DE102020109391A1 - HIGH FREQUENCY SWITCH WITH CONTROLLABLE RESONANCE FREQUENCY - Google Patents

Abstract

High frequency (HF) switch with controllable resonance frequency. An RF switch has a stack of two or more field effect transistors (FETs) that are electrically connected between a first terminal and a second terminal. The RF switch also includes an inductor connected between the first terminal and the second terminal and in parallel with the stack of FETs. A first part of the FETs is controlled to turn the RF switch on or off. In addition, a second part of the FETs is controlled to tune a resonant frequency of the RF switch when the RF switch is off.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority over U.S. Provisional Patent Application No. 62 / 829,219 entitled "RADIO FREQUENCY SWITCHES WITH CONTROLLABLE RESONANT FREQUENCY" and as opposed to U.S. Non-Provisional Patent Application No. 16 / 815,694 . They are hereby incorporated by reference in their entirety.

area

Embodiments of the invention relate to electronic systems and, more particularly, to high frequency switches.

BACKGROUND

A radio frequency (RF) communication system can include RF switches used for a variety of purposes.

In one example, an RF communication system may include a radio frequency transmit / receive switch. The transmit / receive switch can be used to electrically connect an antenna to a transmit path or a receive path of the system, thereby controlling access of the paths to the antenna.

SUMMARY OF THE DISCLOSURE

Radio frequency (RF) switches with controllable resonance frequency are provided herein. In certain embodiments, an RF switch comprises a stack of two or more field effect transistors (FETs) electrically connected between a first terminal and a second terminal. In addition, the RF switch furthermore has an inductor which is connected between the first connection and the second connection and in parallel with the stack of FETs. A first part of the FETs are controlled to turn the RF switch on or off. In addition, a second part of the FETs is controlled to tune a resonant frequency of the RF switch when the RF switch is off. For example, when the RF switch is in an OFF state, the RF switch has a resonance frequency based on a product of an inductance of the inductor and an encapsulation arrangement of the stack of FETs. By controlling the gate voltages of the second part of the FETs in the OFF state, the package arrangement provided by the stack of FETs is changed. Flexibility is thus provided for tuning the resonance frequency of the RF switch, for example to compensate for manufacturing fluctuations and / or to control the resonance frequency on the basis of an operating frequency band in order to increase the separation.

In one aspect, an RF switch with adjustable resonance frequency is provided. The RF switch includes: a plurality of ports including a first port and a second port; an inductor electrically connected between the first terminal and the second terminal; and a plurality of field effect transistors (FETs) electrically connected in series between the first terminal and the second terminal and in parallel with the inductor. A first part of the multiple FETs are controlled by a control signal to set the RF switch in an ON state or an OFF state, and a second part of the multiple FETs are controllable separately from the control signal to set a resonance frequency of the RF To adjust the switch in the OFF state.

In another aspect, a method of RF switching is provided. The method includes: propagating an RF signal through two or more FETs of an RF switch in an ON state of the RF switch; Changing the switch from the ON state to an OFF state using a control signal that controls a first part of the two or more FETs; and adjusting a resonance frequency of the RF switch in the OFF state using a second part of the two or more FETs, the two or more FETs being arranged in a stack that is in parallel with an inductor of the RF switch.

In another aspect, a front-end system is provided. The front-end system has: an antenna connector; a power amplifier; a low noise amplifier; and a transmit / receive switch having a receive branch which is electrically connected between an input to the low-noise amplifier and the antenna connection, and a transmission branch which is electrically connected between an output of the power amplifier and the antenna connection. The receiving branch has several FETs arranged in series and an inductor in parallel with the several FETs. A first part of the plurality of FETs are controlled by a control signal in order to activate or deactivate the receiving branch, and a second part of the plurality of FETs can be controlled separately from the control signal in order to adjust a resonance frequency of the receiving branch when the receiving branch is deactivated.

Figure list

• 1 Figure 13 is a schematic diagram of one embodiment of a phased array antenna system including transmit / receive (T / R) switches.
• 2A Figure 12 is a schematic diagram of one embodiment of a front end system including T / R switches.
• 2 B Figure 13 is a schematic diagram of another embodiment of a front end system including T / R switches.
• 3 Figure 13 is a schematic diagram of an example of a multi-layer high speed data communication network.
• 4th Figure 13 is a schematic diagram of a radio frequency (RF) switch according to an embodiment.
• 5 Figure 13 is a schematic diagram of an RF switch in accordance with another embodiment.
• 6th Figure 13 is a schematic diagram of an RF switch in accordance with another embodiment.
• 7A Figure 13 is a schematic diagram of a first resonant frequency shift setting of an RF switch in accordance with another embodiment.
• 7B FIG. 14 is a schematic diagram of a second resonant frequency shift setting of the RF switch of FIG 7A .
• 8th Figure 13 is a schematic diagram of an RF switch in accordance with another embodiment.
• 9A Figure 3 is a schematic diagram of a T / R switch according to an embodiment.
• 9B FIG. 13 is a schematic diagram of one embodiment of the T / R switch of FIG 9 comprising semiconductor die.
• 10A FIG. 13 is an example of a loss versus frequency graph for the receive leg of the T / R switch of FIG 9A .
• 10B FIG. 13 is an example of a graph of reverse isolation versus frequency for the receive branch of the T / R switch of FIG 9A .
• 10C FIG. 13 is an example of a loss versus frequency graph for the receive leg of the T / R switch of FIG 9A .
• 10D FIG. 13 is an example of a graph of reverse isolation versus frequency for the receive branch of the T / R switch of FIG 9A .

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description of embodiments presents various descriptions of specific embodiments of the invention. However, the invention can be embodied in a variety of different ways. In this description, reference is made to the drawings where like reference numbers may indicate identical or functionally similar elements. It goes without saying that elements shown in the figures are not necessarily drawn to scale. It is also understood that certain embodiments can have more elements than shown in a drawing and / or a subset of the elements shown in a drawing. Furthermore, some embodiments may incorporate any suitable combination of features from two or more drawings.

Radio frequency (HF) switches with controllable resonance frequency are provided here. In certain embodiments, an RF switch comprises a stack of two or more field effect transistors (FETs) that are electrically connected between a first terminal and a second terminal. In addition, the RF switch furthermore has an inductor which is connected between the first connection and the second connection and in parallel with the stack of FETs. A first part of the FETs is controlled to turn the RF switch on or off. In addition, a second part of the FETs is controlled to tune a resonant frequency of the RF switch when the RF switch is off.

For example, when the RF switch is OFF, the RF switch has a resonant frequency that is based on a product of an inductance of the inductor and a capacitance of the stack of FETs. By controlling the gate voltages of the second part of the FETs in the OFF state, the capacitance provided by the stack of FETs is changed. The resonance frequency of the RF switch can be tuned accordingly.

The resonant frequency of the RF switch can be controlled for a variety of purposes. In certain implementations, the resonance frequency is controlled based on an operating frequency band. For example, the resonance frequency can be adjusted to achieve multi-band operation with little or no effect on insertion loss. In addition or as an alternative, the resonance frequency can be controlled in order to compensate for a PVT (process, voltage and / or temperature - process, voltage and / or temperature) fluctuation. For example, the The resonance frequency can be adjusted in order to overcome frequency shifts resulting from a process fluctuation, whereby the desired center frequency of the resonance is tuned back and the design is centered again in order to take a process fluctuation into account.

In certain implementations, the RF switch is implemented as a multi-stage switch that has at least a first branch and a second branch, the inductor being in parallel with the stack of FETs in the first branch of the switch. For example, the RF switch can correspond to a transmit / receive (T / R) switch that has a receive branch and a transmit branch.

When the first branch of the switch is OFF and the second branch of the switch is ON, the inductance and capacitance of the first branch act as a parallel inductor-capacitor (LC) resonator with a resonant frequency. In addition, the resonance frequency can be tuned to resonate at the frequency of interest (e.g., in a particular frequency band), which in turn provides strong separation.

1 Figure 13 is a schematic diagram of one embodiment of a phased array antenna system 10 . The phased array antenna system 10 has a digital processing circuit 1 , a data conversion circuit 2 , a channel processing circuit 3 , RF front ends 5a , 5b , ..., 5n and antennas 6a , 6b , ..., 6n on. Although an example with three RF front ends and three antennas is shown, the phased array antenna system 10 have more or fewer HF front ends and / or more or fewer antennas, as indicated by the ellipses.

The phased array antenna system 10 FIG. 10 illustrates one embodiment of an electronic system that may include one or more switches implemented in accordance with the teachings herein. However, the switches disclosed herein can be used in a wide variety of electronics. A phased array antenna system is also referred to herein as an actively scanned electronically panned array.

As in 1 shown is the channel processing circuit 3 to the antenna 6a , 6b , ..., 6n through HF frontends 5a , 5b , ..., 5n coupled. The channel processing circuit 3 in this embodiment comprises a splitting / combining circuit 7th , a frequency boost / buck circuit 8th and a phase and amplitude control circuit 9 on. The channel processing circuit 3 provides RF signal processing of RF signals transmitted and received by and from each communication channel. In the illustrated embodiment, each communication channel is associated with a corresponding RF front end and antenna.

With further reference to 1 generates the digital processing circuit 1 digital broadcast data for controlling one of the antennas 6a , 6b , ..., 6n emitted transmission beam. The digital processing circuit 1 also processes digital received data representing a received beam. In certain implementations, the digital processing circuitry has 1 one or more baseband processors.

As in 1 shown is the digital processing circuit 1 to the data conversion circuit 2 coupled, which has a digital-to-analog converter (DAC) circuit arrangement for converting digital transmission data into one or more baseband transmission signals and an analog-to-digital converter (ADC) circuit arrangement for converting one or more baseband reception signals into digital reception data.

The frequency boost / buck circuit 8th in this embodiment provides a frequency boost from baseband to RF and a frequency boost from RF to baseband. However, other implementations are possible, such as designs using the phased array antenna system 10 partially works at an intermediate frequency (IF). In certain implementations, the split / combine circuit provides 7th to one or more frequency-boosted transmit signals in order to generate RF signals that are suitable for processing by the RF front-ends 5a , 5b , ..., 5n and a subsequent transmission on the antennas 6a , 6b , ..., 6n suitable. In addition, the splitting / combining circuit combines 7th about the antennas 6a , 6b , ..., 6n and RF front ends 5a , 5b , ..., 5n received RF signals to one or more baseband receive signals for the data conversion circuit 2 to generate.

The channel processing circuit 3 also has the phase and amplitude control circuitry 9 for controlling beamforming operations. For example, the phase and amplitude control circuit controls 9 the amplitudes and phases of via the antennas 6a , 6b , ..., 6n transmitted or received signals to provide beamforming. In terms of signal transmission, those from the antennas aggregate 6a , 6b , ..., 6n radiated RF signal waves through constructive and destructive interference to collectively generate a transmit beam with a specific direction. With regard to the signal reception, the channel processing circuit generates 3 a receive beam by combining those from the antennas 6a , 6b , ..., 6n to Amplitude scaling and phase shifting of received RF signals.

Phased array antenna systems are used in a wide variety of applications, including but not limited to cellular communications, military and defense systems, and / or radar technology.

As in 1 shown have RF front ends 5a , 5b , ..., 5n one or more VGAs each 11a , 11b , ..., 11n on that to scale the amplitude of each one by the antennas 6a , 6b , ..., 6n transmitted or received RF signals. In addition, the HF front ends 5a , 5b , ..., 5n one or more phase shifters each 12a , 12b , ..., 12n to phase shift the RF signals. For example, in certain implementations, the phase and amplitude control circuit generates 9 Gain control signals for controlling the voltage generated by the VGAs 11a , 11b , ..., 11n provided gain and phase control signals for controlling the amount of by the phase shifters 12a , 12b , ..., 12n phase shift provided. Furthermore, the HF front ends 5a , 5b , ..., 5n one or more T / R switches each 13a , 13b , ..., 13n to choose between transmit and receive signals, so the antennas 6a , 6b , ..., 6n can be used together for send and receive operations, such as in applications that use time division duplexing (TDD).

The phased array antenna system 10 works to generate a transmit beam or a receive beam having a main lobe pointing in a desired communication direction. The phased array antenna system 10 realizes an increased signal-to-noise ratio (SNR) in the direction of the main lobe. The transmit or receive beam also has one or more side lobes which point in different directions than the main lobe and are undesirable.

By moving the T / R switch 13a , 13b , ..., 13n according to the teachings herein, a number of advantages can be achieved, such as multi-band operation and / or increased separation between the transmit and receive paths. For example, if the T / R switch 13a , 13b , ..., 13n RF transmission signals to the antennas 5a , 5b , ..., 5n transmitted to form a transmit beam, increased separation is provided for the deactivated receive paths.

2A Figure 3 is a schematic diagram of one embodiment of a front end system 30th with T / R switches. The front-end system 30th has a first T / R switch 21, a second T / R switch 22nd , a receive path VGA 23 , a send path VGA 24 , a receive path controllable phase shifter 25th , a transmit path phase shifter 26th , a low noise amplifier (LNA) 27 and a power amplifier (PA) 28 on. As in 2A shown is the front-end system 30th than to the antenna 20th shown coupled.

The front-end system 30th may be included in a wide variety of RF systems including, but not limited to, phased array antenna systems such as the phased array antenna system 10 from 1 . For example, multiple instantiations of the front-end system 30th to implement the HF frontends 5a , 5b , ..., 5n from 1 be used. In certain implementations, one or more instantiations of the front-end system 30th manufactured on a semiconductor die or chip.

As in 2A shown shows the front-end system 30th the receive path VGA 23 to control an amount of gain that is on the antenna 20th received RF input signal and the transmit path VGA 24 , for controlling an amount of gain, at an on the antenna 20th transmitted RF output signal provided on. The gain control provided by the VGAs can serve a wide variety of purposes including, but not limited to, compensating for temperature and / or process variation. In addition, in beamforming applications, the VGAs can control the sidelobe levels of a beam pattern.

RF systems such as the front-end system 30th from 2A may have one or more T / R switches to control access of transmit and receive paths to an antenna. Although an example of an RF system with T / R switches is shown, the teachings herein apply to RF systems implemented in a wide variety of ways. Furthermore, the teachings herein do not apply to T / R switches but also to RF switches that serve other functions.

2 B Figure 13 is a schematic diagram of another embodiment of a front end system 40 with T / R switches. The front-end system 40 from 2 B is similar to the front-end system 30th from 2A except for the front-end system 40 the second T / R switch 22nd not applicable. As in 2 B shown is the front-end system 40 than to a receiving antenna 31 and to a transmitting antenna 32 shown coupled.

The front-end system 40 works with different antennas for signal transmission and reception. In the illustrated embodiment, the receive path controls VGA 23 an amount of gain, one on the receiving antenna 31 received RF input signal provided, and the Send Path VGA 24 controls an amount of gain, one on the second antenna 32 transmitted RF output signal provided.

Certain RF systems have separate antennas for transmitting and receiving signals.

3 Figure 13 is a schematic diagram of an example of a multi-layer high speed data communication network. For example, the network can have various mobile end users, Industry 4.0 ecosystem support and communication infrastructure for autonomous driving. This supports artificial intelligence data communication and a fast real-time decision-making process as well as secure closed networks.

Wireless traffic has increased at a rate of over 50% per year per subscriber, and this trend is expected to accelerate over the next decade with the continued use of video and the rise of loT. To address this demand, 5G technology plans to use millimeter wave frequencies to expand the available frequency spectrum and provide multi-gigabit-per-second (Gbps) data rates to mobile devices and other UEs. 5G promises great flexibility to support a wide variety of Internet Protocol (IP) facilities, small cell architectures, and / or dense coverage areas.

Current or planned applications for 5G include Tactile Internet, V2V (Vehicle-to-Vehicle) communication, V2I (Vehicle to Infrastructure) communication, peer-to-peer communication and / or machine-to-machine communication, secure closed Communication and external artificial intelligence data processing services on the cloud. Such technologies use high data rates and / or low network latency. For example, certain applications such as V2V communication and / or remote surgery must operate with low latency to ensure human safety.

In the multilayer network of 3 The existing cell-based network is evolving to support 5G, with WiFi takeover, small cells and / or broadband data distribution using servers at the edges of the network (edge servers) to enable new use cases with lower latency. As in the example of 3 shown, a backhaul connects a fixed cellular infrastructure to the core telephone network and the Internet. Thus, backhaul traffic carries between the local sub-network (e.g. connections between UE and network access points such as base stations) and the core network (e.g. the Internet and the cellular connection point). The multi-level network of 3 is also implemented to work using Industry 4.0, which enables augmented reality and / or real-time artificial intelligence (AI) via the cloud.

With further reference to 3 uses the illustrated multi-level architecture 4G (fourth generation) cells with greater coverage with an underlying network of more closely spaced 5G base stations. The implementation of the multilevel network of 3 doing so provides a number of advantages including flexibility in providing different levels of channel access priority for different types of connections. For example, macro cells, small cells, and / or device-to-device connections may operate with varying priorities for channel access.

One way to increase range spectral efficiency is to shrink the cell size, thereby reducing the number of users per cell and providing additional spectrum to each user. Thus, the overall network capacity increases by shrinking cells and reusing spectrum.

The teachings herein can improve the performance of front end systems of base stations and UEs operating in a tiered network. For example, flexibility can be provided to control the resonance frequency based on the working frequency band and / or to compensate for manufacturing fluctuations, thereby increasing the separation.

4th Figure 3 is a schematic diagram of an RF switch 50 according to one embodiment. The RF switch 50 has multiple FETs (in this example 31, 32a, 32b) in series between a first terminal T1 and a second port T2 on. In addition, the RF switch 50 still an inductor 35 on that between the first connector T1 and the second port T2 and is connected in parallel with the FETs. The inductor 35 has an inductance L ₀ in this example.

(das in diesem Beispiel logisch invertiert ist) verwendet, um den FET 31 ein- oder auszuschalten, um dadurch den HF-Schalter 50 zu einem EIN-Zustand oder einem AUS-Zustand zu steuern. Obwohl ein Beispiel mit einem FET, der zum Ein- oder Ausschalten des HF-Schalters verwendet wird, gezeigt ist, können zusätzliche FETs verwendet werden, um den HF-Schalter ein- oder auszuschalten. Beispielsweise können ein oder mehrere zusätzliche FETs in Reihe mit dem FET 31 platziert werden, um die Leistungsverarbeitungsfähigkeit des HF-Schalters 50 zu steigern.A first part or group of the FETs (including FET 31 in this example) are controlled to the RF switch 50 on or off. For example, a control signal

(which is logically inverted in this example) used the FET 31 on or off, thereby activating the RF switch 50 to an ON state or an OFF state. Although an example is shown with a FET used to turn the RF switch on or off additional FETs can be used to turn the RF switch on or off. For example, one or more additional FETs can be in series with the FET 31 placed to the power handling capability of the RF switch 50 to increase.

With further reference to 4th becomes a second part or group of FETs (including FET 32a and FET 32b in this example) controlled to a resonance frequency of the RF switch 50 to adjust. For example, a bit b ₀ controls the FET 32a while a bit b _n-1 controls the FET 32b controls. Although an example is shown with two FETs used for resonance frequency adjustment, more or fewer FETs can be used to control the resonance frequency of the RF switch 50 be used.

When the RF switch 50 is in the OFF state, the RF switch 50 a resonance frequency based on a product of an inductance of the inductor 50 (in this example corresponding to L ₀ ) and a capacitance of the stack of FETs between the first connection T1 and the second port T2 is present, based.

By controlling the gate voltages of the second part of the FETs (in this example corresponding to FET 32a and FET 32b ) to the OFF state, the capacity is changed. Accordingly, the resonance frequency of the RF switch 50 be matched.

den FET 31 ausschaltet, um den HF-Schalter 50 in dem AUS-Zustand zu betreiben, liegen die Gate-Source-Kapazität und die Gate-Drain-Kapazität des FET 31 (in diesem Beispiel beide gleich etwa Coff) in Reihe zwischen dem ersten Anschluss T1 und dem zweiten Anschluss T2 und tragen zu der Kapazität des HF-Schalters 50 bei.For example, if the control signal

the FET 31 turns off to the RF switch 50 to operate in the OFF state, the gate-source capacitance and the gate-drain capacitance of the FET are 31 (in this example both equal to about Coff) in series between the first connection T1 and the second port T2 and contribute to the capacitance of the RF switch 50 at.

In addition, when bit b ₀ controls the FET 32a turns off, carry the gate-source capacitance and the gate-drain capacitance of the FET 32a (in this example both equal to Coff ₁ ) to the capacitance of the RF switch 50 at. However, if the bit b ₀ the FET 32a turns on, becomes a conductive channel through the FET 32a provided, thereby increasing the gate-source and gate-drain capacitance of the FET 32a bypassed what the total capacitance of the RF switch 50 elevated. Likewise, if bit b _n-1 carry the FET 32b turns off, the gate-source capacitance and the gate-drain capacitance (in this example both equal to Coff _n ) to the capacitance of the RF switch 50 at. However, if the bit b _n-1 hits the FET 32b turns on, becomes a conductive channel through the FET 32b provided to bypass these capacities.

Accordingly, bit b ₀ and bit b _{n-1 provide} flexibility for controlling a capacitance of the RF switch 50 in the OFF state and a corresponding resonance frequency. Although shown as two bits, more or fewer bits can be used for the resonance frequency adjustment. Furthermore, the teachings herein can be applied not only to digital multi-bit signals for resonance frequency adjustment, but also to other types of resonance frequency adjustment signals.

an das Gate des FET 31 zu liefern. Außerdem wird der Gatewiderstand 34a verwendet, um das Bit b₀ an das Gate des FET 32a zu liefern, während der Gatewiderstand 34b verwendet wird, um b_n-1 an das Gate des FET 32b zu liefern.In the illustrated embodiment, gate resistors are also included to provide isolation between the RF switch 50 and a control circuit (e.g., the control circuit 101 from 9B) which are used to generate control signals for the RF switch 50 used to boost. As in 4th shown is the gate resistance 33 used to control the signal

to the gate of the FET 31 to deliver. It also becomes the gate resistance 34a used to put the bit b ₀ at the gate of the FET 32a to deliver while the gate resistor 34b used to connect b _n-1 to the gate of the FET 32b to deliver.

When the RF switch is on, the switch's insertion loss is based on the resistance values of the FETs between the first terminal T1 and the second port T2 . In this example, the FET 31 an ON-state resistance value R during the FET 32a an ON-state resistance value R ₁ and the FET 32b has an ON-state resistance value R _n . The number of FETs in series can be based on a variety of factors such as desired power processing capability and / or insertion loss of the RF switch 50 to get voted. The FETs in the second group used for resonant frequency adjustment also help increase power processing capability of the RF switch 50 in the ON state.

The FETs can be implemented in a wide variety of ways, including using metal oxide semiconductor (MOS) transistors such as n-MOS (NMOS) transistors and / or p-MOS (PMOS) transistors. In one example, the MOS transistors are fabricated using a silicon-on-insulator (SOI) process.

zum Ein- oder Ausschalten des HF-Schalters 60 gesteuert. Außerdem sind der FET 32a und der FET 32b Teil einer zweiten Gruppe des Stapels und werden durch das Bit b0 bzw. das Bit b1 gesteuert. 5 Figure 3 is a schematic diagram of an RF switch 60 according to a further embodiment. The RF switch 60 has an inductor 35 parallel to a stack of FETs. The FET 31a , the FET 31b and the FET 31c are part of a first group of the stack and are activated by a control signal

for switching the HF switch on or off 60 controlled. Also, the FET 32a and the FET 32b Part of a second group of the stack and are controlled by bit b0 and bit b1, respectively.

Although the stack of FETs has five transistors in this embodiment, the stack may have more or fewer transistors. For example, the first group and / or the second group can have more or fewer transistors. For example, the number of transistors in the stack can be chosen based on a wide variety of factors such as desired power processing capability, desired ON-state insertion loss, operating frequencies or bands, and / or desired range of resonant frequency tuning.

The first group of FETs is used to turn the RF switch on or off 60 . The second group of FETs also serves to increase the controllability of the resonance frequency of the RF switch 60 provide when the RF switch 60 is turned off.

In the illustrated embodiment, each of the FETs in the stack has a width W and a length L and a corresponding ON-state resistance R. Although an example is shown in which the FETs have approximately the same geometry, the FETs can be implemented with different geometries from one another. In one example, the FETs of the second group have different weights according to any desired weighting scheme. Implementing the FETs of the second group with weighting helps provide a wide tuning range of the resonant frequency.

When FETs in the stack are turned off, the equivalent off capacitance Ceq is approximately Coff / 10, where Coff is the off state gate-source / gate-drain capacitance of each FET. The resonance frequency for this setting corresponds approximately to f ₀ and is associated with b0 = 0 and b1 = 0, in this example. By controlling b0 = 1 and / or b1 = 1, the off-state capacitance can be reduced by the resonance frequency of the RF switch 60 to change.

The equivalent off-capacitance Ceq is controllable when incorporated in a branch of a multi-stage switch (for example a receiving branch of a TR switch) by switching on some or all of the series FETs in the second group (independently of the FETs in the first group), while another branch (for example a transmission branch of the T / R switch) is switched on. This in turn changes the equivalent off capacitance Ceq and leads to a shift in the resonance frequency of the inductance of the inductor 35 and the capacitance of the stack of FETs associated parallel LC resonator.

gesteuerten ersten Gruppe (FET 31a, FET 31b und FET 31c) und einer durch ein Bit b0 bzw. ein Bit b_n-1 gesteuerten zweiten Gruppe (FET 32a und FET 32b). 6th Figure 3 is a schematic diagram of an RF switch 70 according to another embodiment. The RF switch 70 has an inductor 35 parallel to several FETs, with one by a control signal

controlled first group (FET 31a , FET 31b and FET 31c ) and a second group controlled by a bit b0 or a bit b _n-1 (FET 32a and FET 32b ).

Although five FETs are shown, there can be any integer m of FETs in the RF switch 60 be included. In certain embodiments, n FETs are in the second group and mn of the FETs are in the first group, where m is greater than or equal to 2, n is greater than or equal to 1, and m is greater than n.

7A Figure 3 is a schematic diagram of an RF switch 80 according to a further embodiment. The RF switch 80 assigns a first group of FETs to one FET 31a , a FET 31b and a FET 31c on. In addition, the RF switch 80 a second group of FETs with one FET 32a and a FET 32b on. The first group of FETs and the second group of FETs are in series with each other between the first port T1 and the second port T2 . In addition, the inductor lies 35 in parallel with the series combination of FETs.

The FET 32b is sized with a scale factor K relative to the rest of the FETs in the stack.

A first resonance frequency adjustment of the RF switch 80 is in 7A shown in which both the FET 32a as well as the FET 32b both are turned off. In this example, a gate-source capacitance (C _GS ) and a gate-drain capacitance (C _GD ) are the FET 32b each equal to 2C / K, while C _GS and C _{GD of} the other FETs are each equal to 2C. In this example, the equivalent off capacitance Ceq1 for the first resonance frequency adjustment setting corresponds to C / (K + 4).

7B Figure 13 is a schematic diagram of a second resonant frequency shift setting of the RF switch 80 from 7A .

As in 7B shown are the FET 32a and the FET 32b switched on in the second resonance frequency adjustment. The equivalent off capacitance Ceq2 for the second setting corresponds to C / 3.

In one embodiment, the value K is for a dual frequency band response of the RF switch 80 elected. For example, for a frequency f ₁ = 39 GHz (for example a first 5G band) and a frequency f ₂ = 28 GHz (for example a second 5G band) K can be chosen so that equation 1 below is fulfilled: $$\frac{f2}{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="DE102020109391A1\_0006.png,DE102020109391A1\_0007.png"\; state="\{\{state\}\}">f</figure-callout>}1}=\sqrt{\frac{\mathrm{<figure-callout\; id="1"\; label="C.\; e\; q"\; filenames="DE102020109391A1\_0006.png,DE102020109391A1\_0007.png"\; state="\{\{state\}\}">C.</figure-callout>}eq1}{\mathrm{C.}eq2}}=\frac{28GHz}{39GHz}$$

For n = 2 control bits / control FETs and a total of m = 5 FETs, the capacitance ratio to achieve both bands 28 GHz / 39 GHz for 5G for K of about 1.82 is met (corresponding to 0.55 W / L for FET 32B relative to the other FETs).

8th Figure 3 is a schematic diagram of an RF switch 90 according to a further embodiment. The RF switch 90 from 8th is similar to the RF switch 80 from 7A and 7B except that the RF switch 90 corresponds to an example in which the device sizing of the FET 32b is about 0.55 * W / L (corresponding to K = 1.82) and the component rating of the remaining FETs in the stack is about 1.25 * W / L.

To achieve a desired Ron * Coff ratio for a particular application, device sizing can be chosen to resonate at the frequency bands of interest with little to no effect on ON-state operation and / or an increase in path loss .

In the example of 8th the two FETs in the second group of FETs are switched on and off separately with control bits b0 and b1, whereby four resonance frequency adjustment settings are provided. In this example, a setting of b0 = b1 = 0 produces a resonance frequency f0, while a setting of b0 = b1 = 1 produces a resonance frequency of around 0.72 * f0.

9A Figure 3 is a schematic diagram of a T / R switch 100 according to an embodiment. The T / R switch 100 has a receive branch 91 and a send branch 92 on. The receiving branch 91 is connected between a reception connection Rx and an antenna connection, while the transmission branch 92 is connected between a transmission connection Tx and the antenna connection.

gesteuerte erste Gruppe (FET 31a, FET 31b und FET 31c), und eine durch Bit b₀ und Bit b₁ gesteuerte zweite Gruppe von FETs (FET 32a und FET 32b) auf. Außerdem sind Gatewiderstände 33a, 33b und 33c für die FETs 31a, 31b bzw. 31c enthalten, und Gatewiderstände 34a und 34b sind für die FETs 32a bzw. 32b enthalten.The receiving branch 91 has an inductor 35 in parallel with a stack of receive branch FETs. The receive branch FETs have a control signal

controlled first group (FET 31a , FET 31b and FET 31c ), and a second group of FETs controlled by bit b ₀ and bit b ₁ (FET 32a and FET 32b ) on. There are also gate resistors 33a , 33b and 33c for the FETs 31a , 31b or. 31c included, and gate resistors 34a and 34b are for the FETs 32a or. 32b contain.

The broadcast branch 92 has an inductor 45 in parallel with a stack of transmit branch FETs. The transmission branch FETs have a first group controlled by a control signal VC (FET 41 ) and a second second group of FETs controlled by bit a ₀ and bit a ₁ (FET 42a and FET 42b ) on. There is also a gate resistor 43 for the FET 41 included, and gate resistors 44a and 44b are for the FETs 42a or. 42b contain.

The receiving branch 91 and the broadcast branch 92 are controlled in this example by logically inverted control signals. Thus is the receive branch 91 switched off when the send branch 92 is active. There is also the transmission branch 92 switched off when the receive branch 91 is active.

In the embodiment shown, both the receive branch 91 as well as the transmission branch 92 implemented with adjustable resonance frequencies according to the teachings herein. For example, control bits a0 and a1 can be used to switch the reception bands, while control bits b0 and b1 can be used to switch the transmission bands.

Although shown for the case of a transmit / receive switch, the teachings herein apply to any suitable RF switch.

9B Figure 13 is a schematic diagram of one embodiment of a semiconductor die 110 . The semiconductor die 110 points the T / R switch 100 from 9A on. In addition, the semiconductor die 110 furthermore a control circuit connected to a chip interface or a chip bus 101 on. The control circuit 101 generates the control signals for the T / R switch 100 based on data received over the bus.

Although one embodiment of circuitry suitable for controlling an RF switch is shown, the RF switches herein can be controlled in other ways.

The 10A-10D are simulation results for an example implementation of the T / R switch 100 of FIG 9A where the receiving branch 91 and the broadcast branch 92 implemented for 5G dual-band operation at 28 GHz and 39 GHz.

10A Figure 3 is an example of a loss versus frequency graph for the receive branch 91 of the T / R switch 100 of 9A .

10B Figure 3 is an example of a graph of reverse isolation versus frequency for the receive branch 91 of the T / R switch 100 of 9A .

10C Figure 3 is an example of a loss versus frequency graph for the receive branch 91 of the T / R switch 100 of 9A .

10D Figure 3 is an example of a graph of reverse isolation versus frequency for the transmit branch 92 of the T / R switch 100 of 9A .

Although various examples of performance results have been shown, simulation or measurement results may vary based on a wide variety of factors such as simulation models, simulation tools, simulation parameters, measurement conditions, fabrication technology, and / or implementation details. Accordingly, other results are possible.

Applications

Devices using the schemes described above can be implemented in various electronic devices. Examples of electronic devices include, but are not limited to, RF communications systems, consumer electronics products, electronic test equipment, communications infrastructure, etc. For example, one or more RF switches may be included in a wide range of communications systems, including but not limited to radar systems, base stations, mobile devices (e.g., smartphones or handsets ), Phased array antenna systems, laptop computers, tablets, and portable electronics.

The teachings herein apply to RF communication systems that operate over a wide range of frequencies, including not only RF signals between 100 MHz and 7 GHz, but also higher frequencies such as those in the X-band (approximately 7 GHz to 12 GHz) GHz), the K _u band (about 12 GHz to 18 GHz), the K band (about 18 GHz to 27 GHz), the K _a band (about 27 GHz to 40 GHz), the V band (about 40 GHz to 75 GHz) and / or the W band (around 75 GHz to 110 GHz). Accordingly, the teachings herein apply to a wide variety of RF communication systems, including microwave communication systems.

The signals processed by the RF switches herein may be associated with a variety of communication standards including but not limited to GSM (Global System for Mobile Communications), EDGE (Enhanced Data Rates for GSM Evolution), CDMA (Code Division Multiple Access), W- CDMA (Wideband CDMA), 3G, LTE (Long Term Evolution), 4G and / or 5G as well as other proprietary and non-proprietary communication standards.

The above description may refer to elements or features as being "connected" or "coupled" together. As used herein, unless expressly stated otherwise, “connected” means that one element / feature is directly or indirectly connected to another element / feature and is not necessarily mechanically connected. Likewise, unless expressly stated otherwise, “coupled” means that one element / feature is directly or indirectly coupled to another element / feature and not necessarily mechanically. Thus, while the various schemes shown in the figures show example arrangements of elements and components, additional intervening elements, devices, features or components may exist in an actual embodiment (assuming that the functionality of the illustrated circuits is not impaired).

While certain embodiments have been described, these embodiments have been presented as examples only and are not intended to limit the scope of the disclosure. Indeed, the novel apparatus, methods, and systems described herein can be embodied in a variety of other forms; further, various omissions, substitutions, and changes in the form of the methods and systems described herein can be made without departing from the spirit of the disclosure. For example, while the embodiments disclosed herein are presented in a given arrangement, alternative embodiments may perform similar functionality with other components and / or circuit topologies, and some elements may be deleted, moved, added, subdivided, combined, and / or modified. Each of these elements can be implemented in a variety of different ways. Any combination of the elements and acts of the various embodiments described above is conceivable to provide further embodiments. Accordingly, the scope of the present invention is to be defined only by reference to the appended claims. According to one aspect, an RF switch has a stack of two or more field effect transistors (FETs) that are electrically connected between a first connection and a second connection. In addition, the RF switch further includes an inductor connected between the first terminal and the second terminal and in parallel with the stack of FETs. A first part of the FETs is controlled to turn the RF switch on or off. In addition, a second part of the FETs is controlled to tune a resonant frequency of the RF switch when the RF switch is off.

While the claims presented herein are in the form of a single dependency for filing with the USPTO, it should be understood that any claim may depend on any preceding claim of the same type except where it is clearly not technically feasible.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 62/829219 [0001]
• US 16/815694 [0001]

Claims (20)

High frequency (HF) switch with adjustable resonance frequency, the HF switch having: a plurality of ports including a first port and a second port; an inductor electrically connected between the first terminal and the second terminal; and a plurality of field effect transistors (FETs) electrically connected in series between the first terminal and the second terminal and in parallel with the inductor, a first part of the plurality of FETs being controlled by a control signal to make the RF switch in an ON state or to set an OFF state and wherein a second part of the plurality of FETs can be controlled separately from the control signal in order to adjust a resonance frequency of the RF switch in the OFF state. RF switch after Claim 1 wherein at least one FET of the second part is a different size from at least one FET of the first part. RF switch after Claim 1 or 2 wherein the first part comprises at least two FETs. RF switch according to one of the Claims 1 to 3 wherein the second part comprises at least two FETs of different sizes. RF switch according to one of the Claims 1 to 4th , the second part of the FETs being controllable by several digital bits. RF switch after Claim 5 wherein the multiple digital bits are generated based on data received over a bus. RF switch after Claim 5 or 6th , wherein a value of the plurality of digital bits controls an operating frequency band. RF switch according to one of the Claims 5 to 7th , wherein a value of the plurality of digital bits compensates for process variation. RF switch according to one of the Claims 1 to 8th , further comprising a receiving branch and a transmitting branch, the inductor and the plurality of FETs being contained in the receiving branch. RF switch according to one of the Claims 1 to 9 , further comprising a receiving branch and a transmitting branch, the inductor and the plurality of FETs being contained in the transmitting branch. A method for radio frequency (RF) switching, the method comprising: Propagating an RF signal through two or more field effect transistors (FETs) of an RF switch in an ON state of the RF switch; Changing the switch from the ON state to an OFF state using a control signal that controls a first part of the two or more FETs; and Adjusting a resonance frequency of the RF switch in the OFF state using a second part of the two or more FETs, the two or more FETs being arranged in a stack that is in parallel with an inductor of the RF switch. Procedure according to Claim 11 wherein the first part comprises at least two FETs. Procedure according to Claim 11 or 12 wherein the second part comprises at least two FETs. Procedure according to Claim 13 , further comprising controlling the second portion of FETs using multiple digital bits. Procedure according to Claim 14 , further comprising receiving data over a bus and setting a value of the plurality of digital bits based on the data. Procedure according to Claim 14 or 15th , further comprising setting a value of the plurality of digital bits to select an operating frequency band. Method according to one of the Claims 14 to 16 , further comprising setting a value of the plurality of digital bits to compensate for process variation. Front-end system, comprising: an antenna connector; a power amplifier; a low noise amplifier; and a transmit / receive switch having a receive branch which is electrically connected between an input to the low-noise amplifier and the antenna connection, and a transmission branch which is electrically connected between an output of the power amplifier and the antenna connection, the receiving branch having a plurality of field effect transistors (FETs) and arranged in series having an inductor in parallel with the plurality of FETs, wherein a first part of the plurality of FETs is controlled by a control signal to activate or deactivate the receiving branch, and wherein a second part of the plurality of FETs is controllable separately from the control signal to set a resonance frequency of the To adjust the receiving branch if the receiving branch is deactivated. Front-end system Claim 18 , the second part of FETs being controllable by several digital bits. Front-end system Claim 18 or 19th , implemented in a phased array antenna system.

Images