CN108370079B

CN108370079B - Radio frequency signal synthesizer

Info

Publication number: CN108370079B
Application number: CN201580085084.6A
Authority: CN
Inventors: 弗拉德·列尼夫
Original assignee: Zhuji Yihe Project Investment Co ltd
Current assignee: Zhuji yashijie Knitting Co.,Ltd.
Priority date: 2015-12-04
Filing date: 2015-12-04
Publication date: 2020-07-10
Anticipated expiration: 2035-12-04
Also published as: EP3375037A1; CN108370079A; WO2017092820A1

Abstract

A Radio Frequency (RF) signal synthesizer, comprising: an axisymmetric periodic waveguide device having a cylinder and a center conductor coaxially disposed within the cylinder. The center conductor is defined by a pair of orthogonal planes of symmetry. A shorting wall closes an end of the cylinder and is electrically coupled to the center conductor. A magnetic loop coupling element is disposed within the cylinder relative to a first plane of symmetry of the pair of orthogonal planes of symmetry. A plurality of input ports extend through respective openings in the shorting wall, each input port feeding a signal to a corresponding magnetic loop coupling element. An output port is configured to output the combined power of the signals from the plurality of input ports, the output port being disposed on a side of the combiner remote from the shorting wall.

Description

Radio frequency signal synthesizer

Technical Field

Aspects of the present application relate generally to power combiners and, more particularly, to radio frequency signal power combiners for antenna arrays.

Background

Wireless communication systems in densely populated areas face the problem of tight utilization of the available Radio Frequency (RF) radio spectrum. Economic efficiency of mobile network operators results in increased RF power levels required for bit rate throughput within energy efficiency and cost constraints.

The number of inputs to the synthesizer is typically limited by the amount of coupling that can be achieved per input, which in turn is limited by the electromagnetic properties of the synthesizer.

Mixed waves are widely used in antenna technology. The only known synthesizer employing mixed waves is based on an electrical coupling to the lowest main mixed wave. The main technical problem in this case is that the physical coupling of the electrical probes is not sufficient and it is difficult to place more than one pair of electrical probes in the maximum field of the mixed wave. This results in an axisymmetric periodic waveguide or quasi-periodic structure (ASPS) with an overly long coupled probe occupying more than one period, thus making the profile of the synthesizer oversized. A limitation of the electrical probe is that it requires a source signal with an opposite phase.

It is therefore desirable to provide an RF signal power combiner that addresses at least some of the above-mentioned problems.

Disclosure of Invention

It is an object of the present invention to provide an improved radio frequency signal power combiner. This object is solved by the subject matter of the independent claims. Further advantageous modifications can be found in the dependent claims.

The above and other objects and advantages are obtained according to a first aspect of the present invention by a Radio Frequency (RF) signal power combiner. The combiner comprises an axisymmetric periodic waveguide arrangement. The axisymmetric periodic waveguide device includes a cylinder and a center conductor coaxially disposed within the cylinder. The center conductor is defined by a pair of orthogonal planes of symmetry. A shorting wall closes an end of the cylinder and is electrically coupled to the center conductor. At least one pair of magnetic loop coupling elements is disposed within the cylinder relative to a first plane of symmetry defining the pair of orthogonal planes of symmetry of the center conductor. A plurality of input ports extend through respective openings in the shorting wall, each of the plurality of input ports feeding a signal to a respective one of the at least one pair of magnetic loop coupling elements. An output port is disposed on a side of the combiner distal from the shorting wall, the output port configured to output a combined power of signals from the plurality of input ports. Aspects of the disclosed embodiments enable substantially high levels of RF power to be achieved in an antenna array using several relatively low power sources.

In a first possible implementation form of the radio frequency signal synthesizer according to the first aspect, the cylinder comprises (or is) a conductive cylinder, and the at least one pair of magnetic loop coupling elements is carried on a dielectric card. The use of a magnetic loop coupling element enables a greater amount of coupling than can be physically achieved with an electrical probe, and the closed loop is located entirely within the volume of its corresponding compartment.

In a second possible implementation form of the radio frequency signal synthesizer according to the first possible implementation form, the shorting wall electrically couples the center conductor with the conductive cylinder. The electrical coupling may comprise a mechanical connection, a resistive coupling, or a capacitive coupling. The use of a shorting wall to electrically couple the center conductor to the conductive cylinder may provide a more compact form factor and ease of manufacture.

In a third possible implementation of the radio frequency signal synthesizer according to the first and second possible implementations, the at least one pair of magnetic loop coupling elements is printed on the first side of the dielectric card. The use of a magnetic loop coupling element enables a greater amount of coupling than can be physically achieved with an electrical probe, and the closed loop is located entirely within the volume of its corresponding compartment.

In a fourth possible implementation form of the radio frequency signal synthesizer according to the first to third possible implementation forms, one pair of the at least one pair of magnetic loop coupling elements is arranged coplanar to each other and coplanar to the first plane of symmetry. The presence of the electric and magnetic walls enables the provision of magnetic coupling elements that are symmetrical to these surfaces in order to achieve the maximum possible coupling without destroying the intended field distribution.

In a fifth possible implementation form of the radio frequency signal synthesizer according to any one of the first to fourth possible implementation forms, the first magnetic loop coupling element of the pair of coplanar magnetic loop coupling elements and the second magnetic loop coupling element of the pair of coplanar magnetic loop coupling elements are arranged equidistantly with respect to the center conductor. The coupling elements are arranged symmetrically to the electrical and magnetic walls in order to achieve the maximum possible coupling without destroying the desired field distribution.

In a sixth possible implementation form of the radio frequency signal synthesizer according to any one of the first to fifth possible implementation forms, the radio frequency signal synthesizer comprises a conductive track on the second side of the dielectric card, the conductive track being coupled with each of the plurality of input ports. This causes the input signal to couple to the magnetic coupling loop.

In a seventh possible implementation form of the radio frequency signal synthesizer according to any one of the first to sixth possible implementation forms, the magnetic loop coupling element is resistively coupled to the conductive track. This causes the signal from the input port to be fed into the magnetic coupling loop.

In an eighth possible implementation form of the radio frequency signal synthesizer according to any one of the first to seventh possible implementation forms, the dielectric card is disposed in a dielectric card receiving slot of the center conductor. The center conductor can carry the dielectric card within the synthesizer in any number of positions and allows the number of input ports to be increased.

In a ninth possible implementation form of the radio frequency signal synthesizer according to the first aspect as such or according to any of the preceding implementation forms, the magnetic loop coupling element of the at least one pair of magnetic loop coupling elements comprises a figure-8 shaped magnetic loop coupling element. This topology generates magnetic flux of equal strength but opposite direction. The loop has magnetic flux in both forward and return directions, providing the most efficient coupling.

In a tenth possible implementation form of the radio frequency signal synthesizer according to the first aspect as such or any of the preceding implementation forms, at least a first orthogonal plane defining the pair of orthogonal symmetry planes of the center conductor passes through all magnetic loop coupling elements of the at least one pair of magnetic loop coupling elements. This allows the internal volume of the ASPS to be divided into two cells separated by a magnetic wall and allows the magnetic circuit to couple to the magnetic field inside the cells.

In an eleventh possible implementation form of the radio frequency signal synthesizer according to the first aspect, the cylinder comprises (or is) a dielectric cylinder, and the magnetic return coupling elements of the at least one pair of magnetic return coupling elements are arranged on, and preferably printed on, a surface of the dielectric cylinder. The mechanical assembly of the combiner is simplified and the number of input ports is increased and the mechanical components are correspondingly reduced.

In a twelfth possible implementation form of the radio frequency signal synthesizer according to the eleventh possible implementation form, the radio frequency signal synthesizer comprises a conductive cylinder. The shorting wall electrically couples the center conductor with the conductive cylinder. The electrical coupling may comprise a mechanical connection, a resistive coupling, or a capacitive coupling. The use of a dielectric cylinder may enhance inter-port isolation and power handling.

In a thirteenth possible implementation form of the radio frequency signal synthesizer according to the twelfth possible implementation form, the radio frequency signal synthesizer comprises a conductive track arranged, preferably printed, on the inner surface of the dielectric cylinder, the conductive track being coupled with each of the plurality of input ports for feeding a signal to a corresponding one of the at least one pair of magnetic loop coupling elements. The mechanical assembly of the combiner is simplified and the number of input ports is increased and the mechanical components are correspondingly reduced.

In a thirteenth possible implementation form of the radio frequency signal synthesizer of the eleventh and twelfth possible implementation forms, the magnetic loop coupling elements of the at least one pair of magnetic loop coupling elements are disposed equidistant from each other with respect to the center conductor. The coupling elements are arranged symmetrically to the electrical and magnetic walls in order to achieve the maximum possible coupling without destroying the desired field distribution.

In a fourteenth possible implementation form of the radio frequency signal synthesizer according to the first aspect or any of the preceding implementation forms, the axisymmetric periodic waveguide arrangement supports a mixed wave signal. The power combiner of the disclosed embodiments takes advantage of the natural characteristics of the mixed azimuthally inhomogeneous wave.

In a fifteenth possible implementation form of the radio frequency signal synthesizer according to the first aspect as such or any of the preceding implementation forms, the internal volume of the axisymmetric periodic waveguide means is divided by the pair of orthogonal symmetry planes into at least one pair of compartments, wherein a compartment of the at least one pair of compartments has a dedicated magnetic loop coupling element and an input port. When the coupling elements are fed with the correct amplitude and phase, a combination of energies occurs, providing a power combining effect.

In a sixteenth possible implementation of the radio frequency signal synthesizer according to the first aspect or any of the previous implementations, the axisymmetric periodic waveguide device is an on-pole disc antenna assembly. The on-pole disc antenna assembly belongs to a class of guidance that supports hybrid modes. An advantage of this type of guiding structure is that HE with not only one but also two cut-off frequencies can be supported_mnMixed waves, i.e., low and high cutoff frequencies.

In accordance with a second aspect of the present invention, the above and other objects and advantages are obtained by a Radio Frequency (RF) signal power combiner. The combiner comprises an axisymmetric periodic waveguide arrangement. The axisymmetric periodic waveguide device includes a dielectric cylinder and a center conductor coaxially disposed within the dielectric cylinder. The center conductor is defined by a pair of orthogonal planes of symmetry. A shorting wall closes an end of the dielectric cylinder and is electrically coupled to the center conductor. At least one pair of magnetic loop coupling elements is disposed on a surface of the dielectric cylinder relative to a first plane of symmetry defining the pair of orthogonal planes of symmetry of the center conductor. A plurality of input ports extend through respective openings in the shorting wall, each of the plurality of input ports feeding a signal to a respective one of the at least one pair of magnetic loop coupling elements. An output port is disposed on a side of the combiner distal from the shorting wall, the output port configured to output a combined power of signals from the plurality of input ports. Aspects of the disclosed embodiments enable substantially high levels of RF power to be achieved in an antenna array using several relatively low power sources.

In accordance with a third aspect of the present invention, the above and other objects and advantages are obtained by a Radio Frequency (RF) signal power combiner. The synthesizer includes an outer conductive cylinder, a dielectric cylinder coaxially disposed within the outer conductive cylinder, and a center conductor coaxially disposed within the dielectric cylinder. The center conductor is defined by a pair of orthogonal planes of symmetry. A shorting wall closes ends of the dielectric cylinder and the outer conductive cylinder and is electrically coupled to the center conductor and the outer conductive cylinder. The electrical coupling may include one or more of a mechanical connection, a resistive coupling, or a capacitive coupling. At least one pair of magnetic return coupling elements is disposed on a surface of the dielectric cylinder. A plurality of input ports extend through respective openings in the shorting wall, and conductive tracks are provided on, and preferably printed on, the outer and inner surfaces of the dielectric cylinder, and connected with dedicated through-holes. Aspects of the disclosed embodiments enable substantially high levels of RF power to be achieved in an antenna array using several relatively low power sources.

In accordance with a fourth aspect of the present invention, the above and other objects and advantages are obtained by a Radio Frequency (RF) signal power combiner. The combiner comprises an axisymmetric periodic waveguide arrangement. The axisymmetric periodic waveguide device includes a conductive cylinder, a center conductor coaxially disposed within the conductive cylinder, the center conductor defined by a pair of orthogonal symmetry planes. A shorting wall closes an end of the conductive cylinder and electrically couples the center conductor with the conductive cylinder. The electrical coupling may comprise a mechanical connection, a resistive coupling, or a capacitive coupling. The dielectric carrier member carries a center conductor within the electrical conductor. At least one pair of magnetic loop coupling elements is disposed within the conductive cylinder relative to a first plane of symmetry defining the pair of orthogonal planes of symmetry of the center conductor. A dielectric member carries the at least one pair of magnetic loop coupling elements and the end of the center conductor adjacent the shorting wall. The dielectric member is disposed between the shorting wall and the center conductor. A plurality of input ports extend through respective openings in the shorting wall, each of the plurality of input ports feeding a signal to a corresponding one of the at least one pair of magnetic loop coupling elements. An output port is disposed on a side of the combiner distal from the shorting wall, the output port configured to output a combined power of signals from the plurality of input ports. Aspects of the disclosed embodiments enable substantially high levels of RF power to be achieved in an antenna array using several relatively low power sources.

In a first possible implementation of the fourth aspect, the dielectric carrier surrounds a center conductor within the conductive cylinder.

In a second possible implementation of the fourth aspect or of the first possible implementation, the dielectric carrier member is a dielectric foam.

In a third possible implementation of the fourth aspect or of any one of the preceding possible implementations, the dielectric carrier member electrically isolates the center conductor from the conductive cylinder and the shorting wall.

In accordance with a fifth aspect of the present invention, the above and other objects and advantages are obtained by a Radio Frequency (RF) signal power combiner. The combiner comprises an axisymmetric periodic waveguide arrangement. The axisymmetric periodic waveguide device includes a dielectric cylinder, a center conductor coaxially disposed within the dielectric cylinder, the center conductor defined by a pair of orthogonal symmetry planes. A shorting wall closes an end of the dielectric cylinder and is electrically coupled to the center conductor. The electrical coupling may comprise a mechanical connection, a resistive coupling, or a capacitive coupling. A dielectric carrier carries the center conductor within the dielectric cylinder. At least one pair of magnetic loop coupling elements is disposed on a surface of the dielectric cylinder relative to a first plane of symmetry defining the pair of orthogonal planes of symmetry of the center conductor. A dielectric member may carry an end of the center conductor adjacent the shorting wall. The dielectric member is disposed between the shorting wall and the center conductor. A plurality of input ports extend through respective openings in the shorting wall, each of the plurality of input ports feeding a signal to a corresponding one of the at least one pair of magnetic loop coupling elements. An output port is disposed on a side of the combiner distal from the shorting wall, the output port configured to output a combined power of signals from the plurality of input ports. Aspects of the disclosed embodiments enable substantially high levels of RF power to be achieved in an antenna array using several relatively low power sources.

These and other aspects, implementations, and advantages of the exemplary embodiments will become apparent from the embodiments described herein when taken in conjunction with the accompanying drawings. It is to be understood, however, that the description and drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Furthermore, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Drawings

In the following detailed part of the present application, the invention will be explained in more detail with reference to exemplary embodiments shown in the drawings, in which:

FIG. 1 illustrates an exemplary RF signal power combiner assembly incorporating aspects of the disclosed embodiments;

FIG. 2 shows a hollow waveguide structure supporting pure mode waves;

FIG. 3 illustrates a waveguide structure of a power combiner assembly incorporating aspects of the disclosed embodiments;

FIG. 4 illustrates a cross-sectional view of an axisymmetric structure supporting mixed waves for a power combiner assembly incorporating aspects of the disclosed embodiments;

FIGS. 5 and 6 illustrate a minimum primary mix HE of a power combiner assembly incorporating aspects of the disclosed embodiments₁₁An electromagnetic field in a cross-section of the ASPS structure;

FIGS. 7 and 8 illustrate exemplary coupling loops for power combiner components incorporating aspects of the disclosed embodiments;

FIGS. 9 and 10 illustrate the use of electrical wall and coupling loop assemblies in power combiner assemblies incorporating aspects of the disclosed embodiments;

fig. 11 illustrates a configuration of a dielectric card carrying a coupling loop of a power combiner assembly incorporating aspects of the disclosed embodiments;

FIGS. 12 and 13 illustrate the use of magnetic wall and coupling loop assemblies of a power combiner assembly incorporating aspects of the disclosed embodiments;

FIGS. 14-15 illustrate perspective views of a power combiner assembly incorporating aspects of the disclosed embodiments; and

16-17 illustrate perspective views of an output portion of a power combiner assembly incorporating aspects of the disclosed embodiments;

fig. 18 illustrates the use of a dielectric carrier member of a power combiner assembly incorporating aspects of the disclosed embodiments.

Detailed Description

Aspects of the disclosed embodiments relate to an RF signal power combiner apparatus configured for achieving high power levels in a multi-beam antenna array. The synthesizer apparatus is a multi-port synthesizer that employs electromagnetic waves in a mixed azimuthally inhomogeneous electromagnetic wave with electrical and/or magnetic walls associated with the 3D field distribution. The electromagnetic properties of mixed azimuthally inhomogeneous waves supported by axisymmetric periodic structures (ASPS) are used for power synthesis. The term "mixed wave" is used to designate a particular type of wave propagating in an axisymmetric periodic or quasi-periodic structure, generally referred to herein as "ASPS". The term reflects the distinguishing technical features of these waves, i.e. unlike other more common types of waves (TEM, TE and TM waves), which have a longitudinal electric field component and a longitudinal magnetic field component. This property of the mixed wave is defined by a mixing factor, which is a numerical indicator of the energy ratio between the magnetic field part component and the electric field part component of the longitudinal electromagnetic field in the mixed wave. In particular, aspects of the disclosed embodiments utilize azimuth inhomogeneous waves HE in ASPS₁₁Power synthesis is performed.

By exploiting the electromagnetic field properties of the mixed waves supported by the dedicated waveguide structure that can be used as antenna array elements, the power combining function can be integrated within the antenna elements. In one embodiment, the interior volume of the ASPS is partitioned into partial regions or cells defined by electrical and magnetic walls. The electromagnetic field within the ASPS inner volume may be divided into cells accordingly, each cell being fed by a dedicated coupling element. When the coupling elements are fed with the correct amplitude and phase, a combination of energies occurs, providing a power combining effect.

Fig. 1 illustrates one embodiment of an RF signal power combiner apparatus incorporating aspects of the disclosed embodiments. In this example, the synthesizer apparatus 100 comprises a 2-to-1 synthesizer based on an on-pole disc antenna structure 102 (also referred to as an ASPS structure 102). The pole disk antenna structure belongs to the ASPS structural family supporting mixed waves and includes a wavy dielectric rod antenna as a feed end. Various aspects of the disclosed embodiments apply to cellular base stations and/or micro base stations with frequency coverage in the range of 2-6 GHz.

In the example of fig. 1, the power combiner arrangement 100 generally includes a center conductor 106. Referring also to fig. 11, in one embodiment, the center conductor 106 is coaxially disposed within the cylinder 120. In one embodiment, cylinder 120 comprises a conductive material, referred to herein as conductive cylinder 122. In the embodiment shown in FIG. 13, the cylinder 120 comprises a dielectric material, referred to herein as a dielectric cylinder 312. In the example of fig. 11, the housing 20 encloses an ASPS structure 102. One or more disks 104 form part of the on-pole disk structure 102 and are disposed along the length of a center conductor 106 within the housing 20.

The center conductor 106 is defined by a pair of orthogonal planes of symmetry 108 (also referred to as the X and Y planes). For example, referring to fig. 1 and 5, the plane of symmetry is fixed at the longitudinal axis C of the center conductor 106. Although there may be an infinite number of planes of symmetry, only one pair is orthogonal to each other. In the example shown in fig. 1 and 5, a pair of orthogonal planes of symmetry 108 are defined by X and Y planes passing through a generally central or longitudinal axis C of the center conductor 106. The pair of planes of symmetry define a minimum order of rotational symmetry of the center conductor 106 and define a substantially square cross-section.

As shown in fig. 1 and 5, in one embodiment, the X-plane defines a first plane of symmetry 107 or horizontal cross-section through the center conductor 106. The first plane of symmetry 107 comprises a central axis defining the orientation of the central conductor 106 and also comprises an electrical wall. The Y-plane defines a second plane of symmetry 109 or vertical cross-section through center conductor 106. The second plane of symmetry 109 comprises a central axis defining the orientation of the central conductor 106 and comprises magnetic walls. This set of conditions makes the pair of

planes

107, 109 unique and not limited by the symmetry order described with respect to fig. 3 below, since the pair of

planes

107, 109 satisfy the conditions for the lowest order symmetry specified and are associated with the physical characteristics of the propagating wave.

Referring also to fig. 11, one end of the cylinder 120 includes a shorting wall 110. In the example of fig. 11, the shorting wall 110 closes one end of the cylinder 120. The center conductor 106 in the examples of fig. 8, 11, and 13 is electrically coupled to the shorting wall 110.

The shorting wall 110 is configured to electrically couple the center conductor 106 and the outer conductor. In the example of fig. 8 and 11, the cylinder 120 includes a conductive cylinder 122 forming an outer conductor. The shorting wall 110 is electrically coupled to the conductive cylinder 122. In the example of fig. 15, the outer conductor comprises a conductive cylinder 308. In this example, the shorting wall 110 is electrically coupled with the conductive cylinder 308.

The shorting wall 110 may be mechanically, resistively, or capacitively coupled to the outer conductor. For example, the shorting wall 110 may be mechanically coupled with the conductive cylinder 122 of fig. 11 or the conductive cylinder 308 of fig. 15 to form an electrical coupling. In another embodiment, the air gap between the shorting wall 110 and the

conductive cylinders

122, 308 forms an air-filled capacitor that creates an electrical coupling. For example, a portion of the center conductor 106 adjacent to the shorting wall 110 may be removed to form an air gap. As described below, a foam or dielectric member may be introduced into the gap for load bearing. In alternate embodiments, any suitable manner of electrically coupling the shorting wall 110 with the external conductor may be used. In the example of fig. 13, the shorting wall 110 is mechanically coupled to the dielectric cylinder 312.

As shown in fig. 1, center conductor 106 may include one or more slots 112 for placement of dielectric cards 114. The dielectric card 114 typically comprises a Printed Circuit Board (PCB) or similar dielectric substrate that may be provided with conductive tracks or traces, which are generally known. Typically, slots 112 are disposed on opposite sides of center conductor 106. The slot 112 in this example is generally aligned with respect to or with a plane of symmetry of a pair of orthogonal planes of symmetry 108 that define the center conductor 106. In the example of fig. 1, two slots 112 are shown, each having a dielectric card 114 disposed therein. In alternative embodiments, center conductor 106 may include any number of slots 112 to receive corresponding dielectric cards 114.

Referring again to fig. 1, the dielectric card 114 includes a coupling loop element 116, also referred to as a magnetic coupling loop element, on one side of the dielectric card 114. The coupling loop element 116 on the dielectric card 114 is generally aligned with respect to a plane of symmetry of a pair of orthogonal planes of symmetry 108, which define the center conductor 106. In one embodiment, the synthesizer 100 will include at least one pair of coupled loop elements 116. In the example of fig. 1, the coupling loop element 116 is in the form of a figure-8 coupling loop. In alternate embodiments, the coupling loop element 116 may comprise any suitable loop structure.

The opposite or reverse side of the dielectric card 114 includes conductive tracks or elements 118, also referred to herein as feed lines. The conductive tracks or elements 118 are configured to feed electrical signals from the respective input ports P1-P4 to the corresponding coupled loop elements 116. In one embodiment, the coupling between the input ports P1-P4 and the respective coupled loop element 116 is a resistive coupling. In alternative embodiments, the conductive tracks 118 may be coupled to the coupled loop element 116 in any suitable manner other than including resistive coupling. For example, in one embodiment, the conductive tracks 118 may be coupled to the coupling loop element 116 via a capacitive coupling device, such as a capacitor.

The power combiner 100 further comprises an output port 130. In the example of fig. 1 and 16, the output port 130 is disposed at an end of the combiner 100 remote from or opposite the shorting wall 110. The output port 130 is configured to output the combined power of the signals from the plurality of input ports P1-P4.

As with the synthesizer apparatus 100 shown in fig. 1, the aspects of the disclosed embodiments take advantage of the mixed azimuthally inhomogeneous wave characteristics supported by an axisymmetric periodic structure. To achieve dual polarization operation, the antenna aperture in the combiner device 100 should have a certain degree of symmetry. This can be expressed in terms of the order of axial symmetry used in crystallography: c4, C8, C16_∞. However, this limits the choice of a suitable antenna structure.

FIG. 2 illustrates a support-based pure mode wave H_mnAnd E_mnExemplary antenna aperture structure 10 of a hollow waveguide. The common advantage of these simple structures is that they all have a low frequency cut-off, providing a substantial rejection for frequencies below the cut-off frequency, unlike printed dipole/slot antenna aperture structures. Unfortunately, these simple structures may be too large to package in an antenna array, especially if the scanning requirements are applied, as the inter-element distance becomes too large. To overcome this limitation, the second conductor may be disposed coaxially with the first conductor.

Fig. 3 shows an exemplary aperture cross-section of a mixed mode guiding structure in which the second conductor 14 is arranged coaxially with the first conductor 12. These types of axisymmetric structures can support pure mode H_mn，E_mnAnd also includes supporting mixed mode HEs_mnAnd EH_mnA subset of (a). These modes propagate at specific wavelengths associated with the cross-sectional dimensions.

Fig. 4 illustrates a longitudinal cross-sectional view of an exemplary mixed mode boot or ASPS structure 102. The ASPS structure 102 in fig. 4 is a generic ASPS structure, only one of the two conductors containing the corrugations 103 being shown for simplicity. The actual engineering solution may be based on a simpler version derived from such a generic configuration. For example, in the case where d is 0, the ASPS structure 102 degenerates into a circular waveguide with a radius e. In the case of g 2-g 1-gN, the ASPS structure 102 becomes a smooth-walled coaxial antenna structure. In 1₁＝1₂＝1_NAnd eOn → ∞ the ASPS structure 102 becomes a corrugated coaxial ASPS, also known as a pole-on-pole disc antenna. The main advantage of this type of guiding structure is that HE with not only one but also two cut-off frequencies can be supported_mnMixed waves, i.e., low and high cutoff frequencies.

Referring to FIGS. 5 and 6, the lowest azimuth inhomogeneous wave HE is shown₁₁An electromagnetic field or field structure in the cross-section of the ASPS structure 102. In this example, it is assumed that the longitudinal axis Z is the axis of symmetry of the ASPS structure 102. In fig. 6, the cross-section is aligned with the Z-axis. In the example of fig. 5, X, Y are orthogonal axis pairs.

Fig. 5 also shows a magnetic field or magnetic field vector 532 that is orthogonal to the Z-axis. The magnetic field vector 532 in fig. 5 is shown by a dashed line. In fig. 6, a cross-section of magnetic field vector 532 is represented by

elements

531 and 533. Element 533 shows the magnetic field vector 532 passing into the image and element 531 shows the magnetic field vector 532 passing out of the image.

The electric field vector 522 in fig. 6 is shown in bold solid lines. In FIG. 5, the cross-section of the electric field vector 522 of FIG. 6 is represented by

elements

521 and 523. Element 523 shows the electric field vector 522 passing into the image, while element 521 shows the electric field vector 522 passing out of the image. Due to wave HE₁₁Is azimuthally inhomogeneous, so there is a maximum longitudinal electric field strength (in

And

at) and regions where no electric field component is present (at)

And

at (c).

Moreover, the field distributions shown in fig. 5 and 6 indicate the presence of the electrical wall 524 and the magnetic wall 534, which are correspondingly surfaces orthogonal to the electrical or magnetic vector. The positions and structures of the electric wall 524 and the magnetic wall 534 are specified specificallyAs a result of the mode of operation, the particular mode of operation is in this example the lowest azimuthal inhomogeneous wave HE₁₁。

Aspects of the disclosed embodiments utilize azimuthal inhomogeneous waves HE₁₁Power synthesis is performed. In one embodiment, the interior volume of the ASPS structure 102 of fig. 1 is divided into partial regions or cells defined by the electrical walls 524 and the magnetic walls 534. For example, the field distribution in fig. 5 shows a symmetric property. The plane of symmetry is co-located with the

electromagnet walls

524, 534. The electric field 522 has a plane

The plane of inversion symmetry at (electrical wall). This is a surface where there is no tangential electric field, i.e., all electric field lines are orthogonal to the electric wall 524. Overall electric field distribution

The electrical wall 524 is anti-symmetric and the magnetic field distribution is symmetric with respect to the electrical wall 524.

In one embodiment, referring also to fig. 7 and 8, the volume of the ASPS structure 102 may be divided into two compartments, referred to herein generally as the upper compartment 140 and the lower compartment 150, relative to the electrical wall 524. The upper compartment 140 and the lower compartment 150 are formed by being positioned on a plane

Separated by an electrical wall 524. As shown in fig. 8, both the upper compartment 140 and the lower compartment 150 may be fed with one or more dedicated coupling elements 116 and corresponding feed lines 118, which feed lines 118 are coupled with corresponding inputs P1, P2 and P3, P4 shown in fig. 1.

In the example of FIG. 5, the magnetic field 532 is at

The magnetic wall 534 of the degree has an anti-symmetric plane. This is a surface where there is no tangential magnetic field 532, i.e. all magnetic field lines are orthogonal to the magnetic wall 534. Overall magnetic field distribution relative to

The magnetic wall 534 at the degree is antisymmetric. The electric field distribution is symmetric with respect to the magnetic wall 534.

Referring to fig. 7, in one embodiment, the volume of the ASPS structure 102 may also be viewed as two "separate" compartments, one compartment 220 located on the left side of the magnetic wall 534 and one compartment 230 located on the right side of the magnetic wall 534. The electromagnetic field within each

compartment

220, 230 may be excited by a suitable coupling element, for example, a coupling loop element 116 such as a feed line 118 that is fed by a corresponding feed line. Thus, referring to fig. 5, the volume of the ASPS structure 102 is considered to be a plurality of compartments or units, an upper compartment 140 and a lower compartment 150, a left compartment 220 and a right compartment 230.

The compartments 140,150, 220, 230 described above are not exactly "separated", but must contain coherent fields, since their phase and amplitude must be chosen to reconstruct the desired mode HE₁₁The overall field distribution. When this condition is satisfied, a power combining effect is achieved.

When the coupling elements 116 are fed with the correct amplitude and phase, a combination of energies occurs, providing a power combining effect. These principles also apply to higher azimuthal non-uniformity waves HE_mn. For higher azimuthal non-uniformity waves HE_mnThe positions of the electrical wall 524 and the magnetic wall 534 must be adapted accordingly.

As shown in fig. 1, a coupling loop element 116 is disposed in each of the upper compartment 140 and the lower compartment 150. In one embodiment, the coupling loop element 116 is a magnetic loop coupling element that couples with a magnetic field within the respective cell or

compartment

140, 150. One example of a coupling loop element 116 is shown in fig. 9. Fig. 10 shows coupling loop element 116 and associated magnetic field 132. The coupled loop element 116 shown in fig. 9 and 10 has magnetic flux in both forward and return directions, which achieves the most efficient coupling when coupled in both directions. One example of such a coupling element is a "figure 8" coupled loop topology. In the example of fig. 10, each portion or

loop

116a, 116b of the "figure-8" coupled loop generates magnetic flux of equal strength but opposite direction. In alternate embodiments, any suitable type of coupling element may be used to couple with the cells in addition to including the magnetic return coupling element 116.

As shown in the example of fig. 1 and 8, at least one coupling loop element 116 is disposed in each

compartment

140, 150. The configuration shown in FIG. 1 provides a minimum 1+1 differential feed structure of input ports P1-P4, forming a 2 (differential) to 1 combiner, where two differential input ports feed power to support the desired mode HE₁₁A common output port 130. Placing more than one coupled loop element 116 will further increase the number of input ports, configuring the output ports of the combiner to be 1+1 (differential), 2+2 (differential),...., 4+4 (differential), etc. The synthesizer 100 of the disclosed embodiment provides multi-port synthesis functionality.

Fig. 7 and 8 illustrate exemplary implementations of employing an electrical wall 524 in a multi-port power combiner 100 incorporating aspects of the disclosed embodiments. In the cross-sectional view of fig. 8, the ASPS structure 102 is shown disposed within the confines of the conductive cylinder 122. Pairs of coupled loop elements 116 are disposed within the conductive cylinder 122 on one side of the shorting wall 110. The coupling loop element 116 is symmetrically disposed with respect to the electrical wall 524 (shown in bold solid lines) and is orthogonal to the magnetic field lines 532 (shown in dashed lines). The coupled loop element 116 maintains correct phasing based on the phasing of the magnetic field lines 532 forming a closed loop that is symmetrical to the electrical wall 524. As shown in fig. 7, the number of coupling loops 116 in this example is eight, each carried on a dielectric card 114. In one embodiment, each coupling loop 116 requires a pair of coaxial connectors for the inputs, e.g., inputs P1 and P2 or inputs P3 and P4. The inputs P1-P4 are connected to respective supply lines 118.

In practice, referring to fig. 1 and 7, each pair or set of coupling loops 116 may be printed or otherwise disposed on the dielectric card 114. As shown in fig. 1, dielectric cards 114 are mounted on corresponding carrier slots 112 of ASPS structure 102.

The single-ended input ports P1-P4 in the example of fig. 1 are differential ports in number: 2+2 (single-ended), 4+4 (single-ended), …, twice as high as 8+8 (single-ended). The number of coupled loops 116 is limited by the design constraints of a specified level of insertion loss, cross-coupling (isolation) between ports, breakdown voltage, and feeder size, as well as by technical complexity. In one embodiment, the power combiner 100 may be converted to a single-ended configuration, wherein the midpoint of each coupling loop 116 is connected to ground potential through a dedicated connection.

Fig. 11 shows a four-input single-ended feed structure of input ports P1-P4, forming a 4 (single-ended) to 1 combiner with four single-ended input ports. In this example, four dielectric cards 114 are disposed relative to the center conductor 106. A slot 115 in dielectric card 114 carries one or more disks 104 of ASPS structure 102. The coupling loop 116 is connected to input ports P1-P4, the input ports P1-P4 being disposed in respective openings 111 at one end and connected to ground at the other end. One end of the coupling loop 116 is electrically connected to an electrical ground, in this example a conductive cylinder 122. In the present embodiment, the center conductor 106 is shown connected to the shorting wall 110. In an alternative embodiment, the shorting wall 110 is not connected to the center conductor. A single-ended coupling configuration is formed using the conductive cylinder 122 as a ground connection. The energy fed by the input ports P1-P4 is synthesized to support the desired pattern HE₁₁In the common output port 130.

Fig. 12-15 illustrate another example of a power combiner 300 incorporating aspects of the disclosed embodiments. In this example, the ASPS structure 302 is divided into two planes

A compartment or cell, generally indicated as a left compartment 320 and a right compartment 330, separated by a magnetic wall 332.

Fig. 12-15 illustrate the use of the dielectric cylinder 312. In this example, the dielectric cylinder 312 is comprised of a flexible PCB laminated into a cylinder. In one embodiment, the dielectric cylinder 312 may be 3D printed with plastic layers or other dielectric layers having two or more metal layers (electrochemically) deposited between the plastic layers.

The magnetic circuit 316 is used to couple with the magnetic field within the

respective cell

320, 330. The magnetic field distribution is shown in fig. 12. The two shown in dashed lines represent

closed loops

334, 336 of the magnetic field divided into equal halves by the magnetic wall 332.

Each

compartment

320, 330 contains a pair of such "halvesPortion "in the plane

And has a common portion of magnetic flux co-located with electrical wall 322. At least one coupling loop 316 is disposed in a

respective compartment

320, 330. This will give at least a 1+1 (differential), 2+2 (differential), …, 4+4 (differential) synthesizer.

In the exemplary power combiner 300 shown in fig. 12-15, a plurality of coupling loops 316, which in this example are magnetic coupling loops, may be implemented. As shown in the example of fig. 12, the coupling loop 316 is symmetrically disposed with respect to the magnetic wall 332 and orthogonal to the plane of the electrical wall 334. In the embodiment shown in FIG. 12, the magnetic coupling loop 316 is printed on the surface of the dielectric cylinder 312. In one embodiment, the magnetic coupling loop is printed on the outer surface of the dielectric cylinder 312. In this embodiment, where the dielectric cylinder 312 may be 3D printed with plastic layers or other dielectric layers having two or more metal layers (electrochemically) deposited between the plastic layers, the coupling loops 316 may be printed on different layers to provide a plurality of stacked coupling loops 316. The cylinder 312 may be replaced by any shape as long as it has the symmetry or order C4, C8, C16,. C ∞ as described above with reference to fig. 3. Vias 313 such as shown in fig. 15 may be formed by laser cutting or drilling as appropriate, and then plated in each layer to connect portions of the coupling loops to each other and/or to the corresponding input lines 318.

The coupling loop 316 should maintain proper phasing based on the actual phasing of the magnetic wires forming the

closed loops

334, 336 that are symmetrical to the electrical wall 322. The number of coupling loops 316 in this example is eight, with a pair of input connectors P1, P2 associated with each coupling loop 316.

Referring also to fig. 13, in this example, a coupling loop 316 and a corresponding feed conductor or track 318 are disposed on the outer and inner surfaces of the dielectric cylinder 312, respectively. The dielectric cylinder 312 is fixed in a dedicated position within the ASPS structure 302. The synthesizer 300 shown in figure 13 is a 2-to-1 synthesizer implementation based on an on-pole dish. P1-P4 are the input ports of the

combiner

300, and 304 are the corrugated rods or end sides of the on-rod disc antenna structure 302. The center conductor 306 is coaxially disposed within the dielectric cylinder 312.

The conductive tracks 318 on the inner surface of the dielectric cylinder 312 are configured to feed signals from the respective input ports P1, P2 and P3, P4 to the corresponding coupling loops 316. The combiner 300 may also be converted to a single-ended configuration by connecting the midpoint of each coupled loop 316 to ground through a dedicated connection. Unlike in the power combiner 100 shown in fig. 1, it is more difficult to convert the configuration of fig. 13 into a single-ended structure, because the coupling loop 316 is not a "figure 8" type of coupling loop and does not have a natural ground point.

In one embodiment, the number of coupling loops 316 is limited by the particular mode (typically the least dominant azimuthal non-uniformity mode HE)₁₁) And design constraints of specified isolation between ports, insertion loss, breakdown voltage, and feeder size (cross-section), as well as constraints of technical complexity (production cost).

Fig. 14 and 15 illustrate an exemplary power combiner 300 incorporating aspects of the disclosed embodiments, wherein the number of input loops 316 is reduced to only two input loops 316. A plurality of input ports P1-P4 extend through respective openings 311 in the shorting wall 310. The end 340 of each loop 316 is connected to a corresponding or dedicated input port P1-P4 by a coaxial line (not shown). A conductive feed track 318 is disposed on one or more of the outer surface and the inner surface of the dielectric cylinder 312. Vias 313 connect the portions of the coupling loops 316 that are located on opposite (inner and outer) surfaces of the dielectric cylinder 312.

In the example of fig. 15, the dielectric cylinder 312 is coaxially disposed within the conductive cylinder 308. A shorting wall 310 closes the end of the conductive cylinder 308. In this example, the shorting wall 310 is electrically coupled with the conductive cylinder 308 and the center conductor 306.

In the example of fig. 14 and 15, at least one pair of magnetic return coupling elements 316 is disposed on the surface of the dielectric cylinder 312. For example, the magnetic return coupling element 316 may be printed on a surface of the dielectric cylinder, such as one or more of an outer surface and an inner surface. In one embodiment, the magnetic coupling loop element 316 may also be disposed within the wall of the dielectric cylinder 312 or between the outer and inner surfaces, such as the multi-layer flexible design or 3D printed design described above.

Fig. 16 illustrates an example of an output port 130 of a power combiner incorporating aspects of the disclosed embodiments. In this example, output port 130 is a cross-section of an ASPS used in a particular implementation. In the case of a disk-on-rod structure as shown in fig. 1, the output port 130 is a cross-section of the disk-on-rod structure, and the composite of the input signals, or the composite power of the input signals, propagates along the ASPS structure 102. Since the cross-section is limited (from the outside) by the conductive cylinder 122, no radiation occurs there, propagating only along the ASPS structure 102. In one embodiment, the cross-section or output port 130 may be an input to a subsequent filtering structure, antenna, phase shifter, or other suitable component. Although the input ports P1-P4 are coaxial input ports that provide input signals, at the output port 130, a traveling wave is formed that propagates away from the combiner and energy is contained within the cross-section of the ASPS structure 102. As shown in fig. 17, if the ASPS structure 102 is being converted into a more conventional transmission line, e.g., a waveguide, the output port 130 is contained within the cross-section of the output waveguide 402. Fig. 17 shows a four port power combiner 400 that converts into a circular waveguide section 402. In the example of fig. 17, the output port 130 is a cross-section of a circular waveguide 402.

Fig. 18 shows the power combiner of the disclosed embodiment converted into a circular waveguide section 402. In the embodiment of fig. 18, the ASPS structure 102 is carried by a dielectric carrier member 404, such as a dielectric foam. In this example, dielectric foam 404 surrounds ASPS structure 102 and isolates it from conductive cylinder 122. Since the low frequency cutoff of the circular waveguide 402 is substantially higher than the cutoff of the ASPS structure 102, the circular waveguide section 402 provides additional out-of-band rejection at the lower end of the operating frequency range. The remaining empty portion between the shorting wall 110 and the ASPS structure 102 provides more volume to place additional coupling loops and/or to increase the area of each coupling loop. Moreover, this configuration has the advantage of being assembled from both sides of the antenna array. The outer conductive cylinder 122 is part of an antenna array that must be assembled with all of the components of each element. The ASPS structure or pole upper disk section 102 may be assembled from the front of the antenna array without the need for electrical connections between the shorting wall 110 and the ASPS structure 102. The other parts of the synthesizer may be assembled from the rear. In one embodiment, the dielectric carrier 404 forms a dielectric spacer that can be used as a plastic radome to seal the interior of the combiner.

Aspects of the disclosed embodiments relate to power synthesis based on properties of guided waves supported by the ASPS. The multi-port synthesizer of the disclosed embodiments uses a hybrid azimuthally inhomogeneous electromagnetic wave in which the electrical and/or magnetic walls associated with the 3D field distribution are utilized. The coupling is achieved using a magnetic coupling element. An even number of coupling loops are symmetrically arranged with respect to the magnetic wall in a plane or a curved surface collinear with the magnetic wall. The number of turns in the coupling loop and the mutual direction of the turns are set to maintain the correct coupling factor and phasing in accordance with the mutual phasing of the magnet wires of the desired propagation mode. It is not necessary to have the input signal in anti-phase, since the in-phase signal can be combined with the coupling loop to provide the necessary phase shift by changing the winding direction.

Aspects of the disclosed embodiments result in an increased number of ports, improved isolation, insertion loss, and integration of power combining functions into the antenna elements. The properties of the dominant mixing wave ensure additional isolation within the synthesizer. If the synthesizer is integrated into a filter based on a mixed mode design, the coupling requirements will be defined by the corresponding elements of the coupling matrix. This will advantageously result in a reduced overall coupling level required for the combiner. If the synthesizer is integrated into a filtering structure supporting mixed modes, e.g. an ASPS-based bandpass filter, the coupling requirements will be defined by the corresponding elements of the coupling matrix of the filter.

Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to exemplary embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. Moreover, it is expressly intended that all combinations of those elements that perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Claims

1. A radio frequency, RF, signal synthesizer (100), the synthesizer (100) comprising:

an axisymmetric periodic waveguide device (102), the axisymmetric periodic waveguide device (102) comprising:

a cylinder (120);

a center conductor (106) coaxially disposed within the cylinder (120), the center conductor (106) being defined by a pair of orthogonal symmetry planes (108) passing through in an axis of symmetry of the axisymmetric waveguide device (102); and

a shorting wall (110) closing an end of the cylinder (120) and electrically coupled to the center conductor (106);

at least one pair of magnetic loop coupling elements (116) disposed within the cylinder (120) relative to a plane of symmetry defining the pair of orthogonal planes of symmetry (108) of the center conductor (106) and symmetric about the plane of symmetry of the pair of orthogonal planes of symmetry (108), wherein at least a first plane of symmetry defining the pair of orthogonal planes of symmetry (108) of the center conductor (106) passes through all magnetic loop coupling elements of a pair of the at least one pair of magnetic loop coupling elements (116);

a plurality of input ports (P1, P2, P3, P4) extending through respective openings (111) in the shorting wall (110), each of the plurality of input ports (P1, P2, P3, P4) feeding a signal to a corresponding one of the at least one pair of magnetic loop coupling elements (116); and

an output port (130), the output port (130) being arranged on a side of the combiner (100) remote from the shorting wall (110), the output port (130) being configured for outputting a combined power of signals from the plurality of input ports (P1, P2, P3, P4).

2. The Radio Frequency (RF) signal synthesizer of claim 1, wherein the cylinder (120) comprises a conductive cylinder (122), the at least one pair of magnetic loop coupling elements (116) being carried on a dielectric card (114).

3. The radio frequency, RF, signal synthesizer (100) of claim 2, wherein the at least one pair of magnetic loop coupling elements (116) are printed on a first side of the dielectric card (114).

4. The radio frequency, RF, signal synthesizer (100) according to any one of claims 2-3, wherein one of the at least one pair of magnetic loop coupling elements (116) is disposed coplanar with each other and with the plane of symmetry.

5. The radio frequency, RF, signal synthesizer (100) of claim 4, wherein a first magnetic loop coupling element of the pair of magnetic loop coupling elements (116) that are coplanar and a second magnetic loop coupling element of the pair of magnetic loop coupling elements (116) that are coplanar are disposed equidistant with respect to the center conductor (106).

6. The radio frequency, RF, signal synthesizer (100) according to any one of claims 2-3, comprising a conductive track (118) on the second side of the dielectric card (114), the conductive track (118) being coupled with each of the plurality of input ports (P1, P2, P3, P4).

7. A radio frequency, RF, signal synthesizer according to any one of claims 2-3, wherein the dielectric card (114) is arranged in a dielectric card receiving slot (112) of the center conductor (106).

8. The radio frequency, RF, signal synthesizer (100) according to any one of claims 1-3, wherein the magnetic loop coupling element of the at least one pair of magnetic loop coupling elements (116) comprises a figure-8 magnetic loop coupling element.

9. The radio frequency, RF, signal synthesizer (100) of claim 1, wherein the cylinder (120) comprises a dielectric cylinder (312), the magnetic return coupling elements (316) of the at least one pair of magnetic return coupling elements (116) being printed on a surface of the dielectric cylinder (312).

10. The radio frequency, RF, signal synthesizer (100) of claim 9, comprising an electrically conductive track (318) arranged on a surface of the dielectric cylinder (312), the electrically conductive track (318) being coupled with each of the plurality of input ports (P1, P2, P3, P4) for feeding a signal to a corresponding one of the magnetic loop coupling elements (316).

11. The radio frequency, RF, signal synthesizer (100) of claim 10, comprising a conductive track (318) printed on a surface of the dielectric cylinder (312), the conductive track (318) being coupled with each of the plurality of input ports (P1, P2, P3, P4) for feeding a signal to a corresponding one of the magnetic loop coupling elements (316).

12. The radio frequency, RF, signal synthesizer (100) according to any one of claims 9-11, wherein the magnetic loop coupling elements (316) of the at least one pair of magnetic loop coupling elements (116) are arranged equidistant from each other with respect to the center conductor (306).

13. The radio frequency, RF, signal synthesizer (100) according to any one of claims 1-3, 10 or 11, wherein the axisymmetric periodic waveguide arrangement (102) supports mixed wave signals.

14. The radio frequency, RF, signal synthesizer (100) according to any one of claims 1-3, 9-11, wherein an inner volume of the axisymmetric periodic waveguide device (102) is divided by the pair of orthogonal symmetry planes (108) into at least one pair of compartments (140,150), wherein a compartment of the at least one pair of compartments (140,150) has a dedicated magnetic loop coupling element and an input port.

15. A radio frequency, RF, signal synthesizer (100) according to any one of claims 1-3, 9-11, wherein the axisymmetric periodic waveguide device (102) is an on-pole disc antenna assembly.