RF switch with bypass topology

Abstract

The present invention relates to a radio frequency switch with a bypass topology. An RF signal switching circuit allows any of N radio frequency (RF) input terminals to be connected to a switch output port in an in-circuit mode or in a bypass mode. Embodiments of the present invention allow a single switch to be in a series input path while still having the ability to isolate the bypass path from the input matching network. In both modes, the circuit exhibits low input insertion loss (and therefore low noise factor) and high bypass mode isolation.

Description

[0001] This application is a divisional application of the Chinese patent application filed on December 13, 2017, with application number 201680034598.3 and invention name “RF switch with bypass topology”. The international filing date of the parent application is July 20, 2016, and the international application number is PCT / US2016 / 043171.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Application No. 14 / 811,159, filed on July 28, 2015, the entire disclosure of which is incorporated herein by reference. Technical Field

[0004] The present invention relates to electronic radio frequency (RF) circuits, and more particularly, to RF signal switching circuits. Background Art

[0005] Radio frequency (RF) signal switches are common circuits used to route RF signals between various parts of an RF system, such as between one or more antennas and one or more transmitter and / or receiver circuits. For example, RF signal switches are used in devices such as one-way and two-way radios including cellular telephones, and global positioning system (GPS) devices.

[0006] It is common to use RF signal switches in noise-sensitive electronic systems such as radio signal receivers. Such receivers often present very weak signals (e.g., transmitted radio waves captured by an antenna), and therefore, a low noise amplifier (LNA) is often used to amplify such signals. A matching network is also often provided at the input of the LNA to maximize the power transfer to the LNA.

[0007] The noise figure (NF) of a low noise amplifier (LNA) is very sensitive to the presented impedance and the insertion loss (IL) in front of the input of the LNA. For example, in a typical cellular radio LNA configuration, a set of bandpass filters in series with an RF switch are present at the input of the LNA and are used to select a specific frequency band to be presented to the radio transceiver. In order to reduce the NF, an RF signal switch with low insertion loss (IL) is required. However, in some operating modes, the LNA must be bypassable, and in this mode, the LNA should be isolated from the bypass signal path.

[0008] For example, Figure 1 is a schematic diagram of a prior art RF signal switch 100, wherein N RF input terminals RF1-RF NOne of the RF input terminals RF1-RF N The matching network and LNA block 102 are typically external to the RF signal switch 100 and may be connected to a corresponding antenna, as indicated by the dashed lines.

[0009] In the example shown, in the "in-circuit" mode, the input terminal RF1 can be switched by closing the corresponding series switch S1, opening the corresponding shunt switch Sh1, opening the bypass switch, closing the output connector switch S C And disconnect the output connector shunt switch Sh C and connected to the matching network and LNA block 102. In this mode, for each of the other RF input terminals RF2-RF N , the corresponding series switch S2-S N Disconnect, and the corresponding shunt switch S2-S N Closed. Any other RF input terminal RF2-RF N The in-circuit connections to the matching network and LNA block 102 may be made in a similar manner.

[0010] In bypass mode, the input terminal RF1 can be switched off by closing the corresponding series switch S1, opening the corresponding shunt switch Sh1, closing the bypass switch, and opening the output connector switch S C and close the output connector shunt switch Sh C In this mode, for each of the other RF input terminals RF2-RF N , the corresponding series switch S2-S N Disconnect, and the corresponding shunt switch S2-S N Closed. Any other RF input terminal RF2-RF N can be connected in a similar manner to bypass the matching network and LNA block 102.

[0011] Figure 1 The problem with the circuit configuration shown in FIG. 1 is that the matching network at the input of the LNA is not isolated from the bypass path 104 when the LNA is not activated. The matching network can adversely affect the output impedance of the RF signal switch 100 and cause a degradation in the IL of the bypass path 104, the severity of which depends on the design and component values ​​of the LNA input matching network. This degradation in the bypass path IL causes module designers to struggle to find a balance between having a good LNA input match and maintaining a low bypass path IL.

[0012] If it is desired to isolate the bypass path from the LNA input matching network, standard practice is to attach another series / shunt switch pair before the matching network. Figure 2yes Figure 1 Schematic diagram of a prior art RF signal switch, wherein an isolation series / shunt switch pair S is connected before the matching network and LNA block 102 I / Sh I 106. In bypass mode, the series isolation switch S I Open and isolate the shunt switch Sh I is closed, thereby coupling the matching network input to the circuit ground and completely isolating the matching network from the bypass path 104. Conversely, in the in-circuit mode, the isolation series switch S I Close and isolate the shunt switch Sh I disconnect.

[0013] However, with Figure 1 Compared to the configuration shown in Figure 2 A disadvantage of the circuit configuration shown in FIG. 1 is that the additional series switch S I The input IL to the LNA is increased, and hence the system NF. This is because the switches shown are not perfect conductors when closed, but present a certain amount of impedance.

[0014] Therefore, there is a need for an RF signal switching circuit that exhibits both low input IL (and therefore low NF) and high isolation. The present invention addresses this need. Summary of the invention

[0015] The present invention includes an embodiment of an RF signal switching circuit that allows N RF input terminals RF1-RF N Any of the switches is connected to the switch output port in either in-circuit mode or in bypass mode. Embodiments of the present invention allow a single switch to be in the series input path while still having the ability to isolate the bypass path from the input matching network. In both modes, the circuit exhibits low input IL (and therefore low NF) and high bypass mode isolation simultaneously.

[0016] In one embodiment, the in-circuit path of the RF signal switch circuit is coupled to the input of an isolation and / or insertion loss sensitive target circuit (e.g., an LNA or digital step attenuator) that may include an optional matching network. The target circuit and the optional matching network are typically disconnected relative to the RF signal switch circuit, but the entire circuit can be manufactured as a hybrid structure or a monolithic structure. In some embodiments, the matching network can be integrated with the target circuit.

[0017] In one embodiment, the RF input terminals RF1-RF N Each of the three corresponding switches is directly connected to the path of the connector switch IC_S x , shunt switch Sh x and bypass switch BP_Sx (where "x" represents the corresponding RF input terminal identifier, from 1 to N, and where N can be 1). N In each, all paths within the connector switch IC_S x and isolation shunt switch Sh I In an alternative embodiment, the RF input terminals RF1-RF N Each of the ICs may have one or more sets of in-path connector switches IC_S x and a corresponding isolating shunt switch Sh connected to a path in the parallel circuit I For example, such a configuration would allow multiple antennas to be selectively coupled to multiple target circuits without increasing the number of series switches to any one target circuit.

[0018] The output of the target circuit is connected to the switch return path, which can be connected to the output connector in series with the switch S C Selectively connect to the switch output of the RF signal switch circuit, or can be connected to the output connector shunt switch Sh C Connect to circuit ground.

[0019] In operation, application to the RF input terminals RF1-RF N The RF signal of either can be connected to the target circuit (and then to the switch output) through a single switch, or a bypass path applied to the switch output with complete isolation of any matching network coupled to the switch circuit.

[0020] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a prior art RF signal switch, wherein N RF input terminals RF1-RF N One of the two may be connected to the switch output through a matching network and an LNA block or through a bypass path.

[0022] Figure 2 yes Figure 1 Schematic diagram of a prior art RF signal switch, in which an isolation series / shunt switch pair S is connected before the matching network and LNA block I / Sh I .

[0023] Figure 3is a schematic diagram of an embodiment of an RF signal switching circuit according to the present invention.

[0024] Figure 4A yes Figure 3 Schematic diagram of an embodiment configured in in-circuit mode is shown in FIG.

[0025] Figure 4B yes Figure 3 Schematic diagram of an embodiment configured in bypass mode is shown in FIG.

[0026] Figure 5 is used for Figure 3 The bypass switches BP_S1 to BP_S shown in N Schematic diagram of each of the high isolation "T" type series / shunt / series bypass switch replacement circuits.

[0027] Fig. 6A It is for those from Figure 1 , Figure 2 and Figure 3 A graph comparing the insertion loss of the series input path to the LNA versus frequency for each of the three simulated circuit topologies.

[0028] Figure 6B It is for those from Figure 1 , Figure 2 and Figure 3 A graph comparing the insertion loss of the bypass path versus frequency for each of the three simulated circuit topologies.

[0029] Like reference numbers and designations throughout the various drawings refer to like elements. DETAILED DESCRIPTION

[0030] Figure 3 3 is a schematic diagram of an embodiment of an RF signal switching circuit 300 according to the present invention. The RF signal switching circuit 300 allows N RF input terminals RF1-RF N Any of the switches is connected to the switch output port in either in-circuit mode or in bypass mode. Embodiments of the present invention allow a single switch to be in the series input path while still having the ability to isolate the bypass path from the input matching network. In both modes, the circuit exhibits low input IL (and therefore low NF) and high bypass mode isolation simultaneously.

[0031] In the illustrated embodiment, the in-circuit path 302 of the RF signal switch circuit 300 is configured to couple to the input of an isolation and / or insertion loss sensitive target circuit 304 (e.g., an LNA or digital step attenuator) either directly or through an optional matching network 306 (shown in dashed outline). The target circuit 304 and the matching network 306 are typically open circuits relative to the RF signal switch circuit 300, but Figure 3 The entire circuit shown in FIG. 3 can be manufactured as a hybrid structure or a monolithic structure. In some embodiments, the matching network 306 can be integrated with the target circuit 304. However, for convenience, the following description will treat the target circuit 304 and the matching network 306 as discrete components.

[0032] In the illustrated embodiment, the RF input terminals RF1-RF N Each of them is directly connected to three corresponding switches: In-path connector switch IC_S x , shunt switch Sh x and bypass switch BP_S x (where "x" represents the corresponding RF input terminal identifier, from 1 to N, and where N can be 1). N In each, all paths within the connector switch IC_S x and isolation shunt switch Sh I Both are connected to the in-circuit path 302 .

[0033] The RF signal switch includes a switch return path 308 configured to be coupled to the output terminal of the target circuit 304. The switch return path 308 can be connected to the output connector in series with the switch S C The RF signal switching circuit 300 may be selectively connected to the switch output terminal, or the output connector may be used to shunt the switch Sh. C Connect to circuit ground.

[0034] In an alternative embodiment, the RF input terminals RF1-RF N There may be one or more sets of in-path connector switches IC_S x and a corresponding isolating shunt switch Sh connected to the parallel circuit path 302 I For example, this configuration would allow multiple antennas to be selectively coupled to multiple target circuits 304 without increasing the number of series switches to any one target circuit 304. In this configuration, the RF signal switch 300 would have parallel switch return paths 308, each switch return path 308 being configured to be connected in series with a corresponding target circuit 304, a corresponding output connector, and a switch S. C and the corresponding output connector shunt switch Sh C Coupling.

[0035] The above targets Figure 3 All of the switches described may be controlled by external switching circuitry (not shown) of conventional design to set the open or closed state of the switches.

[0036] Figure 4A yes Figure 3Schematic diagram of an embodiment configured in in-circuit mode shown in FIG. In this example, a signal applied to RF input terminal RF1 is coupled to in-circuit path 302 through closed in-path connector switch IC_S1, coupled to target circuit 304 through matching network 306, returned to switch return path 308, and connected to output series switch S through closed output connector series switch S C , and then to the switch output. The shunt switch Sh1 and bypass switch BP_S1 for the RF input terminal RF1 and the isolation shunt switch Sh I and output connector shunt switch Sh C It's also disconnected.

[0037] Other RF input terminals RF2-RF N Each of the two switches Sh2-Sh N shunt to the circuit ground, and its corresponding path within the connector switch IC_S2 to IC_S N and bypass switches BP_S2 to BP_S N disconnected, so the RF input terminal RF1 is connected to the RF input terminal RF2-RF N Isolated from the activated signal path.

[0038] exist Figure 4A In the configuration shown in , the input signal at the RF input terminal RF1 is transmitted through only one switch ( IC_S1 ) before being coupled to the matching network 306 , thus minimizing the insertion loss of the matching network 306 and the target circuit 304 .

[0039] Figure 4B yes Figure 3 Schematic diagram of an embodiment configured in bypass mode is shown in FIG. In this example, a signal applied to RF input terminal RF1 is coupled to the switch output through a closed bypass switch BP_S1. The shunt switch Sh1 and the in-path connector switch IC_S1 for RF input terminal RF1 are open. The isolation shunt switch Sh I and output connector shunt switch Sh C Both are closed, coupling the input to the matching network 306 and coupling the output of the target circuit 304 to circuit ground.

[0040] Other RF input terminals RF2-RF N Each of the two switches Sh2-Sh N is shunted again to the circuit ground, and its corresponding path is connected to the connector switch IC_S2 to IC_S N and bypass switches BP_S2 to BP_S Nis disconnected, so the RF input terminal RF2-RF N Isolated from the activated signal path.

[0041] exist Figure 4B In the configuration shown in , the input signal at the RF input terminal RF1 is transmitted through only one switch ( BP_S1 ) before being coupled to the switch output and is completely isolated from the matching network 306 and the target circuit 304 .

[0042] It should be clear that any other RF input terminals RF2-RF N In a similar manner, the target circuits 304 may be connected in the in-circuit mode or in the bypass mode. In the case of multiple target circuits 304, each inactive target circuit 304 may be isolated by appropriate setting of the shunt and series switches of the corresponding in-circuit path 302 and the switch return path 308 (e.g., by disconnecting the corresponding in-path connector switch IC_S x , close the corresponding isolating shunt switch Sh I , disconnect the corresponding output connector series switch S C , and close the corresponding output connector shunt switch Sh C ).

[0043] Alternative bypass switch circuit

[0044] for Figure 3 In the example shown in FIG. 1 , if a higher isolation between the switch output and the input of the target circuit 304 is desired, the corresponding bypass switches BP_S1 to BP_S N A "T" type series / shunt / series circuit bypass switch configuration may be used instead. This is useful for better isolating the switch output from the input of the target circuit 304, because a single bypass switch BP_S1 (particularly one implemented as a field effect transistor) can behave as a capacitor capable of transferring some of the amplified signal frequencies present on the switch output to the input of the target circuit 304. Better isolation will prevent feedback and increase the stability of the target circuit 304. However, if the target circuit 304 does not provide amplification (such as in the case where the target circuit is a digital step attenuator), then Figure 3 The simpler single-switch bypass switches BP_S1 to BP_S are shown in FIG. N May be preferred.

[0045] Figure 5 is used for Figure 3 The bypass switches BP_S1 to BP_S shown in NSchematic diagram of a high isolation "T" type series / shunt / series bypass switch replacement circuit 500 for each of the RF input terminals. For an activated signal path in bypass mode (e.g., for a signal applied to RF input terminal RF1), series switch SwA is closed, series switch SwB is closed, and shunt switch Sh is open, thereby allowing signal transmission from RF input terminal RF1 to the switch output (but with Figure 3 The single switch bypass switches BP_S1 to BP_S shown in N In comparison, it has a slightly worse bypass path IL due to the addition of a second series switch.

[0046] For the activated signal path in the in-circuit mode and for the inactivated signal path in either mode, the series switch SwA is opened, the series switch SwB is opened, and the shunt switch Sh is closed, thereby grounding the connection point between the two series switches SwA and SwB and thereby significantly increasing the isolation between the input of the target circuit 304 and the switch output.

[0047] Simulation Results

[0048] The selected resistors, capacitors, inductors and the scattering parameters (S parameters) of the selected LNA are used to Figure 1 and Figure 2 The two circuit topologies shown in Figure 3 The novel circuit topology shown in was simulated for comparison. Since it is known that a FET switch behaves as a capacitor when open (non-conducting) and as a resistor when closed (conducting), in the simulation, a capacitor was used to represent the open switch and a resistor was used to represent the closed switch. The capacitor and resistor values ​​were selected based on current RF switch IC technology. Inductors were used in the port locations to simulate the expected external matching network. The S-parameters were measured on a typical LNA (off) using an adjacent matching network that could be used with such a switch. This was done to introduce the effect that a closed LNA with an input matching network would have if its input was not properly isolated from the bypass path. Using Figure 5 The high isolation series / shunt / series configuration shown in Figure 1 is used to simulate a bypass switch.

[0049] Fig. 6A It is for those from Figure 1 (curve 602), Figure 2 (curve 604) and Figure 3 Graph 600 comparing frequency to insertion loss of the series input path to the LNA for each of the three simulated circuit topologies (curve 606). Point m2 represents a frequency of approximately 1.5 GHz, and point m3 represents a frequency of approximately 2.69 GHz. Figure 1 (curve 602) circuit topology and Figure 3 (Curve 606) The circuit topology has similar IL performance, but Figure 2 (curve 604) circuit topology (with a ratio Figure 1 The circuit topology with better isolation) has degraded IL due to the addition of a second switch in the series input path.

[0050] Figure 6B It is for those from Figure 1 (curve 612), Figure 2 (curve 614) and Figure 3 A graph 610 comparing frequency to the insertion loss of the bypass path for each of the three simulated circuit topologies (curve 616). Point m4 represents a frequency of approximately 1.5 GHz, and point m5 represents a frequency of approximately 2.69 GHz. Fig. 6A As a result, Figure 2 (curve 614) circuit topology and Figure 3 (curve 616) The circuit topology has similar IL performance, where Figure 3 (curve 616) The circuit topology is slightly better at all frequencies and significantly better at higher frequencies. The adverse effects of a non-isolated LNA (off) can be seen in Figure 1 (curve 612) This adverse effect deteriorates rapidly with increasing frequency as can be seen in the bypass IL in the circuit topology. In all simulations, the input series IL was optimized by using only an inductor for the input matching network; the severity of the degraded IL in the bypass path is very dependent on the type of input matching network used. Figure 1 (Curve 612) Circuit topology, different matching network circuits may result in a larger amount of IL degradation.

[0051] Compare Fig. 6A and Figure 6B , it is very obvious that Figure 3 The novel circuit topology shown in (curve 606, curve 616) is Figure 1 (curve 602, curve 612) and Figure 2 The circuit topology in (curve 604, curve 614) (which compromises between bypass IL and input series IL) has better overall IL performance.

[0052] It should be apparent to those skilled in the art that various embodiments of the present invention can be implemented to meet a wide variety of specifications. Therefore, selecting appropriate component values ​​is a key design choice. Specifically, Figures 3 to 5The switches shown can be of any type, but are advantageously manufactured as field effect transistors (FETs) on integrated circuits (ICs). Embodiments of the present invention can be implemented in any suitable IC technology (including but not limited to MOSFET and IFGET structures) or in hybrid or discrete circuit form. Integrated circuit implementations can be manufactured using any suitable substrate and process, including but not limited to standard bulk silicon, silicon on insulator (SOI), silicon on sapphire (SOS), GaAs pHEMT and MESFET processes. Voltage levels or reverse voltage polarity can be adjusted depending on specific specifications and / or implementation technology (e.g., NMOS, PMOS or CMOS). Component voltage, current and power handling capabilities can be changed as needed, for example by adjusting device size, "stacking" components to handle larger voltages, and / or using multiple parallel components to handle larger currents.

[0053] method

[0054] Another aspect of the invention includes a method for switching an RF signal, comprising:

[0055] a. Providing at least one RF input port having a shunt switch, a bypass switch and an intra-path connector switch;

[0056] b. coupling each intra-path connector switch to an intra-circuit path, the intra-circuit path being configured to be coupled to an input terminal of a target circuit;

[0057] c. coupling each bypass switch to a switch output port;

[0058] d. coupling each shunt switch to the circuit ground;

[0059] e. coupling the isolation shunt switch to a path within the circuit;

[0060] f. providing a switch return path, the switch return path being configured to be coupled to the output terminal of the target circuit;

[0061] g. coupling the output connector shunt switch to the switch return path; and

[0062] h. Couple the output connector switch to the switch return path and to the switch output port.

[0063] Yet another aspect of the present invention includes the first method set forth above, further comprising configuring an in-circuit mode for a selected RF input port by:

[0064] a. setting the shunt switch and bypass switch for the selected RF input port to an open state, setting the in-path connector switch for the selected RF input port to a closed state, setting the isolation shunt switch to an open state, setting the output connector shunt switch to an open state, and setting the output connector switch to a closed state; and

[0065] b. For each other RF input port, set the corresponding in-path connector switch and bypass switch to the open state, and set the corresponding shunt switch to the closed state.

[0066] Yet another aspect of the present invention includes the first method set forth above, further comprising configuring a bypass mode for a selected RF input port by:

[0067] a. setting the shunt switch and in-path connector switch for the selected RF input port to an open state, setting the bypass switch for the selected RF input port to a closed state, setting the isolation shunt switch to a closed state, setting the output connector shunt switch to a closed state, and setting the output connector switch to an open state; and

[0068] b. For each other RF input port, set the corresponding in-path connector switch and bypass switch to the open state, and set the corresponding shunt switch to the closed state.

[0069] Another aspect of the above method is to configure each bypass switch into a "T" type series / shunt / series circuit, and (a) for the activated signal path in the bypass mode, the first series switch and the second series switch are set to a closed state, and the shunt switch is set to an open state; and (b) for the activated signal path in the in-circuit mode and for the inactivated signal path in either mode, the first series switch and the second series switch are set to an open state, and the shunt switch is set to a closed state.

[0070] A number of embodiments of the present invention have been described. It should be understood that various modifications may be made without departing from the spirit and scope of the present invention. For example, some of the steps described above may be order-independent and may therefore be performed in an order different from the described order. In addition, some of the steps described above may be optional. The various actions described with respect to the above method may be performed in a repeated, continuous or parallel manner. It should be understood that the foregoing description is intended to illustrate rather than limit the scope of the present invention, which is limited by the scope of the appended claims, and other embodiments are within the scope of the claims.

Claims

1. A radio frequency signal switch, comprising: (a) at least one RF input port, each RF input port having a shunt switch coupled between the RF input port and a circuit ground and configured to selectively shunt the RF input port to ground, a bypass switch coupled between the RF input port and a switch output port, and at least one set of connector switches coupled to the RF input port and the shunt switch; (b) at least one conductive path, each conductive path being coupled to a corresponding isolation shunt switch and to a corresponding set of connector switches, each conductive path being configured to be coupled to an input terminal of a corresponding target circuit; (c) at least one switch return path configured to couple to an output of a corresponding target circuit and to couple to a corresponding output connector shunt switch; as well as (d) at least one output connector switch coupled to a corresponding one of the switch return paths and to the switch output port; Wherein, at least one corresponding target circuit includes an isolation and / or insertion loss sensitive circuit.

2. The RF signal switch according to claim 1, wherein: The RF signal switch is configured in an in-circuit mode for a selected RF input port and a selected target circuit, such that a signal applied to the selected RF input port is transmitted only through one of the corresponding connector switches for the selected RF input port and not through other switches between the RF input port and the selected target circuit.

3. The RF signal switch according to claim 1, wherein: The RF signal switch is configured in a bypass mode for the selected RF input port, so that the signal applied to the selected RF input port is transmitted to the switch output port through the corresponding bypass switch for the selected RF input port, and the input end of each target circuit is isolated from the switch output port.

4. The RF signal switch according to claim 1, wherein: The RF signal switch is configured to an in-circuit mode for a selected RF input port and a selected target circuit, wherein: (a) the shunt switch and the bypass switch for the selected RF input port are opened, at least one set of connector switches corresponding to a conductive path for the selected RF input port is closed, the isolation shunt switch corresponding to such a conductive path is opened, the output connector shunt switch corresponding to the switch return path for the selected target circuit is opened, and the output connector switch corresponding to the switch return path for the selected target circuit is closed; and (b) For each other RF input port, the corresponding connector switch and bypass switch are open, and the corresponding shunt switch is closed.

5. The radio frequency signal switch according to claim 4, further comprising: Each unselected target circuit is isolated from each of at least one RF input port and from the switch output port.

6. The radio frequency signal switch according to claim 1, wherein: The RF signal switch is configured to be in bypass mode for the selected RF input port, wherein: (a) the shunt switch and each set of connector switches for the selected RF input port are open, the bypass switch for the selected RF input port is closed, each isolation shunt switch and each output connector shunt switch is closed, and each output connector switch is open; and (b) For each other RF input port, the corresponding connector switch and bypass switch are open, and the corresponding shunt switch is closed.

7. The RF signal switch according to claim 1, wherein: Each bypass switch includes a "T" type series / shunt / series bypass switch circuit.

8. The radio frequency signal switch according to claim 7, wherein: The "T" type series / shunt / series circuit includes a first series switch coupled to a second series switch at a connection point and a shunt switch coupled to the connection point and to the circuit ground, wherein, for an activated RF input port in bypass mode, the first series switch and the second series switch are closed and the shunt switch is open; and wherein, for an activated RF input port in in-circuit mode and for an inactivated RF input port in the in-circuit mode or the bypass mode, the first series switch and the second series switch are open and the shunt switch is closed.

9. A radio frequency signal switch, comprising: (a) at least one RF input port, each RF input port having a shunt switch coupled between the RF input port and a circuit ground and configured to selectively shunt the associated RF input port to ground, a bypass switch coupled between the RF input port and a switch output port, and a connector switch coupled to the RF input port and the shunt switch; (b) a conductive path coupled to a corresponding isolation shunt switch and to the connector switch, the conductive path being configured to couple to an input terminal of a target circuit; (c) a switch return path configured to be coupled to an output terminal of the target circuit and to an output connector shunt switch; as well as (d) an output connector switch coupled to the switch return path and to the switch output port; Wherein, the target circuit includes an isolation and / or insertion loss sensitive circuit.

10. The radio frequency signal switch according to claim 9, wherein: The RF signal switch may be configured to: (1) in an in-circuit mode for a selected RF input port and a selected target circuit, such that a signal applied to the selected RF input port is transmitted only through one of the corresponding connector switches for the selected RF input port and not through other switches between the RF input port and the selected target circuit, or (2) in a bypass mode for a selected RF input port, such that a signal applied to the selected RF input port is transmitted to the switch output port through the corresponding bypass switch for the selected RF input port and the input end of each target circuit is isolated from the switch output port.

11. The radio frequency signal switch according to claim 9, wherein: The RF signal switch is configured in an in-circuit mode for the selected RF input port, wherein: (a) the shunt switch and the bypass switch for the selected RF input port are open, the connector switch for the selected RF input port is closed, the isolation shunt switch and the output connector shunt switch are open, and the output connector switch is closed; and (b) For each other RF input port, the corresponding connector switch and bypass switch are open, and the corresponding shunt switch is closed.

12. The radio frequency signal switch according to claim 9, wherein: The RF signal switch is configured to be in bypass mode for the selected RF input port, wherein: (a) the shunt switch and the connector switch for the selected RF input port are open, the bypass switch for the selected RF input port is closed, the isolation shunt switch and the output connector shunt switch are closed, and the output connector switch is open; and (b) For each other RF input port, the corresponding connector switch and bypass switch are open, and the corresponding shunt switch is closed.

13. The radio frequency signal switch according to claim 9, wherein: Each bypass switch includes a "T" type series / shunt / series bypass switch circuit.

14. A radio frequency signal switch, comprising: (a) at least one RF input port, each RF input port having a shunt switch coupled between the RF input port and a circuit ground and configured to selectively shunt the RF input port to ground, a bypass switch coupled between the RF input port and at least one corresponding switch output port, and at least one set of in-path connector switches coupled to the RF input port and the shunt switch; (b) at least one intra-circuit path, each of the at least one intra-circuit paths being coupled to a corresponding isolation shunt switch and to a corresponding set of intra-path connector switches, each intra-circuit path being configured to couple to at least one corresponding isolation and / or insertion loss sensitive circuit; (c) at least one switch path configured to couple to the at least one corresponding isolation and / or insertion loss sensitive circuit and to a corresponding port connector shunt switch; as well as (d) at least one port connector switch coupled to a corresponding one of the switch paths and to at least one corresponding switch output port; Each switch is a field effect transistor.

15. The radio frequency signal switch according to claim 14, wherein: The RF signal switch is configured in an in-circuit mode for a selected RF input port so that an applied RF signal transmitted through the selected RF input port is transmitted only through one of the corresponding in-path connector switches for the selected RF input port and not through other switches between the RF input port and the selected target circuit.

16. The radio frequency signal switch according to claim 14, wherein: The RF signal switch is configured in a bypass mode for the selected RF input port, so that the applied RF signal is transmitted between the selected RF input port and at least one corresponding switch output port through the corresponding bypass switch for the selected RF input port, and each of the at least one corresponding isolation and / or insertion loss sensitive circuits is isolated from the selected RF input port and the at least one corresponding switch output port.

17. The radio frequency signal switch according to claim 14, wherein: The RF signal switch is configured in an in-circuit mode for the selected RF input port and the at least one corresponding isolation and / or insertion loss sensitive circuit, wherein: (a) the shunt switch and the bypass switch for the selected RF input port are opened, at least one set of in-path connector switches corresponding to an in-circuit path for the selected RF input port are closed, the isolation shunt switch corresponding to such an in-circuit path is opened, the port connector shunt switch corresponding to the switch path for the at least one corresponding isolation and / or insertion loss sensitive circuit is opened, and the port connector switch corresponding to the switch path for the at least one corresponding isolation and / or insertion loss sensitive circuit is closed; and (b) For each other RF input port, the corresponding in-path connector switch and bypass switch are open, and the corresponding shunt switch is closed.

18. The radio frequency signal switch according to claim 17, further comprising: Each isolation and / or insertion loss sensitive circuit corresponding to an unselected RF input port is isolated from each of the at least one RF input port and each of the at least one switch output port.

19. The radio frequency signal switch according to claim 14, wherein: The RF signal switch is configured to be in bypass mode for the selected RF input port, wherein: (a) the shunt switch and each set of in-path connector switches for the selected RF input port are open, the bypass switch for the selected RF input port is closed, each isolation shunt switch and each port connector shunt switch is closed, and each port connector switch is open; and (b) For each other RF input port, the corresponding in-path connector switch and bypass switch are open, and the corresponding isolation shunt switch is closed.

20. The radio frequency signal switch according to claim 14, wherein: Each bypass switch includes a "T" type series / shunt / series bypass switch circuit.

21. The radio frequency signal switch according to claim 20, wherein: The "T" type series / shunt / series circuit includes a first series switch coupled to a second series switch at a connection point and a shunt switch coupled to the connection point and to the circuit ground, wherein (a) for an activated RF input port in bypass mode, the first series switch and the second series switch are closed and the shunt switch is open; and (b) for an activated RF input port in in-circuit mode and for an inactivated RF input port in the in-circuit mode or the bypass mode, the first series switch and the second series switch are open and the shunt switch is closed.

22. The radio frequency signal switch according to claim 14, wherein: The at least one corresponding isolation and / or insertion loss sensitive circuit includes at least one of a low noise amplifier and a digital step attenuator.

23. The radio frequency signal switch according to claim 14, wherein: The radio frequency signal switch and the at least one corresponding isolation and / or insertion loss sensitive circuit are manufactured as a hybrid structure or a monolithic structure.

24. The radio frequency signal switch according to claim 23, wherein: The at least one corresponding isolation and / or insertion loss sensitive circuit includes at least one of a low noise amplifier and a digital step attenuator.

25. The radio frequency signal switch according to claim 14, wherein: There are at least two corresponding switch output ports.

26. A radio frequency signal switch, comprising: (a) at least one RF input port, each RF input port having: (1) a first shunt switch coupled to the RF input port and configured to selectively couple the RF input port to a circuit ground, (2) a first series switch coupled between the RF input port and at least one corresponding switch output port, and (3) at least one set of second series switches coupled to the RF input port; (b) at least one first circuit path, each of the at least one first circuit path being coupled to a corresponding second shunt switch and to a corresponding set of second series switches, each first circuit path being configured to be coupled to at least one target circuit; (c) at least one second circuit path configured to be coupled to at least one target circuit and to a corresponding third shunt switch; as well as (d) at least one third series switch coupled to a corresponding one of the second circuit paths and to at least one corresponding switch output port; Wherein, at least one target circuit includes isolation and / or insertion loss sensitive circuits.

27. A method for switching a radio frequency signal, comprising: (a) providing at least one RF input port, each RF input port having an associated shunt switch, an associated bypass switch and an associated connector switch; (b) for at least one RF input port, coupling the associated connector switch to a corresponding conductive path, the corresponding conductive path being configured to couple to an input terminal of a corresponding target circuit; (c) for the at least one RF input port, coupling the associated bypass switch between such RF input port and a switch output port; (d) for the at least one RF input port, coupling the associated shunt switch to circuit ground and configuring the associated shunt switch to selectively shunt such RF input port to ground; (e) for each conduction path, coupling an associated isolation shunt switch to the corresponding conduction path; (f) providing a switch return path, the switch return path being configured to be coupled to an output terminal of the target circuit; (g) coupling an output connector shunt switch to the switch return path; and (h) coupling an output connector switch to the switch return path and to the switch output port; Wherein, the target circuit includes an isolation and / or insertion loss sensitive circuit.

28. The method of claim 27, further comprising configuring an in-circuit mode for the selected RF input port by: (a) opening the associated shunt switch and the associated bypass switch for the selected RF input port, closing the associated connector switch for the selected RF input port, opening the associated isolation shunt switch for the corresponding conductive path, opening the output connector shunt switch, and closing the output connector switch; and (b) For each other RF input port, the associated connector switch and the associated bypass switch are opened, and the associated shunt switch is closed.

29. The method of claim 27, further comprising configuring a bypass mode for the selected RF input port by: (a) opening the associated shunt switch and the associated connector switch for the selected RF input port, closing the associated bypass switch for the selected RF input port, closing the associated isolation shunt switch for the corresponding conductive path, closing the output connector shunt switch, and opening the output connector switch; and (b) For each other RF input port, the associated connector switch and the associated bypass switch are opened, and the associated shunt switch is closed.

30. The method of claim 27, wherein: Each associated bypass switch includes a "T" type series / shunt / series circuit.

31. A method for switching a radio frequency signal, comprising: (a) providing at least one RF input port, each RF input port having a corresponding shunt switch, a corresponding bypass switch and a corresponding in-path connector switch; (b) For at least one RF input port: (1) coupling the corresponding in-path connector switch to a corresponding in-circuit path, the corresponding in-circuit path being coupled to a corresponding isolation shunt switch and being configured to couple to at least one corresponding isolation and / or insertion loss sensitive circuit; (2) coupling the corresponding bypass switch between such RF input port and at least one corresponding switch output port; as well as (3) coupling the corresponding shunt switch to a circuit ground, and configuring the corresponding shunt switch to selectively shunt such a radio frequency input port to the ground; (c) for each intra-circuit path, providing a corresponding switch path coupled to a corresponding port connector shunt switch and configured to couple to the at least one corresponding isolation and / or insertion loss sensitive circuit; (d) for each switch path, coupling a corresponding port connector switch to the switch path and to at least one corresponding switch output port; Each switch is a field effect transistor.

32. The method of claim 31 , further comprising configuring an in-circuit mode for the selected RF input port by: (a) opening the corresponding shunt switch and the corresponding bypass switch for the selected RF input port, closing the corresponding in-path connector switch for the selected RF input port, opening the corresponding isolation shunt switch for the corresponding in-circuit path, opening the corresponding port connector shunt switch, and closing the corresponding port connector switch; and (b) For each other RF input port, the corresponding in-path connector switch and the corresponding bypass switch are opened, and the corresponding branch switch is closed.

33. The method of claim 31 , further comprising configuring a bypass mode for the selected RF input port by: (a) opening the corresponding shunt switch and the corresponding in-path connector switch for the selected RF input port, closing the corresponding bypass switch for the selected RF input port, closing the corresponding isolation shunt switch for the corresponding in-circuit path, closing the corresponding port connector shunt switch, and opening the corresponding port connector switch; and (b) For each other port, the corresponding in-path connector switch and the corresponding bypass switch are opened, and the corresponding shunt switch is closed.

34. The method of claim 31, wherein: Each corresponding bypass switch includes a "T" type series / shunt / series circuit.

35. The method of claim 31, wherein: The isolation and / or insertion loss sensitive circuit includes at least one of a low noise amplifier and a digital step attenuator.

36. The method of claim 31, further comprising manufacturing the RF signal switch and the isolation and / or insertion loss sensitive circuit as a hybrid structure or a monolithic structure.

37. The method of claim 36, wherein: The isolation and / or insertion loss sensitive circuit includes at least one of a low noise amplifier and a digital step attenuator.

38. The method of claim 31, wherein: There are at least two corresponding switch output ports.

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