Abstract:
The invention relates to a multi port router device capable of carrying a number P, which is greater than or equal to three, of frequency channels, from a number M of input ports to a number N of output ports, at least one of the two numbers M and N being greater than or equal to two, characterised in that it includes at least two filters ( 12, 14, 16, 18 ), each filter comprising at least two coupled resonators, at least one resonator (Rs 1 , Rs 2 ) being common to two different filters, and each input port and each output port being connected directly to at least one resonator. The router device is capable of appropriately performing routing in which it is possible to supply on at least one output port an output multiplex having at least a first and a second frequency channel, among which: the first frequency channel has originated from a first input multiplex, supplied on a first input port and comprising said first frequency channel, and at least one further frequency channel forwarded to a second output port of the device; and the second frequency channel is either forwarded from a second input port, or, when the first input multiplex comprises at least three different multiplexed frequency channels, the second frequency channel originates from the first input multiplex, the first second frequency channels, being frequentially disposed on both sides of a third frequency channel, with the said third frequency channel being routed to a different output port.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of French Patent Application No. 12 59276 filed on Oct. 1, 2012. The entire disclosure of this application is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a multi port router device capable of carrying a number P, which is greater than or equal to three, of frequency channels, from a number M of input ports to a number N of output ports. 
         [0003]    The invention pertains to the domain of hyperfrequency and microwave communications, and finds particular application in the field of telecommunication satellites. 
       BACKGROUND OF THE INVENTION 
       [0004]    The state of the art includes various known technologies including various architectures for devices that are capable of performing hyperfrequency communications functions, in particular functions such as filtering, multiplexing and routing of hyperfrequency microwave signals transmitted by frequency channels each one thereof having an associated hyperfrequency carrier. 
         [0005]    The function of filtering frequency channels consists of filtering one or more carriers in a predetermined frequency channel, thereby enabling the separation of several frequency channels. 
         [0006]    The input multiplexing function consists of either separating a stream of carriers or frequency multiplexes composed of P number of different input frequency channels, received on one single input port of a multiplexing device, into P output frequency channels, with each sent on a different port. In a dual manner, the output multiplexing function consists of combining P frequency channels received on M number of input ports into one output multiplex consisting of P frequency channels forwarded on to an output port. 
         [0007]    The routing function consists of separating P number of frequency channels received on M input ports towards N number of output ports, by recombining the frequency channels of the input multiplexes into the output multiplexes. More specifically, the input routing function, hereinafter to be referred to as shared output routing, consists of separating at least one first channel of a first input multiplex supplied on a first input port and then of directing it towards a first output multiplex of a first output port, the first output multiplex also comprising a second channel originating from a second input multiplex supplied on a second input port. The so called shared input output routing is defined in a dual manner. 
         [0008]    As it may be noted, the routing functions, respectively shared output input routing or shared input output routing, differ from multiplexing because they involve a separation and a recombination of the frequency channels between input and output. The implementation of the routing functions is therefore much more complex than the implementation of the multiplexing functions. 
         [0009]    It is a known practice to develop a router device by combining diplexers or by combining resonator filters, with the connections being made with the use of elements for division and passive combination, such as waveguides, “T” junctions, dividers, circulators and isolators. Such a router device is cumbersome having a large mass and space requirement, as well as resulting in additional insertion loss. 
         [0010]    It is thus desirable to develop multiport router devices that are capable of performing the functions of filtering as well as of shared output input routing and/or shared input output routing, which are more compact and more efficient than currently known devices. 
       SUMMARY OF THE INVENTION 
       [0011]    To this end, the invention provides a multi port router device that is capable of carrying a number P, which is greater than or equal to three, of frequency channels, from a number M of input ports to a number N of output ports, at least one of the two numbers M and N being greater than or equal to two. The router is characterised in that it includes at least two filters, each filter comprising at least two coupled resonators, with at least one resonator being common to two different filters, and each input port and each output port being connected directly to at least one resonator. The router device is capable of appropriately performing routing in which it is possible to supply on at least one output port an output multiplex having at least a first and a second frequency channel, among which:
       the first frequency channel has originated from a first input multiplex supplied on a first input port and having the said first frequency channel and at least one further frequency channel forwarded to a second output port of the device, and   the second frequency channel is either forwarded from a second input port, or, when the said first input multiplex comprises at least three different multiplexed frequency channels, the said second frequency channel originates from the said first input multiplex, the said first and second frequency channels, being frequentially disposed on both sides of a third frequency channel, with the said third frequency channel being routed to a different output port.       
 
         [0014]    Advantageously, the multiport router device according to the invention is compact insofar as each input port and each output port is directly connected to at least one resonator, without connection elements such as waveguides or junctions. Thus, the invention makes it possible to obtain an advantage in terms of space requirement and mass as compared to existing solutions, and also to improve the electrical performance by limiting the insertion losses and eliminating the spiking recombination peaks that are typically due to the use of connection elements such as waveguides. 
         [0015]    According to one feature, the router device is capable of operating in a reversible manner, the said output ports being used as input ports and said input ports being used as output ports. 
         [0016]    Advantageously, the function of filtering and the function of shared output input routing and/or shared input output routing are performed in a single compact multi port router device. 
         [0017]    The multi port router device according to the invention may have one or more of the following characteristic features, taken into consideration individually or in combination:
       the said routing is performed by the couplings between resonators of different filters, said couplings being selected in order to perform the routing according to a predetermined routing plan for the routing of P frequency channels obtained on M input ports to N output ports;   it comprises at least two input ports and at least two output ports;   at least two frequency channels originating from two different input ports are identical;   each input port is coupled to two resonators via a dual-mode resonant cavity;   it comprises a number of filters equal to the number P of frequency channels;   each filter is composed of a group of the same number of resonators coupled in cascade;   at least one filter includes at least one non resonant node.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    Other characteristic features and advantages of the invention shall become apparent from the description which is provided here below, purely by way of an indication and without any limitation whatsoever, with reference made to the accompanying drawings, amongst which: 
           [0026]      FIG. 1  is a schematic functional illustration of a router device with two input ports and two output ports, and four channels; 
           [0027]      FIG. 2  illustrates schematically an embodiment of the multi port router device in  FIG. 1 ; 
           [0028]      FIG. 3  illustrates a variant of the embodiment in  FIG. 2 ; 
           [0029]      FIG. 4  illustrates an embodiment of the compact multi port router device in  FIG. 2  having dual-mode cavities; 
           [0030]      FIG. 5  is a graph illustrating the transmission responses for an example of the embodiment in  FIG. 4 ; 
           [0031]      FIGS. 6 and 7  are graphs of the reflection responses for an example of the embodiment in  FIG. 4 ; 
           [0032]      FIG. 8  functionally illustrates a multi port router device with one input, two outputs, four channels; 
           [0033]      FIG. 9  schematically illustrates an embodiment of the multi port router device in  FIG. 8 ; 
           [0034]      FIG. 10  functionally illustrates a multi port router device with two inputs, three outputs, six channels; 
           [0035]      FIG. 11  schematically illustrates an embodiment of the multi port router device in  FIG. 10 ; 
           [0036]      FIG. 12  functionally illustrates a multi port router device with three inputs, three outputs, five channels, and 
           [0037]      FIG. 13  schematically illustrates an embodiment of the multi port router device in  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0038]      FIG. 1  illustrates in a functional manner a multi port router device having two input ports respectively denoted as PE 1  and PE 2  and two output ports respectively denoted as PS 1  and PS 2 , capable of separating four frequency channels, each frequency channel having an associated carrier respectively denoted as F 1 , F 2 , F 3  and F 4 . 
         [0039]    In order to simplify the expression each frequency channel shall hereinafter be designated by the associated carrier or carriers. 
         [0040]    A first input multiplex, forwarded on to the input port PE 1 , comprises two carrier frequency channels F 1  and F 2 , and a second input multiplex, forwarded on to the input port PE 2 , comprises two carrier frequency channels F 3  and F 4 . The channels are respectively separated and recombined. Thus, the frequency channel F 1  of the first input multiplex is supplied over the first output multiplex on the output port PS 1 . The first output multiplex also includes the frequency channel F 3  originating from the second input multiplex supplied on the second input port. The second output multiplex supplied on the output port PS 2  recombines the frequency channel F 2  originating from the first input multiplex supplied on the first input port PE 1  and the frequency channel F 4  originating from the second input multiplex supplied on the second input port PE 2 . For example, in one of the possible applications of the invention which is a telecommunications application, the frequency channels have a bandwidth of 33 MHz, the carrier frequencies being included in the frequency band Ku, of 10.7 GHz to 12.75 GHz. 
         [0041]    A multi port router device  10  according to the invention with two inputs, two outputs and four channels, also called 2×2 router with 4 channels is schematically illustrated in  FIG. 2 . The router device  10  in this example includes two input ports respectively denoted as PE 1  and PE 2 , and two output ports PS 1  and PS 2 , as in the previous generic example in  FIG. 1 . Each input multiplex comprises two frequency channels. 
         [0042]    The frequency channels are separated by filters  12 ,  14 ,  16 ,  18 , each filter being formed by a group of resonators coupled in cascade as illustrated in  FIG. 2 . 
         [0043]    In a more general manner, a filter comprises resonators interconnected with each other, and may also include, by way of a variant, nodes that are non-resonant (“non-resonating nodes”) between two resonators. 
         [0044]    The input port PE 1  is directly coupled to the resonators R 1  and R 5 , the input port PE 2  is directly coupled to the resonators R 12  and R 16 . The output port PS 1  is coupled to the common resonator Rs 1 , and the output port PS 2  is coupled to the common resonator Rs 2 . 
         [0045]    The filter  12  is a band pass filter tuned to the carrier frequency F 1  corresponding to the first input channel of the first input multiplex. This filter includes the resonators denoted as R 1 , R 2 , R 3 , R 4  and Rs 1 , coupled in series. 
         [0046]    The filter  14  is a band pass filter tuned to the carrier frequency F 2  corresponding to the second input channel of the first input multiplex. This filter includes the resonators denoted as R 5 , R 6 , R 7 , R 8  and Rs 2 , connected in series. 
         [0047]    The filter  16  is a band pass filter tuned to the carrier frequency F 3  corresponding to the first input channel of the second input multiplex. This filter includes the resonators denoted as R 12 , R 11 , R 10 , R 9  and Rs 1 , coupled in series. 
         [0048]    Filter  18  is a band pass filter tuned to the carrier frequency F 4  corresponding to the second input channel of the second input multiplex. This filter includes the resonators denoted as R 16 , R 15 , R 14 , R 13  and Rs 2 , coupled in series. 
         [0049]    As it may be noted, in the topology example shown in  FIG. 2 , the resonator Rs 1  is electromagnetically coupled to the resonator R 4  and participates in the filter  12 , but also, in the same way, Rs 1  is electromagnetically coupled to the resonator R 9  and participates in the filter  16 . In a similar manner, the resonator Rs 2  is electromagnetically coupled to the resonator R 8  and participates in the filter  14 , but also, in the same way, Rs 2  is electromagnetically coupled to the resonator R 13  and participates in the filter  18 . Each of the respective resonators Rs 1  and Rs 2  is common to two different filters. 
         [0050]    According to a variant, other couplings between the resonators forming a filter are possible, based on variations of known coupling topology. For example, in the filter  12 , the resonators R 1  and R 4  may also be coupled in order to improve the electrical performance of the system, by the creation of transmission zeros for example. 
         [0051]      FIG. 3  illustrates a variant of the router with two inputs, two outputs, and four channels as in  FIG. 2 . In this variant, the resonators R 3  and R 7  and the filters F 1  and F 2  are also coupled with each other. In addition, the resonators R 11  and R 13  and the respective filters F 3  and F 4  are also coupled with each other. 
         [0052]    It is to be understood that, other connection topologies (not shown) may also be considered. For example, all the resonators could be common to the filters, with vertical or diagonal connections between resonators. 
         [0053]    The couplings between the resonators are selected in order to perform the routing in accordance with a predetermined routing plan for routing P frequency channels obtained on M input ports to N output ports. 
         [0054]    According to the embodiment illustrated in  FIG. 4 , the multi port router device is built by means of a device  20  with dual-mode cavities. The device  20  comprises of nine dual-mode cavities, respectively denoted as C 1  to C 9 . Each cavity comprises of a pair of resonators, which based on different modes of resonance, are polarised at 90° from each other; respectively the cavity C 1  includes the resonators R 1  and R 5 , and the cavity C 2  includes the resonators R 2  and R 6 , and so on. 
         [0055]    Adjacent cavities are coupled by irises  22  in this embodiment. In addition, coupling and tuning screws  24  are also used to tune the resonance frequencies and to couple the polarisations between one another. 
         [0056]    The cavity denoted as C 5  includes two resonators Rs 1  and Rs 2  to which are coupled the output ports PS 1  and PS 2 . As illustrated in  FIG. 4 , the output ports PS 1  and PS 2  are arranged at the periphery of the cavity C 5  in positions that are angularly different. 
         [0057]    The filters  12  and  14  have been developed as dual-band filters by means of the cavities C 1  to C 5  and the filters  16  and  18  have been developed as dual-band filters by means of the cavities C 5  to C 9 . According to one embodiment, which is called co-frequency embodiment, the carrier frequencies F 1  and F 4  and/or the carrier frequencies F 2  and F 3  are identical (principle of frequency reuse for satellite communications applications). Advantageously, it is possible to perform the routing function for applications using the same frequency channels to transmit various different data. 
         [0058]    A multi port router device as described with reference to  FIG. 2  is characterised by a normalised coupling matrix obtained in a prior phase of synthesis which makes it possible to define the optimal architecture that implements the selected routing plan. A coupling matrix is a matrix that represents the electromagnetic coupling for each pair of elements of the router device (denoted as M ij ), the resonance frequency for each resonator participating in the filtering function (represented by the term M ii ) and the electromagnetic coupling at the input and output on each of the ports with the resonator or resonators brought into play (denoted as R in  and R out , respectively input and output resistances). In an exemplary embodiment illustrated in detail here below, the coupling matrix is a symmetrical square matrix, and all of the coupling values are 0 except for the following coupling values, where C(Ei, Ej) represents the coupling value between the elements Ei and Ej:
   C(PE 1 , R 1 )=1.010; C(PE 1 , R 5 )=1.010;   C(PE 2 , R 12 )=1.010; C(PE 2 , R 16 )=1.010;   C(R 1 , R 1 )=−3.838; C(R 1 ,R 2 )=0.759;   C(R 2 ,R 2 )=−3.460; C(R 2 ,R 3 )=0.636;   C(R 3 ,R 3 )=−3.215; C(R 3 ,R 4 )=1.017;   C(R 4 ,R 4 )=−1.678; C(R 4 ,Rs 1 )=2.360;   C(R 5 ,R 5 )=−0.753; C(R 5 ,R 6 )=0.747;   C(R 6 ,R 6 )=−1.121; C(R 6 ,R 7 )=0.581;   C(R 7 ,R 7 )=−1.182; C(R 7 ,R 8 )=0.594;   C(R 8 ,R 8 )=−1.167; C(R 8 ,Rs 2 )=1.137   C(Rs 1 , Rs 1 )=−1.140; C(Rs 1 ,R 9 )=1.133; C(Rs 1 , PS 1 )=1.383;   C(Rs 2 , Rs 2 )=1.079; C(Rs 2 , R 13 )=2.349; C(Rs 2 , PE 2 )=1.383;   C(R 9 ,R 9 )=1.162; C(R 9 ,R 10 )=0.592;   C(R 10 ,R 10 )=1.178; C(R 10 ,R 11 )=0.580;   C(R 11 ,R 11 )=1.117; C(R 11 ,R 12 )=0.745;   C(R 12 , R 12 )=0.750;   C(R 13 ,R 13 )=1.667;C(R 13 ,R 14 )=0.999;   C(R 14 ,R 14 )=3.216; C(R 14 ,R 15 )=0.629;   C(R 15 , R 15 )=3.446; C(R 15 ,R 16 )=0.751;   C(R 16 ,R 16 )=3.834;   
 
         [0079]    The values provided are normalised relative to a frequency f 0  such that 
         [0000]    
       
         
           
             
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         [0000]    with ƒ 0  being the central frequency of the channel, ƒ i  the resonance frequency of the resonator i considered, M ii  the normalised parameter of the coupling matrix relative to the resonance frequency of the resonator i, and Δf the equiripple bandwidth of the channel considered. 
         [0080]    The input/output resistances R in  and R out  depend on the excitation systems and are therefore directly related to a parameter called external quality factor Q ext  by the relationship: 
         [0000]    
       
         
           
             R 
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         [0081]    The terms M ij , have also been normalised and express the different couplings between the resonance elements and are linked to the coupling coefficients k ij  by the following formula: 
         [0000]    
       
         
           
             
               k 
               ij 
             
             = 
             
               
                 
                   Δ 
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         [0082]    These coefficients represent the intensity of the interaction between two resonances. 
         [0083]    The respective carrier frequencies are as follows in this example : F 1 =11.843 GHz, F 2 =11.881 GHz, F 3 =11.919 GHz and F 4 =11.957 GHz. 
         [0084]      FIG. 5  illustrates, in this embodiment and for the coupling matrix whose values have been described here above as an example, the transmission losses between the various ports, expressed in Decibels (dB) depending on the frequency expressed in GHz. 
         [0085]      FIGS. 6 and 7  illustrate the reflection responses for each of the ports. 
         [0086]      FIG. 8  functionally illustrates a multi port router device  30  which has one single input port and two output ports, so M=1 and N=2, and the number of channels to be separated and recombined is P=4 (1×2 router, 4 channels). In a more general manner, there is a shared input output routing when the number of input channels of different carrier frequencies to be separated and recombined is greater than or equal to 3, in the event of the router device having one input port and two output ports. 
         [0087]    In this particular case functionally illustrated in  FIG. 8 , an input multiplex carrying the channels F 1 +F 2 +F 3 +F 4 , the respective carrier frequencies F 1 , F 2 , F 3  and F 4  being different, is routed to two output ports PS 1  and PS 2 , with a recombination of the non adjacent frequency channels: the first output multiplex, forwarded on to the port PS 1 , is composed of the frequency channels F 1 +F 3 , and the second output multiplex, forwarded on to the port PS 2  is composed of the frequency channels F 2 +F 4 . It is to be emphasised that it indeed involves execution of the function of shared input output routing in this example, and not a simple multiplexing function to the extent where the output frequency channels are separated and recombined, the recombination consisting of recombining into one output multiplex at least two channels (for example F 1  and F 3 ) which are frequentially situated on both sides of a channel (for example F 2 ) which is forwarded on to another output port (port PS 2  in this example). 
         [0088]    According to an embodiment shown in  FIG. 9 , the router device with one input port and two output ports is developed with the use of four filters  32 ,  34 ,  36  and  38 , each consisting of four coupled resonators. The input port PE 1  is directly connected to a resonator Re 1 , which is for example of the cavity type, like in the implementation example in  FIG. 4 . The resonator Re 1  is coupled to the respective resonators R′ 4 , R′ 8 , R′ 9  and R′ 13 , forming part of the filters of the respective carrier frequency channels F 1 , F 2 , F 3  and F 4 . 
         [0089]    A third example of a multi port router device according to the invention is illustrated in  FIGS. 10 and 11 . In this example, the router device  40  is a 2×3 router, with 6 channels having two input ports (M=2) denoted respectively as PE 1  and PE 2  and three output ports (N=3), denoted as PS 1 , PS 2  and PS 3 . A number P=6 of frequency channels is routed: each input multiplex is a multiplex with three frequency channels, and each output multiplex is a multiplex with two frequency channels. The frequency channels are separated and recombined according to the routing plan shown in  FIG. 10 . As illustrated in  FIG. 11 , according to an embodiment for the routing function illustrated in  FIG. 10 , each respective input port is directly coupled to three resonators, and each output port is directly coupled to one single resonator. Thus, according to one embodiment of the invention, generalised to any number of input and output ports, each port may be coupled to as many resonators as the number of frequency channels forwarded on to this port. 
         [0090]    In the example in  FIG. 11 , each respective filter  42 ,  44 ,  46 ,  48 ,  50  and  52 , is formed by a group of four resonators coupled in series. However, the number of resonators in series may, in a variant, vary from one filter to another. 
         [0091]    A multi port resonator device  40  may for example be built with the technology of coupled tri-mode cavities. 
         [0092]    A fourth routing function of a compact multi port router device according to the invention is illustrated in  FIGS. 12 and 13 . The router device  60  is a 3×3 router, with 5 channels, which thus comprises M=3 input ports, N=3 output ports, and is capable of carrying P=5 frequency channels. According to the routing plan illustrated in  FIG. 12 , the first two-channel time multiplex is forwarded on to the input port PE 1 , a second two-channel time multiplex is forwarded on to the input port PE 2  and one single frequency channel is sent to the input port PE 3 . The output ports are denoted as PS 1 , PS 2  and PS 3 , and only the frequency channel of the carrier frequency F 1  is forwarded on to PS 1 , whereas the other frequency channels are recombined on to the multiplexes with two frequency channels on the respective ports PS 2  and PS 3 . 
         [0093]    An embodiment of the routing function with coupled resonators is illustrated in  FIG. 13 . The router device  60  includes five filters denoted respectively as  62 ,  64 ,  66 ,  68  and  70 , formed of resonators coupled in series. The filters  64 ,  66  each comprise four resonators, the resonator coupled to the output port PS 2  being common to both filters. In a similar manner, the filters  68 ,  70  each have four resonators, including a common resonator coupled to the output port PS 3 . 
         [0094]    The input ports PE 1  and PE 2  are each coupled to two resonators belonging to two different filters, respectively the filters  62  and  64  for the input port PE 1  and the filters  66  and  68  to the input port PE 2 . The input port PE 3  is directly coupled to a single resonator of the filter  70 . At the output, the ports PS 2  and PS 3  are each coupled to a common resonator of two different filters, while the output port PS 1  is coupled to a single resonator of the filter  62 . 
         [0095]    It is to be noted that the multi port router devices according to the invention are reversible, and thus usable with the output ports being used as input ports and the input ports being used as output ports. 
         [0096]    The examples provided here above have been described with an embodiment of the resonators making up the multi port router devices with dual-mode or tri-mode cavities. Alternatively, other known technologies for building resonators may be considered, as well as other modes of coupling. 
         [0097]    According to alternative embodiments, parallel couplings between different resonators participating in different filters may be added in order to execute the routing functions according to a predetermined routing plan. 
         [0098]    Advantageously, the invention makes it possible to develop compact multi port router devices, without the need for additional junction elements, while also improving the electrical performance in comparison with existing router devices, through the reduction of insertion losses and elimination of spiking recombination peaks.