CA1205902A - Electrical power dividers - Google Patents
Electrical power dividersInfo
- Publication number
- CA1205902A CA1205902A CA000486087A CA486087A CA1205902A CA 1205902 A CA1205902 A CA 1205902A CA 000486087 A CA000486087 A CA 000486087A CA 486087 A CA486087 A CA 486087A CA 1205902 A CA1205902 A CA 1205902A
- Authority
- CA
- Canada
- Prior art keywords
- frequency band
- receiver
- transmitter
- forming network
- coupling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000004044 response Effects 0.000 claims abstract description 17
- 230000008878 coupling Effects 0.000 claims description 27
- 238000010168 coupling process Methods 0.000 claims description 27
- 238000005859 coupling reaction Methods 0.000 claims description 27
- 230000001702 transmitter Effects 0.000 claims 1
- 238000000034 method Methods 0.000 description 5
- 230000010363 phase shift Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 239000013598 vector Substances 0.000 description 2
- 241001274613 Corvus frugilegus Species 0.000 description 1
- 241000578500 Ninox novaeseelandiae Species 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- VMXUWOKSQNHOCA-UKTHLTGXSA-N ranitidine Chemical compound [O-][N+](=O)\C=C(/NC)NCCSCC1=CC=C(CN(C)C)O1 VMXUWOKSQNHOCA-UKTHLTGXSA-N 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/30—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array
- H01Q3/34—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array by electrical means
- H01Q3/40—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array by electrical means with phasing matrix
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
Landscapes
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
ELECTRICAL POWER DIVIDERS
ABSTRACT OF THE DISCLOSURE
A Beam-forming Network includes a plurality of directional couplers and phase shifters and which can interconnect both a transmitter and a receiver to the same group of radiating elements of an antenna even though the transmitter frequency band is differ-ent and well spaced from the receiver frequency band.
This is accomplished, in accordance with the inven-tion, by using directional couplers each of which has a variable response over a wide band of frequencies but which is designed so that its response over the transmitter frequency band is stable and its response over the receiver frequency band is also stable.
ABSTRACT OF THE DISCLOSURE
A Beam-forming Network includes a plurality of directional couplers and phase shifters and which can interconnect both a transmitter and a receiver to the same group of radiating elements of an antenna even though the transmitter frequency band is differ-ent and well spaced from the receiver frequency band.
This is accomplished, in accordance with the inven-tion, by using directional couplers each of which has a variable response over a wide band of frequencies but which is designed so that its response over the transmitter frequency band is stable and its response over the receiver frequency band is also stable.
Description
:~L2~5~
BACKGRO~D OF INVE~TION
Field of the Invention The present invention pertains generally to electrical power dividers and specifically to methods for connecting one or more porks to a number of other ports in such a way that the amplitude and phase ex-citations o~ the ports can be controlled within close limits over a wide range of frequencies.
The invention more specifically pertains to Beam-forming Networks including power dividers having wide band frequency responses.
Description of Prior Art Beam-forming ~etworks, or BF~'s~ are employed in many antenna applications to generate multiple beams or combinations of beams in both terrestrial and space-borne applications. In the former, BF~'s can be used for the generation of spatially coincident beams at different frequencies.
In the space-borne case, BFN's can be used to form shaped beams covering limited footprints on the earth's surface.
The BF~'s are composed of a number of different parts, for example, radiating elements, interconnecting transmission lines, power dividing elements, phase shifters and transformers. The radiating elements are typically used for feeding a collimating objective, such as a lens or reflector, in such a way that an individual elemental beam is associated with each radiating element. The final beam configuration formed by the BFN i~n association
BACKGRO~D OF INVE~TION
Field of the Invention The present invention pertains generally to electrical power dividers and specifically to methods for connecting one or more porks to a number of other ports in such a way that the amplitude and phase ex-citations o~ the ports can be controlled within close limits over a wide range of frequencies.
The invention more specifically pertains to Beam-forming Networks including power dividers having wide band frequency responses.
Description of Prior Art Beam-forming ~etworks, or BF~'s~ are employed in many antenna applications to generate multiple beams or combinations of beams in both terrestrial and space-borne applications. In the former, BF~'s can be used for the generation of spatially coincident beams at different frequencies.
In the space-borne case, BFN's can be used to form shaped beams covering limited footprints on the earth's surface.
The BF~'s are composed of a number of different parts, for example, radiating elements, interconnecting transmission lines, power dividing elements, phase shifters and transformers. The radiating elements are typically used for feeding a collimating objective, such as a lens or reflector, in such a way that an individual elemental beam is associated with each radiating element. The final beam configuration formed by the BFN i~n association
2 __ with the objectlve is the vector sum of th~ elemen-tal beams with amplitudes and phases determined by the design of the BF~o The BFN may also be used to feed an array of radiators forming several beams without the use of a collimating objectiveO
l~e principal part determining the amplitude excitations of the radiating elements is the power dividing ~art. In many systems, this part may take the form of a directional coupler of which several forms exist in many widely used types of transmission lines. ~ypical directional couplers in which the power division ratio can be easily and conveniently altered include such devices as branch-line couplers, short slot hybrids, and proximity couplers.
One of the principal limitations in the design of BFN's is the relatively narrow bandwidth of the parts forming the BF~. Bandwidths up to 1S%
are typically required for many applications which require relatively stable variation of coupling radio and p~ase as a function of frequency. In the types of couplers described above, which, in their waveguide applications are suitable for very high radio-frequency powers, coupling ratio flatness of 0.25dB is achievable over these 15% bandwidths. At ; 25 larger bandwidths, the flatness degrades.
In several instances, BFN~s must be de-signed to accommodate widely separated frequency bands. For example, the BFN may have to carry a transmit band and a receive band of frequencies.
Where the frequency separation is large, prior j lZ~?S~2 experience of the available bandwidth of power dividers has dictated that the individual BF~ts be designed to separate the transmit and receive bands into two networks. The two networks are then combined by means of a number of frequency combining networks (or diplexers), one for each radiating element.
As will be appreciated, especially in space applications, it is desirable to reduce the weight of the space borne components as a reduction in weight means`that less fuel is required to control the spacecraftO Accordingl~,, with the same fuel load, a lighter spacecraft will be able to stay aloft or a greater period of time.
It would therefore be desirable to provide a BF~ whose frequency response is broad enough so that it is responsive to both receive and transmit frequencies. With such a BF~, only a single BF~
would be needed for both the transmit and receive functions thus eliminating a complete BF~ relative to the prior art. Such a BF~ would not need a di-plexer for each radiating element, the weight of such a BFN would be less than half of the weight of a presently existing BF~.
; SUMMAR~ OF INVE~TION
It is therefore an object of the invention to provide a BFN for use with two widely separated frequencies or frequency bands whose response is broad enough to include both the freq~lencies or frequency bands.
It is a more specific object of the inven-tion to provide such BF~'s which include power ~z~s~z .1 dividers, the frequency response of the power dividers being broad enough to include the two frequencies or frequency bands.
In accordance with the invention there is provided a Beam-forming ~etwork for use in association with a plurality of radiating elements, transmitter means having an output terminal and being operable at a transmitter frequency band and receiver means having an input terminal and being operable at a receiver frequency band. The transmitter frequency band is different and spaced from the receiver fre-quency band~ The Beam-forming ~etwork interconnects the transmitter means and the radiating elements and the Beam-forming ~etwork interconnects the receiver means and the radiating elements. The Beam-forming ~etwork may be connected to a diplexer means having at least a first port, a second port and a third port, the first port being connected to the output terminal of the transmitter and the second port being connected to the input terminal o~ the receiver, and the third port being connected to the BF~. The BF~ i5 composed of individual power divider elements or couplers which may have different coupling ratios and which ~re variably responsive to a wide band of frequencies, the ~5 wide band including the transmitter frequency band and the receiver frequency band, the power divider means being designed for stable response within the transmitter frequency band and within the receiver frequency band.
The variability in the response of the indiv-idual couplers are such that the responses ~ffectively - 12G~S9(~Z
compensate for the amplitude slope in most cases, resulting in wide bandwid~h of flat frequency response simultaneously in the transmitter and receiver fre-quency bands.
BRIEF DESCRIPTIO~ OF DRAWI~GS
The invention will be better understood by an examination of the following description; together with the accompanying drawings, in which:
FIGURE 1 illustrates a typical Beam-foxming Network of :the prior art, FIGURE 2 illustrates how BFN~s of the prior art may be combined by means of a Frequency-combining ~etwork ~FCN), or diplaxer, so as to perform separate transmit and receive functions, FIGURE 3 is a graph which depicts the way in which a power-dividing element, such as a directional coupler, can be designed so as to permit independent control of the coupling ratios in two separate frequency ~ands;
FIGURE 4 shows a block diagram of a Beam-forming Network in accordance with the invention;
FIGURE ~ illustrates how a BF~ in accordance with the i.nvention provides 510pe compensation, and FIGURE 6 illustrates a further en~odiment of the invention.
s~
DESCRIPTIO~ OF PREFERRED EMBODIME~TS
Turning now to Figure 1, a prior ar-t BFN
will comprise a plurality of power dividing means such as the directional couplers Cl, C2 and C3. Such a system is illustrated in, for example, U. S. Patent 2,245,660, Feldman et al. As seen in Figure 1, the port at one side of C3 is connected to, for example, a transmitter. The two ports on the other side of C3 are connected, respectively, to ports on the one side of Cl and C2~
The beam forming network illustrated in Figure 1 also includes phase shift means ~. The two ports on the other side of Cl and C~ are connected to the phase shift means, and the phase shift means are in turn connected, respectively, to radiating elements 1, 2, 3 and 4. The radiating elements may, for example, be feedhorns feeding a collimatiny objective as dis-cussed above, or as in Feldman may be elements of an array.
Figure 2 illustrates a transmit BF~ 100 and a receive BFN 200, and illustrates how these are com-bined so that they can use a single antenna in the case when transmit and receive frequencies are widely sep-arated and the power dividing elements Cl through C6 have insufficient bandwidth to carry more than one band of frequencies. As can be seen, the phase shiters of both BF~ts are connected, respectively, to diplexers D, and the diplexers are, in turn, connected to the radiating elements 1, 2, 3 and 4.
The diplexers may be of the type which are shown,in, for example, U. S. Patent 3,252,113, Veltrop or ``` l~(~S~
U. S. Patent 4,147,9~0, Rook~ It can therefore be seen that two complete BFN~s are necessary to connect a transmitter and receiver to a single an~enna when the transmit and receive frequencies are widely separated~
In addition, such combining requires a separate di-plexer for each radiating element.
Turning now to ~igure 3, we see a graph of frequency versus coupling ratio for a power divider, or coupler, to be used in a BF~ in accordance with the present invention. As is well known, coupling ratio may be defined as a decibel equivalent of the power transferred into the coupled arm relative to the power entering the coupler.
The coupler, whose response is illustrated in Figure 3, would be designed to couple a band o transmit frequencies, Fl to F2, and a band of receive frequencies, F3 to F4. The design frequency o~ the coupler is ~0.
It can be clearly seen that the design frequency of the coupler whose response is illustrated in Figure 3 is not midway between the band of ~re-quencies but is rather biased toward the upper band of frequencies~ In this case, the coupling ratio for the higher band of frequencies will be greater than the coupling ra~io for the lower band of fre-quencies.
As the variation of coupling ratic versus frequency is typically symmetric about the design frequency, a higher coupling xatio can be designed for one frequency band versus another~by simply biasing the design frequency of the coupler to be closer to the one frequency band. It can also be seen that, with a single coupler, two diff~rent coupling ratios can be provided at two different bands of frequencies. In addition, the coupling ratio response within each band is relatively flat, though possessing slope, so that a single coupler can provide stable operation in two frequency bands even when the frequency bands are widely separated.
By appropriate design techniques, the other characteristics of the coupler, namely phase, direct-ivity, return loss and insertion loss, can also be kept very stable over frequency. In particular, output phase difference can be kept at a constant 90 over both of the required bandwidths.
The coupler may also be arranged to operate at the same coupling ratio in both requency bands by simply designing the coupler so that its design frequency is midway between the bands.
Figure 4 illustrates a transmit/receive BF~
design in accordance with the present invention. The BFN, comprising couplers Cl, C2 and C3, is connected to the third port of a diplexer D having a first port connected to a transmitter and a second port connected to a receiver. The third port of the diplexer is connected to a port at one side of a power divider such as directional coupler C3. r~O poxts on the other side of the diractional coupler are connected, respectively, to ports on the one side of directional couplers Cl and C2. Each of the two ports on the other side of Cl and C2 are respective~ly connected to phase shifters P which are in turn connected to ~2~S~9~Z
radiating elements 1, 2, 3 and 4. In accordance with the invention, the directional couplers have the design characteristics as illustrated in Figure 3.
That is, they will exhibit appropriate, and possibly different, coupling ratios at the transmit and receive frequencies. Moreover, as illustrated in Figure 5, the slopes in amplitude of the coupled and transmitted through signals are self-compensating when more than one directional coupler is used in the BFN so that the frequency response of the BFN consisting of th2 assembly of Cl, C2 and C3 is generally flat~ For examp:Le in passing a signal through C3, and then through Cl, (Figure 5), the amplitude slopes imparted as a result of these passages are opposite, positive and negative, and thus self compensateO That is, when the amplitude of Cl is high, the amplitude of C3 is l~w and vice versa.
Accordingly, as can be seen in the bottom-most graph, the response of the combination o-f the couplers is sub-stantially flat over the transmitter frequency band and over the receiver frequency band.
As can be seen, the BFN contains less than half of the elements of a similar functioning BF~
illustrated in Figure 2. Thus, the inventive BF~ as illustrated requires only three directional couplers versus six in the privr art, it requires only four phase shifter.s versus eight in the prior art, and it requires only a single diplexer versus four in the prior art. Accordingly, the weight of the inventive arrangement would be less than half the weight of the prior art arrangement.
Another class of BFN uses the so called S~
dual-mod~ technique which is illustrated in Figure 6. A slightly more complex example of this dual-mode technique is covered in U. S. Patent 4,223,283 issued September 16, 1980 to K. K. Chan.
In the dual-mode technique, ~wo independent frequency sources, A and B, will be connected to the same group of radiating elements without any cross~
coupling using the directional coupler illustrated schematically at 300 in Figure 6. Each of the power sources is fed to a separate diplexer, and the other of the diplexers are fed to the directional cou~ler~
The directional coupler may be connected to two receivers at ports C and D. Alternatively, ports C and D can be connected to an external circuit, for example, the in-phase arm of a '`Magic T" whose port E
would be connected to a single receiver. The table of vectors in Figure 6 shows the phase relationships in this simple circuit and illustrates the in-phase equi-amplitude excita~ion of the two radiating elements as required for a single mode circuit~
Although particular embodiments have been illustrated, this was for the purpose of describing, but not limiting, the invention. Various modifica-tions, which will come readily to the mind of one skilled in the art, are within the scope of the invention as defined in the appended claims.
~ 11 --
l~e principal part determining the amplitude excitations of the radiating elements is the power dividing ~art. In many systems, this part may take the form of a directional coupler of which several forms exist in many widely used types of transmission lines. ~ypical directional couplers in which the power division ratio can be easily and conveniently altered include such devices as branch-line couplers, short slot hybrids, and proximity couplers.
One of the principal limitations in the design of BFN's is the relatively narrow bandwidth of the parts forming the BF~. Bandwidths up to 1S%
are typically required for many applications which require relatively stable variation of coupling radio and p~ase as a function of frequency. In the types of couplers described above, which, in their waveguide applications are suitable for very high radio-frequency powers, coupling ratio flatness of 0.25dB is achievable over these 15% bandwidths. At ; 25 larger bandwidths, the flatness degrades.
In several instances, BFN~s must be de-signed to accommodate widely separated frequency bands. For example, the BFN may have to carry a transmit band and a receive band of frequencies.
Where the frequency separation is large, prior j lZ~?S~2 experience of the available bandwidth of power dividers has dictated that the individual BF~ts be designed to separate the transmit and receive bands into two networks. The two networks are then combined by means of a number of frequency combining networks (or diplexers), one for each radiating element.
As will be appreciated, especially in space applications, it is desirable to reduce the weight of the space borne components as a reduction in weight means`that less fuel is required to control the spacecraftO Accordingl~,, with the same fuel load, a lighter spacecraft will be able to stay aloft or a greater period of time.
It would therefore be desirable to provide a BF~ whose frequency response is broad enough so that it is responsive to both receive and transmit frequencies. With such a BF~, only a single BF~
would be needed for both the transmit and receive functions thus eliminating a complete BF~ relative to the prior art. Such a BF~ would not need a di-plexer for each radiating element, the weight of such a BFN would be less than half of the weight of a presently existing BF~.
; SUMMAR~ OF INVE~TION
It is therefore an object of the invention to provide a BFN for use with two widely separated frequencies or frequency bands whose response is broad enough to include both the freq~lencies or frequency bands.
It is a more specific object of the inven-tion to provide such BF~'s which include power ~z~s~z .1 dividers, the frequency response of the power dividers being broad enough to include the two frequencies or frequency bands.
In accordance with the invention there is provided a Beam-forming ~etwork for use in association with a plurality of radiating elements, transmitter means having an output terminal and being operable at a transmitter frequency band and receiver means having an input terminal and being operable at a receiver frequency band. The transmitter frequency band is different and spaced from the receiver fre-quency band~ The Beam-forming ~etwork interconnects the transmitter means and the radiating elements and the Beam-forming ~etwork interconnects the receiver means and the radiating elements. The Beam-forming ~etwork may be connected to a diplexer means having at least a first port, a second port and a third port, the first port being connected to the output terminal of the transmitter and the second port being connected to the input terminal o~ the receiver, and the third port being connected to the BF~. The BF~ i5 composed of individual power divider elements or couplers which may have different coupling ratios and which ~re variably responsive to a wide band of frequencies, the ~5 wide band including the transmitter frequency band and the receiver frequency band, the power divider means being designed for stable response within the transmitter frequency band and within the receiver frequency band.
The variability in the response of the indiv-idual couplers are such that the responses ~ffectively - 12G~S9(~Z
compensate for the amplitude slope in most cases, resulting in wide bandwid~h of flat frequency response simultaneously in the transmitter and receiver fre-quency bands.
BRIEF DESCRIPTIO~ OF DRAWI~GS
The invention will be better understood by an examination of the following description; together with the accompanying drawings, in which:
FIGURE 1 illustrates a typical Beam-foxming Network of :the prior art, FIGURE 2 illustrates how BFN~s of the prior art may be combined by means of a Frequency-combining ~etwork ~FCN), or diplaxer, so as to perform separate transmit and receive functions, FIGURE 3 is a graph which depicts the way in which a power-dividing element, such as a directional coupler, can be designed so as to permit independent control of the coupling ratios in two separate frequency ~ands;
FIGURE 4 shows a block diagram of a Beam-forming Network in accordance with the invention;
FIGURE ~ illustrates how a BF~ in accordance with the i.nvention provides 510pe compensation, and FIGURE 6 illustrates a further en~odiment of the invention.
s~
DESCRIPTIO~ OF PREFERRED EMBODIME~TS
Turning now to Figure 1, a prior ar-t BFN
will comprise a plurality of power dividing means such as the directional couplers Cl, C2 and C3. Such a system is illustrated in, for example, U. S. Patent 2,245,660, Feldman et al. As seen in Figure 1, the port at one side of C3 is connected to, for example, a transmitter. The two ports on the other side of C3 are connected, respectively, to ports on the one side of Cl and C2~
The beam forming network illustrated in Figure 1 also includes phase shift means ~. The two ports on the other side of Cl and C~ are connected to the phase shift means, and the phase shift means are in turn connected, respectively, to radiating elements 1, 2, 3 and 4. The radiating elements may, for example, be feedhorns feeding a collimatiny objective as dis-cussed above, or as in Feldman may be elements of an array.
Figure 2 illustrates a transmit BF~ 100 and a receive BFN 200, and illustrates how these are com-bined so that they can use a single antenna in the case when transmit and receive frequencies are widely sep-arated and the power dividing elements Cl through C6 have insufficient bandwidth to carry more than one band of frequencies. As can be seen, the phase shiters of both BF~ts are connected, respectively, to diplexers D, and the diplexers are, in turn, connected to the radiating elements 1, 2, 3 and 4.
The diplexers may be of the type which are shown,in, for example, U. S. Patent 3,252,113, Veltrop or ``` l~(~S~
U. S. Patent 4,147,9~0, Rook~ It can therefore be seen that two complete BFN~s are necessary to connect a transmitter and receiver to a single an~enna when the transmit and receive frequencies are widely separated~
In addition, such combining requires a separate di-plexer for each radiating element.
Turning now to ~igure 3, we see a graph of frequency versus coupling ratio for a power divider, or coupler, to be used in a BF~ in accordance with the present invention. As is well known, coupling ratio may be defined as a decibel equivalent of the power transferred into the coupled arm relative to the power entering the coupler.
The coupler, whose response is illustrated in Figure 3, would be designed to couple a band o transmit frequencies, Fl to F2, and a band of receive frequencies, F3 to F4. The design frequency o~ the coupler is ~0.
It can be clearly seen that the design frequency of the coupler whose response is illustrated in Figure 3 is not midway between the band of ~re-quencies but is rather biased toward the upper band of frequencies~ In this case, the coupling ratio for the higher band of frequencies will be greater than the coupling ra~io for the lower band of fre-quencies.
As the variation of coupling ratic versus frequency is typically symmetric about the design frequency, a higher coupling xatio can be designed for one frequency band versus another~by simply biasing the design frequency of the coupler to be closer to the one frequency band. It can also be seen that, with a single coupler, two diff~rent coupling ratios can be provided at two different bands of frequencies. In addition, the coupling ratio response within each band is relatively flat, though possessing slope, so that a single coupler can provide stable operation in two frequency bands even when the frequency bands are widely separated.
By appropriate design techniques, the other characteristics of the coupler, namely phase, direct-ivity, return loss and insertion loss, can also be kept very stable over frequency. In particular, output phase difference can be kept at a constant 90 over both of the required bandwidths.
The coupler may also be arranged to operate at the same coupling ratio in both requency bands by simply designing the coupler so that its design frequency is midway between the bands.
Figure 4 illustrates a transmit/receive BF~
design in accordance with the present invention. The BFN, comprising couplers Cl, C2 and C3, is connected to the third port of a diplexer D having a first port connected to a transmitter and a second port connected to a receiver. The third port of the diplexer is connected to a port at one side of a power divider such as directional coupler C3. r~O poxts on the other side of the diractional coupler are connected, respectively, to ports on the one side of directional couplers Cl and C2. Each of the two ports on the other side of Cl and C2 are respective~ly connected to phase shifters P which are in turn connected to ~2~S~9~Z
radiating elements 1, 2, 3 and 4. In accordance with the invention, the directional couplers have the design characteristics as illustrated in Figure 3.
That is, they will exhibit appropriate, and possibly different, coupling ratios at the transmit and receive frequencies. Moreover, as illustrated in Figure 5, the slopes in amplitude of the coupled and transmitted through signals are self-compensating when more than one directional coupler is used in the BFN so that the frequency response of the BFN consisting of th2 assembly of Cl, C2 and C3 is generally flat~ For examp:Le in passing a signal through C3, and then through Cl, (Figure 5), the amplitude slopes imparted as a result of these passages are opposite, positive and negative, and thus self compensateO That is, when the amplitude of Cl is high, the amplitude of C3 is l~w and vice versa.
Accordingly, as can be seen in the bottom-most graph, the response of the combination o-f the couplers is sub-stantially flat over the transmitter frequency band and over the receiver frequency band.
As can be seen, the BFN contains less than half of the elements of a similar functioning BF~
illustrated in Figure 2. Thus, the inventive BF~ as illustrated requires only three directional couplers versus six in the privr art, it requires only four phase shifter.s versus eight in the prior art, and it requires only a single diplexer versus four in the prior art. Accordingly, the weight of the inventive arrangement would be less than half the weight of the prior art arrangement.
Another class of BFN uses the so called S~
dual-mod~ technique which is illustrated in Figure 6. A slightly more complex example of this dual-mode technique is covered in U. S. Patent 4,223,283 issued September 16, 1980 to K. K. Chan.
In the dual-mode technique, ~wo independent frequency sources, A and B, will be connected to the same group of radiating elements without any cross~
coupling using the directional coupler illustrated schematically at 300 in Figure 6. Each of the power sources is fed to a separate diplexer, and the other of the diplexers are fed to the directional cou~ler~
The directional coupler may be connected to two receivers at ports C and D. Alternatively, ports C and D can be connected to an external circuit, for example, the in-phase arm of a '`Magic T" whose port E
would be connected to a single receiver. The table of vectors in Figure 6 shows the phase relationships in this simple circuit and illustrates the in-phase equi-amplitude excita~ion of the two radiating elements as required for a single mode circuit~
Although particular embodiments have been illustrated, this was for the purpose of describing, but not limiting, the invention. Various modifica-tions, which will come readily to the mind of one skilled in the art, are within the scope of the invention as defined in the appended claims.
~ 11 --
Claims (8)
1. A Beam-forming Network for use in association with:
a plurality of radiating elements;
transmitter means having an output terminal and being operable at a transmitter frequency band; and receiver means having an input terminal and being operable at a receiver frequency band;
a diplexer having a first input port operable at a transmitter frequency band, having also a second output port operable at receiver frequency band, and having also a third input/output port operable simul-taneously at both a transmitter and a receiver frequency band;
said Beam-forming Network interconnecting said transmitter means, said diplexer and said radiating elements and said Beam-forming Network also inter-connecting said radiating elements, said diplexer and said receiver means;
said Beam-forming Network comprising a plurality of coupling means wherein said coupling means are variably responsive to a wide band of frequencies including trans-mitter and receiver frequency bands, and wherein said plurality of coupling means have equal or different coupling ratios; wherein said coupling ratios are self-compensatingly responsive to said wide band of fre-quencies.
a plurality of radiating elements;
transmitter means having an output terminal and being operable at a transmitter frequency band; and receiver means having an input terminal and being operable at a receiver frequency band;
a diplexer having a first input port operable at a transmitter frequency band, having also a second output port operable at receiver frequency band, and having also a third input/output port operable simul-taneously at both a transmitter and a receiver frequency band;
said Beam-forming Network interconnecting said transmitter means, said diplexer and said radiating elements and said Beam-forming Network also inter-connecting said radiating elements, said diplexer and said receiver means;
said Beam-forming Network comprising a plurality of coupling means wherein said coupling means are variably responsive to a wide band of frequencies including trans-mitter and receiver frequency bands, and wherein said plurality of coupling means have equal or different coupling ratios; wherein said coupling ratios are self-compensatingly responsive to said wide band of fre-quencies.
2. A Beam-forming Network as defined in claim 1 wherein said frequency band includes said transmitter frequency band and said receiver frequency band;
whereby said couplers present a substantially flat response over said transmitter frequency band and over said receiver frequency band.
whereby said couplers present a substantially flat response over said transmitter frequency band and over said receiver frequency band.
3. A Beam-forming Network as defined in claim 2 wherein said coupling means comprises directional couplers.
4. A Beam-forming Network as defined in claim 3 wherein each said coupler is designed to have a design frequency intermediate said transmitter frequency band and said receiver frequency band.
5. A Beam-forming Network as defined in claim 4 wherein each said coupler is designed to have a first coupling ratio at said transmitter frequency band and a second coupling ratio at said receiver fre-quency band.
6. A Beam-forming Network as defined in claim 5 wherein said first coupling ratio is equal to said second coupling ratio.
7. A Beam-forming Network as defined in claim 5 wherein said first coupling ratio is not equal to said second coupling ratio.
8. A Beam-forming Network as defined in claims 6 or 7, and further including phase shifter means disposed between each said radiating element and its associated coupler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000486087A CA1205902A (en) | 1985-06-28 | 1985-06-28 | Electrical power dividers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000486087A CA1205902A (en) | 1985-06-28 | 1985-06-28 | Electrical power dividers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1205902A true CA1205902A (en) | 1986-06-10 |
Family
ID=4130901
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000486087A Expired CA1205902A (en) | 1985-06-28 | 1985-06-28 | Electrical power dividers |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1205902A (en) |
-
1985
- 1985-06-28 CA CA000486087A patent/CA1205902A/en not_active Expired
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