a dual feed horn design for a first satellite for TV service data signals at 28.2 ° E and a second satellite for TV and internet service data signals at 31 ° E on a GD 74 offset dish
However when the two sets of data signals are received from the same satellites or satellites co-located at the same orbit slot there is only one antenna beam needed for all three data signal frequency bands which are respectively used to carry the DBS TV data signals on the Ku Band, the TV service data signals in the Ka band and the internet service data signals on the Ka band. This presents a significant problem in that the conventional separate data signal channels cannot be used and there is a need to be able to deal with the received data signals at the different frequency bands separately at various stages.
US7408427 and WO98/07211 disclose apparatus for the reception of data signals in different frequencies which use the same channel along a feedhorn. WO2015/035463 discloses a feedhorn used to illuminate a reflector antenna with a dielectric dome element at its centre. CHAN KK et al: "Multifrequency band earth station feed design", 19900507: 19900507-19900511, 7 May 1990 (1990-05-07), PAGES 960-963, XP010000479 discloses a particular feed design.
An aim of the present invention is therefore to provide apparatus which allows the reception and transmission of data signals at different frequency ranges from the same satellite or from satellites which are co-located.
In a first aspect of the invention there is provided apparatus for the reception of data signals transmitted from a satellite or co-located satellites and/or the transmission of data signals, said data signals provided in a plurality of frequency bands, wherein said apparatus includes a feed horn assembly to allow said data signals to utilise the same channel provided along the feed-horn assembly, wherein the feed horn assembly produces a common beam in three frequency bands, wherein the three frequency bands are Ku, K and Ka bands; wherein the feed horn assembly includes a first, inner waveguide for Ka band data signals, wherein a second waveguide is provided which surrounds the first waveguide wherein the second waveguide is provided to receive data signals at a lower frequency band than the frequency band of the data signals received by the first, inner, waveguide wherein the feedhorn assembly includes a cross structure which forms four separate quadrants wherein the cross structure creates four quasi-rectangular waveguides between the outer and inner waveguides wherein the apparatus further includes at least one Ka reject filter located between the first and second waveguides to minimise the Ka band data signals leaking from a Ku band output.
In one embodiment the feed horn assembly is a triple band feed horn assembly.
In one embodiment the said Ku output is fed to a Low Noise Block (LNB) directly. In one embodiment the LNB is provided integrally with the feed horn assembly.
In another embodiment the said Ku output is fed to a universal Ku interface flange to which a Ku LNB can be connected.
Typically the K/Ka output is a universal Ka flange with which a Ka transceiver can be interfaced.
Typically dual orthogonal polarizations are created in each frequency band and the polarizations can be configured separately.
In one embodiment the feed horn assembly can operate with respect to the data signal frequency bands of Ku 10.7 - 12.75 GHz, Ka Receiving 18.1 - 20.2 GHz and Ka transmission of 27.9 -30 GHz
Typically the polarisations of the respective data signal bands can be Vertical (V) and Horizontal (H) linear or Right Hand (RH) and Left Hand (LH) circular and the same can be determined independently for each band
In one embodiment the impedance matching is -20 dB return loss in all bands
Typically an isolation of >25 dB is achieved in bands between two orthogonal polarizations, and >40 dB across the bands.
Typically there is a common phase centre among all bands with a -10 dB edge taper at 35 degree subtended angle, >30 dB cross-polarization discrimination (XPD)on boresight, and a 10 dB Gain.
In one embodiment the feed horn assembly is manufactured using metal die-casting
In one embodiment the feed horn assembly includes a substantially tubular inner waveguide for the Ka band data signals.
In one embodiment a dielectric radiator is provided at, or adjacent to, a first end of the said inner waveguide, typically that at which the received data signals enter and transmitted data signals leave, the feedhorn assembly.
In one embodiment the radiator for the K/Ka band is shaped such as a dome or cone, and is selectively formed so as to select the beamwidth.
Typically the bandwidth is wider when the radiator is dome shaped than if, for example, the radiator was conically shaped.
The data signals can then be passed along each of the quadrants to a combiner at the opposing end of the waveguide from which the data signals enter the assembly.
In one embodiment at least one ridge is located in each quasi-rectangular waveguide to increase the frequency bandwidth.
In one embodiment the feed horn includes a series of corrugated ribs which flare outwardly towards the end of the assembly through which the data signals are received and emitted.
Specific embodiments of the invention are now described with reference to the accompanying drawings; wherein

Figure 1 illustrate schematically a satellite broadcast system of the type to which the invention relates;
Figures 2a and b illustrates a conventional dual feedhorn apparatus;
Figure 3 illustrates a first connection embodiment of a feedhorn assembly in accordance with the invention;
Figure 4 illustrates a second connection embodiment of a feed horn assembly in accordance with the invention;
Figures 5a and b illustrate elevation and plan views of the feed horn assembly of Figures 3 and 4;
Figures 6a and b illustrate graphically test results obtained using the feedhorn assembly of Figures 5a and b;
Figures 7a and b illustrate a further embodiment of a feedhorn in accordance with the invention; and
Figure 8 illustrates a further feedhorn assembly in accordance with the invention.

Referring firstly to Figure 1 there is illustrated apparatus 2 provided at a receiving location 4 such as a domestic premises to receive and process data received from a satellite broadcast system. The apparatus includes at the receiving location at least one antenna dish 6 connected to a feed horn assembly 8 and LNB's 10 mounted on an arm 12 which depends to the front of the antenna 6.. The LNB's are connected to cables 14 to allow the onward distribution of the data therefrom to within the receiving location 4. The data signals 16 are transmitted from the same satellite 18 or may be transmitted from collated satellites in terms of their orbital position.
Figures 2a and b illustrates a conventional apparatus arrangement in which satellite signals are received from two separate non co located satellites and in this case the dish A receives data for a first data signal and a second data signal from two different satellites. The conventional multiple feed horn B as shown in Figure 2b has a first feedhorn C for Ka data signals and which is coupled to an LNB via Ka Interface flange D and a second and separate horn E for Ku data signals which can be coupled to a separate LNB via interface F. This design can therefore be relatively straight forward. It is to the problem where the two sets of data signals are received from the same satellite or collocated satellites that the current invention is addressed.
Figures 3 and 4 show two embodiments of the invention and in both cases there is provided a common feed horn assembly 20 which is capable of receiving data signals at a Ka band frequency and at a Ku band frequency and also transmitting data signals therefrom. In Figure 3 the assembly is provided with a Ku interface 22 and a Ka interface 24 to allow connection to Ku and Ka LNB's 26,28 respectively.
In Figure 4 there is again provided a Ka interface 24 for connection with a Ka LNB 28 but the Ku LNB 30 is provided in this case integrally with the feed horn assembly 20.
Turning now to Figures 5a-e there is shown the feed horn assembly in greater detail. The assembly has a first end 32 through which the received Ka and Ku data signals enter the assembly in the direction 34 via corrugated ribs 36 and from which transmitted data passes in the direction of arrow 38 and via a domed radiator cap 42. The cap 42 is connected to an inner waveguide 44 which is surrounded by an outer waveguide 46. The outer waveguides is split into quadrant sectors 48, 50,52, 54 at the portion 56 located towards the rear end 58 of the assembly.
The inner waveguide 44 has a tapered or conical end portion 60 which is located within the said portion 56 of the outer waveguide.
At the end 58 of the outer waveguide there is provided one or more polarisation means to allow the received data signals to be separated and passed to the ports 62,64 for the Ku LNB and the port 66 for the Ka LNB.
A feasibility study was performed using the assembly as shown in Figures 5a and b and the graphs 6a and b illustrate graphically the test results in relation to key performance parameters of waveguide mode generation, propagation, radiation patterns, Gains, X-pol, impedance matching and isolations in all three bands and which show that the feedhorn assembly in accordance with the invention allows the provision of the triple band data signals to be achieved from the common feed horn assembly and therefore, the assembly provides for three frequency bands operation with two orthogonal polarizations (V&H LP or LH&RH CP) in each band. It also offers the maximum flexibility in configuring a complete system and the possibility of utilising and interfacing with further components without the requirement to redesign the same, such as Ku LNBs, Ka transceivers and dish antennas.
Referring now to Figures 7a and b there is illustrated in elevation with the components shown, and in plan, a feedhorn assembly in accordance with another embodiment of the invention. In this case the feedhorn assembly 100 again includes a first, inner waveguide 102 and a second, outer, waveguide 104 which in combination form a channel 106 along which selected data signals can pass at selected frequency bands. A polyrod 108 extends along the waveguide channel and has at a first end 110 a cone shape although it should be appreciated that the cone shape can be replaced by a ball or another shape, and a corrugated feedhorn 111.
At the opposing end 112 of the channel formed by the waveguides the second, outer, waveguide is divided by a cross wall structure 122 into sectors 114, 116,118,120 so as to have a sectoral or quasi-rectangular waveguide form. In addition, in this embodiment, linear ridges 124 are provided at spaced locations around the central axis 126 and extend along at least a portion of the waveguide depending from the said end 112.
A series of Ka reject filters, in the form of iris rings 128 are located at spaced intervals along the axis 126 and are located in between the outer and inner waveguides 102, 104.
In Figure 8 a further embodiment is illustrated in perspective with the various components illustrated and in this case the feedhorn assembly has a polyrod 108 which has a ball shape 130 at it's end. The same has similar components to those shown in Figures 7a and b and similar reference numbers are used where appropriate. In this case Ka reject filters 132 can be selectively positioned as indicated by the arrows and again, towards the end 112 of the channel 106 the outer waveguide is split into four sectors 114, 116,118,120 by cross structure walls 122. Towards the end 112 are located the Ortho Mode Transducer (OMT) or LNB 134 for the Ku band data signals which pass along paths 136, 138 connected to respective ports into the channel 106. The Ka data signals arte typiocally connected to the channel 106 at the end 112 thereof.
There is therefore provided in accordance with the invention apparatus for receiving and/or transmitting data signals via satellite, and in particular to a feedhorn assembly which allows the provision of data signals carried on at least triple frequency bands to be achieved with a common feed horn assembly. In one embodiment the assembly provides for three frequency bands of operation with two orthogonal polarizations (V&H LP or LH&RH CP) in each band. The feedhorn assembly in accordance with the invention also allows the possibility of utilising and interfacing with further components without the requirement to redesign the same, such as Ku LNBs and/or OMT's, Ka transceivers and dish antennas.

Claims

Apparatus for the reception of data signals transmitted from a satellite (18) or co-located satellites and/or the transmission of data signals, said data signals provided in a plurality of frequency bands, wherein said apparatus includes a feed horn assembly (20; 100) to allow said data signals to utilise the same channel (106) provided along the feed-horn assembly, wherein the feed horn assembly is configured to produce a common beam in three frequency bands, wherein the three frequency bands are Ku, K and Ka bands; wherein the feed horn assembly includes a first, inner waveguide (44; 102) for Ka band data signals, wherein a second waveguide (46; 104) is provided which surrounds the first waveguide, wherein the second waveguide is provided to receive data signals at a lower frequency band than the frequency band of the data signals received by the first, inner, waveguide, wherein the feedhorn assembly includes a cross structure (122) which forms four separate quadrants (48,50,52,54; 114, 116,118,120), wherein the cross structure creates four quasi-rectangular waveguides between the outer and inner waveguides (44,46), wherein the apparatus further includes at least one Ka reject filter (132) located between the first and second waveguides (44,46) to minimise the Ka band data signals leaking from a Ku band output.
Apparatus according to claim 1 wherein the feed horn assembly is a triple band feed horn assembly.
Apparatus according to claim 1 wherein a dielectric radiator (42) is provided at, or adjacent to, a first end (32) of the said first, inner, waveguide (44;102) wherein preferably said dielectric radiator for the K/Ka band is shaped as a dome or cone and is selectively formed so as to select the beamwidth.
Apparatus according to claim 1 wherein at least one ridge (124) is located in each quasi-rectangular waveguide to increase the frequency bandwidth.
Apparatus according to claim 1 wherein the apparatus includes a combiner located at the opposing end (58; 112) of the waveguide from which the data signals enter the assembly such that the data signals pass along each of the quadrants to the combiner.
Apparatus according to any of claims 1-5 wherein the feed horn includes a series of corrugated ribs (36) which flare outwardly towards the end (32) of the assembly through which the data signals can be received and emitted.
Apparatus according to claim 1 wherein the feed horn assembly is configured to illuminate a dish antenna (6) and to diplex the Ku band from the K/Ka bands.
Apparatus according to claim 7 wherein said Ku output is configured to be fed to a Low Noise Block ,LNB, (26; 134) directly or wherein said Ku band output is configured to be fed to a universal Ku interface flange to which a Ku LNB (26;134 ) can be connected or wherein a K/Ka band output of the apparatus is a universal Ka flange with which a Ka transceiver (28) can be interfaced.
Apparatus according to any of the preceding claims configured such that dual orthogonal polarizations are created in each frequency band and the polarizations are configured separately.
Apparatus according to any of the preceding claims wherein the feed horn assembly is operable with respect to the data signal of Ku band 10.7 - 12.75 GHz, K band reception of 18.1 - 20.2 GHz and Ka band transmission of 27.9 -30 GHz.
A satellite data transmission system wherein said system includes the apparatus as defined by any of claims 1-10.