JP4587963B2 - High power switch - Google Patents

Description

  The present invention relates to a high power resistant switch that operates in a high frequency band of several tens of MHz or more.

  A high power-resistant switch using a transistor is widely used in a phase array antenna and various transmission circuits in a microwave band and a millimeter wave band (see, for example, Patent Document 1).

  FIG. 9 is a diagram showing a transceiver using a high power-resistant switch. First, when transmitting a signal, the RF signal input from the transmission terminal 1 is amplified by the high-power amplifier 2 and transmitted from the antenna 4 through the circulator 3. At this time, a part of the transmission power enters the reception path. Therefore, a high power resistant switch 5 is inserted between the low noise amplifier 6 and the circulator 3. Then, the circulator 3 and the dummy resistor 7 are connected by the high power resistant switch 5 to suppress the input of power from the circulator 3 to the low noise amplifier 6. At this time, high power may be input to the high power durability switch 5.

  On the other hand, when receiving a signal, the circulator 3 and the low noise amplifier 6 are connected by the high power resistance switch 5, and the signal from the antenna 4 is output to the reception terminal 8 through the high power resistance switch 5 and the low noise amplifier 6. The Since the power handled at this time is very small, it is necessary to reduce the loss of the high power-resistant switch 5 as much as possible.

  FIG. 10 is a diagram showing a conventional high power durability switch. As shown in the figure, a capacitor 13, a transmission line 14 whose line length is ¼ of a desired wavelength, and a capacitor 15 are connected in series between the input terminal 11 and the receiving terminal 12. One end of the source or drain of the transistor 16 is connected to the connection point between the transmission line 14 and the capacitor 15, and the other end is grounded. Further, an inductor 17 is provided in parallel with the transistor 16.

  A parallel resonant circuit 19 is provided between the input terminal 11 and the dummy terminal 18, specifically, between the connection point (hereinafter referred to as a branch point) between the capacitor 13 and the transmission line 14 and the dummy terminal 18. ing. The parallel resonant circuit 19 includes a transistor 20 and an inductor 21 connected in parallel.

  Here, the capacitors 13 and 15 are capacitors for DC cut. The inductor 17 is designed to resonate with the off-capacitance when the transistor 16 is OFF and to open at a predetermined frequency. Similarly, the inductor 21 is designed to resonate with the off-capacitance and open at a desired frequency when the transistor 20 is OFF.

  Next, the operation of the conventional high power durability switch will be described. First, when the input terminal 11 and the dummy terminal 18 are connected, 0 V is applied to the control terminals Vc1 and Vc2 of the transistors 16 and 20, and the transistors 16 and 20 are turned on. In this case, since the branch point is grounded via the transmission line 14 and the transistor 16 whose line length is ¼ of the desired wavelength λ, the branch point and the reception terminal 12 are open. Therefore, the input terminal 11 and the receiving terminal 12 are in an open state. In this state, a large amount of current flows between the source and drain of the transistors 16 and 20, but the voltage is small. Therefore, by optimizing the size of the transistors 16 and 20, high power can be handled.

  On the other hand, when the input terminal 11 and the reception terminal 12 are connected, for example, −5 V, which is equal to or lower than the pinch-off voltage, is applied to the control terminals Vc1 and Vc2 of the transistors 16 and 20, and the transistors 16 and 20 are turned off. Since the transistor 16 and the inductor 17 and the transistor 20 and the inductor 21 are resonated and are in an open state, the input terminal 11 and the dummy terminal 18 are in an open state, and the input terminal 11 and the reception terminal 12 are in a connected state. In this state, since a voltage is generated between the source and drain of the transistors 16 and 20, large power cannot be handled.

JP 2002-164703 A

  In the conventional high power withstand switch, since the stop band of the parallel resonance circuit 19 inserted between the input terminal 11 and the dummy terminal 18 is narrow, a low loss signal is transmitted from the input terminal 11 to the reception terminal 12 with low loss. The operating band that can be passed through is narrow, and there is a problem that it is sensitive to capacitance changes and transistor parameter changes due to manufacturing variations.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a high power-resistant switch that has a wide operating band and is resistant to manufacturing variations.

A high power durability switch according to the present invention includes a transmission line, a first inductor and a second inductor, a first inductor and a second inductor, which are connected in series between an input terminal and a first output terminal. A first transistor having one end of the source or drain connected to the connection point and the other end grounded, a parallel resonant circuit provided between the input terminal and the second output terminal, and a second output terminal And a first capacitor connected in parallel with the series resonant circuit, wherein the first inductor and the second inductor have a low frequency together with the off-capacitance of the first transistor. A pass filter is formed, the parallel resonant circuit has a second transistor and a third inductor connected in parallel, and the series resonant circuit has a third transistor and a fourth inductor connected in series. First Capacitor, the third transistor is in an open state resonates with the series resonant circuit when is ON. Other features of the present invention will become apparent below.

  According to the present invention, it is possible to obtain a high power-resistant switch that has a wide operating band and is resistant to manufacturing variations.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a high power resistant switch according to Embodiment 1 of the present invention. As shown in the figure, between the input terminal 11 and the receiving terminal 12 (first output terminal), the capacitor 13, the transmission line 14 whose line length is ¼ of the desired wavelength λ, and the inductor 22 (first ), An inductor 23 (second inductor), and a capacitor 15 are connected in series. One end of the source or drain of the transistor 16 (first transistor) is connected to the connection point between the inductor 22 and the inductor 23, and the other end is grounded.

  Further, between the input terminal 11 and the dummy terminal 18 (second output terminal), specifically, between the connection point (hereinafter referred to as a branch point) between the capacitor 13 and the transmission line 14 and the dummy terminal 18. A parallel resonant circuit 19 is provided. The parallel resonant circuit 19 includes a transistor 20 (second transistor) and an inductor 21 (third inductor) connected in parallel.

  A series resonance circuit 24 is provided between the dummy terminal 18 and the ground point. The series resonance circuit 24 includes a transistor 25 (third transistor) and an inductor 26 (fourth inductor) connected in series. A capacitor 27 (first capacitor) is connected in parallel with the series resonance circuit 24. The capacitor 27 is designed to resonate with the series resonance circuit 24 and to be in an open state when the transistor 25 is ON.

  Next, the operation of the high power durability switch will be described. First, when the input terminal 11 and the receiving terminal 12 are connected, a voltage lower than the pinch-off, for example −5 V, is applied to the control terminals Vc1, Vc2, and Vc3 of the transistors 16, 20, and 25, and each transistor is turned off. At this time, the inductors 22 and 23 form a low-pass filter 28 together with the off-capacitance of the transistor 16. For this reason, the input terminal 11 and the receiving terminal 12 can be connected with low loss in a predetermined band. On the other hand, as the transistor 20 and the inductor 21 resonate, the input terminal 11 and the dummy terminal 18 are cut off. In addition, since the transistor 25 and the inductor 26 resonate, the dummy terminal 18 is grounded with a low impedance. This increases the amount of isolation between the input terminal 11 and the dummy terminal 18.

  Next, when the input terminal 11 and the dummy terminal 18 are connected, 0 V is applied to the control terminals Vc1, Vc2, and Vc3 of the transistors 16, 20, and 25, and each transistor is turned on. Since the branch point and the receiving terminal 12 are grounded by the transistor 16 via the transmission line 14, the open state is established. The inductor 26 and the capacitor 27 are opened by resonance, and the input terminal 11 and the dummy terminal 18 are connected by the transistor 20.

  Thus, when each transistor is turned on, a high voltage does not occur at both ends of each transistor, so that a high-power signal is passed from the input terminal 11 to the dummy terminal 18 as in the conventional high power-resistant switch. Can be made.

  When each transistor is turned off, the power from the input terminal 11 to the dummy terminal 18 is reflected by the band rejection circuit including the parallel resonance circuit 19 and the series resonance circuit 24, and the leakage power to the dummy terminal 18 is reduced. . Further, the circuit constituted by the transistors 20 and 25 and the inductors 21 and 26 can constitute a band rejection filter by optimizing the circuit constants. Thereby, since the input terminal 11 and the dummy terminal 18 can be cut | disconnected over a wide band, a switch with a wide operation | movement band and a strong manufacturing variation can be obtained.

  In this embodiment, a transistor is used as a control device. However, the present invention is not limited to this, and any device that can realize a capacitance difference between ON and OFF, such as a diode with a control circuit or MEMS, may be used. Further, as the inductor, a spiral inductor configured on a substrate or a transmission line having high characteristic impedance may be used. And as a capacitor, you may use the MIM capacitor comprised on the board | substrate, and the interdigital capacitor. In the present embodiment, the high power resistant switch that protects the receiving circuit when a high power signal is input has been described. However, the present invention is not limited to this, and the present invention is also applicable to a general high power resistant switch. can do. The frequencies of the high power signal and the low power signal may be the same frequency or different frequencies.

Embodiment 2. FIG.
FIG. 2 is a circuit diagram showing the high power resistant switch according to the present embodiment. In addition to the configuration of the first embodiment, this high power durability switch includes a series-connected inductor 29 (fifth) provided between a connection point A between the parallel resonant circuit 19 and the series resonant circuit 24 and the dummy terminal 18. And the capacitor 30 (second capacitor). Other configurations are the same as those of the first embodiment.

  Here, when the transistors 20 and 25 are turned on, the equivalent circuit has the same role as a short circuit. In this case, the parameters are set so that the inductors 26 and 29, the capacitors 27 and 30, and the transistor 25 constitute a band-pass filter that passes a desired band.

  Thereby, since the input terminal 11 and the dummy terminal 18 can be cut over a wider band, a switch having a wider operating band than that of the first embodiment and strong against manufacturing variations can be obtained.

Embodiment 3 FIG.
FIG. 3 is a circuit diagram showing the high power resistant switch according to the present embodiment. In this high power resistant switch, a circuit 31 including an inductor 29 and a capacitor 30 is stagger-tuned by connecting two or more stages in parallel at different resonance frequencies. Other configurations are the same as those of the second embodiment. Thereby, since the stop band becomes a superposition of the stop bands of the respective stages, the input terminal 11 and the dummy terminal 18 can be cut over a wider band, so that the operation band is wider than that of the second embodiment, A switch that is resistant to manufacturing variations can be obtained.

Embodiment 4 FIG.
FIG. 4 is a circuit diagram showing the high power resistant switch according to the present embodiment. In this high power resistant switch, the parallel resonant circuit 19 is stagger-tuned by connecting two or more stages in series at different resonant frequencies. Other configurations are the same as those of the first embodiment.

  As a result, the stop band is a superposition of the stop bands of the respective stages, so that the input terminal 11 and the dummy terminal 18 can be cut over a wider band. A switch resistant to variations can be obtained.

Embodiment 5 FIG.
FIG. 5 is a circuit diagram showing the high power resistant switch according to the present embodiment. This high power withstand switch is stagger-tuned by connecting two or more stages of series resonance circuit 24 and capacitor 27 in parallel at different resonance frequencies. Other configurations are the same as those of the first embodiment.

  As a result, the stop band is a superposition of the stop bands of the respective stages, so that the input terminal 11 and the dummy terminal 18 can be cut over a wider band. A switch resistant to variations can be obtained.

Embodiment 6 FIG.
FIG. 6 is a circuit diagram showing the high power resistant switch according to the present embodiment. This high power-resistant switch has a distributed configuration in which two or more stages of T-type low-pass filters 28 including inductors 22 and 23 and a transistor 16 are connected in series.

  Thereby, it is possible to obtain a switch having a wider operating band than that of the first embodiment and strong against manufacturing variations. In addition, since the transistors 16 are connected in parallel, the number of connection points B connected to the ground point is increased when a large signal is input, and isolation is increased, so that leakage power to the reception terminal 12 can be reduced. it can.

Embodiment 7 FIG.
In the present embodiment, when the small signal is passed from the input terminal 11 to the reception terminal 12 in the high power durability switch according to the second embodiment, the band rejection filter including the parallel resonance circuit 19 and the series resonance circuit 24 is blocked. and the center frequency of the band, set from the input terminal 11 when passing the large signal to the dummy terminal 18, a capacitor 27 and 30, as the center frequency of the band bandpass filter composed of the inductor 26, 29 passes are different is doing.

  Specifically, the circuit 31 including the inductor 29 and the capacitor 30 is set so as to have a low impedance at substantially the center of the band when the input terminal 11 and the dummy terminal 18 are connected in the second embodiment. In this embodiment, this band is shifted.

  As a result, when passing a small signal from the input terminal 11 to the receiving terminal 12, the impedance at which the dummy terminal 18 is expected from the connection point A is increased, so that the isolation between the input terminal 11 and the dummy terminal 18 is increased. Can do.

Embodiment 8 FIG.
FIG. 7 is a circuit diagram showing the high power resistant switch according to the present embodiment. This high power withstand switch is stagger-tuned by connecting two or more stages of band rejection circuits 32 including a parallel resonance circuit 19, a series resonance circuit 24, and a capacitor 27 in series at different resonance frequencies . Thereby, since the input terminal 11 and the dummy terminal 18 can be disconnected over a wider band, a switch having a wider operating band than that of the first embodiment and strong against manufacturing variations can be obtained.

Embodiment 9 FIG.
FIG. 8 is a circuit diagram showing the high power resistant switch according to the present embodiment. This high power withstand switch is obtained by replacing the parallel resonant circuit 19 in the first embodiment with a transmission line 33 (second transmission line) whose line length is ¼ of the desired wavelength λ.

  When passing a small signal from the input terminal 11 to the receiving terminal 12, since the dummy terminal 18 is grounded, high isolation can be maintained even if it is replaced with the transmission line 33. Therefore, the same effects as those of the first embodiment are obtained. Furthermore, there is an effect that manufacturing variation is small as compared with the parallel resonant circuit 19 using the transistor 20.

1 is a circuit diagram showing a high power resistant switch according to Embodiment 1 of the present invention. FIG. It is a circuit diagram which shows the high electric power tolerance switch which concerns on Embodiment 2 of this invention. It is a circuit diagram which shows the high power durability switch which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows the high electric power durability switch which concerns on Embodiment 4 of this invention. FIG. 10 is a circuit diagram showing a high power resistant switch according to Embodiment 5 of the present invention. It is a circuit diagram which shows the high electric power tolerance switch which concerns on Embodiment 6 of this invention. It is a circuit diagram which shows the high electric power durability switch which concerns on Embodiment 8 of this invention. It is a circuit diagram which shows the high power durability switch which concerns on Embodiment 9 of this invention. It is a figure which shows the transmitter / receiver using a high power-resistant switch. It is a figure which shows the conventional high power durability switch.

Explanation of symbols

11 Input terminal 12 Reception terminal (first output terminal)
14 Transmission line (first transmission line)
16 transistor (first transistor)
18 Dummy terminal (second output terminal)
19 Parallel resonant circuit 20 Transistor (second transistor)
21 Inductor (third inductor)
22 Inductor (first inductor)
23 Inductor (second inductor)
24 series resonance circuit 25 transistor (third transistor)
26 Inductor (fourth inductor)
27 Capacitor (first capacitor)
28 Low-pass filter 29 Inductor (fifth inductor)
30 capacitor (second capacitor)
31 Circuit 32 Band stop circuit 33 Transmission line (second transmission line)

Claims (9)

A transmission line, a first inductor and a second inductor connected in series between the input terminal and the first output terminal;
A first transistor having one end of a source or a drain connected to a connection point between the first inductor and the second inductor and the other end grounded;
A parallel resonant circuit provided between the input terminal and the second output terminal;
A series resonant circuit provided between the second output terminal and a ground point;
A first capacitor connected in parallel with the series resonant circuit;
The first inductor and the second inductor form a low-pass filter together with the off-capacitance of the first transistor;
The parallel resonant circuit includes a second transistor and a third inductor connected in parallel,
The series resonant circuit includes a third transistor and a fourth inductor connected in series,
The high power durability switch, wherein the first capacitor is in an open state by resonating with the series resonance circuit when the third transistor is ON.   2. The apparatus according to claim 1, further comprising a fifth inductor and a second capacitor connected in series between a connection point of the parallel resonance circuit and the series resonance circuit and the second output terminal. High power durability switch.   3. The high power resistant switch according to claim 2, wherein the circuit composed of the fifth inductor and the second capacitor is stagger-tuned by connecting two or more stages in parallel at different resonance frequencies.   The high-withstand power switch according to any one of claims 1 to 3, wherein the parallel resonant circuits are stagger-tuned by connecting two or more stages in series at different resonant frequencies.   The pair of the series resonant circuit and the first capacitor is stagger-tuned by connecting two or more stages in parallel at different resonant frequencies, respectively. High power durability switch.   6. The high withstand voltage according to claim 1, wherein two or more stages of low-pass filters including the first inductor, the second inductor, and the first transistor are connected in series. Power switch.   A center frequency of a band blocked by a band-stop filter composed of the parallel resonant circuit and the series resonant circuit, and a band pass composed of the first capacitor, the fourth inductor, the fifth inductor, and the second capacitor. The high-power-resistant switch according to claim 2, wherein a center frequency of a band through which the filter passes is different.   A connection point between the input terminal and the second output is provided between the input terminal and the second output terminal, the circuit including the parallel resonant circuit, the series resonant circuit, and the first capacitor. 8. The high power-resistant switch according to claim 1, wherein two or more stages are connected in series and stagger-tuned with respect to a connection point to a terminal as a reference, respectively. A first transmission line, a first inductor and a second inductor connected in series between the input terminal and the first output terminal;
A first transistor having one end of a source or a drain connected to a connection point between the first inductor and the second inductor and the other end grounded;
A second transmission line provided between the input terminal and the second output terminal;
A series resonant circuit provided between the second output terminal and a ground point;
A first capacitor connected in parallel with the series resonant circuit;
The first inductor and the second inductor form a low-pass filter together with the off-capacitance of the first transistor;
The series resonant circuit includes a second transistor and a third inductor connected in series,
The high-power-resistant switch, wherein the first capacitor is in an open state by resonating with the series resonance circuit when the second transistor is ON.

Images