HIGH-FREQUENCY AMPLIFIER UNIT WITH AMPLIFIER MODULES ARRANGED ON OUTER CONDUCTOR

Description

[0001] The present invention relates to a high-frequency (HF) amplifier unit comprising several amplifier modules for amplifying high-frequency input signals to high-frequency output signals and a coaxial combiner with an outer conductor and an inner conductor arranged coaxially thereto for combining the high-frequency output signals of the amplifier modules. The invention also relates to an amplifier system.

[0002] Acceleration resonators, especially superconducting cavities of particle accelerators, are determined by the accelerator design (cyclotron, linear accelerator, and synchrotron) and by the type of particles to be accelerated. All resonators share the requirement of high RF power to ensure the necessary accelerating field strengths and the desired energy gain of the particles. Recently developed transistor-based amplifier modules enable output power of up to 500 W per module, and in some cases even higher.

[0003] Even small accelerators require RF power outputs well over 10 kW to operate the accelerator and, in particular, the accelerating resonator. Large cyclotrons or the accelerating resonators of synchrotrons and storage rings demand RF power outputs of up to 100 kW and more. The output power of dozens of amplifier units must therefore be combined for operation, meaning it must be summed or amplified. For this purpose, the amplified RF output signals from the amplifier units are transmitted via coaxial cables to RF power combiners, which combine the amplified RF output signals. In RF technology, a combiner is understood to be a component that combines several weaker signals (usually of the same frequency) into a stronger signal.At the same time, it usually isolates the inputs from each other so that they do not influence each other, or the other signal generators.

[0004] One problem is that the amplifier units typically generate considerable heat, which must be dissipated. This requirement limits the possible design of both the individual high-frequency amplifier unit and the entire amplifier system, resulting in correspondingly large, room-filling installations at high power levels. Furthermore, this approach becomes increasingly unattractive as the frequency of the amplified high-frequency output signals being combined increases due to the significantly increasing Joule losses in the coaxial cables.

[0005] From the article "Design of high power radio frequency radial combiner for proton accelerator", Akhilesh Jain et al., rev.sci.instrum. 80, 016106 (2009), 1-3, a disc-shaped radial combiner is known to which the amplifier modules are connected in a star configuration via 50-ohm coaxial feed lines. The power is coupled out at the center of the disc-shaped radial combiner via a waveguide positioned perpendicular to it.

[0006] A comparable radial combiner is known from the article "High power solid state rf amplifier for proton accelerator", Akhilesh Jain et al., rev.sci.instrum. 79, 014702 (2008), 1-7.

[0007] Therefore, important requirements for a high-frequency amplifier unit with a power combiner are: 1. High cost-effectiveness (lowest possible investment and operating costs), 2. Lowest possible line losses (cables) and combination losses, and therefore high efficiency, 3. Compact design, and 4. Easy accessibility and interchangeability of the high-frequency amplifier units and / or amplifier modules.

[0008] The present invention therefore aims to provide a high-frequency amplifier unit and amplifier system that meets some or all of these requirements.

[0009] According to a first aspect of the invention, the problem of a high-frequency amplifier unit comprising several amplifier modules for amplifying high-frequency input signals to high-frequency output signals and a coaxial combiner with an outer conductor and an inner conductor arranged coaxially thereto for combining the high-frequency output signals of the amplifier modules is solved by the features of claim 1. Here, the amplifier modules are arranged externally on the outer conductor of the coaxial combiner, and the amplifier modules are connected to the coaxial inner conductor of the coaxial combiner for transmitting the high-frequency output signals.

[0010] By arranging the amplifier modules on the outer conductor of the coaxial combiner and simultaneously connecting them to the coaxial inner conductor for transmitting the high-frequency output signals, a highly compact and space-saving high-frequency amplifier unit can be realized, especially compared to a waveguide (without an inner conductor). The transmission of the (amplified) high-frequency output signals, i.e., the power transmission from the amplifier modules to the coaxial combiner, can be wireless due to the arrangement of the amplifier modules on the outer conductor. Because no cables are required between the amplifier modules and the coaxial combiner, the high-frequency amplifier unit is subject to minimal signal loss and is easily accessible when needed.In particular, it has been shown that the output power of the amplifier modules can be transferred directly to the coaxial combiner by connecting it to the inner conductor of the coaxial combiner, while the outer conductor of the coaxial combiner can simultaneously be used advantageously for cooling the amplifier modules.

[0011] The high-frequency signals in this case are preferably signals with frequencies in the radio wave range, and in particular the microwave range. This means that they are preferably waves with a frequency of at least 50 MHz, more preferably at least 70 MHz, more preferably at least 100 MHz, and particularly preferably at least 300 MHz. It is also preferred if the waves have a frequency of at most 300 GHz, more preferably at most 3 GHz. A preferred range is, for example, 1 to 3 GHz. A typical frequency for the application of particle accelerators is, for example, between approximately 70 MHz and 3 GHz (for example, at 1.3 GHz, 1.5 GHz, or 1.75 GHz). Accordingly, the devices in question are preferably high-frequency amplifier units, amplifier modules, and coaxial combiners designed for generating, amplifying, or guiding such microwaves.The energy of the signals is transported in the dielectric (preferably air) between the outer conductor and the inner conductor.

[0012] An amplifier module comprises, in particular, a transistor amplifier, which may, for example, include one or more power transistors, or, in the case of push-pull operation, two power transistors. Furthermore, an amplifier module may include a circulator, which serves to protect the upstream transistor(s). An amplifier module may, for example, be designed as a circuit board or pallet, which may be a single piece but may also, for example, comprise a transistor board and a circulator board. An amplifier module preferably delivers a (nominal) power of at least 300 W, more preferably at least 400 W, and more preferably at least or more than 500 W. An amplifier module has a metal layer, in particular made of copper or aluminum, on the side facing the coaxial combiner (in particular the mounting side or underside).

[0013] The high-frequency amplifier unit can further comprise one (or more) drivers, one (or more) preamplifiers, and / or a splitter, which serves to divide the signals into multiple high-frequency input signals for multiple amplifier modules. Such components, like the amplifier modules, can be arranged externally on the coaxial combiner or be part of it. Alternatively, such components can also be arranged separately, particularly if the amplifier modules already occupy substantially all the space on the outer conductor of the coaxial combiner. Preferably, a high-frequency amplifier unit comprises at least four, more preferably at least six, and further preferably at least eight amplifier modules.

[0014] It has proven advantageous if the coaxial combiner preferably extends in a longitudinal direction and thus has a tower-like geometry with longitudinally extending side surfaces (formed by the outer conductor). The coaxial combiner, in particular the outer conductor and the coaxial inner conductor, is / are preferably made of metal, especially copper and / or aluminum.

[0015] The fact that the amplifier modules are each connected to the coaxial inner conductor means, in particular, that the output of the amplifier module (for example, a coupling circuit of the amplifier module) is electrically connected to the inner conductor. This connection can be made, for example, via electrically conductive coupling pins. In this way, the amplifier modules are then connected to the coaxial inner conductor, especially at an input-side end. The power is then coupled out from the high-frequency amplifier unit, for example, via an output-side end of the coaxial inner conductor, for instance, by extending the coaxial inner conductor beyond the outer conductor at the output side and serving, for example, as a probe (especially as a (rod) antenna) for coupling into a waveguide.

[0016] According to one embodiment of the high-frequency amplifier unit, the coaxial combiner runs longitudinally, and the outer conductor has a polygonal, particularly quadrilateral, cross-section on its outer surface. In this way, the coaxial combiner, or rather its outer conductor, can easily form external surfaces or sides that can serve as mounting surfaces for the amplifier modules. It has been shown that this design allows for an extremely compact construction and arrangement of the high-frequency amplifier units on further combiners, while ensuring sufficient cooling and low combination losses.

[0017] Preferably, only the outer surface of the outer conductor has a corresponding cross-sectional geometry, while the inner surface of the outer conductor and / or the outer surface of the inner conductor have a different, in particular round, cross-sectional geometry. However, it is also possible that not only the outer conductor but also the inner surface of the outer conductor and / or the outer surface of the inner conductor have a corresponding or different polygonal cross-sectional geometry.

[0018] In one example, with an n-sided cross-section (and thus n sides), preferably n amplifier modules can be arranged on the outer surface of the outer conductor of the coaxial combiner (one on each side). If the coaxial combiner or outer conductor is sufficiently long longitudinally, two amplifier modules can be arranged longitudinally on each side, so that a total of 2n amplifier modules can be arranged on the outer surface of the outer conductor of the coaxial combiner.

[0019] According to the invention, the amplifier modules are essentially planar and arranged essentially planar on the outer conductor of the coaxial combiner. Preferably, the amplifier modules substantially cover the outer surface of the outer conductor. As already described, preferably at least one amplifier module is arranged on each side surface in the circumferential direction.

[0020] According to the invention, the amplifier modules are arranged externally on the coaxial combiner in such a way that the outer conductor of the coaxial combiner can serve to cool the amplifier modules. In this way, active cooling of the amplifier modules can be achieved in a compact design. Previous approaches in the prior art, however, involved a central cooling board onto which amplifier boards were mounted on both sides to save space. Since the cooling device was then located between the amplifier modules, the output power had to be dissipated from the top via coaxial cables. According to the described embodiment, both heat and power dissipation to the coaxial combiner are possible from the underside of the modules, particularly without an additional, separate cooling device. For this purpose, the amplifier modules are arranged directly on the outer conductor of the coaxial combiner.

[0021] The cooling of the amplifier modules preferably takes place exclusively (apart from an unavoidable slow heat transfer through the amplifier module and the ambient air itself) through the outer conductor of the coaxial combiner.

[0022] To achieve high cooling efficiency and thus high output power, in a preferred embodiment of the high-frequency amplifier unit, the outer conductor of the coaxial combiner is designed as part of a coolant circuit for cooling the amplifier modules. Water (e.g., demineralized water) is used as the coolant. For this purpose, the coaxial combiner has, for example, at least one coolant inlet and at least one coolant outlet. Preferably, the outer conductor of the coaxial combine has integral (especially in the corners) longitudinally extending coolant lines (e.g., bores) extending at least partially in the longitudinal direction.

[0023] To further optimize the cooling performance and output power of the high-frequency amplifier unit, according to a preferred embodiment of the high-frequency amplifier unit, the amplifier modules are arranged circumferentially on the outer conductor of the coaxial combiner. As already described, preferably at least one amplifier module is arranged on each side surface provided by the outer conductor in the circumferential direction. In other words, the amplifier modules are arranged next to each other in the circumferential direction.

[0024] According to a preferred embodiment of the high-frequency amplifier unit, at least some of the amplifier modules are connected to the coaxial inner conductor at the same level when viewed longitudinally. This results in the simplest possible geometry of the coaxial combiner and, in particular, the coaxial inner conductor, with the lowest possible losses when transmitting the high-frequency output signals to the coaxial combiner. The electrical connections (e.g., the coupling pins) for connecting the corresponding amplifier modules then run in a plane, in particular perpendicular to the longitudinal direction of the coaxial combiner. However, different groups of amplifier modules can also be provided, whereby the amplifier modules of one group are connected to the coaxial inner conductor at the same level, but the amplifier modules of different groups are connected at different levels, as described in more detail below.

[0025] According to a preferred embodiment of the high-frequency amplifier unit, amplifier modules of a first group are arranged on the outer conductor of the coaxial combiner in a first longitudinal section, and amplifier modules of a second group are arranged on the outer conductor of the coaxial combiner in a second longitudinal section. It has been shown that, despite the longitudinally offset amplifier modules, a high-efficiency transmission of the high-frequency output signals to the coaxial combiner can be achieved, thus effectively doubling the output power of the high-frequency amplifier unit.

[0026] The first longitudinal section preferably connects directly to the second longitudinal section. Preferably, the output power of all amplifier modules of the high-frequency amplifier unit is coupled out via an output-side end of the coaxial inner conductor (for example, into a waveguide), as already described, which in this case is located at an end region of the first longitudinal section facing away from the second longitudinal section.

[0027] According to a preferred embodiment of the high-frequency amplifier unit, the amplifier modules of the first group are connected to the coaxial inner conductor at an end region of the first longitudinal section of the coaxial combiner facing the second longitudinal section of the coaxial combiner, and / or the amplifier modules of the second group are connected to the coaxial inner conductor at an end region of the second longitudinal section of the coaxial combiner facing the first longitudinal section of the coaxial combiner.

[0028] This has the advantage that the connections of the amplifier modules to the inner conductor of the coaxial combiner are geometrically very close to one another, which keeps combination losses low even with a simple coaxial combiner geometry. It was also recognized that the connections of the amplifier modules to the inner conductor of the coaxial combiner (and thus the transmission of the high-frequency output signals to the coaxial combiner) do not necessarily all have to be at exactly the same height (longitudinally), which allows for a longitudinally offset arrangement of the amplifier modules. The first and second longitudinal sections are preferably essentially the same length.

[0029] To achieve the connection of the second group of amplifier modules (and thus double the output power) with minimal combination losses and a compact design, a preferred embodiment of the high-frequency amplifier unit has found it advantageous for the coaxial inner conductor to extend into the end region of the second longitudinal section of the coaxial combiner, which faces the first longitudinal section of the coaxial combiner. The second longitudinal section of the coaxial combiner can be terminated, if necessary (for example, by a circuit board spaced apart from the inner conductor or by a solid outer conductor in the interior of the second longitudinal section), which prevents the combined high-frequency output signals from propagating from the connection area between the amplifier modules and the inner conductor (coupling area) towards the second longitudinal section.

[0030] According to a preferred embodiment of the high-frequency amplifier unit, the amplifier modules of the first group and the amplifier modules of the second group are each connected to the coaxial inner conductor at the same level when viewed longitudinally along the coaxial combiner. In other words, the amplifier modules of the first group are connected to the coaxial inner conductor at a first level when viewed longitudinally along the coaxial combiner, and the amplifier modules of the second group are connected to the coaxial inner conductor at a second level when viewed longitudinally along the coaxial combiner.

[0031] To reduce or largely avoid unwanted reflections of the high-power output signals and thus combination losses, a preferred embodiment of the high-frequency amplifier unit in the coaxial combiner incorporates a transformer section with transformation characteristics such that the input-side characteristic impedance (caused in particular by the connected amplifier modules) is transformed at the coaxial combiner to an output-side characteristic impedance. As a result, during transmission line transformation, the input-side characteristic impedance (in the region of the connection between the coaxial inner conductor and the amplifier modules) is transformed to a different output-side characteristic impedance.Thus, the input-side characteristic impedance of the coaxial combiner with N amplifier modules (whose lines typically have a characteristic impedance of R1 = 50 ohms) is only approximately R / N due to the combination (which can be considered a parallel connection). To transform the line to a desired characteristic impedance R2 (typically back to the original characteristic impedance R1), a transformer section can be, for example, a λ / 4 transformer or a transformer acting as a λ / 4 transformer, whose length is approximately (but not necessarily exactly) one-quarter of the wavelength λ of the high-frequency signals. For example, the transformer section can also be implemented in a "stepped impedance" design with stepwise changing diameters of the inner and / or outer conductors, so that the length of the transformer section becomes significantly shorter than λ / 4.The characteristic impedance of the transformer section RT can be estimated using (R₁ / N * R₂) 1 / 2. For example, if N = 4 and R₁ = R₂ = 50 ohms, the characteristic impedance for the transformer section is approximately RT = 25 ohms. However, the values ​​of R₁ and / or R₂ do not necessarily have to be 50 ohms.

[0032] An advantageous geometry of the coaxial combiner has been found to exist in a preferred embodiment of the high-frequency amplifier unit in which, within the transformer section, the coaxial inner conductor of the coaxial combiner has a first outer diameter and the outer conductor of the coaxial combiner has a first inner diameter, and in an output section adjoining the transformer section, the coaxial inner conductor of the coaxial combiner has a second outer diameter and / or the outer conductor of the coaxial combiner has a second inner diameter. The outer diameter of the coaxial inner conductor in the output section is preferably smaller than the outer diameter of the coaxial inner conductor in the transformer section. Alternatively or additionally, the inner diameter of the outer conductor in the output section is preferably smaller than the inner diameter of the outer conductor in the transformer section.However, from a manufacturing perspective, it is advantageous if either only the outer diameter of the coaxial inner conductor changes from a first to a different (smaller) second outer diameter, or if only the inner diameter of the outer conductor of the coaxial combiner changes from a first to a different (smaller) second inner diameter, while the other diameter remains the same. This means that the second inner or outer diameter can also be the same as the first inner or outer diameter.

[0033] To reduce or largely avoid unwanted reflections of the high-power output signals and thus combination losses, a preferred embodiment of the high-frequency amplifier unit features a ratio of the first inner diameter of the outer conductor to the first outer diameter of the inner conductor in the transformer section that is smaller than the ratio of the second inner diameter of the outer conductor to the second outer diameter of the inner conductor in the output section. Since the characteristic impedance depends on the ratio of the inner diameter of the outer conductor to the outer diameter of the inner conductor, this allows for transmission line transformation. For example, the ratio of the inner diameter of the outer conductor to the outer diameter of the inner conductor in the output section is greater than 1.5, preferably greater than 2.

[0034] According to a preferred embodiment of the high-frequency amplifier unit, the unit can provide an output power of at least 2 kW, preferably at least 4 kW. It has been shown that the described high-frequency amplifier unit can provide correspondingly high power outputs in a compact design.

[0035] According to a second aspect of the invention, the problem is also solved by an amplifier system comprising several high-frequency amplifier units according to the first aspect and a high-frequency waveguide, wherein the high-frequency amplifier units are arranged along the longitudinal direction of the high-frequency waveguide so that the high-frequency waveguide can combine the output powers of the high-frequency amplifier units. The high-frequency waveguide is, in particular, a waveguide, preferably with a rectangular cross-section. For example, at least two, preferably at least four, and more preferably at least eight high-frequency amplifier units are arranged on one side of the high-frequency waveguide. If the high-frequency waveguides are arranged on both sides of the high-frequency waveguide, the number of high-frequency amplifier units and thus the output power can be doubled.

[0036] A particularly space-saving design results if, according to a preferred embodiment of the amplifier system, the longitudinal axes of the high-frequency amplifier units are each located transversely, in particular perpendicularly, to the longitudinal axis of the high-frequency waveguide.

[0037] Particularly advantageous in one embodiment of the amplifier system is the use of the coaxial inner conductors of the high-frequency amplifier units at the output end as probes (for example, as (rod) antennas) for coupling the power of the coaxial combiners into the high-frequency waveguide.

[0038] The described high-frequency amplifier units enable the amplifier system to provide an output power of, for example, at least 24 kW, 48 kW or even 96 kW.

[0039] According to a preferred embodiment of the amplifier system, the high-frequency amplifier units are arranged offset from one another in the transverse direction of the high-frequency waveguide and / or on both sides of the high-frequency waveguide. The high-frequency amplifier units are arranged longitudinally, in particular, at intervals of half a (conductor) wavelength. Especially in combination with a substantially square cross-section of the high-frequency amplifier units, this results in a particularly space-saving design.

[0040] The embodiments and exemplary configurations of all aspects of the present invention described above are also to be understood as disclosed in all combinations with one another. However, the above combinations are only included in the invention if they fall within the scope of the claims.

[0041] Further advantageous exemplary embodiments of the various aspects can be found in the following detailed description of some exemplary embodiments of the aspects, particularly in conjunction with the figures. However, the figures accompanying the application are intended only for illustrative purposes and not to determine the scope of protection of the invention. The accompanying drawings are not necessarily to scale and are intended only to reflect the general concept of the present aspects by way of example. In particular, features included in the figures should by no means be considered a necessary component of the present invention.

[0042] They show: Fig. 1a shows an embodiment of a high-frequency amplifier unit according to the invention in cross-section and longitudinal section; Fig. 2 shows a further embodiment of a high-frequency amplifier unit according to the invention in longitudinal section; Fig. 3 shows a further embodiment of a high-frequency amplifier unit according to the invention in cross-section; Fig. 4a shows an embodiment of an amplifier system according to the invention in cross-section and top view; and Fig. 5 shows a further embodiment of an amplifier system according to the invention.

[0043] Fig. 1 Figure 1 shows first an embodiment of a high-frequency amplifier unit 100 according to the invention in cross-section ( Fig. 1a ) and in longitudinal section ( Fig. 1b The high-frequency amplifier unit 100 comprises several (here four) amplifier modules 10 for amplifying high-frequency input signals to high-frequency output signals. The amplifier modules 10 are designed as flat circuit boards and each includes a transistor amplifier 11 and a circulator 12. The underside of the amplifier modules 10 has a metal layer 13. The high-frequency amplifier unit 100 also includes a coaxial combiner 102 with an outer conductor 104 and an inner conductor 106 arranged coaxially with it for combining the high-frequency output signals of the amplifier modules 10. The coaxial combiner 102 runs longitudinally, and the outer conductor 104 has a square cross-section on its outer side, thus forming four outer faces, while the outer conductor 104 and the inner conductor 106 have a circular cross-section on their inner sides.

[0044] The amplifier modules 10 are arranged flat on the outer surface of the outer conductor 104 of the coaxial combiner 102. One amplifier module 10 is arranged on each of the four outer surfaces provided by the outer conductor 104. The amplifier modules 10 are arranged circumferentially around the outer conductor 104 of the coaxial combiner 102.

[0045] The amplifier modules 10 are also arranged on the coaxial combiner 102 in such a way that the outer conductor 104 of the coaxial combiner 102 can be used to cool the amplifier modules 10 during operation. For this purpose, the outer conductor 104 of the coaxial combiner 102 is designed as part of a coolant circuit for cooling the amplifier modules 10, so that the outer conductor can be supplied with coolant via coolant lines 110.

[0046] The amplifier modules 10 are connected to the coaxial inner conductor 106 of the coaxial combiner 102 via coupling pins 108 for the transmission of the high-frequency output signals to the coaxial combiner 102. The four amplifier modules 10 are connected to the coaxial inner conductor 106 at the same height when viewed longitudinally.

[0047] The coaxial combiner 102 further comprises a transformer section 112. This transformer section gives the coaxial combiner 102 a transformation characteristic whereby the input-side characteristic impedance at the coaxial combiner 102 in the region of the coupling pins 108 is transformed to an output-side characteristic impedance in the region of the output section 114 of the coaxial combiner 102. In this case, the transformer section 112 represents a λ / 4 transformer, at whose input a characteristic impedance of 50 ohms / 4 is present due to the four amplifier modules 10, each of which has a line resistance of 50 ohms. The characteristic impedance of the transformer section 112 is approximately 25 ohms in order to match the characteristic impedance of 50 ohms at the output of the output section 114.

[0048] In transformer section 112, the coaxial inner conductor 106 of the coaxial combiner 102 has a first outer diameter d1, and the outer conductor 104 of the coaxial combiner 102 has a first inner diameter D1. In the output section 114 following transformer section 112, the coaxial inner conductor 106 of the coaxial combiner 102 has a second outer diameter d2, and the outer conductor 104 of the coaxial combiner 102 has a second inner diameter D2. The ratio D1 / d1 of the first inner diameter of the outer conductor 104 to the first outer diameter of the inner conductor 106 in transformer section 112 is smaller than the ratio D2 / d2 of the second inner diameter of the outer conductor 104 to the second outer diameter of the inner conductor 106 in output section 114.

[0049] Because the coaxial inner conductor 106 extends beyond the outer conductor 104 on the output side, it can serve as a rod antenna 116 and couple the power out of the high-frequency amplifier unit 100 or couple it into a high-frequency waveguide (see Fig. 4 or 5 ).

[0050] In the present example, the individual amplifier modules 10 provide a power of approximately 500 W, so that the high-frequency amplifier unit 100 can provide an output power of approximately 2 kW in operation.

[0051] Fig. 2 Figure 1 shows a further embodiment of a high-frequency amplifier unit 200 according to the invention in longitudinal section. The high-frequency amplifier unit 200 is constructed similarly to the high-frequency amplifier unit 100, so that initially, Fig. 1 Reference is made to the above. The following section will focus in particular on the differences, using the corresponding reference number 200 instead of 100.

[0052] The high-frequency amplifier unit 200 thus features a longitudinally longer coaxial combiner 202 with a particularly longer outer conductor 204. This allows not only (in this case, four) amplifier modules 10 of a first (lower) group of amplifier modules 10 to be arranged on the outer conductor 204 of the coaxial combiner 202 in a first longitudinal section 220, but also (in this case, four) further amplifier modules 10' of a second (upper) group of amplifier modules 10' to be arranged on the outer conductor 204 of the coaxial combiner 202 in a second longitudinal section 230. In this way, the output power of the coaxial combiner 202 is doubled.

[0053] The amplifier modules 10 of the first (lower) group are connected to the coaxial inner conductor 206 at an end region 222 of the first longitudinal section 220 of the coaxial combiner 202, which faces the second longitudinal section 230 of the coaxial combiner 202. The amplifier modules 10' of the second (upper) group are connected to the coaxial inner conductor 206 at an end region 232 of the second longitudinal section 230 of the coaxial combiner 202, which faces the first longitudinal section 220 of the coaxial combiner 202. For this purpose, the coaxial inner conductor 206 extends into the end region 232 of the second longitudinal section 230 of the coaxial combiner 202, which faces the first longitudinal section 220 of the coaxial combiner 202.Furthermore, the second longitudinal section 230 of the coaxial combiner 202, after an air gap following the end of the inner conductor 206, is formed with a solid outer conductor 204, so that the high-frequency field does not extend upwards into and out of the coaxial combiner 202 in the opposite direction to the desired direction. Alternatively, it would also be sufficient to provide a wall (circuit board) as a termination.

[0054] As with the coaxial combiner 102, the amplifier modules 10 of the first group are connected to the coaxial inner conductor 206 at the same level by means of the coupling pins 208 in the longitudinal direction of the coaxial combiner 202. Likewise, the amplifier modules 10' of the second group are connected to the coaxial inner conductor 206, which extends into the second longitudinal section 230, at the same level by means of the coupling pins 208' in the longitudinal direction of the coaxial combiner 202.

[0055] Fig. 3 Figure 1 shows a further embodiment of a high-frequency amplifier unit 300 according to the invention in cross-section. Viewed in longitudinal section, the high-frequency amplifier unit 300 can be constructed as shown in Figure 2. Fig. 1b or Fig. 2 The high-frequency amplifier units 100 and 200 shown are shown. In contrast to these embodiments, the outer conductor 304 of the coaxial combiner 302 is, in this case, not square but octagonal in cross-section. This allows eight amplifier modules 10 to be arranged flat on the outer conductor 304. A number of radially inward-extending coupling pins 308 corresponding to the number of amplifier modules 10 are also provided for connecting the amplifier modules 10 to the inner conductor 306. Like the inner conductor 306, the outer conductor 304 of the coaxial combiner 302 is again round or circular.

[0056] Fig. 4 shows an embodiment of an amplifier system 400 according to the invention in cross-section ( Fig. 4a ) and in top view ( Fig. 4b The amplifier system 400 comprises several of the high-frequency amplifier units 200. Fig. 2 However, the high-frequency amplifier units can also be made from 100 Fig. 1 or the high-frequency amplifier units 300 from Fig. 3 The amplifier system 400 further comprises a high-frequency waveguide 402 with a rectangular cross-section. The high-frequency amplifier units 200 are arranged along the longitudinal direction of the high-frequency waveguide 402. The longitudinal axes of the high-frequency amplifier units 200 are each perpendicular to the longitudinal axis of the high-frequency waveguide 402. The high-frequency amplifier units 200 are also offset transversely to the central axis of the high-frequency waveguide 402 and alternately offset from each other and longitudinally at intervals of half a wavelength on the high-frequency waveguide 402. Alternatively, the high-frequency amplifier units 200 can also be arranged only centrally on the central axis of the high-frequency waveguide 402.The high-frequency amplifier units 200 can also be arranged transversely to the central axis, but in pairs at the same height when viewed longitudinally. The high-frequency amplifier units 200 can also be mounted on both opposite side walls (in ). Fig. 4b (only the front of the high-frequency waveguide 402 is visible) can be arranged. Combinations of the aforementioned possibilities are also conceivable. As can be seen, the rectangular or square design of the coaxial combiner 202 in particular leads to a compact form factor.

[0057] The output powers of the 200 high-frequency amplifier units are combined by the 402 high-frequency waveguide. As in Fig. 4a (which merely represents the area of ​​the high-frequency waveguide), the coaxial inner conductors 206 project into the high-frequency waveguide 402 at the output end. Thus, the coaxial inner conductors 206 of the high-frequency amplifier units 200 each serve as a probe in the form of a rod antenna 216 at the output end for coupling the power of the coaxial combiners 202 into the high-frequency waveguide 402.

[0058] Assuming an output power of 200 of the individual high-frequency amplifier units (8 x 500 W = 4 kW), the amplifier system can deliver an output power of 24 kW.

[0059] Fig. 5 shows a further embodiment of an amplifier system 500 according to the invention, which is similar to the one already described in Fig. 4 The amplifier system 400 shown is also present. Here, too, the high-frequency amplifier units 200 are arranged on a high-frequency waveguide 502, and other high-frequency amplifier units 200 can also be used. In contrast to the one in Fig. 4 In the depicted system 400, the high-frequency amplifier units 200 are arranged on both sides of the high-frequency waveguide 502. This results in a doubled output power of 48 kW compared to amplifier system 400. Coolant lines 504 are also visible, which transport a coolant to the high-frequency amplifier units 200, allowing the outer conductors 204 of the coaxial combiner 202 to be permeated with the coolant and to dissipate the waste heat from the amplifier modules 10, 10' without the need for additional cooling devices between the amplifier modules 10, 10' and the coaxial combiner 202.

Claims

1. High-frequency amplifier unit (100, 200, 300) comprising - a plurality of amplifier modules (10, 10') for amplifying high-frequency input signals to high-frequency output signals, and - a coaxial combiner (102, 202, 302) with an outer conductor (104, 204, 304) and an inner conductor (106, 206, 306) arranged coaxially thereto for combining the high-frequency output signals of the amplifier modules (10, 10'), - the amplifier modules (10, 10') being arranged on the outside on the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302), - the amplifier modules (10, 10') are connected to the coaxial inner conductor (106, 206, 306) of the coaxial combiner (102, 202, 302) for transferring the high-frequency output signals to the coaxial combiner (102, 202, 302), characterized in that - the amplifier modules (10, 10') are essentially flat in design and are arranged essentially flat on the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302), and - the amplifier modules (10, 10') are arranged on the outside of the coaxial combiner (102, 202, 302) in such a way that the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302) can serve to cool the amplifier modules (10, 10').

2. High-frequency amplifier unit according to claim 1, characterized in that the coaxial combiner (102, 202, 302) extends in a longitudinal direction and the outer conductor (104, 204, 304) is polygonal, in particular quadrangular, in cross-section on the outside.

3. High-frequency amplifier unit according to one of the preceding claims, characterized in that the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302) is designed as part of a coolant circuit for cooling the amplifier modules (10, 10').

4. High-frequency amplifier unit according to one of the preceding claims, characterized in that the amplifier modules (10, 10') are arranged circumferentially on the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302).

5. High-frequency amplifier unit according to one of the preceding claims, characterized in that at least some of the amplifier modules (10, 10') are connected at the same height as the coaxial inner conductor (106, 206, 306) when viewed in the longitudinal direction.

6. High-frequency amplifier unit according to one of the preceding claims, characterized in that amplifier modules (10, 10') of a first group of amplifier modules (10, 10') are arranged in a first longitudinal section (220) of the coaxial combiner (102, 202, 302) on the outside to the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302) and amplifier modules (10, 10') of a second group of amplifier modules (10, 10') are arranged in a second longitudinal section (230) of the coaxial combiner (102, 202, 302) on the outside of the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302).

7. High-frequency amplifier unit according to the preceding claim, characterized in that the amplifier modules (10, 10') of the first group are connected to the coaxial inner conductor (106, 206, 306) at an end region (222) of the first longitudinal section (220) of the coaxial combiner (102, 202, 302) facing the second longitudinal section (230) of the coaxial combiner (102, 202, 302) 302) and / or the amplifier modules (10, 10') of the second group are connected to the coaxial inner conductor (106, 206, 306) at an end region (232) of the second longitudinal section (230) of the coaxial combiner (102, 202, 302) facing the first longitudinal section (220) of the coaxial combiner (102, 202, 302).

8. High-frequency amplifier unit according to one of claims 6 or 7, characterized in that the coaxial inner conductor (106, 206, 306) extends into the end region (232) of the second longitudinal section (230) of the coaxial combiner (102, 202, 302) facing the first longitudinal section (220) of the coaxial combiner (102, 202, 302).

9. High-frequency amplifier unit according to one of claims 6 to 8, characterized in that the amplifier modules (10, 10') of the first group and the amplifier modules (10, 10') of the second group are connected, as seen in the longitudinal direction of the coaxial combiner (102, 202, 302), at the same height as the coaxial inner conductor (106, 206, 306).

10. High-frequency amplifier unit according to one of the preceding claims, characterized in that the coaxial combiner (102, 202, 302) has a transformer section (112, 212) with a transformation behavior such that the input-side characteristic impedance at the coaxial combiner (102, 202, 302) is transformed to an output-side characteristic impedance at the coaxial combiner (102, 202, 302).

11. High-frequency amplifier unit according to the preceding claim, characterized in that in the transformer section (112, 212), the coaxial inner conductor (106, 206, 306) of the coaxial combiner (102, 202, 302) has a first outer diameter (d1) and the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302) has a first inner diameter (D1) and that in an output section (114, 214) adjoining the transformer section (112, 212), the coaxial inner conductor (106, 206, 306) of the coaxial combiner (102, 202, 302) has a second outer diameter (d2) and the outer conductor (104, 204, 304) of the coaxial combiner (102, 202, 302) has a second inner diameter (D2).

12. High-frequency amplifier unit according to the preceding claim, characterized in that the ratio of the first inner diameter (D1) of the outer conductor (104, 204, 304) to the first outer diameter (d1) of the inner conductor (106, 206, 306) in the transformer section (112, 212) is smaller than the ratio of the second inner diameter (D2) of the outer conductor (104, 204, 304) to the second outer diameter (d2) of the inner conductor (106, 206, 306) in the output section (114, 214).

13. High-frequency amplifier unit according to one of the preceding claims, characterized in that the high-frequency amplifier unit (100, 200, 300) can provide an output power of at least 2 kW, preferably at least 4 kW.

14. Amplifier system comprising - a plurality of high-frequency amplifier units (100, 200, 300) according to one of the preceding claims and - a high-frequency waveguide (402, 502), wherein the high-frequency amplifier units (100, 200, 300) are arranged along the longitudinal direction of the high-frequency waveguide (402, 502) on the high-frequency waveguide (402, 502) so that the high-frequency waveguide (402, 502) can combine the output powers of the high-frequency amplifier units (100, 200, 300).

15. Amplifier system according to claim 14, characterized in that the longitudinal axes of the high-frequency amplifier units (100, 200, 300) are each transverse, in particular perpendicular, to the longitudinal axis of the high-frequency waveguide (402, 502).

16. Amplifier system according to claim 14 or 15, characterized in that the coaxial inner conductors (106, 206, 306) of the high-frequency amplifier units (100, 200, 300) serve at the output end as probes (116, 216) for coupling the power of the coaxial combiners (102, 202, 302) into the high-frequency waveguide (402, 502).

17. Amplifier system according to one of claims 14 to 16, characterized in that the high-frequency amplifier units (100, 200, 300) are arranged offset from one another in the transverse direction of the high-frequency waveguide (402, 502) and / or on both sides of the high-frequency waveguide (402, 502).