Compact high power radio frequency polarizer group

Abstract

A waveguide apparatus, associated components and methods. The waveguide device may include a rectangular waveguide having a first rectangular port and a second rectangular port at one end, and a first circular waveguide and a second circular waveguide extending from a broad side opposite the waveguide to provide full isolation or full transmission between the first port and the second port. The waveguides may include a fixed short circuit at one circular waveguide and a short circuit with an adjustable bias structure at the other circular waveguide to accommodate a wider range of high power capabilities. The waveguide devices may be stacked by connecting circular waveguides of adjacent structures to provide an isolator with additional ports or adjustable directional couplers. The adjustable shorting structure may include a plunger or a helical thread. The waveguide may include a rectangular waveguide in a four-port network in which the circular waveguide extends to a fifth port supporting two modes of operation and may be shorted by a contoured disk of non-reciprocal material.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This PCT application claims the benefit of priority to U.S. Provisional Application No. 63 / 330,678, filed on April 13, 2022, which is incorporated herein by reference in its entirety. STATEMENT AS TO RIGHTS TO INVENTS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0002] This invention was made with government support under DE-SC0017857 awarded by the U.S. Department of Energy. The government has certain rights in this invention. Background Art

[0003] The present invention relates generally to RF waveguide devices, and in particular to high power RF waveguide devices that are also compact and broadband.

[0004] Microwave waveguide polarizers are a broad class of devices that include, but are not limited to, couplers, isolators, phase shifters, loads, and bidirectional devices. These devices are widely used in particle accelerators, communications, and defense technology. However, most existing designs either lack high power handling capabilities or are large in overall size. One approach to remedy this situation can be found in U.S. Patent No. 9,419,322 and explained in more detail in the following references - Franzi, M., Wang, J., Dolgashev, V., and Tantawi, S., 2016. Compact RF polarizers and their application to pulse compression systems. Physical Review: Accelerators and Beams, 19(6), p. 062002. There are several different types of polarizer devices available. Typically, the coupling rate of waveguide directional couplers is fixed, making it difficult to achieve tunable coupling rate and good directivity.

[0005] In conventional phase shifter design, propagation constants are usually adjusted by inserting external ferrites and dielectrics to change the phase. However, the insertion loss of ferrites and dielectrics reduces efficiency, and the large size of ferrite materials limits the operating frequency. (See Chang, C., Guo, L., Tantawi, S.G., Liu, Y., Li, J., Chen, C. and Huang, W., 2015. A new type of compact high-power microwave phase shifter. IEEE Transactions on Microwave Theory and Techniques, 63(6), pp. 1875-1882).

[0006] Currently, RF polarizers are typically implemented with complex structures such as irises, diaphragms, corrugations, and grooves that convert circular polarization to linear polarization. This increases the electromagnetic field, thereby significantly reducing the power handling capability of the device due to heating and breakdown. These conventional devices suffer from limitations and disadvantages associated with their basic design (see Franzi et al., Tantawi, SG, 2004. Multimode reflective delay lines and their application in resonant delay line RF pulse compression systems. Physical Review Special Topics - Accelerators and Beams, 7(3), p.032001).

[0007] Therefore, there is a need for an improved RF waveguide device for a more compact high power system. There is a further need for such a device having broadband capabilities. There is also a need for such a device that can be tuned without requiring complex structures and maintains high power handling capabilities. Summary of the invention

[0008] The present invention is directed to improved RF multi-port waveguide devices that have inherently high power handling and are more compact than conventional waveguide devices.

[0009] In one aspect, the RF waveguide device includes a rectangular waveguide, two circular waveguides extending from opposite wide walls of the rectangular waveguide. In some embodiments, the rectangular waveguide has two symmetrical rectangular waveguide ports. In some embodiments, the two symmetrical rectangular waveguide ports feed a cylindrical transmission line via an over-moded rectangular waveguide. In some embodiments, such waveguides are stacked in a network to accommodate additional ports or capabilities. In some embodiments, the waveguide includes an adjustable bias structure on each circular waveguide, for example, a magnet or choke design mounted on a movable plunger. Such multi-port waveguides and waveguide networks can be configured as an isolator or directional coupler, and by using a movable short-circuit structure, as a tunable isolator or directional coupler.

[0010] In another aspect, the present invention relates to a multi-port waveguide, comprising: a rectangular waveguide extending between a first end and a second end opposite to the first end along an xy plane, wherein the rectangular waveguide has relative wide walls and relative side walls, the rectangular waveguide has a first port and a second port arranged at or near the first end, wherein each of the first port and the first port is single-mode, the rectangular waveguide has a third port and a fourth port arranged at or near the second end, wherein each of the third port and the fourth port is single-mode; and a first circular waveguide extending from the first wide wall of the rectangular waveguide to a fifth port, the fifth port supporting at least two TE modes, so that the multi-port waveguide can be used as a six-port polarizer.

[0011] In some embodiments, the multi-port waveguide further comprises a matching post extending in the z direction along opposite outwardly facing side walls of the rectangular waveguide extending to each of the first port and the second port, and a matching post extending in the z direction along opposite outwardly facing side walls of the rectangular waveguide extending to each of the third port and the fourth port. In some embodiments, the multi-port waveguide further comprises a pair of phase shifting recesses extending in the z direction along opposite sides of the circular waveguide portion extending to the fifth port. In some embodiments, the multi-port waveguide further comprises a pair of inductive rectangular posts partially arranged on opposite sides of the circular waveguide in the y direction along a central portion of a wide wall of the rectangular portion and extending in the z direction. In some embodiments, the multi-port waveguide further comprises a pair of inductive rectangular dimples on opposite sides of the circular waveguide portion in the x direction along an outwardly facing side of the rectangular waveguide, the pair of inductive rectangular dimples extending in the z direction and formed as recesses in the side walls of the rectangular waveguide. In some embodiments, the multi-port waveguide comprises all or any combination of the above features.

[0012] In some embodiments, the fifth port of the multi-port waveguide further includes a short circuit, which can be provided by a short circuit plate at its terminal. In some embodiments, the distant portion of the circular waveguide extending to the short circuit expands to a larger diameter than the near portion of the circular waveguide extending from the wide wall of the rectangular waveguide. The multi-port waveguide may further include a disk of non-reciprocal material, which is arranged on top of the short circuit. The non-reciprocal material can be garnet, ferrite or any suitable material. In some embodiments, the top surface of the non-reciprocal material is contoured inwardly toward the short circuit plane to optimize operation and field distribution along the disk in different modes. In some embodiments, the top surface of the non-reciprocal material is concave. The top surface profile can be elliptical or any suitable shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A multi-port waveguide according to some embodiments of the present invention is shown.

[0014] Figure 2A-2B Shows a demo Figure 1 Electric field model of the isolator behavior between port P1 and port P2 of a multi-port waveguide.

[0015] Figure 3 Shows Figure 1 The isolator is designed for broadband response.

[0016] Figure 4A-4B Shown before assembly and testing Figure 1 Exemplary components of an RF waveguide structure in FIG.

[0017] Figure 5A stack of multi-port waveguides configured as directional couplers is shown in accordance with some embodiments.

[0018] Figure 6A-6B Shows Figure 5 The coupling rate and directivity of the directional coupler in.

[0019] Figure 7A-7D A multi-port waveguide configured as a stack of four-port isolators with an adjustable bias structure is shown in accordance with some embodiments.

[0020] Figure 8A-8C Shows Fig. 7A Parts of the isolator.

[0021] Figures 9A-9B A stacked multi-port waveguide configured as a directional coupler having a shorting structure on an adjustable plunger and a shielding structure for the magnets of the shorting structure is shown in accordance with some embodiments.

[0022] Fig.10 Shows Fig.9A Directional couplers in a stack of multi-port waveguides.

[0023] Fig.11 A method for Fig.9A An exemplary adjustable plunger and magnet with shielding for a directional coupler in FIG.

[0024] Fig.12 An exemplary six-port polarizer is shown in accordance with some embodiments.

[0025] Fig.13 An exemplary four-port polarizer with a flared circular waveguide is shown in accordance with some embodiments.

[0026] Figure 14A-14B The geometry of an exemplary engraved garnet / ferrite disk for use with polarizers according to some embodiments is shown.

[0027] Figure 15A-15B and Figure 16A-16B According to some embodiments Fig.13 Image of the electric field excitation of the polarizer in Figure 1 and detail of the short-circuited section of the circular waveguide port, showing that the excitation field peaks at different locations in the disk of non-reciprocal material in different operating modes. DETAILED DESCRIPTION

[0028] The present invention relates to a multi-port waveguide structure that is compact and has high power handling capabilities. The present device utilizes a dual circular polarizer design within the multi-port waveguide structure, making the device both compact and capable of handling high power operation and broadband. In some embodiments, the multi-port waveguide is adjustable so as to be tunable to handle a wide range of high power applications. In embodiments, the waveguide structure can be easily adapted to accommodate any of a wide range of bandwidths including S, X, and Ku bands.

[0029] Microwave waveguide polarizers are a broad category of devices that include couplers, isolators, phase shifters, loads, and duplexers. These devices are widely used in particle accelerators, communications, and defense technology. However, most existing designs either lack high power handling capabilities or have large overall sizes. These shortcomings can be further understood by referring to Franzi et al. There are a few different types of polarizer devices. The coupling rate of waveguide directional couplers is usually fixed, making it difficult to obtain tunable coupling rate and good directivity. In phase shifter designs, the propagation constant is usually adjusted by inserting external ferrites, dielectrics, and thus the phase. However, the insertion loss of ferrites and dielectrics reduces the efficiency, and the large size of the ferrite material limits the operating frequency. See Change et al., 2015.

[0030] Furthermore, RF polarizers are often implemented with complex structures such as irises, diaphragms, corrugations, and grooves to convert circular polarization to linear polarization. This increases the electromagnetic field, which significantly reduces the power handling capability of the device due to heating and breakdown. See Franzi et al.

[0031] Conventional circular polarizers for microwave applications are typically composed of circular and rectangular waveguides, and large grooves often end up resulting in particularly large devices. Complex structures are often used in such polarizer designs, and still often result in reduced power handling. Microwave waveguide polarizers include couplers, isolators, phase shifters, loads, and duplexers, and have important and widespread applications in particle accelerators, medical devices, communications, and defense technology. Other types of circular polarizers, such as microstrip polarizers, have the disadvantages of narrow bandwidth and low efficiency due to losses in conductors, dielectrics, and surface waves. These aspects can be further understood by referring to Chang, C., Tantawi, S., Church, S., Neilson, J., and Larkoski, P., 2013, New Compact Waveguide Dual Circular Polarizer, Progress in Electromagnetic Research, 136, pp. 1-16. Typically, conventional waveguide polarizers use complex structures, such as rigid steps, pins, and cones, to achieve polarization transformation and port matching. These complex structures often lead to field enhancements that reduce power handling, as shown by Chang et al. 2015. This increases the electromagnetic field, which significantly reduces the power handling capability of the device due to heating and breakdown. Dual circular polarizers consist of circular and rectangular waveguides, and the large grooves often end up resulting in particularly large devices. Complex structures are often used in polarizer design, but ultimately reduce power handling.

[0032] Typically, good isolation and power handling cannot be achieved simultaneously. Further, in conventional coupler / phase shifter designs, the propagation constant is usually adjusted by inserting external ferrites or dielectrics to change the phase. However, the insertion loss of ferrites and dielectrics reduces efficiency, and the large size of the ferrite material limits the operating frequency (see Chang et al. 2015). Similarly, the power handling is limited due to the breakdown of the ferrites and dielectrics.

[0033] Some conventional directional couplers are easy to construct, but have several considerable disadvantages, such as the coupling rate is fixed, the coupling is only available on the forward path, and high losses due to internal terminations. Conventional dual circular polarizers exploit the symmetry of the geometry with two over-modulated rectangular waveguides, and circular polarization is performed under appropriate tuning of the input power. When the incident power comes from two opposing rectangular ports, the output power of the circular port has an opposite circular polarization. However, there is a further need for devices that are broadband and can accommodate a wide range of high-power applications, while still remaining relatively compact.

[0034] The multi-port waveguide structure described herein solves all the shortcomings of the above-mentioned conventional designs in the same device. By adopting the same ideas for various applications, especially high-power applications (such as hundreds of megawatts (MW)), these concepts can be adapted and incorporated into a network or system with multiple such waveguide structures. The waveguide design described herein is based on a compact dual circular polarizer design, which can be easily modified into several devices, including but not limited to isolators, directional couplers and phase shifters. The polarizer consists of two symmetrical rectangular waveguide ports, which feed cylindrical transmission lines via over-moded rectangular waveguides. The superposition of orthogonal modes in the circular waveguide will produce a wave "similar" to right-hand circular polarization (RHCP) or left-hand circular polarization (LHCP). Therefore, it can have good transmission at one port and excellent isolation at another port. However, the design of this article can further include additional cylindrical waveguide ports, which support two additional modes, thereby allowing complete isolation and complete transmission.

[0035] Six-port polarizer

[0036] In one aspect, the present invention relates to a 6-port RF waveguide network. In some embodiments, the network includes a rectangular waveguide extending between a first end and a second end, a pair of symmetrical rectangular waveguide ports coupled to the first end and a closed second end, a first circular waveguide extending from one wide wall of the rectangular waveguide supporting two modes, and a second circular waveguide extending from the opposite wide wall of the rectangular waveguide and supporting two modes. In fact, each rectangular port is regarded as two ports because each circular waveguide supports two modes.

[0037] Figure 1An example of a multi-port waveguide 100 including two symmetrical rectangular waveguide ports feeding a cylindrical transmission line via an over-moded rectangular waveguide is shown. The rectangular waveguide 10 extends along the xy plane between a first end and a second end, the rectangular waveguide having opposite wide walls and opposite side walls. The waveguide includes a first port P1 and a second port P2 disposed at or near the first end. In this embodiment, the waveguide has a Y-shape or a T-shape, wherein the rectangular waveguide 10 defines a base, and has a first top arm 1 and a second top arm 2, the first arm 1 extending to the port P1, and the second arm 2 extending to the port P2. Each of the ports P1 and P2 is a rectangular waveguide port and is single-mode. The first circular waveguide 3 extends from the first wide wall of the rectangular waveguide to the third port P3, and the second circular waveguide 4 extends from the opposite wide side of the rectangular waveguide to the fourth port P4. In this embodiment, each of the ports P3 and P4 supports at least two TE modes. This design allows the user to isolate through the port P1 or the port P2, or to guide all power through the port P4. Port P4 can be completely isolated from port P1 and port P2, or all power from port P1 can be directed to port P4, or all power from port 2 can be directed to port P4. Conventional isolator designs isolate port 1 and port 2 from each other, while this design allows these ports to be isolated or connected, for example, by satisfying the scattering matrix mentioned below, which allows the waveguide to be completely isolated or transmitted. This design is suitable for isolators, however, it is understood that this or similar waveguide designs can be used for various other applications, including directional couplers, loads, and duplexers.

[0038] In some embodiments, the waveguide further includes additional design features to provide transmission and / or reflection characteristics to achieve the following scattering matrix, including in an inwardly angled V-shaped portion 5 between ports P1, P2 extending to the diaphragm 6. Step portions 11, 12 between the base and each of the first and second arms. Each step portion may additionally include a curved inner corner 11a, 11b. The circular waveguide 3, 4 may include a dome portion 13a extending around a portion of the base of the circular waveguide extending from the wide wall of the rectangular waveguide. In this embodiment, the second end 14 of the rectangular waveguide is bent inward or angled toward its central longitudinal axis and further includes a curved outer corner 14a. It should be understood that in some embodiments, alternatives or modifications of these features may be used. Port P3 can be shorted to change the phase of the reflection, thereby creating an isolator behavior between ports P1 and P2. Adding a short circuit to port P3 causes the transmission from P1 to P3 to be 1 or 0. Typically, the short circuit is a circular metal plate with a garnet sheet or layer on it, with a magnetic bias attached to the bias to produce a magnetic field with a direction axially parallel to the circular waveguide axis and in one direction. Excitation at port P1 produces a transient wave in the garnet layer in one spiral direction, and since the garnet has a magnetic field in one direction, it reacts on one spiral. The thickness of the garnet layer and the strength of the magnetic field can be selected so that the system is completely isolated in one direction and completely transmitted in the other direction. For example, for port P4, in the case of complete isolation, all power goes from port P1 to port P4, and a load can be applied to absorb this power. It should be noted that the location of the short circuit will be different depending on whether the input is port P1 or port P2. It should be noted that there are two distances along the circular waveguide 3 at which the short circuit can be placed to achieve complete isolation / transmission. In this design, the distance selected is the distance that makes the field on the ferrite very low in the case of complete transmission, because this is when the device receives full power. Thus, when the isolator is protecting a device, the device can receive high power, which allows the device to be used in extremely high power operations, much higher than normal operations permitted by conventional isolators.

[0039] In one aspect, ports P1 and P2 are single-mode (e.g., supporting the TE10 mode), and the entire rectangular waveguide supports the TE10 and TE20 modes. The circular waveguide supports two different modes (e.g., TE10 and TE20). During the bending process in the vertical rectangular waveguide section, convergence occurs between the TE10 and TE20 modes below the circular waveguide, and the TE20 and TE10 modes are coupled below to the two polarizations of TE11 of the circular waveguide with one polarization and TE11 of the circular waveguide with opposite polarization. Advantageously, this design allows the TE10 and TE20 modes under the circular waveguide to be correct in amplitude and phase to achieve this coupling. It should be understood that although specific sizes are shown here, the waveguide size and dimensions are frequency-dependent, so that the design can be enlarged or reduced to accommodate the frequency / power requirements of a given application and keep the rectangular waveguide port at a standard size. The device is configured for 9.3 GHz, however it should be understood that the design can be sized for various other frequencies (e.g., L-band to W-band).

[0040] In one aspect, the present invention relates to a waveguide device configured as an isolator, wherein the input port and the output port can be selectively isolated from each other or connected to each other. To allow this feature, the device is designed to satisfy a 6x6 scattering matrix. In some embodiments, the waveguide is designed to conform to the 6x6 scattering matrix as shown below. This is the most general form of the matrix that supports the original polarizer scattering matrix and respects the geometric symmetry of the system (e.g., symmetry along the XY, ZY planes). The S-matrix has 4 complex numbers and 2 real numbers. Applying the uniformity STS=1 condition results in the following matrix, which has a single parameter θ and 2 real parameters e1 and e2, which are assumed to be 0 in this case and are non-essential parameters in any case. In one embodiment, for the best case, α is 2 / 3, β is -1 / 3, γ is -1 / 3, and in particular δ is 2 / 3. With an appropriate choice of parameter θ, when a short is added to port 3, the position of the short along the Z axis can cause the transmission from port P1 to port P3 to be either 1 or 0. The correct value for parameter θ is Sin^(-1)(1 / 3). With this value in place, a piece of garnet material of appropriate size can be placed in the port to change the phase of the reflection from port P3 depending on the helicity of the incident wave. This results in isolator behavior between ports P1 and P2.

[0041] Figure 2 shows the simulation results of the 6-port isolator, which demonstrates the isolator behavior between ports P1 and P2. The simulation was performed using high frequency simulation software (HFSS). The S-matrix data contained in Table 1 below shows the asymmetry, with one port receiving an S12 value of -0.0412dB and an S21 value of -38.9dB. Table 1: S matrix data

[0042] In one aspect, circular waveguide ports P3 and P4 can be used to measure the forward and reverse power between ports P1 and P2. For example, when power is input at port P1 and output at port P2, a small portion of the power goes to port P3, so that the measurement of the power at P3 corresponds to the power going to port P2. Similarly, when port P2 is a power input with port P1 as output, a small portion of the power goes to port P4, which corresponds to the power going to port P1. The power going to P3 is controlled by the position of the short circuit in P3. In some embodiments, the position of the short circuit can be adjusted or controlled, for example, by using an adjustable plunger and / or magnet, as in other embodiments described below.

[0043] Figure 3 According to the waveguide concept described in this article, a very wide band response is shown, an additional advantage of this isolator design. This waveguide design provides a band response that is about 10 times wider than conventional circulators available on the market. This has a much smaller impact on the frequency offset of the RF system. In comparison, the typical bandwidth of classical devices is 10MHz, making the curve graph resemble a narrow notch with steep slopes on both sides.

[0044] Figure 4A-4B Shown before assembly and testing Figure 1 Components of the RF waveguide structure. Figure 4A An assembly of an aluminum component having an upper half 101a and a lower half 101b is shown. Figure 4B Only the lower half 101b is shown to show the interior. Typically, this component is made of aluminum with the inner surface coated with copper. It should be understood that the waveguide can be formed of any suitable conductive material, for example, brass, copper, silver, aluminum or any metal with low bulk resistivity.

[0045] Figure 5 Shows something like Figure 1A 6-port polarizer design 200 in FIG. 1 has been stacked with another multi-port waveguide device and configured as a directional coupler. Specifically, the waveguide device is configured as a tunable directional coupler. In this design, the directional coupler includes an upper waveguide device 210 and a lower waveguide device 220, each having a first port P1 and a second port P2 and a first and a second circular waveguide P3, P4. As shown, the waveguides are stacked so that the circular waveguide P3 of the upper waveguide is coupled with the circular waveguide P4 of the lower waveguide. In this embodiment, the circular waveguide P4 of the upper waveguide 210 is short-circuited by a circular metal sheet 15 disposed in the first (top) cylindrical waveguide of the upper 6-port waveguide device. The metal sheet is positioned at a position where S21 reaches a minimum value in the cylindrical waveguide so that all power is distributed to the bottom circular port P3. Simulations are then performed to verify that the directivity remains almost constantly low when the distance between the top and bottom circulators varies. Another metal sheet with a central hole 16 inside the connected circular waveguides P3, P4' enables differential nominal coupling ratios through the top and bottom waveguide devices. The bottom circular waveguide P3' of the lower waveguide device 220 includes a short-circuit structure 17, which is a choke design with two spaced-apart metal plates. This choke design shorts the circular waveguide without contacting the inside of the circular waveguide. The position of the short-circuit structure 17 can be adjusted, for example by movement of a plunger 18, to tune the device.

[0046] Figure 6A-6B shows the short-circuit structure based on Figure 5 The coupling ratio and directivity of the plunger position in the lower circular waveguide structure of the directional coupler. Fig. 6A As shown, when the plunger 18 at the bottom circular waveguide moves the short circuit 17 by ±0.5 inches, the coupling ratio of the device can be tuned from 27dB to 41dB. Figure 6B The change in directivity as the plunger moves across the short circuit is shown. These changes in coupling ratio and directivity allow the waveguide structure to be tuned to accommodate the different power requirements needed for a given application.

[0047] In another aspect, Figure 7A-7C As shown in , the multi-port waveguide can be configured as a 4-port isolator 300. Specifically, the waveguide device utilizes a stacked multi-port waveguide, wherein the circular waveguides of adjacent waveguides in the stack are connected, and the lower circular waveguide of the lower waveguide structure has a short circuit and a removable / replaceable adjustable bias structure 305 with a permanent magnet 304. Fig. 6A A perspective view is shown. In this design, the directional coupler includes an upper waveguide device having rectangular ports P1 and P2 and top and bottom circular waveguides P3 and P4, and a lower waveguide device similarly having rectangular ports P1 and P2 and top and bottom circular waveguides P3 and P4. The bottom circular waveguide P3 of the upper waveguide is coupled to the top circular waveguide P4 of the lower waveguide, as shown in FIG. Fig.7DIn this embodiment, the short circuit in P3 includes a thin garnet disk 306 supported by a thin short plate made of copper that allows the magnetic field from the adjustable bias structure to bias the garnet disk 306 located at the end of feature P3 (e.g., Fig.7D ), which makes the device non-reciprocal, so the 4-port device acts as a 4-port circulator.

[0048] In this embodiment, the waveguide is defined as an assembly of three waveguide components, such as Figure 6B As shown, the upper component 301, the middle component 302 and the lower component 303. The upper component 301 and the middle component 302 together form an upper waveguide structure, and the middle component 302 and the lower component 303 define a lower waveguide structure. The middle component 302 couples the top and bottom circular waveguides of the adjacent waveguides. Fig. 8A and Figure 8B Detailed views of the upper component 310 and the lower component 330 can be seen in FIG. 1 , respectively. The middle component is formed of similar material as the top and bottom components and joins each of the upper and lower components to form a stacked multi-port waveguide structure. Similar to the previous waveguide embodiments, this component can be formed of any suitable material, preferably copper clad aluminum. In this embodiment, the first and second rectangular waveguide ports at the first end of the upper waveguide are oriented in parallel directions toward the second end of the waveguide, as can be seen in FIG. Fig. 8A The first and second rectangular waveguide ports P1 and P2 of the lower waveguide extend in opposite directions perpendicular to the entire rectangular waveguide direction (similar to Figure 1 This approach allows ready access to each of the four rectangular ports. It will be appreciated that the ports may be configured in various other orientations if desired.

[0049] In this embodiment, the top circular waveguide structure is short-circuited at a fixed position, and the bottom waveguide is short-circuited, and further includes a biasing structure 340, such as Figure 8C In this embodiment, the bias structure 340 is adjustable and / or removable to allow the isolator to be adjusted to suit different power requirements or applications. In some embodiments, the bias structure 340 includes a permanent magnet 341, an adjustable magnetic field shaping and shielding structure 344 having threads 342 that fit around a circular waveguide containing the garnet ( Fig.7D The features 306 in the bias structure 340 are used to provide an appropriate magnetic field to bias the garnet. The position of the magnets in the bias structure 340 can be adjusted individually. The adjustment features 343 are used to adjust the position of the magnets in the bias structure 340 to adjust the relative position between the magnets and the garnet.

[0050] Figure 9A-Figure 11Another embodiment of a tunable directional coupler 400 utilizing a multi-port waveguide structure is depicted. Similar to the previous embodiments, the device utilizes a stacked multi-port waveguide structure defined by upper, middle, and lower components 410, 420, 430 and an adjustable short bias structure 440 that is operably coupled to a circular waveguide structure P4 extending from one of the multi-port waveguides. In this embodiment, one circular waveguide includes a short circuit structure 441 of a choke design having two connected metal disks 442. By using this adjustable bias short circuit in the absence of a garnet, the device functions as a directional coupler with adjustable coupling. The directional coupler can be broadband and tuned over a power range suitable for various high power operations.

[0051] The methods, systems, and devices discussed above are examples. Various configurations may omit, replace, or add various procedures or components as appropriate. For example, in an optional configuration, the method may be performed in an order different from that described, and / or various stages may be added, omitted, and / or combined. In addition, features described with respect to certain configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. And further, technology is constantly evolving, and some of the elements described are provided as non-limiting examples, and therefore do not limit the scope of the present disclosure or claims.

[0052] Specific details are given in the description to provide a thorough understanding of the exemplary configurations (including implementations). However, the configurations can be made without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary details to avoid obscuring the configurations. This description provides exemplary configurations that do not limit the scope, applicability, or configurations of the claims. Instead, the foregoing description of the configurations will provide those skilled in the art with an implementation description for implementing the described techniques.

[0053] In addition, the configuration can be described as a process, which is depicted as a flow chart or block diagram. Although each operation can be described as a continuous process, some operations can be performed in parallel or concurrently. In addition, examples of methods can be implemented by hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segments for performing the necessary tasks can be stored in a non-transient computer readable medium, such as a storage medium. The processor can perform the described tasks.

[0054] In another aspect, additional embodiments may be implemented with additional features that may enhance the polarizer concept presented above. The first is another embodiment of a 6-port polarizer, such as Fig.12 As shown, only one circular physical port contains two modes, and the rest of the ports are rectangular ports.

[0055] Fig.12 The geometry of an exemplary six-port polarizer 500 is shown. The port numbers are shown as P1, P2, P3, P4, P5, and P6. It should be noted that port P5 and port P6 represent two different operating modes of the respective circular waveguides. Therefore, the fifth port of the circular waveguide can be used as port P5 or port P6. The six-port polarizer 500 may include additional features of the polarizer around the circular waveguide to enhance operation, including: 1) phase shift recess 510; 2) inductive indentation 520; and 3) inductive rectangular column 530. In addition, on the rectangular waveguide ports, there may be four matching columns 540, which extend vertically along the corresponding portions of the rectangular waveguide extending to port P1, port P2, port P3, and port P4. This combination of features is designed to optimize the performance of the device. It should be understood that in other embodiments, these or similar features may be used alone or in any combination, or if desired, various other features may be included.

[0056] In some embodiments, the unit scattering matrix of the device is given by:

[0057] In this embodiment, the first four ports are rectangular ports, and port P5 and port P6 represent two linear polarization modes in a circular waveguide. Note that these two modes are excited with a 90 degree phase shift and equal amplitude by any excitation from any of the rectangular ports P1 to P4 (i.e., induced circularly polarized waves). In addition, port P1 and port P3 excite them with the same helicity, while port P2 and port P4 excite them with opposite helicities. It should also be noted that port P1 and port P4, as well as port P2 and port P3, are completely isolated.

[0058] Through this scattering matrix, the short circuit in the circular waveguide port will reflect mode 5 and mode 6, and the resulting structure is a four-port network. The resulting four-port network depends on the phase φ determined by the short circuit position, which is given by:

[0059] Based on the scattering matrix above, the excitation of a signal in port P1 will distribute power between ports P2 and P3; the distribution ratio depends only on the angle φ; i.e. the location of the short circuit. Therefore, by choosing this angle (which can be physically done by moving the location of the short circuit), power can be completely transferred from port P2 to port P3, and vice versa. The excitation of port P2 will distribute power between ports P1 and P4, and the excitation of port P3 will also do the same between ports P2 and P4. Therefore, the excitation of port P4 will distribute power between ports P3 and P2.

[0060] The above device has many uses, one of which is indeed to use it as a switch to transfer power from one port to another, or to use a variable power divider. In fact, the position of the short circuit, and accordingly the angle φ of the reflection coefficient, can be changed mechanically or electronically by adding active components at the end of the circular port.

[0061] Another important application of the above device is to use it as a four-port circulator. As described in the previous embodiment, this can be achieved by adding a non-reciprocal disk at the end of the circular port. The excitation in port P1 will cause one helicity in the circular port to be excited, while the excitation in port P2 will cause the opposite helicity in the circular power. Then, since the plate of ferrite or garnet material is supported by a short-circuit plate and biased by a magnetic field along the axis of the circular port, the reflection at the circular port can be 180 degrees different for the excitation from port P1 compared to the excitation from port P2. As a result, all power from port P1 can be directed to port P2, and then all power excitation at port P2 will be directed to port P4. Similarly, examination of the signal excitation at ports P3 and P4 shows that the device can operate as a four-port circulator.

[0062] In another aspect, additional features associated with the short circuit of the circular waveguide port can further enhance the proposed polarizer concept. This aspect includes terminating the circular waveguide port with a non-reciprocal material at the short circuit. For different incident helicities, this feature can result in reflection coefficients that differ by 180 degrees. The purpose of this feature is to increase the power handling capability of the polarizer device. In particular, when the circulator is terminated by a short circuit (i.e., a short-circuit plate) at the receiving end, the circular waveguide port receives the incident power and the reflected power.

[0063] In some embodiments, this increased power handling provided by the short circuit can be mitigated by one or more features, preferably two features. First, the circular waveguide can be further expanded to a larger diameter, such as Fig.13As shown, a device 500' is shown having a circular waveguide including a flared portion 552 that expands to a larger diameter than the more proximal portion in order to reduce the field on the non-reciprocal material. A non-reciprocal disk 551 (e.g., a plate of garnet or ferrite material) is disposed at the end of the circular waveguide port along a short circuit. This will result in a lower power density and thus a lower field. However, this will also result in an over-mode system, especially inside the material (e.g., inside a ferrite or garnet plate). This feature can be used to excite two different modes within the material, one for each helicity.

[0064] like Figure 14A-14B To tailor these modes so that the peak fields within the material do not overlap, the plate material can be engraved so that it is flat on one side (on the short sides) and has curved indentations on the other side (facing outwards), as shown. Fig.14A As can be seen in FIG. 1 , the top surface of the plate of material of the disk is curved or concave inwardly. Fig. 14B As shown in the side view of FIG. 1 , the top surface is recessed inwardly, while the bottom underside surface is flat for placement on top of a shorting plate. The top surface may be carved into an oval or any suitable shape to optimize performance. In this embodiment, the plate material is a carved ferrite, but it will be appreciated that the material may be garnet or any suitable non-reciprocal material.

[0065] The addition of this feature optimizes the performance of the device. Figures 15A-16B As can be seen in the electric field images during operation of the two different modes shown, the appropriate curvature and plate thickness results in a field distribution with one helicity peak in the center and the other helicity peaks at the sides. At the same time, the phase shift of the reflection from each helicity differs by 180 degrees. This is achieved for both above-resonance bias and below-resonance bias. Fig.15A , during operation of the device 500' in isolation mode, with port P2 excited and port P4 receiving, the disk 551 of non-reciprocal material has a maximum field along its center portion (shown in red), as shown in FIG. Fig. 15B As shown. Fig.16A During operation of the device 500' in transmission mode, with port P1 excited and port P2 in reception, the maximum field (shown in red) along the disk 551 of non-reciprocal material is offset and forms a circle around the center of the disk, as shown in FIG. Fig. 16B shown.

[0066] Having described several exemplary configurations, various modifications, alternative structures, and equivalents may be used without departing from the spirit of the present disclosure. The above elements may be components of a larger system, in which other rules may take precedence over or modify the application of the present invention. Therefore, the above description does not limit the scope of the claims. All patents, patent applications, and other publications cited in this application are incorporated by reference in their entirety for all purposes.

Claims

1. A multi-port waveguide comprising: a rectangular waveguide extending along an xy plane between a first end and a second end opposite the first end, wherein the rectangular waveguide has opposing wide walls and opposing side walls, the rectangular waveguide having a first port and a second port disposed at or near the first end, wherein each of the first port and the second port is single mode; a first circular waveguide extending from the first wide wall of the rectangular waveguide to a third port, the first circular waveguide supporting at least two TE modes; and A second circular waveguide extends from a second wide wall opposite to the first wide wall, the second circular waveguide supporting at least two TE modes.

2. The multi-port waveguide according to claim 1, characterized in that The waveguide is designed to satisfy the following scattering matrix:

3. The multi-port waveguide according to claim 1, characterized in that The first port and the second port are each a rectangular waveguide port.

4. The multi-port waveguide according to claim 3, characterized in that: The multi-port waveguide is configured as an isolator between the first port and the second port.

5. The multi-port waveguide according to claim 4, characterized in that: The third port is short-circuited.

6. The multi-port waveguide according to claim 5, characterized in that The second circular waveguide includes a short-circuit structure arranged along the second circular waveguide in the z-axis direction at a position where a magnetic field on a ferrite of the short-circuit structure is minimized when fully transmitted through the second circular waveguide.

7. A multi-port waveguide according to any one of the preceding claims, characterized in that The waveguide is symmetric about the yz plane.

8. The multi-port waveguide according to claim 7, characterized in that: The waveguide comprises a Y-shaped or T-shaped structure having a base extending in the y-axis direction and a first top arm and a second top arm extending in the x-axis direction at the first end, wherein the first top arm and the second top arm terminate in the first port and the second port, respectively.

9. The multi-port waveguide according to claim 8, characterized in that The rectangular waveguide includes a diaphragm extending along a y-axis direction of the rectangular waveguide between the first port and the second port.

10. The multi-port waveguide according to claim 9, characterized in that The rectangular waveguide includes a V-shaped portion extending inwardly to the diaphragm between the first port and the second port.

11. The multi-port waveguide according to claim 9, characterized in that The rectangular waveguide includes a stepped portion between the base and each of the first top arm and the second top arm.

12. The multi-port waveguide according to claim 11, characterized in that Each wide wall of the rectangular waveguide includes a partial dome surface surrounding a base of the respective circular waveguide extending therefrom.

13. The multi-port waveguide according to claim 12, characterized in that: The second end of the rectangular waveguide is closed and includes a distal surface.

14. The multi-port waveguide according to claim 13, characterized in that The distal surface of the second end is angled or curved inwardly in the y-axis direction.

15. The multi-port waveguide according to claim 14, characterized in that The distal surface has two corner edges extending along the z-axis direction, wherein the corner edges are curved.

16. The multi-port waveguide according to claim 14, characterized in that The stepped portion, the partially domed surface, and the distal end surface are sized to satisfy the following scattering matrix:

17. The multi-port waveguide according to claim 16, characterized in that For the optimal case, α is 2 / 3 and β is -1 / 3.

18. The multi-port waveguide of claim 1, further comprising one or more additional multi-port waveguides as in claim 1 stacked with the multi-port waveguide such that the first circular waveguide of one multi-port waveguide is coupled with the second circular waveguide of an adjacent multi-port waveguide.

19. The multi-port waveguide according to claim 1, characterized in that The waveguide is configured as a directional coupler.

20. The multi-port waveguide according to claim 1, characterized in that The directional coupler comprises: The first multiport waveguide according to claim 1, and A second multi-port waveguide according to claim 1.

21. The multi-port waveguide according to claim 20, characterized in that The first circular waveguide of the first multi-port waveguide is coupled to the second circular waveguide of the second multi-port waveguide, and a choke structure is arranged in the second multi-port waveguide for a differential nominal coupling ratio through the choke structure.

22. The multi-port waveguide according to claim 21, characterized in that The first circular waveguide of the second multi-port waveguide includes a short-circuit structure disposed on a plunger, wherein the short-circuit structure is adjustable within the first circular waveguide, so that the directional coupler is tunable by adjusting the plunger.

23. A four-port isolator comprising: The first multi-port waveguide according to claim 1, the first multi-port waveguide having first and second rectangular waveguide ports and first and second circular waveguides extending from the first multi-port waveguide, and The second multi-port waveguide according to claim 1, the second multi-port waveguide having first and second rectangular waveguide ports and first and second circular waveguides extending from the second multi-port waveguide; Wherein the first circular waveguide of the first multi-port waveguide is coupled to the second circular waveguide of the second multi-port waveguide.

24. The four-port isolator according to claim 23, characterized in that The first rectangular port and the second rectangular port of the second multi-port waveguide face in opposite directions.

25. The multi-port waveguide according to claim 23 or claim 24, characterized in that The first port and the second port of the first multi-port waveguide face inwardly along the y-axis in the same direction.

26. The multi-port waveguide according to any one of claims 23 to 25, characterized in that: The second circular waveguide of the first multi-port waveguide is closed at its distal end, and the first circular waveguide of the second multi-port waveguide is closed or short-circuited.

27. The multi-port waveguide according to any one of claims 23 to 25, characterized in that: The waveguide is defined by a plurality of components including a lower waveguide component, a middle waveguide component and an upper waveguide component that interface within the assembly.

28. The multi-port waveguide according to claim 27 It is characterized in that The upper waveguide body and the middle waveguide component together define the first multi-port waveguide; and The lower waveguide component and the middle waveguide component together define the second multi-port waveguide.

29. The four-port isolator according to any one of claims 23 to 28, characterized in that: The first circular waveguide of the second multi-port waveguide is short-circuited by a fixed short-circuit structure.

30. The four-port isolator according to any one of claims 23 to 28, characterized in that: The first circular waveguide of the second multi-port waveguide is short-circuited at a position corresponding to a desired power capability.

31. The four-port isolator according to any one of claims 23 to 28, characterized in that: The first circular waveguide of the second multi-port waveguide includes a short circuit and an adjustable bias structure.

32. The four-port isolator according to claim 31, characterized in that The adjustable biasing structure has threads that interface with corresponding threads on the circular waveguide structure and a magnet for biasing the short circuit.

33. The four-port isolator according to claim 31, characterized in that The adjustable biasing structure includes an adjustable feature for adjusting the distance between the magnet and the short circuit.

34. The four-port isolator according to claim 32, characterized in that The magnet comprises an electromagnet having an adjustable field strength by powering the electromagnet.

35. The four-port isolator according to claim 33, characterized in that The electromagnet includes a stainless steel shield.

36. The four-port isolator according to any one of claims 26 to 35, characterized in that: The short circuit comprises a thin garnet disk supported by a thin short circuit plate made of copper, which allows the magnetic field from the adjustable bias structure to bias the garnet disk so that the isolator is non-reciprocal, thereby acting as a four-port circulator.

37. A multi-port waveguide comprising: a rectangular waveguide extending along an xy plane between a first end and a second end opposite the first end, wherein the rectangular waveguide has opposing wide walls and opposing side walls, wherein the rectangular waveguide has a first port and a second port disposed at or near the first end, wherein each of the first port and the second port is single mode, wherein the rectangular waveguide has a third port and a fourth port disposed at or near the second end, wherein each of the third port and the fourth port is single mode; as well as A first circular waveguide extending from the first wide wall of the rectangular waveguide to a fifth port supporting at least two TE modes so that the multi-port waveguide can be used as a six-port polarizer.

38. The multi-port waveguide according to claim 37, characterized in that The short circuit in the fifth port of the circular waveguide forms a four-port network designed to satisfy the following scattering matrix:

39. The multi-port waveguide of claim 37, further comprising: a matching post extending in the z-direction along a corresponding outwardly facing sidewall of the rectangular waveguide extending to each of the first port and the second port; as well as The matching post extends in the z-direction along a corresponding outwardly facing sidewall of the rectangular waveguide extending to each of the third port and the fourth port.

40. The multi-port waveguide of claim 37, further comprising: A pair of phase shifting recesses extend in the z-direction along opposite sides of the circular waveguide portion extending to the fifth port.

41. The multi-port waveguide of claim 37, further comprising: A pair of inductive rectangular pillars are arranged on opposite sides of the circular waveguide in a y-direction portion along a central portion of the wide wall of the rectangular portion and extend in the z-direction.

42. The multi-port waveguide of claim 37, further comprising: a pair of inductive rectangular indentations on opposite sides of the circular waveguide portion in the x-direction along an outwardly facing side of the rectangular waveguide, the pair of inductive rectangular indentations extending in the z-direction and formed as depressions in the sidewalls of the rectangular waveguide.

43. The multi-port waveguide of claim 37, further comprising: Any combination of claim 39 to claim 42.

44. The multi-port waveguide according to any one of claims 37 to 43, characterized in that: The fifth port includes a short circuit provided by a short circuit plate at a terminal end of the short circuit plate.

45. The multi-port waveguide according to claim 44, characterized in that The distal portion of the circular waveguide extending to the short circuit expands to a larger diameter than the proximal portion of the circular waveguide extending from the wide wall of the rectangular waveguide.

46. ​​The multi-port waveguide of claim 44, further comprising: A disk of non-reciprocal material is placed on top of the short.

47. The multi-port waveguide according to claim 46, characterized in that The non-reciprocal material is garnet or ferrite.

48. The multi-port waveguide according to claim 46, characterized in that The top surface of the non-reciprocal material is contoured inwardly towards the shorting plane to optimize operation and field distribution along the disk in different modes.

49. The multi-port waveguide according to claim 48, characterized in that The top surface of the non-reciprocal material is concave.

50. The multi-port waveguide according to claim 49, characterized in that The top surface of the non-reciprocal material is elliptical.

51. The multi-port waveguide according to claim 49, characterized in that The top surface of the non-reciprocal material is of any suitable shape.

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