Radio frequency circuit, radio frequency system and method for radio frequency circuit

Abstract

The invention relates to a radio frequency circuit, a radio frequency system and a method for the radio frequency circuit. An RF circuit is presented that includes an input node configured to receive an RF signal, an output node configured to output the RF signal, an RF switch assembly coupled between the input node and the output node, where the RF switch assembly is configured to selectively connect or disconnect the input node and the output node, and wherein the RF switch assembly comprises a first stage comprising a first RF switch and a second stage comprising a second RF switch wherein the first stage is configured to attenuate a signal power of the RF signal or to isolate the output node from the input node in an off-state of the RF switch assembly wherein the first stage and the second stage are in the off-state.

Description

Technical Field

[0001] The present disclosure relates to radio frequency (RF) switches. Examples relate to RF circuits, RF systems, and methods for RF circuits. Background Art

[0002] RF switches are essential components in various electronic systems, including radar systems. In many applications, it is necessary to achieve a high degree of isolation between the connected path and the disconnected path to prevent unwanted signal leakage and interference. However, in the case of conventional RF switch circuits, especially when operating at high power levels, negative effects on isolation performance may occur: when the switch is in the off state, it is expected to exhibit minimal or negligible signal conduction between the input terminal and the output terminal. However, as the input power level increases, significant voltage swings may occur across the switch. This voltage swing may cause unwanted electrical breakdown and unexpected conduction between the switch terminals, thereby compromising isolation. Therefore, there is a need for an improved RF switch circuit. Summary of the invention

[0003] This need is met by the subject matter of the independent claims.

[0004] Some aspects of the present disclosure relate to an RF circuit, which includes an input node configured to receive an RF signal, an output node configured to output the RF signal, and an RF switch component coupled between the input node and the output node, wherein the RF switch component is configured to selectively connect or disconnect the input node and the output node, and wherein the RF switch component includes a first stage and a second stage, the first stage including a first RF switch, the second stage including a second RF switch, wherein the first stage is configured to: attenuate the signal power of the RF signal or isolate the output node from the input node in an off state of the RF switch component (wherein the first stage and the second stage are in the off state).

[0005] Some aspects of the present disclosure relate to a method for an RF circuit, which includes an RF switch component, which includes a first stage and a second stage coupled between an input node and an output node, the first stage including a first RF switch, and the second stage including a second RF switch, the method including: receiving an RF signal at the input node; selectively connecting or disconnecting the input node and the output node by the RF switch component; selectively outputting the RF signal at the output node; and attenuating the signal power of the RF signal at the first stage or isolating the output node from the input node at the first stage in an off state of the RF switch component (wherein the first stage and the second stage are in the off state). BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Some examples of apparatus and / or methods will be described below, by way of example only, and with reference to the accompanying drawings, in which:

[0007] Figure 1a and Figure 1b Examples of RF circuits in an off state and an on state are illustrated respectively;

[0008] Figure 2a to Figure 2g Examples of RF circuits having different topologies are illustrated;

[0009] Figure 3 An example of an RF circuit having a resonator is illustrated;

[0010] Figure 4 An example of an RF circuit having a transformer is illustrated;

[0011] Figure 5 An example of an RF system is illustrated;

[0012] Figure 6 An example of an RF system with a shared amplifier is illustrated;

[0013] Figure 7 illustrates an example of an RF system with a shared antenna; and

[0014] Figure 8 An example of a method for an RF circuit is illustrated. DETAILED DESCRIPTION

[0015] Some examples are now described in more detail with reference to the disclosed drawings. However, other possible examples are not limited to the features of these embodiments described in detail. Other examples may include modifications to features and equivalents and substitutes of features. In addition, the terms used to describe certain examples herein should not limit other possible examples.

[0016] Throughout the description of the drawings, the same or similar reference numerals refer to the same or similar elements and / or features, which may be implemented in an equivalent or modified form while providing the same or similar functions. For clarity, the thickness of the lines, layers and / or regions in the drawings may also be exaggerated.

[0017] When two elements A and B are combined using "or", this should be understood to disclose all possible combinations, i.e. only A, only B, and A and B, unless otherwise explicitly defined in individual cases. As alternative words for the same combination, "at least one of A and B" or "A and / or B" may be used. This is equally applicable to combinations of more than two elements.

[0018] If singular forms, such as "a", "an" and "the" are used, and the use of only a single element is not explicitly or implicitly defined as mandatory, other examples may also use several elements to implement the same functionality. If a functionality is described below as being implemented using multiple elements, other examples may use a single element or a single processing entity to implement the same functionality. It should also be understood that the terms "include", "including", "comprise" and / or "comprising" when used describe specified features, integers, steps, operations, processes, elements, components and / or groups thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components and / or groups thereof.

[0019] Figure 1a and Figure 1b The RF circuit 100 is illustrated in an off state and in an on state, respectively. The RF circuit 100 is an electronic circuit designed to operate RF signals (i.e., signals in the radio frequency range, spanning, for example, from a few kilohertz (kHz) to a few hundred megahertz (GHz)). The RF circuit 100 can provide RF signals for any RF application, such as wireless communication systems, television broadcasts, cellular phones, WiFi (wireless fidelity) networks, radar systems, and satellite communication systems. The RF circuit 100 can be integrated into such a system or device, or can alternatively be external thereto and coupled thereto via a wired or wireless connection.

[0020] The RF circuit 100 includes an (RF) input node 110 that is configured to receive an RF signal (r_fin_1). The input node 110 may be a point, interface, or terminal within the RF circuit 100 where an external RF signal (e.g., in the form of a voltage or current) is applied to the RF circuit 100. The input node 110 may serve as an entry point for RF signals into the RF circuit 100 and may be connected to other RF components (e.g., RF antennas, filters, amplifiers, mixers, oscillators, etc.) depending on the particular application.

[0021] The RF circuit 100 further includes an (RF) output node 120 configured to output an RF signal (rf_out_1). The output node 120 may be a point, interface, or terminal within the RF circuit 100 where the RF circuit 100 delivers its output RF signal, voltage, or current to an external device or component (e.g., an RF antenna, filter, amplifier, mixer, oscillator, etc.). Depending on the state of the RF circuit 100, the output node 120 may output the RF signal as received at the input node 110 (after deducting losses due to the RF circuit 100) or may output substantially no signal. In particular, in the off state ( Figure 1a ), the RF circuit 100 can isolate the output node 120 from the input node 110, and in the on state ( Figure 1b ), the RF circuit 100 can pass the RF signal from the input node 110 to the output node 120.

[0022] This is achieved by an RF switch component 130 of the RF circuit 100 coupled between the input node 110 and the output node 120. For example, the RF switch component 130 can be electrically coupled to the input node 110 and the output node 120 via an electrical connection. The RF switch component 130 is configured to selectively connect or disconnect the input node 110 and the output node 120, which produces an on state and an off state, respectively. The selection of connection or disconnection can be automatically controlled, for example by using a control signal or digital logic in the RF circuit 100.

[0023] The RF switch assembly 130 includes a first stage 130-1 and a second stage 130-2, the first stage 130-1 including a first RF switch 140-1, and the second stage 130-2 including a second RF switch 140-2. The term "stage" refers to a functional part or block that performs a switch function within the RF circuit 100. The stages 130-1, 130-2 are characterized by including at least one corresponding RF switch (such as including RF switches 140-1, 140-2, respectively). The first stage 130-1 and the second stage 130-2 are electrically coupled to each other. They can be directly coupled to each other (i.e., without intermediate components between them), or alternatively indirectly coupled (i.e., with intermediate components between them). The first stage 130-1 can be (e.g., directly) coupled to the input node 110, and the second stage 130-2 can be (e.g., directly) coupled to the output node 120. For example, the first stage 130-1 and the second stage 130-2 can be adjacent within the RF circuit 100. This means that the first stage 130-1 and the second stage 130-2 may be located physically close to each other on a circuit board implementing the RF circuit 100 or within a schematic diagram of the RF circuit. This physical proximity or direct connection implies that the first stage 130-1 and the second stage 130-2 share a common connection point (node), such as connected by a conductive trace or by a wire.

[0024] The first RF switch 140-1 and the second RF switch 140-2 may be any switch designed for routing RF signals. It may be or may include a transistor and / or diode switch, and switch between conduction and isolation / attenuation between its respective terminals, for example, based on a control signal applied to the respective control terminals of the RF switches 140-1, 140-2. The RF switches 140-1, 140-2 may include at least one of a positive intrinsic negative (PIN) diode, a bipolar transistor (e.g., an npn or pnp transistor), or a unipolar transistor (e.g., a junction field effect transistor JEFT, a metal oxide semiconductor field effect transistor MOSFET, a gallium arsenide field effect transistor GaAs FET). The first RF switch 140-1 and the second RF switch 140-2 are not necessarily of the same type. Different configurations of implementation methods in their respective stages 130-1, 130-2 are further explained below with respect to the first RF switch 140-1 and the second RF switch 140-2.

[0025] Figure 1a The off state of the RF switch assembly 130 shown in FIG. 1 indicates that both the first stage 130-1 and the second stage 130-2 are in the off state. That is, the first RF switch 140-1 is turned on or off depending on its configuration and type, so that the first stage 130-1 is in the off state. Similarly, the second RF switch 140-2 is turned on or off depending on its configuration and type, so that the second stage 130-2 is in the off state.

[0026] The first stage 130-1 is configured to attenuate the signal power of the RF signal or isolate the output node 120 from the input node 110 in the off state of the RF switch assembly 130. In the latter case, the first stage 130-1 may have provided complete isolation. In the former case, the first stage 130-1 outputs an attenuated RF signal at its output terminal, and the second stage 130-2 can then provide complete isolation and then be responsible for handling lower signal swings (attenuated RF signals). In other words, when the RF switch assembly 130 is turned off (isolated), the first stage 130-1 attenuates the signal power received by the second stage 130-2, which can therefore provide high insulation. Applying the former or the latter may depend on the power of the RF signal.

[0027] When the RF switch assembly 130 is in Figure 1b When in the on state (conducting) shown in , both stages 130 - 1 and 130 - 2 may conduct and cause insertion loss.

[0028] Each stage 130-1, 130-2 of the RF circuit 100 can be implemented using a basic switching topology or a more complex topology that addresses different requirements of the target application. More details about the configuration or topology of the stage 130-1, 130-2 are explained below:

[0029] At least one of the first stage 130-1 and the second stage 130-2 may include a shunt switch or a series switch. For example, the first RF switch 140-1 may be a shunt switch or a series switch, and the second RF switch 140-2 may be a shunt switch or a series switch. The shunt switch may be a type of switch in which a switch element is connected in parallel or shunted with a signal path of an RF signal (a signal path between an input node 110 and an output node 120) or an output node 120 coupled to a load. When the shunt switch is in its on state, it provides a low-resistance path for the RF signal to flow in parallel with the load, effectively bypassing the load. In addition, when the shunt switch is in its off state, it exhibits a high impedance or open circuit, preventing the RF signal from being cut off in its flow to the output node 120. The serial switch may be a type of switch in which a switch element is connected in series with the output node 120 or the signal path of the RF signal. When the series switch is in its on state, it forms a continuous conductive path with the output node 120 and the load coupled to the output node 120 to allow the RF signal to flow through both the switch and the load. In the off state, the series switch interrupts the path, creating an open circuit and preventing the RF signal from flowing to the output node 120.

[0030] To combine the two topologies (shunt switch and series switch), one of the first stage 130-1 and the second stage 130-2 includes a shunt switch, and the other of the first stage 130-1 and the second stage 130-2 includes a series switch. For example, the first stage 130-1 may include a shunt switch, and the second stage 130-2 may include a series switch. The shunt switch may then attenuate the power of the RF signal, and the series switch may cut off the attenuated RF signal from the output node 120. Alternatively, the stages 130-1, 130-2 may include the same type of RF switches.

[0031] One or both of the RF switches 140-1, 140-2 may be resonated by an inductor. The RF circuit 100 may therefore include an inductor coupled in parallel to at least one of the first RF switch 140-1 and the second RF switch 140-2. The inductor may be a resonant inductor to produce a resonant frequency response adapted to the capacity of the associated RF switch. Thus, it may form a resonant LC (inductor-capacitor) circuit having equal but opposite inductive and capacitive reactances such that their effects are canceled.

[0032] A quarter wave (λ / 4) transmission line may be selectively used. This may be particularly useful for high frequencies where the quarter wave transmission line has a small size. A quarter wave transmission line (also a quarter wave line or a quarter wavelength transmission line) is a specific type of transmission line having a length equal to one quarter (1 / 4) of the wavelength of an electromagnetic wave (RF signal) propagating through it at a particular frequency. In this way, the quarter wave line introduces a 90° phase shift into the RF signal, which changes the impedance seen at the node. The quarter wave transmission line may be used for impedance matching, signal conversion, and the like. The quarter wave transmission line may be combined with a shunt switch: thus, at least one of the first stage 130-1 and the second stage 130-2 may include a shunt switch and a quarter wave transmission line. The quarter wave transmission line may, for example, be connected in series to a signal path between the input node 110 and the output node 120.

[0033] One or each of the stages 130-1, 130-2 may optionally include more than one RF switch. For example, the above quarter-wave transmission line may be replaced by a series switch, which is particularly advantageous when lower frequencies or area consumption are critical. In addition, series switches and shunt switches may generally be combined in one or both of the stages 130-1, 130-2 to improve isolation characteristics. In this case, at least one of the first stage 130-1 and the second stage 130-2 includes a series switch and a shunt switch.

[0034] Depending on the specific use case, the RF switch assembly 130 can be used for purposes such as distributing a transmitter signal to multiple antennas, sharing a transmitter signal between several antennas, or enabling a single antenna to be used for both transmission and reception. In all of these scenarios, the RF circuit 100 can provide low insertion loss and high isolation even when handling considerable input power levels. This is because its two stages can operate in a cooperative manner.

[0035] Particularly in radar systems, where the intended application may require multiple transmitters and receivers, there may be challenges with the area consumption and subsequent increased costs associated with having numerous independent transmitters and receivers. A conventional solution that allows a single transmitter or receiver to be shared across multiple antennas is to use a basic (i.e., single-stage) switch topology (such as a series switch). However, this conventional approach may only be suitable for specific applications such as those where linearity requirements are not strict (e.g., when a receiver signal is distributed to multiple antennas). However, this may be unacceptable in other applications where linearity (or power handling) is critical. The reason for this limitation is that under high input power conditions of the RF signal, there is a significant voltage swing across the off-state switch. Therefore, the switch begins to conduct, compromising its isolation. Another conventional topology is a switch based on a quarter-wavelength transmission line. Unfortunately, it may share the same disadvantages in terms of power handling, because at high input power, the shunt switch in the off state begins to conduct, affecting its insertion loss in the on state. Therefore, these methods are not suitable for use at the transmitter output. Another conventional approach involves the use of specific technologies, such as CMOS SOI (complementary metal oxide semiconductor silicon on insulator) or MEMS (microelectromechanical system). However, these solutions have certain disadvantages, including increased cost, larger system footprint due to multi-technology integration, increased complexity, or compromises in other areas (such as digital design). In contrast, RF circuit 100 can provide high isolation and low insertion loss while still maintaining relatively low cost and footprint.

[0036] Figure 2a to Figure 2g Several topologies of RF circuit 100 are illustrated. Figure 2a to Figure 2g An example of an RF circuit 200 is shown.

[0037] exist Figure 2a , the first stage 230-1 includes a quarter-wave transmission line 231 directly coupled to the input node 210 and a shunt switch 232 (first RF switch 240-1) coupled in parallel to a signal path (channel 1) between the input node 210 and the output node 220. The use of the quarter-wave transmission line 231 may be advantageous for high frequencies, where the quarter-wave transmission line 231 has a smaller size.

[0038] One terminal of the shunt switch 232 is directly coupled between the quarter-wave transmission line 231 and the second stage 230-2. The shunt switch 232 resonates, that is, is coupled in parallel to the inductor 233. Figure 2aIn the example of FIG. 2 , the shunt switch 232 includes an N-channel MOSFET as a switching element. The shunt switch 232 is controlled by a control signal (ch1_en_n; inverted channel 1 enable signal) applied to a gate of the MOSFET.

[0039] exist Figure 2a In the embodiment, the second stage 230-1 includes a series switch (second RF switch 240-2) which is directly coupled between the terminal of the shunt switch 232 and the output node 220. The series switch 234 resonates, ie, is coupled in parallel to the inductor 235. Figure 2a In the example of FIG. 1 , the series switch 234 includes an N-channel MOSFET as a switching element. The series switch 234 is controlled by a control signal (ch1_en; channel 1 enable signal) applied to the gate of the MOSFET.

[0040] In the off state of the RF switch assembly 230, the control signal can control the shunt switch 232 in the conducting state, and thus the shunt switch 232 can bypass the RF signal or part of the RF signal to the ground. At the second stage 230-2, no signal or an attenuated RF signal can be received. The control signal of the series switch 234 can control the series switch 234 in the isolation state, and thus the series switch 234 can provide additional isolation between the input node 210 and the output node 220. The control signal of the shunt switch 232 and the control signal of the series switch 234 can be synchronized and inverted to each other.

[0041] exist Figure 2b In the example, the first stage 230-1 corresponds to Figure 2a The second stage 230-2 includes Figure 2a In addition to the resonant shunt switch 234, a second (another) shunt switch 236 is also included, which is coupled in parallel to the signal path. One terminal of the second shunt switch 236 is directly coupled between the series switch 234 and the output node 220. The other terminal of the second shunt switch 236 is connected to the ground. The shunt switch 236 generates resonance, that is, it is coupled in parallel to the inductor 237.

[0042] exist Figure 2bIn the example of , the shunt switch 236 includes an n-channel MOSFET as a switching element. The shunt switch 236 is controlled by a control signal (ch1_en_n; inverted channel 1 enable signal) applied to the gate of the MOSFET. The additional shunt switch 236 provides even higher isolation between the input node 210 and the output node 220. This is particularly advantageous in applications with high isolation requirements. The use of multiple switches can enable control of the RF switch in a more sophisticated and safer manner. The control signals of multiple switches can be interlocked to jointly trigger the required state of the corresponding switches, thereby achieving an on state or an off state of the RF switch assembly 230.

[0043] exist Figure 2c In the example, the second stage 230-2 corresponds to Figure 2a The first stage 230-1 includes Figure 2a The resonant shunt switch 234 in FIG. 2 is replaced with a non-resonant series switch 238 in place of the quarter-wave transmission line 231. The series switch 238 is directly coupled between the input node 210 and the terminal of the shunt switch 232. Figure 2c In the example of , the series switch 238 includes an n-channel MOSFET as a switching element. The series switch 238 is controlled by a control signal (ch1_en; channel 1 enable signal) applied to the gate of the MOSFET. Figure 2c In the example of , the first stage 230 - 1 therefore includes a series switch 238 followed by a shunt switch 232 , while the second stage 230 - 2 includes a series switch 234 .

[0044] (First) the series switch 238 need not resonate because resonance may be ineffective for high power RF signals because the high power input signal (RF signal) causes the series switch 238 to partially turn on. Using the series switch 238 may be particularly advantageous when area is critical or at lower frequencies where a series switch may perform better (and the transmission line may be too bulky).

[0045] exist Figure 2d In the example, the first stage 230-1 corresponds to Figure 2a or Figure 2b The second stage 230-2 includes Figure 2b 2, but the second stage 230-2 includes a second (another) quarter-wave transmission line 239 instead of the series switch 234. This may be advantageous in applications with lower area constraints or at higher frequencies.

[0046] Reference Figure 1a and Figure 1bAs mentioned above, the RF circuit 100 can be implemented in a multipath or multichannel environment to share components (e.g., an antenna between a receiver and a transmitter or a receiver / transmitter between antennas, etc.). In these cases, the RF circuit 100 can further include a second output node and a second RF switch component, the second output node is configured to output an RF signal, and the second RF switch component is coupled between the input node and the second output node. The second RF switch component includes a third stage and a fourth stage, the third stage includes a third RF switch, and the fourth stage includes a fourth RF switch. This is Figure 2e to Figure 2g As shown in the picture.

[0047] exist Figure 2e and Figure 2f In the embodiment, the RF switch components 230 correspond to Figure 2b and Figure 2c The topology of the RF circuit 200 is shown in FIG. 2 . The signal path between the input node 210 and the output node 220 forms a first channel of the RF circuit 200. The RF circuit 200 further includes a second output node 250 configured to output an RF signal. The signal path between the input node 210 and the second output node 250 forms a second channel of the RF circuit 200. The RF circuit 200 further includes a second RF switch component 235 coupled between the input node 210 and the second output node 250. The second RF switch component 235 includes a third stage 230-3 and a fourth stage 230-4, the third stage 230-3 includes a third RF switch 240-3, and the fourth stage 230-4 includes a fourth RF switch 240-4. The topology of the second RF switch component 235 corresponds to the topology of the RF switch component 230. The first channel and the second channel of the RF circuit 200 can be independently controllable. This can be achieved by a second control signal for the switch of the second RF switch component 235.

[0048] Multi-channel configurations (such as in Figure 2e and Figure 2f (middle) can be used to create a SPDT (single pole double throw) switch, for example to share a transmitter between two (or more) antennas. Figure 2e The configuration is particularly advantageous at higher frequencies where the quarter-λ transmission line has smaller dimensions. Figure 2f The configuration is particularly advantageous at lower frequencies or when area consumption is critical.

[0049] exist Figure 2g In the example, the topology of the RF switch assembly 230 corresponds to Figure 2cThe output node 220 is connected to the receiver circuit Rx. The input node 210 is connected to the antenna. The second output node 250 is directly connected to the input node 210 to minimize losses. At the same time, the RF switch component 230 is placed between the antenna and the receiver. In this configuration, the RF switch component 230 protects the receiver input in addition to providing insulation. In other examples, the same Figure 2c The topology of different RF switch components 230, such as Figure 2a topological structure.

[0050] Reference Figure 1a and Figure 1b , the RF circuit 100 may also require ESD (electrostatic discharge) protection or other tuning of the electronic properties of the RF circuit 100 (such as resonance). In this case, the RF circuit 100 may include a (resonant) stub or pad stub coupled between the output node 120 and the RF switch assembly 130. A resonator is a transmission line or resonant element that may have a short transmission line length (e.g., a transmission line designed to resonate on it at a quarter of the wavelength of the RF signal). The resonator may be coupled in parallel with the signal path and may be connected to ground. Figure 3 An example using a resonator is illustrated. Figure 3 An example of an RF circuit 300 is shown.

[0051] The RF circuit 300 includes an input node 310 configured to receive an RF signal. The RF circuit 300 includes two channels having corresponding output nodes (a first output node 320 and a second output node 350), both of which are configured to output RF signals. Figure 3 In the example of FIG. 5 , the output nodes 320 , 350 are two of the plurality of pads.

[0052] As described herein, the RF circuit 300 further includes two RF switch assemblies 360-1, 360-2 (such as the RF switch assembly 100). Figure 3 In the example, RF switch components 360-1 and 360-2 show Figure 2a The RF switch components 360 - 1 and 360 - 2 are coupled between the input node 310 and the corresponding output nodes 320 and 350 .

[0053] The RF circuit 300 further includes two resonators 370-1, 370-2. The first resonator 370-1 is directly coupled between the first output node 320 and the first RF switch component 360-1, and the second resonator 370-2 is directly coupled between the second output node 350 and the second RF switch component 360-2. The resonators 370-1, 370-2 at the pads can aggregate the resonant inductors of the switches in the RF circuit 300 and can provide additional impedance matching or tuning.

[0054] Another option for implementing ESD protection may be implemented in the following way: In addition to or as an alternative to the resonator, the RF circuit may further include a transformer coupled between the output node 120 and the RF switch component 130 . Figure 4 An example using a transformer is shown. Figure 4 An example of an RF circuit 400 is shown.

[0055] The RF circuit 400 includes an input node 410 configured to receive an RF signal. The RF circuit 400 includes two channels having corresponding output nodes (a first output node 420 and a second output node 450), both of which are configured to transmit RF signals. Figure 4 In the example of FIG. 4 , the output nodes 420 , 450 are two of the plurality of pads.

[0056] The RF circuit 400 further includes two RF switch assemblies 460-1, 460-2 as described above (such as the RF switch assembly 100). Figure 4 In the embodiment, RF switch components 460-1 and 460-2 show Figure 2e The RF switch components 460 - 1 and 460 - 2 are coupled between the input node 410 and the corresponding output nodes 420 and 450 .

[0057] The RF circuit 400 further includes two transformers 480-1, 480-2. The first transformer 480-1 is directly coupled between the first output node 420 and the first RF switch component 460-1, and the second transformer 480-2 is directly coupled between the second output node 450 and the second RF switch component 460-2. The transformers 480-1, 480-2 at the pads can replace the pile and resonate the off-state capacitance. This can increase ESD protection without using anti-parallel diodes.

[0058] The RF circuit presented herein has the potential to reduce chip area within an RF system by enabling sharing of certain electronic components. In addition, the RF circuit provides high linearity, enhanced power handling capability, and significant isolation between components. In addition, it can be implemented cost-effectively without introducing excessive complexity.

[0059] Figure 5 An example of an RF system 500 is illustrated. The RF system 500 may be a radar system, such as, for example, an FMCW (frequency modulated continuous wave) radar system. The RF system 500 includes an RF circuit 505 (such as the RF circuit 100) as described herein and an antenna 590 coupled to an input node 510. The antenna 590 is configured to generate an RF signal, for example, based on a received free space wave. Therefore, the antenna 590 is a receiving antenna. Alternatively, the antenna 590 may be (directly) coupled to the output node 520. In this case, the antenna 590 may be configured to receive an RF signal (e.g., for transmission through free space). In the latter case, the antenna 590 may be a transmitting antenna. In some examples, i.e., when the antenna 590 is shared between a receiver and a transmitter, the antenna 590 may be a receiving antenna or a transmitting antenna.

[0060] The RF system 500 may further include at least one of an amplifier circuit and a passive mixer coupled to the other of the output node 520 and the input node 510. That is, at the end of the RF circuit 505 opposite to the antenna 590, an amplifier circuit or a passive mixer may be implemented. Figure 5 In the example of , at least one of an amplifier circuit and a passive mixer may be coupled to output node 520. The amplifier circuit or the passive mixer may be shared between antenna 590 and other antennas.

[0061] A passive mixer is an electronic component or circuit used to combine or mix two or more RF signals together. A passive mixer may rely solely on passive components (such as diodes or resistors for the mixing process). This may be advantageous in applications where simplicity and low power consumption are more important than high gain. The amplifier circuit may be or include a power amplifier or a low noise amplifier. A power amplifier is an electronic device or circuit that increases the amplitude (power) of an input signal to a higher level to generate RF for the purpose of driving the antenna 590. A low noise amplifier (LNA) is an electronic amplifier designed to amplify weak signals with minimal additional noise. LNAs may be used in the front end of an RF receiver to increase the sensitivity of the receiver.

[0062] To bidirectionally use antenna 590, RF circuit 505 may be implemented as a time division duplex (TDD) switch. A TDD switch may transmit and receive RF signals using the same frequency and switch between these two functions in a time-based and synchronized manner.

[0063] The multi-channel application mentioned above can be realized by introducing multiple RF circuits as described herein including RF circuit 505. Multiple RF circuits are coupled to at least one of an amplifier circuit and a passive mixer, that is, multiple RF circuits share one amplifier circuit or passive mixer. RF system 500 may further include multiple antennas, each antenna being coupled to a corresponding RF circuit of the multiple RF circuits. Figure 6 An example of a multi-channel application is shown.

[0064] Figure 6 An example of an RF system 600 is shown. The RF system 600 includes a plurality of RF circuits 610-1 to 610-5, each of which is an RF circuit as described above (such as the RF circuit 100). The RF system 600 further includes a plurality of antennas 620-1 to 620-5, each of which is an RF circuit as described above (such as the RF circuit 100). Figure 5 The antennas described above. Antennas 620-1 and 620-2 are transmit antennas (Tx), and antennas 620-3 to 620-5 are receive antennas (Rx). Each of the plurality of antennas 620-1 to 620-5 is coupled to a corresponding RF circuit of the plurality of RF circuits 610-1 to 610-5.

[0065] The transmit antennas 620-1, 620-2 share a power amplifier 630, which is coupled to the RF circuits 610-1, 610-2. The receive antennas 620-3 to 620-5 share an LNA 640, which is coupled to the RF circuits 610-3 to 610-5. The power amplifier 630 is further coupled to a phase-locked loop (PLL) 650 in parallel with an oscillator 655 to generate an RF signal. An oscillator (e.g., a voltage-controlled oscillator (VCO)) can generate a carrier frequency signal for the RF system 600. The PLL 650 can control and stabilize the frequency of the oscillator 655, for example, by comparing the output frequency of the oscillator 655 with a reference frequency (e.g., the frequency of a crystal oscillator).

[0066] LNA 640 is further coupled to mixer 660, which is connected to PLL 650 and oscillator 655. Upstream of mixer 660, LNA 640 is further coupled to analog baseband circuitry 662, analog-to-digital converter (ADC) 664, and digital signal processing (DSP) circuitry 666.

[0067] Figure 7 An example of an RF system 700 as a TDD system is shown, which can be used as an RF front end (e.g., a 5G RF front end). Figure 7 In an example, the RF circuit described above can be used to share an antenna between a transmitter and a receiver.

[0068] The RF system 700 includes a plurality of RF front ends 710-1 to 710-4, each of which is coupled to a corresponding antenna ( Figure 7 710-1 to 710-4). Each of the plurality of RF front ends 710-1 to 710-4 includes a corresponding RF circuit 720 as described herein. The RF circuit 720 is configured as a TDD switch. The RF circuit 720 is coupled to a filter 730, one or more power amplifiers 731, and an LNA 732. The TDD switch can enable switching between the power amplifier 731 and the LNA 732 in a time-varying manner so as to use the antenna as a transmit antenna or a receive antenna, respectively. Both the power amplifier 731 and the LNA 732 are coupled to a transceiver 733, which generates or receives an RF signal. The RF front ends 710-1 to 710-4 are further coupled to a DSP circuit 750 via corresponding ADCs and DACs (digital-to-analog converters).

[0069] The RF system 700 may optionally include a baseband processor. For example, the baseband processor may include a DSP circuit 750. It may be responsible for handling and processing baseband signals (i.e., signals at their original frequency range before they are modulated onto a carrier frequency for transmission or signals demodulated from a received RF signal). The baseband processor may be a digital signal processing unit or an integrated circuit (IC) within the RF system 700 that manages and processes baseband signals. The baseband signal may represent data or information in its original form (e.g., in the form of digital bits or analog signals within a specified frequency range). The baseband processor may be configured to modulate digital data onto a carrier signal for transmission, and demodulate the received signal to extract the initial baseband data. It may further be configured to perform error correction (e.g., error encoding and decoding) to ensure reliable data transmission, signal filtering, digital signal processing, data formatting and framing, etc.

[0070] Figure 8 An example of a method for an RF circuit as described herein, such as RF circuit 100, 200, 300, or 400, is illustrated. Method 800 includes receiving (810) an RF signal at an input node of the RF circuit, and selectively connecting or disconnecting (820) the input node and an output node by an RF switch component. Method 800 further includes selectively outputting (830) the RF signal at the output node, and in an off state of the RF switch component (where the first stage and the second stage are in the off state), attenuating (840) the signal power of the RF signal at the first stage or isolating the output node from the input node at the first stage.

[0071] More details and aspects of method 800 are explained in conjunction with the proposed conclusion or one or more examples described above (e.g., with reference to FIG. 1 ). Method 800 may include one or more additional optional features corresponding to one or more aspects of the proposed technology or one or more examples described above.

[0072] Some examples of the proposed technique are presented below:

[0073] An example (e.g., Example 1) relates to an RF circuit comprising an input node configured to receive an RF signal, an output node configured to output an RF signal, an RF switch component coupled between the input node and the output node, wherein the RF switch component is configured to selectively connect or disconnect the input node and the output node, and wherein the RF switch component comprises a first stage and a second stage, the first stage comprising a first RF switch, and the second stage comprising a second RF switch, wherein the first stage is configured to: attenuate the signal power of the RF signal or isolate the output node from the input node in an off state of the RF switch component (wherein the first stage and the second stage are in the off state).

[0074] Another example (eg, Example 2) relates to the previous example (eg, Example 1) or any other example, further comprising a first stage and a second stage directly coupled to each other, the first stage being adjacent to the second stage within the RF circuit.

[0075] Another example (eg, Example 3) relates to the previous example (eg, one of Examples 1 or 2) or any other example, further comprising: at least one of the first stage and the second stage comprises a shunt switch or a series switch.

[0076] Another example (e.g., Example 4) relates to a previous example (e.g., one of Examples 1 to 3) or any other example, further comprising: one of the first stage and the second stage includes a shunt switch, and wherein the other of the first stage and the second stage includes a series switch.

[0077] Another example (eg, Example 5) relates to a previous example (eg, one of Examples 1 to 4) or any other example, further comprising an inductor coupled in parallel to at least one of the first RF switch and the second RF switch.

[0078] Another example (eg, Example 6) relates to the previous example (eg, one of Examples 1 to 5) or any other example, further comprising: at least one of the first stage and the second stage comprises a shunt switch and a quarter-wave transmission line.

[0079] Another example (eg, Example 7) relates to the previous example (eg, one of Examples 1 to 6) or any other example, further comprising: at least one of the first stage and the second stage comprises a series switch and a shunt switch.

[0080] Another example (eg, Example 8) relates to the previous example (eg, one of Examples 1 to 7) or any other example, further comprising a resonator coupled between the output node and the RF switch component.

[0081] Another example (eg, Example 9) relates to the previous example (eg, one of Examples 1-8) or any other example, further comprising a transformer coupled between the output node and the RF switch component.

[0082] Another example (e.g., Example 10) relates to a previous example (e.g., one of Examples 1 to 9) or any other example, further including: a second output node configured to output an RF signal; a second RF switch component coupled between the input node and the second output node, wherein the second RF switch component includes: a third stage including a third RF switch; and a fourth stage including a fourth RF switch.

[0083] An example (e.g., Example 11) relates to an RF system comprising an RF circuit according to a previous example (e.g., one of Examples 1 to 10), and an antenna coupled to one of the output node and the input node, wherein the antenna is configured to receive and / or generate RF signals.

[0084] Another example (eg, Example 12) relates to the previous example (eg, Example 11) or any other example, further including at least one of an amplifier circuit and a passive mixer coupled to the other of the output node and the input node.

[0085] Another example (e.g., Example 13) relates to the previous example (e.g., Example 12) or any other example, further including: multiple RF circuits according to any one of Examples 1 to 10, which are coupled to at least one of the amplifier circuit and the passive mixer; and multiple antennas, each coupled to a corresponding RF circuit of the multiple RF circuits.

[0086] Another example (eg, Example 14) relates to the previous example (eg, one of Examples 12 or 13) or any other example, further comprising: the amplifier circuit comprises a power amplifier or a low noise amplifier.

[0087] Another example (eg, Example 15) relates to the previous example (eg, one of Examples 11 to 14) or any other example, further comprising: the RF circuit is a time division duplex switch.

[0088] An example (e.g., Example 16) relates to a method for an RF circuit, the RF circuit including an RF switch component, which includes a first stage and a second stage coupled between an input node and an output node, the first stage including a first RF switch and the second stage including a second RF switch, the method including: receiving an RF signal at the input node; selectively connecting or disconnecting the input node and the output node by the RF switch component; selectively outputting the RF signal at the output node; and attenuating the signal power of the RF signal at the first stage or isolating the output node from the input node at the first stage in an off state of the RF switch component (wherein the first stage and the second stage are in the off state).

[0089] The aspects and features described with respect to a specific example in the previous examples may also be combined with one or more aspects and features of other examples to replace equivalent or similar features of other examples, or to additionally introduce features into other examples.

[0090] The example may further be or relate to a (computer) program, which includes a program code that performs one or more of the above methods when the program is executed on a computer, a processor or other programmable hardware component. Therefore, the steps, operations or processes of the different methods in the above method can also be performed by a programmed computer, a processor or other programmable hardware component. The example may also cover a program storage device (such as a digital data storage medium), which is machine-readable, processor-readable or computer-readable, and encodes and / or includes machine-executable, processor-executable or computer-executable programs and instructions. For example, a program storage device may include or may be a digital storage device, a magnetic storage medium (such as a disk and a tape), a hard drive or an optically readable digital data storage medium. Other examples may also include a computer, a processor, a control unit, a (field) programmable logic array ((F) PLA), a (field) programmable gate array ((F) PGA), a graphics processor unit (GPU), an application-specific integrated circuit (ASIC), an integrated circuit (IC) or a system on a chip (SoC) system, which is programmed to perform the steps of the above method.

[0091] It is further understood that, unless explicitly stated in individual cases or necessary for technical reasons, the disclosure of several steps, processes, operations or functions disclosed in the specification or claims should not be interpreted as implying that these operations must depend on the described order. Therefore, the foregoing description does not limit the execution of several steps or functions to a certain order. In addition, in other examples, a single step, function, process or operation may include and / or be decomposed into several sub-steps, sub-functions, sub-processes or sub-operations.

[0092] If some aspects have been described with respect to a device or system, these aspects should also be understood as descriptions of the corresponding methods. For example, a block, device, or functional aspect of a device or system may correspond to a feature of a corresponding method, such as a method step. Therefore, aspects described with respect to a method should also be understood as descriptions of corresponding blocks, corresponding elements, attributes, or functional features of a corresponding device or system.

[0093] The following claims are hereby incorporated into the detailed description, where each claim may stand on its own as a separate example. It should also be noted that, although in the claims, a dependent claim refers to a specific combination with one or more other claims, other examples may also include a combination of a dependent claim with the subject matter of any other dependent claim or independent claim. Unless it is stated in individual cases that a specific combination is not intended, such a combination is hereby explicitly proposed. In addition, features of a claim should also be included with respect to any other independent claim, even if the claim is not directly defined as dependent on the other independent claim.

Claims

1. A radio frequency (RF) circuit (100), comprising: An input node (110) configured to receive an RF signal; An output node (120) configured to output the RF signal; An RF switch component (130) is coupled between the input node (110) and the output node (120), wherein the RF switch component (130) is configured to selectively connect or disconnect the input node (110) and the output node (120), and wherein the RF switch component (130) includes: A first stage (130-1), comprising a first RF switch (140-1); as well as The second stage (130-2) comprises a second RF switch (140-2), wherein the first stage (130-1) is configured to attenuate the signal power of the RF signal or isolate the output node (120) from the input node (110) in an off state of the RF switch component (130), and in the off state of the RF switch component (130), the first stage (130-1) and the second stage (130-2) are in an off state.

2. The RF circuit (100) of claim 1, wherein the first stage (130-1) and the second stage (130-2) are directly coupled to each other, the first stage (130-1) being adjacent to the second stage (130-2) within the RF circuit (100).

3. The RF circuit (100) of any one of the preceding claims, wherein at least one of the first stage (130-1) and the second stage (130-2) comprises a shunt switch (232) or a series switch (235).

4. The RF circuit (100) of any preceding claim, wherein one of the first stage (130-1) and the second stage (130-2) comprises a shunt switch (232), and wherein the other of the first stage (130-1) and the second stage (130-2) comprises a series switch (235).

5. The RF circuit (100) of any one of the preceding claims, further comprising an inductor (233) coupled in parallel to at least one of the first RF switch (140-1) and the second RF switch (140-2).

6. The RF circuit (100) of any one of the preceding claims, wherein at least one of the first stage (130-1) and the second stage (130-2) comprises a shunt switch (232) and a quarter wave transmission line (231).

7. The RF circuit (100) of any one of the preceding claims, wherein at least one of the first stage (130-1) and the second stage (130-2) comprises a series switch (235) and a shunt switch (232).

8. The RF circuit (100) of any preceding claim, further comprising a resonator (370-1, 370-2) coupled between the output node (120) and the RF switch assembly (130).

9. The RF circuit (100) of any preceding claim, further comprising a transformer (480-1, 480-2) coupled between the output node (120) and the RF switch assembly (130).

10. The RF circuit (100) according to any one of the preceding claims, further comprising: A second output node (250) configured to output the RF signal; A second RF switch component (235) is coupled between the input node (110) and the second output node (250), wherein the second RF switch component (235) comprises: a third stage (230-3), comprising a third RF switch (240-3); as well as The fourth stage (230-4) includes a fourth RF switch (240-4).

11. A radio frequency (RF) system (500), comprising: An RF circuit (505) according to any one of the preceding claims; as well as An antenna (590) is coupled to one of the output node and the input node, wherein the antenna (590) is configured to receive and / or generate the RF signal.

12. The RF system (500) of claim 11, further comprising at least one of an amplifier circuit (630) and a passive mixer coupled to the other of the output node and the input node.

13. The RF system (500) of claim 12, further comprising: a plurality of RF circuits (610-1 to 610-5) according to any one of claims 1 to 10, coupled to at least one of the amplifier circuit (630, 640) and the passive mixer; as well as A plurality of antennas (620-1 to 620-5), each coupled to a corresponding RF circuit of the plurality of RF circuits (610-1 to 610-5).

14. The RF system (500) of any one of claims 11 to 13, wherein the RF circuit (505) is a time division duplex switch (720).

15. A method (800) for a radio frequency (RF) circuit, the RF circuit comprising an RF switch assembly, the RF switch assembly comprising a first stage and a second stage coupled between an input node and an output node, the first stage comprising a first RF switch, and the second stage comprising a second RF switch, the method comprising: receiving (810) an RF signal at the input node; The RF switch assembly selectively connects (820) or disconnects (820) the input node and the output node; selectively outputting (830) the RF signal at the output node; as well as In an off state of the RF switch assembly, a signal power of the RF signal is attenuated (840) at the first stage or the output node is isolated from the input node (840) at the first stage, and in the off state of the RF switch assembly, the first stage and the second stage are in an off state.

Images