High-frequency assembly with impedance matching filter

Abstract

High-frequency assembly, RF assembly, (10), comprising: a signal source (20) having a semiconductor amplifier output (22); an impedance matching filter (30) having a first interface (31) and a second interface (39); and a high-frequency waveguide, RF waveguide, (50); wherein the first interface (31) is communicatively coupled to the signal source (20) in order to be able to transmit a high-frequency signal, RF signal, from the signal source (20) to the impedance matching filter (30); wherein the second interface (39) is communicatively coupled to the RF waveguide (50) in order to be able to transmit an RF signal from the impedance matching filter (30) to the RF waveguide (50); wherein a first impedance value at the first interface (31) corresponds to an impedance value at the semiconductor amplifier output (22); wherein a second impedance value at the second interface (39) corresponds to an impedance value at the RF waveguide (50); wherein the first impedance value and the second impedance value have different values; wherein the impedance matching filter (30) is designed as a waveguide and has a plurality of resonators (32) arranged one behind the other along a signal propagation direction (36) in the impedance matching filter (30); wherein at least two of the plurality of resonators (32) arranged one behind the other along the signal propagation direction (36) differ from one another in their geometry along the signal propagation direction (36).

Description

Technical area

[0001] This description relates to radio-frequency technology. In particular, the description relates to a radio-frequency module with an impedance matching filter arranged between two components with different impedances. Furthermore, the description relates to an antenna arrangement with one or more such radio-frequency modules, wherein the radio-frequency modules can be used, for example, as part of a communications device or a data transmission link, in particular a satellite transmission link or a satellite radio transmission link. Last but not least, the description relates to a satellite with such an antenna arrangement. background

[0002] Radio frequency systems are used to transmit signals and data from a transmitting station to a receiving station. Radio frequency technology is preferred when data needs to be transmitted over long distances (up to several hundred or several thousand kilometers).

[0003] Before signals are transmitted to the air interface (e.g., antenna), they may require processing, amplification, or conditioning. Radio frequency technology is used, for example, on communications satellites to amplify, combine, and filter communication signals.

[0004] A high-frequency system often consists of individual modules (low-noise amplifiers, LNAs, filters, couplers, isolators, preamplifiers, power amplifiers, etc.) that are interconnected. Matching is often necessary at the connection between two directly connected modules. Power matching is typically achieved by matching the impedances of the interconnected modules.

[0005] EP 2 775 612 A1 and US 9,530,604 B2 describe a signal transmission unit which is used in the high frequency range and is used in particular in a communications satellite.

[0006] US 2012 / 0 007 666 A1 describes a device for impedance matching of a component, with a filter with adjustable impedance based on a perovskite-like material.

[0007] US 2019 / 0 260 460 A1 describes a signal amplifier comprising two antennas coupled to a signal amplifier and a wireless charging circuit. The signal amplifier is configured to amplify signals for a wireless device. The wireless charging circuit can charge the wireless device when the wireless device is placed near the signal amplifier.

[0008] US 2003 / 0 227 575 A1 describes a bandpass filter. Description of the invention

[0009] It can be considered a task to improve the efficiency of a high-frequency assembly.

[0010] This object is achieved by the subject matter of the independent claims. Further embodiments emerge from the dependent claims and from the following description.

[0011] According to a first aspect of the invention, a radio-frequency assembly, also referred to as an RF assembly, is provided. The RF assembly comprises a signal source, an impedance matching filter, and a radio-frequency waveguide, also referred to as an RF waveguide. The signal source has a semiconductor amplifier output. The impedance matching filter has a first interface and a second interface. The first interface is communicatively coupled to the signal source in order to be able to transmit a radio-frequency signal, an RF signal, from the signal source to the impedance matching filter. The second interface is communicatively coupled to the RF waveguide in order to be able to transmit an RF signal from the impedance matching filter to the RF waveguide.A first impedance value at the first interface corresponds to an impedance value at the semiconductor amplifier output (this optimal impedance for the output of the semiconductor amplifier is usually complex-valued, i.e., consists of magnitude and phase). A second impedance value at the second interface corresponds to an impedance value at the RF waveguide. The first impedance value and the second impedance value have different values. According to the invention, the impedance matching filter is designed as a waveguide and has a plurality of resonators arranged one behind the other along a signal propagation direction in the impedance matching filter, wherein at least two of the plurality of resonators arranged one behind the other along the signal propagation direction differ from one another in their geometry along the signal propagation direction.

[0012] In other words, the impedance matching filter has a different impedance value on the input side (at the interface to the semiconductor amplifier output) than on the output side (at the interface to the RF waveguide) and is designed on the input side so that the semiconductor amplifier output is presented with an optimal impedance for the desired operating case (maximum efficiency, maximum gain, maximum linearity, maximum output power), and is matched on the output side to the high-frequency waveguide, whereby in this case we are talking in particular about a power matching for optimal efficiency.

[0013] This eliminates the need for a separate matching circuit between the semiconductor amplifier output and the high-frequency waveguide, because the impedance matching filter not only performs its filtering function but also matches the connected components. Likewise, a dedicated waveguide transition is no longer necessary, as the filter has a waveguide output. Furthermore, dedicated blocking capacitors for DC blocking (removing DC components from the RF signal) are also unnecessary, as the impedance matching filter features capacitive coupling.

[0014] The semiconductor amplifier output is a semiconductor device, such as a transistor, which outputs an RF signal that is fed to the impedance matching filter.

[0015] The impedance matching filter has two functions. A first function is that the impedance matching filter fulfills the function of a frequency filter, acting, for example, as a bandpass filter. A second function is that the impedance matching filter is matched to the impedance of the semiconductor amplifier output at its first interface and to the impedance of the RF waveguide at its second interface. This matching is preferably a power matching, i.e., the impedance value of the first interface corresponds to the impedance value of the amplifier output, and the impedance value of the second interface corresponds to the impedance value of the RF waveguide.

[0016] This reduces power losses due to the required impedance matching, as the impedance matching filter using waveguide technology has significantly lower losses than, for example, a microstrip matching structure implemented on the power amplifier substrate or a PCB. Furthermore, this design of the RF module eliminates the need for a separate matching circuit. Instead, the matching takes place within the impedance matching filter. The number of components is reduced, which reduces both power consumption and thermal load. Overall, the design described here improves power efficiency (the ratio of output power to input power relative to the RF module). The impedance values ​​referred to here are preferably complex values ​​and refer to the magnitude and phase at the respective positions in the RF module.Furthermore, the filter is designed in such a way that structures necessary for the mechanical connection between filter and amplifier (e.g. wire bonds, microstrip lines) can be compensated.

[0017] A communicative coupling between the first interface and the signal source, or between the second interface and the RF waveguide, means that these two couplings are designed to allow the transmission of electrical and / or electromagnetic signals. This does not necessarily require a galvanic, electrically conductive connection between the aforementioned components. Rather, signals, especially high-frequency signals, can also be transmitted via capacitive coupling. Capacitive coupling eliminates the need for dedicated blocking capacitors in the RF path and thus also reduces RF losses by the amount caused by the capacitors.

[0018] According to one embodiment, the semiconductor amplifier output has a lower impedance value than the RF waveguide.

[0019] Semiconductor amplifier outputs, for example in the form of transistors, typically have a real impedance value between 10 and 30 ohms. RF waveguides in the form of coaxial cables or waveguides, on the other hand, typically have a real impedance value of about 50 ohms or more.

[0020] The impedance matching filter provides an adjustment between these components with their different impedance values.

[0021] According to the invention, the impedance matching filter is designed as a waveguide with at least two resonators. In one embodiment, the impedance matching filter is designed as a waveguide with at least one window.

[0022] The impedance matching filter is designed using waveguide technology. Therefore, it is characterized by high efficiency and low losses, which improves the overall power efficiency of the RF module.

[0023] The resonators and / or windows are components of the impedance matching filter which, through their structure and shape, influence the filter function and the characteristic impedance of the impedance matching filter.

[0024] According to the invention, the impedance matching filter comprises a plurality of resonators arranged one behind the other along a signal propagation direction in the impedance matching filter. In one embodiment, the impedance matching filter comprises a plurality of windows arranged one behind the other along a signal propagation direction in the impedance matching filter.

[0025] The plurality of resonators and / or windows arranged one behind the other and spaced apart from one another provide for an adaptation of the impedance of the impedance matching filter and also serve to implement the filter function.

[0026] Preferably, a window is arranged between each two successively arranged resonators, wherein a window corresponds to a cross-sectional constriction of the impedance matching filter.

[0027] According to the invention, at least two of the plurality of resonators arranged one behind the other along the signal propagation direction differ from one another in their geometry along the signal propagation direction.

[0028] This means that the resonators have different dimensions and / or shapes. For example, resonators arranged one after the other can have different heights, material thicknesses, and / or shapes. This allows for adaptation to the impedance values ​​of the amplifier output on the one hand and the RF waveguide on the other.

[0029] The resonators are designed so that at least two resonators have different geometries. However, it is also conceivable that each resonator has a geometry (dimension, shape, etc.) that occurs only once in the impedance matching filter.

[0030] The impedance matching filter can be designed as a waveguide with or without a bridge.

[0031] According to a second aspect of the invention, a radio-frequency assembly, also referred to as an RF assembly, is provided. The RF assembly comprises a signal source, an impedance matching filter, and a radio-frequency waveguide, also referred to as an RF waveguide. The signal source has a semiconductor amplifier output. The impedance matching filter has a first interface and a second interface. The first interface is communicatively coupled to the signal source in order to be able to transmit a radio-frequency signal, an RF signal, from the signal source to the impedance matching filter. The second interface is communicatively coupled to the RF waveguide in order to be able to transmit an RF signal from the impedance matching filter to the RF waveguide.A first impedance value at the first interface corresponds to an impedance value at the semiconductor amplifier output (this optimal impedance for the semiconductor amplifier output is usually complex-valued, i.e., consists of magnitude and phase). A second impedance value at the second interface corresponds to an impedance value at the RF waveguide. The first impedance value and the second impedance value have different values. According to the invention, the impedance matching filter is designed as a waveguide with a ridge, and one ridge has several ridge sections with different geometries.

[0032] The ridge sections are arranged one behind the other in the signal propagation direction. In particular, the ridge sections are arranged directly adjacent to one another. The ridge sections have, for example, different heights and / or widths. The multiple ridge sections arranged one behind the other and of different configurations ensure that the impedance of the impedance matching filter is matched because the differently configured ridge sections have different characteristic impedances.

[0033] Unless otherwise stated, the embodiments given below relate to the first aspect and the second aspect of the invention.

[0034] According to a further embodiment, the RF module further comprises a base plate, wherein the semiconductor amplifier output is arranged on the base plate and is galvanically coupled to a transmission path on the base plate via one or more lines. The transmission path comprises a capacitive coupling element, which is opposite the first interface and is arranged to capacitively couple high-frequency signals into the first interface.

[0035] The capacitive coupling element is galvanically isolated from the first interface and separated from it by a gap. High-frequency signals in a frequency range of several GHz are fed from the semiconductor amplifier output into the transmission path and the capacitive coupling element. Due to the high frequencies, these signals are fed capacitively, i.e., without a galvanic connection, from the capacitive coupling element into the first interface of the impedance matching filter.

[0036] Because the semiconductor amplifier output is galvanically isolated from the impedance matching filter, a DC component of the RF signal or a DC current present at the transmission path and / or the coupling element is prevented from being transmitted from the transmission path or from the capacitive coupling element to the impedance matching filter.

[0037] The base plate is usually a circuit board or PCB (printed circuit board).

[0038] According to a further embodiment, the RF module further comprises a power source which is galvanically coupled to the transmission path and is designed to supply a power supply in the form of direct current, DC, to the transmission path and to provide it to the semiconductor amplifier output via the one or more lines.

[0039] The DC power is absorbed by the semiconductor amplifier output, such as the transistor, as operating energy. This is direct current. The direct current is transmitted via the same transmission path as the RF signal.

[0040] According to a further embodiment, the power source comprises a DC filter which is designed to be impermeable to high-frequency signals on the transmission path.

[0041] The DC filter, for example, is designed as a low-pass filter. Thus, the DC filter allows direct current signals to pass through and is impermeable to high-frequency signals. The DC filter is impermeable to the RF signals on the transmission path, i.e., the useful signals output by the semiconductor amplifier output, so the DC power supply has no significant influence on the impedance value of the semiconductor amplifier output and its behavior toward high-frequency signals.

[0042] According to a further embodiment, the RF module has a plurality of semiconductor amplifier outputs which are capacitively coupled to the first interface of the impedance matching filter.

[0043] In this embodiment, several semiconductor amplifier outputs are coupled to an impedance matching filter. This multiplies the power fed into the impedance matching filter. In this variant, the power is combined or multiplied on the input side of the impedance matching filter.

[0044] According to a further embodiment, the RF assembly comprises a plurality of impedance matching filters, each of which is coupled to at least one semiconductor amplifier output, wherein the plurality of impedance matching filters are coupled to a single RF waveguide.

[0045] Alternatively or in addition to the previous embodiment, in this embodiment, power is combined on the output side of the impedance matching filter. This embodiment also serves to multiply the output power. The multiple impedance matching filters are connected to the same RF waveguide on the output side, i.e., at their respective second interfaces. It is conceivable that the respective second interfaces are first connected to one another and then a common output of the plurality of impedance matching filters is routed to a single RF waveguide. Alternatively, the respective second interfaces are individually coupled to the RF waveguide. Two or more impedance matching filters can be coupled on the output side with a so-called 3 dB coupler and routed to the RF waveguide.

[0046] According to a further embodiment, the RF waveguide is a waveguide, a ridge waveguide, or a coaxial conductor.

[0047] According to another aspect, an antenna arrangement is provided. The antenna arrangement comprises an antenna and a plurality of RF assemblies as described herein. The plurality of RF assemblies are connected to the antenna to transmit a useful signal to the antenna.

[0048] According to a further aspect, a communications satellite is provided having an antenna arrangement as described herein.

[0049] The antenna array is, for example, part of a data transmission path in the communications satellite. A communications satellite is a spacecraft intended for use in Earth orbit, which contains a communications system for receiving and transmitting data or signals. In addition, a communications satellite can also contain units for processing the data. The RF module can preferably be used in a signal processing path of the communications system of the communications satellite.

[0050] In the context of this description, i.e., with reference to the RF module, the antenna array, and the communications satellite, radio frequency refers to a frequency range above one GHz (gigahertz, 1 × 10E9 hertz). Such frequency ranges are used, for example, in satellite radio transmission links. Such a satellite radio transmission link can, for example, be a Ka-band transmission link in a frequency range of 17.7–21.2 GHz for the downlink and 27.5–31 GHz for the uplink, a Ku- or X-band implementation in the range around 11 or 7 GHz, respectively, or an L-band (around 1.5 GHz), S-band (around 2.5 GHz), or C-band (around 4 GHz) implementation.

[0051] The semiconductor amplifier output can be a component of an amplifier connected upstream of the antenna. A high-power transistor amplifier, for example, can be used as an amplifier. A high-power transistor amplifier can also be referred to as a solid-state power amplifier (SSPA). This type of amplifier is used at high frequencies as an alternative or in addition to traveling-wave tube amplifiers. SSPAs are available in various power classes and for very high frequency bands. For example, SSPAs can be used in the following frequency bands: C-, X-, Ku-, Ka-, and Q-band. Short description of the characters

[0052] Embodiments of the invention are described in more detail below with reference to the accompanying drawings. The illustrations are schematic and not to scale. Like reference numerals refer to like or similar elements. They show: Fig. 1 a schematic representation of an RF module. Fig. 2 a schematic representation of part of an RF assembly. Fig. 3 a schematic representation of the connection between an RF amplifier output and an impedance matching filter. Fig. 4 a schematic representation of the connection between an RF amplifier output and an impedance matching filter. Fig. 5 a schematic representation of a connection between an RF amplifier output and a multi-branch impedance matching filter. Fig. 6 a schematic isometric representation of the connection between an RF amplifier output and a multi-resonator impedance matching filter. Fig. 7 a schematic representation of a satellite with an RF assembly and an antenna. Fig. 8 a schematic representation of an RF module with an impedance matching filter in the form of a ridge waveguide with several ridge sections. Fig. 9 a schematic representation of an antenna arrangement. Detailed description of implementation examples

[0053] Fig. Figure 1 shows a schematic diagram of an RF module 10. The RF module 10 has a signal source 20. The signal source 20 outputs a signal that follows a signal transmission path. The signal transmission path runs in the illustration of Fig. 1 from left to right. An RF signal is initially output from the signal source 20 via the first line 23 and the second line 24 to the transmission path 25 and the capacitive coupling element 26. From the capacitive coupling element 26, the RF signal is fed capacitively, i.e., wirelessly, into the first interface 31 of the impedance matching filter 31. The RF signal propagates via the impedance matching filter 30 to the second interface 39, from where the RF signal is fed into the RF waveguide 50.

[0054] A power source 60, for example in the form of a direct current supply, is connected to the transmission path 25 via a connecting line 62. A direct current energy supply is supplied from the power source 60 to the transmission path 25 and from there via the first line 23 and the second line 24 to the semiconductor amplifier output 22. Thus, both an RF signal and the energy supply for the semiconductor amplifier output 22 are transmitted via the first line 23 and the second line 24. The power source 60 also has a direct current filter (DC filter) 61. The DC filter 61 has the function of allowing direct current to pass through and preventing or significantly attenuating high-frequency signals.

[0055] The signal source 20 is, for example, a power amplifier and consists of an amplifier unit 21 and a semiconductor amplifier output 22. The semiconductor amplifier output 22 is, for example, a transistor that outputs a signal amplified by the amplifier unit 21. In this respect, the semiconductor amplifier output 22 can be integrated into the amplifier unit 21 or provided separately.

[0056] In this example, signal source 20 is a radio-frequency power amplifier module. Radio-frequency power amplifier modules are frequently used in satellite communications. They are used to boost a transmitted signal to the required power level in order to achieve a signal level that can still be received at a remote station, e.g., on Earth. Historically, vacuum tube amplifiers were used for this purpose – especially at higher frequencies above 6 GHz. These have excellent properties, in particular high efficiency (measured by low DC power consumption for the available RF output power) with good linearity (low signal distortion). However, semiconductor-based amplifiers offer significant advantages, particularly in terms of size and cost, especially for use in so-called active antennas, i.e., electronically controllable antennas.An active antenna requires a large number of amplifiers with relatively low power, as each antenna element requires its own amplifier. However, high linearity with very high power efficiency is also required. Conventional semiconductor-based amplifiers generally have some shortcomings in this area. This leads not only to high energy consumption but also to high heat generation. This can make the thermal design of the antenna difficult or even impossible. These disadvantages are overcome by the RF module design proposed here for use in active antennas. Of course, high efficiency is also desirable for other amplifier applications; the present RF module can easily be used for other power amplifier applications (e.g., gateway amplifiers, channel amplifiers, etc.).

[0057] Integrated components in GaN or GaAs technology can be used in the amplifier unit 21 and the semiconductor amplifier output 22 of the signal source 20.

[0058] The RF module described here can, for example, be used in an active antenna module with a bandwidth of 17.8 - 20.2 GHz (in the Ka-band). However, transfer to other amplifier applications and frequencies is easily possible (e.g., Ku-band 10.7 - 12.7 GHz, Q-band 37.5 - 42.5 GHz), provided suitable transistors are available. The RF module can be designed to meet a linearity requirement (given by 17 dB NPR - noise power ratio) and an efficiency requirement of > 30% (for the output stage, given by a maximum total antenna power of approximately 600 W for multiple amplifier paths) with given dimensions of approximately 7 × 3 mm^2 for a single amplifier channel.

[0059] The signal source 20 is connected to a transmission path 25 via two lines 23, 24, so that electromagnetic signals can be inductively transmitted from the amplifier output 22 to the transmission path 25. The transmission path 25 is, for example, a conductor track on a circuit board. The transmission path 25 transitions into a capacitive coupling element 26. The capacitive coupling element 26 is, for example, directly connected to the transmission path 25, or these two elements are part of the same conductor track on the circuit board.

[0060] A single transistor in GaN (or GaAs) technology is used as the semiconductor for the amplifier output 22, without an integrated matching and stabilization network. In particular, the matching at the transistor output is achieved via a waveguide structure (namely, the impedance matching filter 30). Two variants are conceivable here. A first variant is shown in the Fig. 4 to 6 with a filter with resonators and windows and a second variant is shown in Fig. 8 with a ridge waveguide.

[0061] Coupling into the waveguide structure of the impedance matching filter is as direct as possible. A short piece of PCB / ceramic substrate or a coaxial structure is conceivable. The DC power supply of the transistor acting as the amplifier output is either fed through a filter, whereby the otherwise usual blocking with capacitances can be moved to the filter input, or is blocked with capacitors. Thus, an additional DC block is no longer necessary on the RF line (first line 23, second line 24), since the RF signal is coupled capacitively into the waveguide structure of the impedance matching filter.

[0062] The impedance matching filter 30 is coupled to the RF waveguide 50 by means of a coupling unit 40. The coupling unit 40 can be, for example, a flange or other connection.

[0063] The impedance matching filter 30 is manufactured using waveguide technology and has the function of filtering signals output from the amplifier output 22 and matching them to the amplifier output 22 on the one hand, and to the RF waveguide 50 on the other. This design reduces the number of components required for a matching circuit, which improves the efficiency of the RF module 10 and provides high linearity. In particular, a matching network at the amplifier output, which is otherwise commonly used in semiconductor amplifiers, can be omitted. Such a matching network typically leads to high losses, which reduces the efficiency of the amplifier.

[0064] These disadvantages are avoided by the fact that the impedance matching filter 30 is designed using waveguide technology and a capacitive junction is used as a barrier for direct current components between the amplifier output and the impedance matching filter.

[0065] Fig. 2 shows an exemplary connection of several signal sources 20 with a single impedance matching filter 30. Any number of signal sources (determined by the available installation space and the requirements for the signal level) can be connected to the impedance matching filter, wherein the connection between the signal sources 20 and the impedance matching filter 30 is designed as in Fig. 1 with respect to the transmission path 25 and the capacitive coupling element 26.

[0066] The circuit of the Fig. 2 serves to achieve higher power levels. However, it is also conceivable that several impedance matching filters 30 are connected to each other on the output side to increase the output power level.

[0067] Fig. Figure 3 shows a detailed view of the semiconductor amplifier output 22, which is connected to the transmission path 25 by two lines. The semiconductor amplifier output 22 is arranged on a base plate 28. A connecting line 62 for the DC power supply of the semiconductor amplifier output 22 is connected to the transmission path 25. The transmission path 25 merges into the capacitive coupling element 26. An RF signal is output from the semiconductor amplifier output 22 onto the transmission path 25, then propagates towards the capacitive coupling element 26, from where the RF signal is capacitively fed into the impedance matching filter. Fig. 3 shows only one resonator 32. A gap can be seen between the resonator 32 and the capacitive coupling element 26.

[0068] The DC power supply for the semiconductor amplifier output 22 is supplied to the corresponding transistor as a drain voltage and is implemented, for example, via a PCB-integrated filter in combination with discrete capacitors. Alternatively, the filter can also be implemented as a quarter-wave line with parallel capacitors. In this case, the drain voltage is connected to the transmission path 25 and can also be connected to any other part of the line leading to the filter.

[0069] Fig. 4 shows a larger section of an RF assembly, where the Fig. 4 shown RF module in its structure of the RF module from Fig. 3 corresponds. Fig. 4 shows a power source 60, which provides electrical energy to the semiconductor amplifier output 22. The semiconductor amplifier output 22 outputs an RF signal via the transmission path and the capacitive coupling element, which RF signal propagates along the signal propagation direction 36 in the impedance matching filter 30. The impedance matching filter 30 has a plurality of resonators 32 arranged one behind the other in the signal propagation direction 36 (in the example of Fig. 4 these are cylindrical bases) and windows 34 (cross-sectional constrictions) between the resonators.

[0070] In the Fig. 3 and Fig. In the variant shown in Figure 4, the matching is achieved via a cavity filter structure in the impedance matching filter designed as a waveguide. In principle, all known filter topologies and filter types are suitable for this purpose (rectangular / circular waveguide filters, coaxial filters, dielectric filters). A four-circuit coaxial filter is shown as an example.

[0071] The impedance matching filter 30 is detuned during the development process so that it provides the desired match in terms of magnitude and phase at the first interface 31 to the transistor of the semiconductor amplifier output 22. The match can be determined, for example, by a so-called load-pull measurement or simulation. The impedance matching filter cannot therefore be used as a standalone filter; however, if it is operated at the output of the transistor of the semiconductor amplifier output 22, it allows the transistor to be operated at its optimal operating point (e.g., best efficiency relative to power matching). In addition to generating the required match for the semiconductor amplifier output, the impedance matching filter 30, in combination with the transistor of the semiconductor amplifier output 22, also has a frequency-selective effect. A dedicated output filter can be omitted. This, in turn, improves efficiency, since no additional filter losses need to be taken into account.The number of circuits and the topology of the impedance matching filter depend on the requirements of the output filter. Filters with and without transmission zeros and with and without group delay equalization can be used. Typical circuit numbers range from 1 circuit to 14 or more (in practical applications, 4 to 12 circuits are more common). The RF signal is coupled into the impedance matching filter capacitively via a PCB, ceramic, or coaxial structure (for example, through a discretely manufactured inner conductor with insulating material). PCBs or ceramics have the advantage of simpler and more cost-effective production, and the coaxial structure delivers the best efficiency (low losses).

[0072] In principle, an inductive coupling into the impedance matching filter is of course also conceivable, but in such a case a dedicated DC block (e.g. capacitor or PCB structure) is necessary.

[0073] The connection of the transistor of the semiconductor amplifier output with the coupling structure in the impedance matching filter is made in the example shown with bond wires (first line 23, second line 24, see Fig. 3). The transistor of the semiconductor amplifier output can be located in a recess in the PCB directly on the housing or a spacer, but also directly on the PCB or a ceramic. The transistor can be (conductively) glued or soldered; silver sintering or similar connection techniques are also conceivable.

[0074] Fig. Figure 5 shows an RF module with multiple paths or branches. A signal is applied to the base plate 28 via an input interface 18. The signal is processed and / or amplified there. The plurality of impedance matching filters 22A, 22B, 22C, 22D each output a signal to a path of the impedance matching filter 30.

[0075] Fig. 6 shows a cross-sectional view of a single path from Fig. 5. Shown are the power source 60, the signal source 20, and an impedance matching filter 30 along the signal propagation direction 36. In the impedance matching filter 30, four resonators 32A, 32B, 32C, 32D are arranged one behind the other and spaced apart from each other in the signal propagation direction 36. It can be seen that the resonators have different heights. In addition to different heights, the resonators can also differ from each other in other properties, e.g., shape, diameter, etc. This deviation serves to achieve a targeted detuning of the impedance matching filter so that the input-side impedance and the output-side impedance differ from each other and are power-matched on the input side to the semiconductor amplifier output and on the output side to the RF waveguide.

[0076] Fig. 7 shows a schematic representation of a communications satellite 1. A radio frequency module 10 is arranged in the communications satellite 1.

[0077] The radio-frequency module 10 can be part of a signal transmission path in the communications satellite. For example, the radio-frequency module 10 can output a signal to a transmission unit 2 in the form of an antenna.

[0078] The high-frequency module described herein is particularly suitable for the signal connection of transistor amplifiers or semiconductor amplifiers (SSPA) to an antenna.

[0079] Fig. Figure 8 shows an RF module 10 with an impedance matching filter in ridge waveguide technology. For the general structure and function of the RF module 10, please refer to the description of the above Fig. 1 to 7.

[0080] In the variant Fig. 8, the impedance matching filter uses a waveguide with a ridge 80 for matching. The ridge 80 is divided into several ridge sections 80A, 80B, 80C, 80D. The ridge 80 is designed differently in the ridge sections. From a functional perspective, this corresponds to the differently designed resonators, as for example in Fig. 6 are shown.

[0081] The base plate 28 carries the semiconductor amplifier output 22 and is covered with a cover 75.

[0082] In the variant of the Fig. Direct current is supplied for the operation of the semiconductor amplifier output and capacitively coupled to the impedance matching filter as described above. The high-frequency signal is coupled into the web waveguide of the impedance matching filter through a slot 71 in the PCB. There, web sections with several differently configured stages are arranged (corresponding to line sections with different characteristic impedances) and provide the corresponding matching of the input and output impedance of the impedance matching filter.

[0083] Finally, Fig. Figure 9 shows an antenna arrangement 100 with several high-frequency building blocks 10, which are connected to an antenna 2. This antenna arrangement 100 can be used, for example, in communication satellites. List of reference signs 1 Satellite 2 Transmission unit, antenna 10 High-frequency building block 18 Input interface 20 Signal source 21 Amplifier unit 22 Semiconductor amplifier output (semiconductor, transistor) 23 first line 24 second line 25 Transmission path (cable, conductor track on board) 26 capacitive coupling element 28 Base plate 29 Gap, galvanic isolation 30 impedance matching filters 31 first interface 32 resonators 34 windows 36 Signal propagation direction, transmission direction 39 second interface 40 coupling unit 50 high-frequency waveguides (waveguides, ridge waveguides, coaxial cables) 60 Power source (DC power supply) 61 DC filters 62 connecting cable 71 coupling slot 75 Cover 80 bridge 80A, 80B, 80C bridge section 100 antenna arrangement

Claims

[1] High-frequency assembly, RF assembly, (10), comprising: a signal source (20) having a semiconductor amplifier output (22); an impedance matching filter (30) having a first interface (31) and a second interface (39); and a high-frequency waveguide, RF waveguide, (50); wherein the first interface (31) is communicatively coupled to the signal source (20) in order to be able to transmit a high-frequency signal, RF signal, from the signal source (20) to the impedance matching filter (30); wherein the second interface (39) is communicatively coupled to the RF waveguide (50) in order to be able to transmit an RF signal from the impedance matching filter (30) to the RF waveguide (50); wherein a first impedance value at the first interface (31) corresponds to an impedance value at the semiconductor amplifier output (22); wherein a second impedance value at the second interface (39) corresponds to an impedance value at the RF waveguide (50); wherein the first impedance value and the second impedance value have different values; wherein the impedance matching filter (30) is designed as a waveguide and has a plurality of resonators (32) arranged one behind the other along a signal propagation direction (36) in the impedance matching filter (30); wherein at least two of the plurality of resonators (32) arranged one behind the other along the signal propagation direction (36) differ from one another in their geometry along the signal propagation direction (36). [2] The RF assembly (10) of claim 1, wherein the semiconductor amplifier output (22) has a lower impedance value than the RF waveguide (50). [3] RF module (10) according to claim 1 or 2, wherein the impedance matching filter (30) has a plurality of windows (34) arranged one behind the other along a signal propagation direction (36) in the impedance matching filter (30). [4] High-frequency assembly, RF assembly, (10), comprising: a signal source (20) having a semiconductor amplifier output (22); an impedance matching filter (30) having a first interface (31) and a second interface (39); and a high-frequency waveguide, RF waveguide, (50); wherein the first interface (31) is communicatively coupled to the signal source (20) in order to be able to transmit a high-frequency signal, RF signal, from the signal source (20) to the impedance matching filter (30); wherein the second interface (39) is communicatively coupled to the RF waveguide (50) in order to be able to transmit an RF signal from the impedance matching filter (30) to the RF waveguide (50); wherein a first impedance value at the first interface (31) corresponds to an impedance value at the semiconductor amplifier output (22); wherein a second impedance value at the second interface (39) corresponds to an impedance value at the RF waveguide (50); wherein the first impedance value and the second impedance value have different values; wherein the impedance matching filter (30) is designed as a waveguide with a web (80); wherein the one web (80) has a plurality of web sections (80A, 80B, 80C) which have different geometries. [5] RF assembly (10) according to one of the preceding claims, further comprising a base plate (28); wherein the semiconductor amplifier output (22) is arranged on the base plate (28) and is galvanically coupled to a transmission path (25) on the base plate (28) via one or more lines (23, 24); wherein the transmission path (25) has a capacitive coupling element (26) which is opposite the first interface (31) and is arranged to capacitively couple high-frequency signals into the first interface (31). [6] RF assembly (10) according to claim 5, further comprising a power source (60) which is galvanically coupled to the transmission path (25) and is designed to apply a power supply in the form of direct current, DC, to the transmission path and to provide it to the semiconductor amplifier output via the one or more lines (23, 24). [7] RF assembly (10) according to claim 6, wherein the power source (60) comprises a DC filter (61) configured to be impermeable to high-frequency signals on the transmission path (25). [8] RF module (10) according to one of the preceding claims, comprising a plurality of semiconductor amplifier outputs (22A, 22B, 22C, 22D) which are capacitively coupled to the first interface (31) of the impedance matching filter. [9] RF module (10) according to one of the preceding claims, comprising a plurality of impedance matching filters (30), each of which is coupled to at least one semiconductor amplifier output (22); wherein the plurality of impedance matching filters (30) are coupled to a single RF waveguide (50). [10] RF module (10) according to one of the preceding claims, wherein the RF waveguide (50) is a waveguide, a ridge waveguide, or a coaxial conductor. [11] Antenna arrangement (100), comprising: an antenna (2); and a plurality of RF modules (10) according to one of the preceding claims; wherein the plurality of RF modules (10) are connected to the antenna to transmit a useful signal to the antenna. [12] Communication satellite (1) comprising an antenna arrangement (100) according to claim 11.

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