JP4885034B2 - ASK modulation circuit and transmission apparatus - Google Patents

Description

  The present invention relates to an ASK modulation circuit and a transmission device, and more particularly to an ASK modulation technique for changing the amplitude of a high-frequency signal by switching the operation state of a switch circuit based on a data signal in a microwave and millimeter wave band wireless communication system. Is.

  Conventionally, an ASK (Amplitude Shift Keying) modulation circuit used in a microwave / millimeter wave band wireless communication system is known. In the ASK modulation circuit, a switch circuit composed of a non-linear element such as a diode is disposed between a point on the transmission path of the high-frequency signal and the ground. Thus, the amplitude of the high frequency signal is modulated by opening and closing the switch based on the data signal.

  An SPST (Single Pole Single Throw) switch circuit can be used for the ASK modulation circuit having the above configuration. As a switch circuit, semiconductor elements such as field effect transistors and diodes are arranged in a high-frequency signal transmission path and a shunt path between the transmission path and the ground, and switching is performed by opening and closing the semiconductor elements in these paths. There is a configuration that operates.

  In other words, the conventional switch circuit controls the high-frequency signal passing characteristic in the high-frequency signal transmission path by performing a switching operation. Therefore, when a switching operation for passing a high-frequency signal through the transmission path is performed, it is desirable that the high-frequency signal pass through the transmission path without loss. However, there is a problem that a high-frequency signal flows through the shunt path and leaks to the ground.

  Therefore, for example, Patent Document 1 discloses a distributed constant line having a line length that is an odd multiple of one-fourth of the wavelength of the high-frequency signal passing through the transmission line between the transmission path and the semiconductor element that performs the switching operation. The switch circuit to be provided is described.

  FIG. 13 is a circuit diagram showing a configuration of a conventional switch circuit 100.

  As shown in FIG. 13, the conventional switch circuit 100 includes a transmission line 103 and a field effect transistor 104 between a point on the transmission path of a high-frequency signal from the input terminal 101 to the output terminal 102 and the ground. It is configured.

  A control signal is supplied from the control signal input terminal 106 to the gate terminal of the field effect transistor 104 via the resistor 105, and the field effect transistor 104 is turned on / off (open / closed). The transmission line 103 has a line length of a quarter wavelength of a high-frequency signal passing through the transmission line, and converts low impedance to high impedance and high impedance to low impedance.

  Therefore, the impedance when the transmission line 103 side is viewed from the connection point 107 between the transmission path of the high-frequency signal and the transmission line 103 is high when the field effect transistor 104 is turned on and the drain terminal is low impedance. . Thereby, the high-frequency signal is transmitted from the input terminal 101 to the output terminal 102 with the passage loss suppressed.

  On the other hand, when the field effect transistor 104 is off, the drain terminal has a high impedance. Thereby, it is converted into low impedance by the transmission line 103, and the impedance when the transmission line 103 side is viewed from the connection point 107 becomes low impedance. Therefore, the high frequency signal is reflected and is not transmitted to the output terminal 102.

  Such a conventional switch circuit 100 can be configured as an ASK modulation circuit by switching on / off of the field effect transistor 104 based on a data signal as a control signal.

  However, in the conventional switch circuit 100, when the source terminal of the field effect transistor 104 is grounded using a through hole or via hole, the capacitance component in the field effect transistor 104, the through hole or via hole portion increases as the frequency increases. The influence of the inductance component cannot be ignored.

  That is, there has been a problem that the phase is changed by the capacitance component and the inductance component. For this reason, especially in the millimeter wave band, the phase change in the on / off state of the field effect transistor 104 cannot be ignored, and it becomes difficult to obtain desired characteristics.

  For example, when the field effect transistor 104 is in the on state, it is desirable that the source and drain are short-circuited with a low resistance. However, the phase rotates depending on the capacitance component, inductance component, and connection length to the ground (for example, the connection length from the source terminal to the via hole and the electrical connection length of the via hole). As a result, the transmission line 103 cannot be converted into a desired impedance, and thus the high-frequency signal passage loss increases.

  Similarly, even when the field effect transistor 104 is in an OFF state, the phase is rotated by the capacitance component and the inductance component, and cannot be converted into a desired impedance by the transmission line 103. For this reason, the high frequency signal cannot be sufficiently attenuated.

  In particular, in the millimeter wave band, a high frequency signal leaks due to a parasitic capacitance between the source and the drain when the field effect transistor 104 is in an off state, and thus cannot be converted into a desired impedance. Therefore, in the configuration of the conventional switch circuit 100, it is difficult to realize a sufficient off state in the millimeter wave band.

  Further, an equivalent circuit when the field effect transistor 104 is on can be considered as an on-resistance, and an equivalent circuit when the field-effect transistor 104 is off can be considered as a parallel connection of an off-resistance and a source-drain parasitic capacitance. .

  In this case, the amount of phase rotation differs between the on state and the off state of the field effect transistor 104. Therefore, the configuration of the conventional switch circuit 100 cannot improve both the on-state and off-state characteristics. Therefore, it is difficult to ensure a sufficient on / off ratio.

Thus, for example, Patent Document 2 describes a switch circuit in which a transmission line whose other end is open and a resistor whose other end is grounded are connected to the source terminal of a field effect transistor. Since the source terminal of the field effect transistor is DC-grounded via a resistor, a bias voltage can be applied between the gate terminal and the source terminal of the field effect transistor. As a result, a transmission line with the other end opened without using a through hole or via hole can be used for high-frequency grounding of the source terminal, so that deterioration of switch characteristics is suppressed even when the frequency is increased. Is possible.
JP 7-235802 A (published September 5, 1995) JP 9-275303 A (published on October 21, 1997)

  However, the switch circuit described in Patent Document 2 has not yet solved the problem that a high-frequency signal flows through the shunt path and leaks to the ground. The reason is that the influence due to the difference in phase change accompanying the change in capacitance component when the field effect transistor is turned on / off and the connection length between the main transmission line and the field effect transistor are not considered.

  Further, in the switch circuit described in Patent Document 2, a deterioration in switch characteristics due to an increase in frequency is suppressed by connecting a transmission line with the other end open to the source terminal of the field effect transistor. .

  However, by grounding using a through hole or via hole, for example, from the first layer to the second layer in a two-layer printed wiring board, from the fourth layer to the second layer in a four-layer printed wiring board, etc. There is an advantage that the design range of the wiring pattern is widened. Therefore, when the transmission line and the resistor having the other end opened are provided, there is a problem that the substrate size is increased as compared with the case of grounding using a through hole or a via hole.

  Further, in the switch circuit described in Patent Document 2, since the resistor is provided at the source terminal of the field effect transistor, it cannot be said that there is no influence of the inductance component of the resistor.

  Therefore, in consideration of the influence of the capacitance component in the field-effect transistor and the inductance component of the through-hole and via-hole at the millimeter waveband frequency, the high-frequency signal passing loss is reduced, and the on-state and off-state of the field-effect transistor are reduced. Therefore, it is desired to secure a sufficient on / off ratio with a simple configuration by improving both characteristics.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an ASK modulation circuit and a transmission device that can reduce the passage loss of a high-frequency signal and improve the on / off ratio. There is.

In order to solve the above problems, an ASK modulation circuit of the present invention includes a first transmission line and a non-linear element from the main transmission line side between a point on the main transmission line that transmits a high-frequency signal and the ground. Comprises an ASK modulation circuit that changes the amplitude of the high-frequency signal by switching the operation state of the nonlinear element based on a control signal, the high-frequency circuit provided in this order, An open-ended transmission line is provided at a connection point to which the high-frequency circuit is connected , the nonlinear element is a high-frequency transistor, has a length of approximately a quarter wavelength of the high-frequency signal, and one terminal Is connected to the control terminal of the high-frequency transistor and the other terminal is grounded via a capacitive element, and a data signal is supplied to the other terminal of the second transmission line. And signal supply means, characterized by comprising a DC voltage supply means for supplying a DC voltage to the other terminal of said second transmission line.

  According to the above configuration, when the nonlinear element is switched to the off operation state based on the control signal, the impedance of the terminal on the first transmission line side of the nonlinear element is reduced by the first transmission line. The impedance when the high frequency circuit side is viewed from the connection point on the main transmission line is low impedance, that is, substantially short-circuited. Thereby, the passage amount of the high frequency signal transmitted through the main transmission line is reduced.

  On the other hand, when the nonlinear element is switched to the ON operation state based on the control signal, the terminal on the first transmission line side of the nonlinear element has a low impedance. For this reason, it is converted into high impedance by the first transmission line, and the impedance when the high frequency circuit side is viewed from the connection point on the main transmission line is high impedance.

  However, as the frequency becomes higher, for example, in the millimeter wave band, the impedance when the high frequency circuit side is viewed from the connection point is not sufficiently high due to the influence of the inductance component and the capacitance component of the high frequency circuit portion. .

  On the other hand, since the open end transmission line is provided at the connection point on the main transmission line, the impedance is changed by the open end transmission line. Therefore, the combined impedance composed of the open-ended transmission line and the high frequency circuit can be made high impedance. Therefore, it is possible to suppress a decrease in impedance due to the above influence and reduce the passage loss of the high-frequency signal.

  Therefore, even in the millimeter wave band, it is possible to increase the difference between the amount of high-frequency signal passing when the nonlinear element is in the on-operation state and the amount of high-frequency signal passage when the nonlinear element is in the off-operating state. Become. That is, the on / off ratio can be improved.

  Therefore, the ASK modulation circuit of the present invention can reduce the passage loss of the high frequency signal and improve the on / off ratio. Moreover, since the ASK modulation circuit of the present invention has a configuration in which the high-frequency circuit and the open-ended transmission line are connected to the same portion on the main transmission line, it is advantageous for downsizing the circuit.

In the ASK modulation circuit of the present invention, the first transmission line and the non-linear element are provided in this order from the main transmission line side between one point on the main transmission line that transmits a high-frequency signal and the ground. And an ASK modulation circuit that changes the amplitude of the high-frequency signal by switching the operating state of the nonlinear element based on a control signal, the high-frequency circuit being a predetermined signal on the main transmission line. Are provided at a plurality of positions separated by a distance of, and each of the plurality of connection points to which the main transmission line and the high-frequency circuit provided at the plurality of positions are connected, each provided with an open-ended transmission line , The nonlinear element is a high-frequency transistor, has a length of approximately a quarter wavelength of the high-frequency signal, one terminal is connected to the control terminal of the high-frequency transistor, and the other A second transmission line having a child grounded via a capacitive element, a data signal supply means for supplying a data signal to the other terminal of the second transmission line, and a second terminal of the second transmission line. DC voltage supply means for supplying a DC voltage is provided .

  According to the above configuration, when the nonlinear element is switched to the off operation state based on the control signal, the impedance of the terminal on the first transmission line side of the nonlinear element is reduced by the first transmission line. The impedance when the high frequency circuit side is viewed from the connection point on the main transmission line is low impedance, that is, substantially short-circuited. Thereby, the passage amount of the high frequency signal transmitted through the main transmission line is reduced.

  On the other hand, when the nonlinear element is switched to the ON operation state based on the control signal, the terminal on the first transmission line side of the nonlinear element has a low impedance. For this reason, it is converted into high impedance by the first transmission line, and the impedance when the high frequency circuit side is viewed from the connection point on the main transmission line is high impedance.

  However, as the frequency becomes higher, for example, in the millimeter wave band, the impedance when the high frequency circuit side is viewed from the connection point is not sufficiently high due to the influence of the inductance component and the capacitance component of the high frequency circuit portion. .

  On the other hand, since the open end transmission line is provided at the connection point on the main transmission line, the impedance is changed by the open end transmission line. Therefore, the combined impedance composed of the open-ended transmission line and the high frequency circuit can be made high impedance. Therefore, it is possible to suppress a decrease in impedance due to the above influence and reduce the passage loss of the high-frequency signal.

  Therefore, even in the millimeter wave band, it is possible to increase the difference between the amount of high-frequency signal passing when the nonlinear element is in the on-operation state and the amount of high-frequency signal passage when the nonlinear element is in the off-operating state. Become. That is, the on / off ratio can be improved.

  Further, the on / off ratio can be further improved by providing a set of the high-frequency circuit and the open-ended transmission line at a plurality of positions separated by a predetermined interval on the main transmission line. It becomes possible. Therefore, the ASK modulation circuit of the present invention can reduce the passage loss of the high frequency signal and further improve the on / off ratio.

Further, ASK modulation circuit of the present invention, as described above, the nonlinear element is Ru high-frequency transistor der. As a result, integration with an active circuit such as an amplifier circuit becomes possible.

  In the ASK modulation circuit of the present invention, the first transmission line has one terminal connected to one point on the main transmission line, the other terminal connected to the first conduction terminal of the high-frequency transistor, In the high frequency transistor, it is preferable that the control signal is supplied to the control terminal and the second conduction terminal is grounded.

  According to the above configuration, for example, when the high-frequency transistor is a field effect transistor, the control terminal is a gate terminal, the first conduction terminal is a drain terminal, and the second conduction terminal is a source terminal. When the high-frequency transistor is a bipolar transistor, the control terminal is a base terminal, the first conduction terminal is a collector terminal, and the second conduction terminal is an emitter terminal.

  As a result, it is possible to easily switch the impedance value when the high frequency circuit side is viewed from the connection point only by controlling the voltage signal or current signal supplied to the control terminal of the high frequency transistor.

  In the ASK modulation circuit of the present invention, it is preferable that the predetermined interval has a length of approximately a quarter wavelength of the operating frequency.

  According to the above configuration, by setting the predetermined interval to a length of about one-quarter wavelength of the operating frequency, for example, the high-frequency circuit and the open-ended transmission line are respectively provided at two locations on the main transmission line. When the connection point between the main transmission line and the high-frequency circuit is substantially short-circuited when the non-linear element is in an off state, the impedance when the other connection point is viewed from one connection point is converted to a high impedance. For this reason, it becomes possible to attenuate a high frequency signal more.

The ASK modulation circuit which is a reference of the present invention preferably includes control signal supply means for supplying the control signal to the nonlinear element. Thereby, it becomes possible to suitably supply a control signal to the nonlinear element.

The ASK modulation circuit which is a reference of the present invention includes data signal supply means for supplying a data signal to the control terminal of the high-frequency transistor, and DC voltage supply means for supplying a DC voltage to the control terminal of the high-frequency transistor. It is preferable.

  According to the above configuration, the data signal supply means for supplying the data signal to the control terminal of the high frequency transistor and the DC voltage supply means for supplying the DC voltage to the control terminal of the high frequency transistor are provided. A data signal superimposed with is supplied to the control terminal of the high-frequency transistor. As a result, the bias point of the high-frequency transistor can be adjusted, and the on / off operation can be optimally performed.

In the ASK modulation circuit which is a reference of the present invention, a resistor is preferably provided between the control terminal of the high-frequency transistor, the data signal supply means, and the DC voltage supply means.

  According to said structure, the data signal with which the DC voltage was superimposed is supplied to the control terminal of a high frequency transistor via resistance. Thereby, it is possible to suppress leakage of the high frequency signal from the control terminal of the high frequency transistor to the data signal supply means and the DC voltage supply means. Therefore, it is possible to reduce the passage loss when the high-frequency transistor is in the ON operation state.

Further, as described above , the ASK modulation circuit of the present invention has a length of approximately a quarter wavelength of the high-frequency signal, one terminal is connected to the control terminal of the high-frequency transistor, and the other terminal is A second transmission line grounded via a capacitive element; data signal supply means for supplying a data signal to the other terminal of the second transmission line; and a DC voltage applied to the other terminal of the second transmission line. Ru and a DC voltage supply means for supplying a.

  According to the above configuration, since the second transmission line has a length of approximately a quarter wavelength of the high-frequency signal, the other terminal is grounded via the capacitive element, so that the control terminal of the high-frequency transistor Thus, the impedance viewed from the second transmission line side can be set to a high impedance.

  As a result, it is possible to reduce the leakage of the high-frequency signal from the gate terminal of the high-frequency transistor, for example, via the gate-source capacitance or the gate-drain capacitance. Therefore, it is possible to reduce the passage loss when the high-frequency transistor is in the ON operation state.

  In the ASK modulation circuit of the present invention, the data signal supply means includes a blocking means for blocking a DC component of the input data signal, and an amplifying means for setting the amplitude of the data signal output from the blocking means to a constant value. And extracting means for removing unnecessary signal components of the data signal output from the amplifying means, and attenuating means for setting the amplitude of the data signal output from the extracting means to a predetermined value.

  According to the above configuration, even if the amplitude of the input data signal deviates from a predetermined value due to wiring loss or the like, the amplitude is finally adjusted to a predetermined value. Can be secured. This makes it possible to ensure a stable communication state.

  Further, a transmission apparatus of the present invention is a transmission apparatus that includes the ASK modulation circuit that performs ASK modulation on a high-frequency signal and that transmits a modulation signal output from the ASK modulation circuit.

  According to the above configuration, by providing the ASK modulation circuit, it is possible to perform ASK modulation with reduced pass loss even in the millimeter wave band. In addition, since the ASK modulation circuit has a simple configuration, an increase in chip area can be suppressed even when a configuration circuit adjacent to the ASK modulation circuit in the transmission apparatus is integrated with the ASK modulation circuit. It becomes. Therefore, the transmission device can be reduced in size.

As described above, in the ASK modulation circuit of the present invention, the first transmission line and the non-linear element are arranged in this order from the main transmission line side between one point on the main transmission line that transmits a high-frequency signal and the ground. An ASK modulation circuit that changes the amplitude of the high-frequency signal by switching the operation state of the nonlinear element based on a control signal, the main transmission line, the high-frequency circuit, Is connected to the connection point to which the open-ended transmission line is connected , the nonlinear element is a high-frequency transistor, has a length of about a quarter wavelength of the high-frequency signal, and one terminal has the high-frequency signal. A second transmission line connected to the control terminal of the transistor and having the other terminal grounded via a capacitive element; and a data signal supplier for supplying a data signal to the other terminal of the second transmission line. When a configuration and a DC voltage supply means for supplying a DC voltage to the other terminal of said second transmission line.

  Therefore, by providing the open-ended transmission line at the connection point on the main transmission line, the combined impedance composed of the open-ended transmission line and the high-frequency circuit can be made high impedance. Therefore, it is possible to suppress a decrease in impedance due to the influence of the inductance component and the capacitance component of the high frequency circuit portion, and to reduce the passage loss of the high frequency signal.

  Therefore, even in the millimeter wave band, it is possible to increase the difference between the amount of high-frequency signal passing when the nonlinear element is on and the amount of high-frequency signal passing when the nonlinear element is off. That is, the on / off ratio can be improved.

  Therefore, the ASK modulation circuit of the present invention has an effect of reducing the passage loss of the high frequency signal and improving the on / off ratio. In addition, since the ASK modulation circuit of the present invention is configured to connect the high-frequency circuit and the open-ended transmission line to the same portion on the main transmission line, there is an effect that it is advantageous for downsizing of the circuit.

In the ASK modulation circuit of the present invention, the first transmission line and the non-linear element are provided in this order from the main transmission line side between one point on the main transmission line that transmits a high-frequency signal and the ground. And an ASK modulation circuit that changes the amplitude of the high-frequency signal by switching the operating state of the nonlinear element based on a control signal, the high-frequency circuit being a predetermined signal on the main transmission line. Are provided at a plurality of positions separated by a distance of, and each of the plurality of connection points to which the main transmission line and the high-frequency circuit provided at the plurality of positions are connected, each provided with an open-ended transmission line , The nonlinear element is a high-frequency transistor, has a length of approximately a quarter wavelength of the high-frequency signal, one terminal is connected to the control terminal of the high-frequency transistor, and the other A second transmission line having a child grounded via a capacitive element, a data signal supply means for supplying a data signal to the other terminal of the second transmission line, and a second terminal of the second transmission line. DC voltage supply means for supplying a DC voltage .

  Therefore, by providing the open-ended transmission line at the connection point on the main transmission line, the combined impedance composed of the open-ended transmission line and the high-frequency circuit can be made high impedance. Therefore, it is possible to suppress a decrease in impedance due to the influence of the inductance component and the capacitance component of the high frequency circuit portion, and to reduce the passage loss of the high frequency signal.

  Therefore, even in the millimeter wave band, it is possible to increase the difference between the amount of high-frequency signal passing when the nonlinear element is on and the amount of high-frequency signal passing when the nonlinear element is off. That is, the on / off ratio can be improved.

  Further, the on / off ratio can be further improved by providing a set of the high-frequency circuit and the open-ended transmission line at a plurality of positions separated by a predetermined interval on the main transmission line. it can. Therefore, the ASK modulation circuit of the present invention has an effect of reducing the passage loss of the high-frequency signal and further improving the on / off ratio.

  Further, a transmission apparatus of the present invention is a transmission apparatus that includes the ASK modulation circuit that performs ASK modulation on a high-frequency signal and that transmits a modulation signal output from the ASK modulation circuit.

  Therefore, by providing the ASK modulation circuit, it is possible to perform ASK modulation with reduced passage loss even in the millimeter wave band. Further, since the ASK modulation circuit has a simple configuration, an increase in the chip area can be suppressed even when a configuration circuit adjacent to the ASK modulation circuit in the transmission apparatus is integrated with the ASK modulation circuit. . Therefore, there is an effect that the transmission device can be reduced in size.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to the drawings. First, the configuration of the ASK modulation circuit 10 of the present embodiment will be described, and then the operation of the ASK modulation circuit 10 of the present embodiment will be described.

  FIG. 1 is a circuit diagram showing a configuration example of the ASK modulation circuit 10 according to the present embodiment.

  The ASK modulation circuit 10 according to the present embodiment has a function of ASK-modulating an input high-frequency signal and outputting a modulation signal. As shown in FIG. 1, the ASK modulation circuit 10 of the present embodiment includes an input terminal 11, an output terminal 12, a first transmission line 13, a second transmission line 14, an open-ended transmission line 15, a control signal input terminal 21, And a high-frequency circuit 20.

  The input terminal 11, the first transmission line 13, the second transmission line 14, and the output terminal 12 are connected in series in this order. The high-frequency signal is input to the input terminal 11 and is output as an ASK-modulated modulation signal from the output terminal 12 via the first transmission line 13 and the second transmission line 14. Here, a path constituted by the input terminal 11, the first transmission line 13, the second transmission line 14, and the output terminal 12 is a main transmission path in the ASK modulation circuit 10.

  The open-ended transmission line 15 is an open-ended transmission line (open stub), and one end thereof is connected to a connection point 16 between the first transmission line 13 and the second transmission line 14 on the main transmission path. ing.

  The high frequency circuit 20 is provided between the connection point 16 on the main transmission line and the ground, and one terminal is connected to the connection point 16 between the first transmission line 13 and the second transmission line 14. The other terminal is connected to the control signal input terminal 21. As shown in FIG. 1, the high-frequency circuit 20 includes a resistor 22, a third transmission line 23 (first transmission line), a high-frequency transistor 24 (nonlinear element), a fourth transmission line 25, and an inductance 26.

  The resistor 22 has one terminal connected to the control signal input terminal 21 and the other terminal connected to the control terminal of the high-frequency transistor 24. The resistor 22 is provided to prevent the high frequency signal from leaking from the gate terminal due to, for example, the gate-drain capacitance in the high frequency transistor 24.

  The third transmission line 23 has one terminal connected to the connection point 16 and the other terminal connected to the first conduction terminal of the high-frequency transistor 24. The third transmission line 23 is set to have a line length such that when the high-frequency transistor 24 is in an off state, the impedance state when the high-frequency circuit 20 side is viewed from the connection point 16 is low impedance (substantially short-circuited). .

  The high-frequency transistor 24 has a second conduction terminal that is grounded, for example, via a via hole. That is, the fourth transmission line 25 indicates a connection length from the high-frequency transistor 24 to the ground, for example, a connection length between the via hole and the high-frequency transistor 24. Moreover, the inductance 26 represents the inductance component which a via hole has, for example.

  The high frequency transistor 24 performs an on / off operation based on a control signal input from the control signal input terminal 21. As the high-frequency transistor 24, HEMT (High Electron Mobility Transistor), MESFET (Metal Semiconductor Field Effect Transistor) or HBT (Heterojunction Bipolar Transistor) can be used. When the high-frequency transistor 24 is a HEMT or MESFET, the control terminal is a gate terminal, the first conduction terminal is a drain terminal, and the second conduction terminal is a source terminal. When the high-frequency transistor 24 is an HBT, the control terminal is a base terminal, the first conduction terminal is a collector terminal, and the second conduction terminal is an emitter terminal.

  Here, with the above configuration, in the ASK modulation circuit 10 of the present embodiment, the open-ended transmission line 15 and the high-frequency circuit 20 are connected to the same point (connection point 16) on the main transmission path. Recognize.

  Next, the operation of the ASK modulation circuit 10 of this embodiment will be described.

  When a high-frequency signal is input to the input terminal 11, the high-frequency signal basically transmits the main transmission line. That is, the high-frequency signal is output as a modulation signal from the output terminal 12 via the first transmission line 13 and the second transmission line 14 in this order.

  At this time, since the high frequency circuit 20 is connected to the connection point 16 between the first transmission line 13 and the second transmission line 14, the impedance value when the high frequency circuit 20 side is viewed from the connection point 16 is obtained. Accordingly, the amplitude of the high frequency signal is modulated to become a modulated signal.

  In the high frequency circuit 20, the on / off operation state of the high frequency transistor 24 is switched based on the control signal input to the control signal input terminal 21, whereby the impedance when the high frequency circuit 20 side is viewed from the connection point 16. The value of switches.

  For example, it is assumed that a control signal (such as a voltage signal or a current signal according to the high frequency transistor 24) for switching the high frequency transistor 24 to the OFF state is input to the control signal input terminal 21, and the high frequency transistor 24 is switched to the OFF state. In this case, the first conduction terminal of the high-frequency transistor 24 has a high impedance and is in a sufficiently close state.

  Thereby, the high impedance is converted into a low impedance by the third transmission line 23, and the impedance state when the high frequency circuit 20 side is viewed from the connection point 16 is low impedance. For this reason, the high frequency signal input from the input terminal 11 is reflected at the connection point 16 and is not transmitted to the output terminal 12.

  On the other hand, it is assumed that a control signal for turning on the high-frequency transistor 24 is input to the control signal input terminal 21 and the high-frequency transistor 24 is turned on. In this case, the first conduction terminal of the high-frequency transistor 24 has a low impedance and is converted to a high impedance by the third transmission line 23. For this reason, the impedance state when the high frequency circuit 20 side is seen from the connection point 16 becomes a high impedance.

  Here, if the impedance is sufficiently high, the high-frequency signal input from the input terminal 11 is transmitted to the output terminal 12 without loss. However, in reality, as indicated by the fourth transmission line 25 and the inductance 26, the impedance is not sufficiently high due to the influence of the inductance component of the through-hole and via-hole portions and the capacitance component of the high-frequency transistor 24. Therefore, the passage loss of the high frequency signal is increased.

  On the other hand, in the ASK modulation circuit 10 of the present embodiment, it is possible to reduce the high-frequency signal passing loss. Subsequently, the action and effect produced by the ASK modulation circuit 10 of the present embodiment will be described in detail with specific examples.

  First, referring to FIGS. 2 and 3, the influence of the inductance component of the through-hole and via-hole portions and the capacitance component of the high-frequency transistor 24 in the ASK modulation circuit 10 of the present embodiment will be described. . Thereafter, referring to FIGS. 4 to 7, a description will be given of the point that the reduction in impedance due to the above influence is suppressed and the passage loss of the high frequency signal is reduced.

  FIG. 2 is a diagram in which the high-frequency circuit 20 is extracted from the configuration of the ASK modulation circuit 10. In FIG. 2, a terminal 11 a connected to the connection point 16 is provided as a point where the characteristics of the high-frequency circuit 20 are viewed.

  FIG. 3 is a Smith chart showing the reflection characteristic S11 viewed from the terminal 11a in the circuit configuration of the high-frequency circuit 20 shown in FIG. Note that the positions indicated by arrows OFF and ON indicate reflection characteristics when the operating frequency is 60 GHz.

  When measuring the reflection characteristic S11 shown in FIG. 3, the high-frequency circuit 20 was formed on a GaAs substrate having a substrate thickness of 100 μm. As the high-frequency transistor 24, a two-finger HEMT having a gate length of 0.15 μm and a gate width of 50 μm was used. The fourth transmission line 25 indicating the connection length between the via hole and the high-frequency transistor 24 has a line width of 50 μm and a length of 10 μm. The inductance 26 representing the inductance component of the via hole was set to 28 pH.

  The third transmission line 23 has a line width of 50 μm and a length of 90 μm. This is set so that when −1V is applied to the gate terminal of the high-frequency transistor 24 and in the OFF state, the impedance when the high-frequency circuit 20 side is viewed from the terminal 11a becomes low impedance at an operating frequency of 60 GHz. Therefore, when the high frequency transistor 24 is in the OFF state, as shown by the arrow OFF in FIG. 3, the impedance when the high frequency circuit 20 side is viewed from the terminal 11a is low impedance.

  On the other hand, the length of the third transmission line 23 was similarly set to 90 μm, the gate terminal of the high frequency transistor 24 was set to 0 V, and the high frequency transistor 24 was turned on. Here, when the high-frequency transistor 24 is in the ON state, as shown in FIG. 3, the phase is rotated from the point of low impedance on the real axis due to the influence of the third transmission line 23 and the parasitic inductance component. I understand. However, as indicated by the arrow ON in FIG. 3, the amount of rotation is small and it has not been converted to high impedance. Therefore, when the high frequency transistor 24 is in the on state, the impedance when the high frequency circuit 20 side is viewed from the terminal 11a is not sufficiently high.

  Here, the ASK modulation circuit 10 of the present embodiment includes an open-ended transmission line 15 connected to the connection point 16. Thereby, it is possible to suppress a decrease in impedance due to the above-described influence.

  FIG. 4 is a diagram in which the high-frequency circuit 20 shown in FIG. In FIG. 4, a terminal 11b connected to the connection point 16 is provided as a point where the characteristics of the high-frequency circuit 20 are viewed.

  FIG. 5 is a Smith chart showing the reflection characteristic S11 viewed from the terminal 11b in the circuit configuration of the open-ended transmission line 15 and the high-frequency circuit 20 shown in FIG. Note that the positions indicated by arrows OFF and ON indicate reflection characteristics when the operating frequency is 60 GHz.

  When the reflection characteristic S11 shown in FIG. 5 is measured, the parameters of the GaAs substrate, the third transmission line 23, the high frequency transistor 24, the fourth transmission line 25, and the inductance 26 are the same as when the reflection characteristic S11 shown in FIG. Same as above. The open-ended transmission line 15 has a line width of 50 μm and a length of 200 μm.

  When the high-frequency transistor 24 is in the OFF state, as shown by the arrow OFF in FIG. 5, the impedance when the high-frequency circuit 20 side is viewed from the terminal 11b is substantially the same as the case where the open-ended transmission line 15 is not provided. ing.

  On the other hand, when the high-frequency transistor 24 is in the ON state, as shown by an arrow ON in FIG. 5, it can be seen that the impedance viewed from the terminal 11b toward the high-frequency circuit 20 is converted to a high impedance on the real axis.

  Next, FIG. 6 shows a graph showing the transmission characteristic S21 and the reflection characteristic S11 when the high-frequency transistor 24 is in the ON state in the ASK modulation circuit 10 shown in FIG. In FIG. 6, the vertical axis indicates the transmission characteristic S21 and the reflection characteristic S11 (dB), the horizontal axis indicates the frequency (GHz), and the solid line indicates the transmission characteristic S21 and the reflection characteristic S11 when the open-ended transmission line 15 is provided. The broken line indicates the transmission characteristic S21 and the reflection characteristic S11 when the open-ended transmission line 15 is not provided.

  When measuring the transmission characteristic S21 and the reflection characteristic S11 shown in FIG. 6, the parameters of the GaAs substrate, the third transmission line 23, the high frequency transistor 24, the fourth transmission line 25, and the inductance 26 are the reflection characteristics S11 shown in FIG. It was the same as that measured, and the open-ended transmission line 15 was the same as when the reflection characteristic S11 shown in FIG. 5 was measured. The first transmission line 13 and the second transmission line 14 have a line width of 50 μm and a length of 10 μm.

  Referring to FIG. 6, the pass characteristic S21 is improved when the open-ended transmission line 15 is provided rather than when the open-ended transmission line 15 is not provided. Further, the reflection characteristic S11 is reduced when the open-ended transmission line 15 is provided than when the open-ended transmission line 15 is not provided. Therefore, it is recognized that the provision of the open-ended transmission line 15 reduces the passage loss and improves the return loss.

  FIG. 7 is a graph showing the transmission characteristic S21 and the reflection characteristic S11 when the high frequency transistor 24 is in the OFF state in the ASK modulation circuit 10 shown in FIG. In FIG. 7, the vertical axis indicates the transmission characteristic S21 and the reflection characteristic S11 (dB), the horizontal axis indicates the frequency (GHz), and the solid line indicates the transmission characteristic S21 and the reflection characteristic S11 when the open-ended transmission line 15 is provided. The broken line indicates the transmission characteristic S21 and the reflection characteristic S11 when the open-ended transmission line 15 is not provided.

  Referring to FIG. 7, at the operating frequency of 60 GHz, it is recognized that both the transmission characteristic S21 and the reflection characteristic S11 hardly change regardless of whether or not the open-ended transmission line 15 is provided. Therefore, in the ASK modulation circuit 10, by providing the open-ended transmission line 15 without affecting the transmission characteristics S21 and the reflection characteristics S11 when the high frequency transistor 24 is in the off state, the transmission characteristics when the high frequency transistor 24 is in the on state. It becomes possible to improve S21 and the reflection characteristic S11.

  As described above, the ASK modulation circuit 10 according to the present embodiment has the third transmission line from the main transmission line side between the one point on the main transmission line from the input terminal 11 to the output terminal 12 that transmits a high-frequency signal and the ground. The transmission line 23 and the high-frequency transistor 24 include the high-frequency circuit 20 provided in this order, and the amplitude of the high-frequency signal is changed by switching the on / off state of the high-frequency transistor 24 based on the control signal. A connection point 16 where the main transmission line and the high-frequency circuit 20 are connected has a configuration including an open-ended transmission line 15.

  According to the above configuration, when the high-frequency transistor 24 is in the off state, the impedance of the high-frequency circuit 20 side viewed from the connection point 16 is substantially short-circuited (low impedance), thereby passing the high-frequency signal transmitted through the main transmission line. Reduce the amount.

  Conversely, when the high-frequency transistor 24 is in the on state, the impedance when the high-frequency circuit 20 side is viewed from the connection point 16 is set to high impedance.

  However, as the frequency becomes higher, for example, in the millimeter wave band, the impedance when the high frequency circuit 20 side is viewed from the connection point 16 is sufficiently high under the influence of the inductance component and the capacitance component in the high frequency circuit 20. Not.

  On the other hand, the ASK modulation circuit 10 according to the present embodiment includes the open-ended transmission line 15 at the connection point 16 on the main transmission line, so that the impedance is changed by the open-ended transmission line 15. Therefore, the combined impedance composed of the open-ended transmission line 15 and the high frequency circuit 20 can be made high impedance. Therefore, it is possible to suppress a decrease in impedance due to the above influence and reduce the passage loss of the high-frequency signal.

  Therefore, even in the millimeter wave band, it is possible to increase the difference between the amount of high-frequency signal passing when the high-frequency transistor 24 is on and the amount of high-frequency signal passing when the high-frequency transistor 24 is off. That is, the on / off ratio can be improved.

  Therefore, the ASK modulation circuit 10 of the present embodiment can reduce the passage loss of the high frequency signal and improve the on / off ratio. In addition, since the ASK modulation circuit 10 of the present embodiment is configured to connect the high-frequency circuit 20 and the open-ended transmission line 15 to the same portion (connection point 16) on the main transmission line, the circuit can be reduced in size. It will be advantageous.

  Further, in the ASK modulation circuit 10 of the present embodiment, the impedance switching when the high frequency circuit 20 side is viewed from the connection point 16 is performed by switching on / off of the high frequency transistor 24. As a result, it is possible to easily switch the impedance value when the high frequency circuit 20 side is viewed from the connection point 16 only by controlling the voltage signal or current signal supplied to the control terminal of the high frequency transistor 24.

  In addition, although the high frequency transistor 24 is used, not only this but a diode etc. may be used, for example.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to the drawings. Configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and explanation thereof is omitted.

  FIG. 8 is a circuit diagram showing a configuration example of the ASK modulation circuit 30 according to the present embodiment.

  As shown in FIG. 8, the ASK modulation circuit 30 of the present embodiment includes an input terminal 11, an output terminal 12, first transmission lines 13a and 13b, a second transmission line 14, open-ended transmission lines 15a and 15b, control signals. An input terminal 21 and high-frequency circuits 20a and 20b are provided.

  The input terminal 11, the first transmission line 13a, the second transmission line 14, the first transmission line 13b, and the output terminal 12 are connected in series in this order. The high-frequency signal is input to the input terminal 11, and is output as an ASK-modulated modulation signal from the output terminal 12 via the first transmission line 13a, the second transmission line 14, and the first transmission line 13b. Here, a path constituted by the input terminal 11, the first transmission line 13 a, the second transmission line 14, the first transmission line 13 b, and the output terminal 12 is defined as a main transmission path in the ASK modulation circuit 30.

  Further, the open-ended transmission line 15a and the high-frequency circuit 20a are connected to a connection point 16a between the first transmission line 13a and the second transmission line 14, and between the second transmission line 14 and the first transmission line 13b. The open-ended transmission line 15b and the high-frequency circuit 20b are connected to the connection point 16b.

  That is, the ASK modulation circuit 30 has a configuration including two each of the first transmission line 13, the open-ended transmission line 15, and the high-frequency circuit 20 of the ASK modulation circuit 10 of the above-described embodiment. The control signal input terminal 21 is commonly connected to the high frequency circuits 20a and 20b.

  Next, FIG. 9 is a graph showing the pass characteristic S21 at the operating frequency of 60 GHz in the ASK modulation circuit 30 when the high-frequency transistors 24a and 24b are turned on / off with respect to the line length of the second transmission line. In FIG. 9, the vertical axis indicates the pass characteristic S21 (dB), the horizontal axis indicates the line length (μm) of the second transmission line 14, and the solid line indicates the pass characteristic S21 when the open-ended transmission lines 15a and 15b are provided. The broken line shows the pass characteristic S21 when the open-ended transmission lines 15a and 15b are not provided.

  When measuring the pass characteristic S21 shown in FIG. 9, the ASK modulation circuit 30 was formed on a GaAs substrate having a substrate thickness of 100 μm. The parameters of the third transmission lines 23a and 23b, the high-frequency transistors 24a and 24b, the fourth transmission lines 25a and 25b, and the inductances 26a and 26b are the same as when the reflection characteristic S11 shown in FIG. The open transmission lines 15a and 15b were the same as when the reflection characteristic S11 shown in FIG. 5 was measured. The first transmission lines 13a and 13b have a line width of 50 μm and a length of 10 μm.

  Referring to FIG. 9, when the high-frequency transistors 24a and 24b are in the on state, the pass characteristic S21 is improved when the open-ended transmission lines 15a and 15b are provided rather than when the open-ended transmission lines 15a and 15b are not provided. is doing. Therefore, it can be seen that by providing the open-ended transmission lines 15a and 15b, the passage loss is reduced and the return loss is improved.

  On the other hand, when the high-frequency transistors 24a and 24b are in the OFF state, it is recognized that the pass characteristic S21 hardly changes even if the open-ended transmission lines 15a and 15b are provided. Therefore, in the ASK modulation circuit 30, the open-ended transmission lines 15a and 15b are provided without affecting the transmission characteristics S21 when the high-frequency transistors 24a and 24b are in the off state, so that the high-frequency transistors 24a and 24b are in the on-state. It is possible to improve the pass characteristic S21.

  Further, as shown in FIG. 9, when the line length of the second transmission line 14 is 400 μm to 500 μm, that is, when the length of the operating frequency is approximately a quarter wavelength, a large on / off ratio can be obtained. Recognize.

  This is because, when the line length of the second transmission line 14 is approximately a quarter wavelength of the operating frequency, the high-frequency transistors 24a and 24b are in an off state, and the connection point between the main transmission line and the high-frequency circuit is approximately. At the time of short circuit, the impedance when the connection point 16b is viewed from the connection point 16a and the impedance when the connection point 16b is viewed from the connection point 16b are converted into high impedance. This is because the high frequency signal can be further attenuated.

  In addition, when the line length of the second transmission line 14 is 100 μm to 400 μm, the effect of improving the pass characteristic S21 is great. Therefore, the ASK modulation circuit 30 is advantageous for downsizing.

  Further, the ASK modulation circuit 30 of the present embodiment has a configuration including two open-ended transmission lines 15 and two high-frequency circuits 20 of the ASK modulation circuit 10 of the above-described embodiment, but is not limited thereto.

  That is, a set of the open-ended transmission line 15 and the high-frequency circuit 20 at a plurality of positions (connection points 16a, 16b, 16c,...) Separated by a predetermined interval on the main transmission line, You may prepare. As a result, the on / off ratio can be further improved. Moreover, the said predetermined | prescribed space | interval has shown the line length of the 2nd transmission line 14, and as above-mentioned, the length of about 1/4 wavelength of an operating frequency is suitable.

[Embodiment 3]
The following will describe another embodiment of the present invention with reference to the drawings. Configurations other than those described in the present embodiment are the same as those in the first and second embodiments. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 and 2 are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 10 is a circuit diagram illustrating a configuration example of the ASK modulation circuit 40 according to the present embodiment.

  As shown in FIG. 10, in addition to the configuration of the ASK modulation circuit 30 of the second embodiment, the ASK modulation circuit 40 of the present embodiment includes fifth transmission lines 41a and 41b (second transmission lines), and And capacitors 42a and 42b (capacitance elements).

  The fifth transmission lines 41a and 41b have a length of approximately a quarter wavelength of the operating frequency. The fifth transmission line 41a has one terminal connected to the control terminal of the high-frequency transistor 24a, the other terminal connected to the resistor 22a, and grounded via the capacitor 42a. The fifth transmission line 41b has one terminal connected to the control terminal of the high-frequency transistor 24b and the other terminal connected to the resistor 22b and grounded via the capacitor 42b. In addition, since the structure and effect of 5th transmission line 41a and 41b are the same, below, 5th transmission line 41a is described as a representative.

  The ASK modulation circuit 30 of the second embodiment is configured to supply a control signal to the control terminal of the high-frequency transistor 24a via the resistor 22a, whereas the ASK modulation circuit 40 of the present embodiment is a high-frequency transistor. A control signal is supplied to the control terminal of the transistor 24a via the resistor 22a and the fifth transmission line 41a.

  According to the above configuration, the fifth transmission line 41a has a length of approximately a quarter wavelength of the high-frequency signal, so that the other terminal is grounded via the capacitor 42a. For this reason, for example, even if it is difficult to form a high resistance on the semiconductor substrate due to the material, the design rule, and the limited layout area, the fifth transmission line 41a from the control terminal of the high-frequency transistor 24a. The impedance viewed from the side can be made high impedance.

  As a result, the high-frequency transistor 24a can be prevented from leaking a high-frequency signal from the gate terminal via, for example, the gate-source capacitance or the gate-drain capacitance, and the passage loss can be reduced. Become.

[Embodiment 4]
The following will describe another embodiment of the present invention with reference to the drawings. Configurations other than those described in the present embodiment are the same as those in the first to third embodiments. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 3 are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 11 is a block diagram illustrating a configuration example of the ASK modulation circuit 50 according to the present embodiment.

  The ASK modulation circuit 50 according to the present embodiment further includes means for supplying a data signal to the ASK modulation unit 60 using the ASK modulation circuit 10, 30 or 40 according to the first to third embodiments.

  As shown in FIG. 11, the ASK modulation circuit 50 of the present embodiment includes a data input terminal 51, a data signal supply circuit 61 (control signal supply means, data signal supply means), and a DC voltage supply circuit 62 (control signal supply means). , A DC voltage supply means, a control signal input terminal 21, an input terminal 11, an output terminal 12, and an ASK modulator 60.

  The data signal supply circuit 61 includes a capacitor 52 (blocking unit), an amplitude limiting amplifier 53 (amplifying unit), a low-pass filter (LPF) 54 (extracting unit), an attenuator (attenuator) 55 (attenuating unit), and a capacitor 56. Has been.

  The DC voltage supply circuit 62 only needs to have a configuration capable of supplying a DC voltage. For example, the DC voltage supply circuit 62 includes a choke inductor 57 and a DC power supply 58.

  According to the above configuration, the data signal is input from the data input terminal 51, and the DC component is blocked by the capacitor 52. The data signal that has passed through the capacitor 52 is made to have a constant amplitude by the amplitude limiting amplifier 53, and unnecessary high frequency components are removed by the LPF. Thereafter, the data signal that has passed through the LPF 54 has a desired amplitude by the attenuator 55, and is combined with the DC signal from the DC voltage supply circuit 62 via the capacitor 56. This data signal becomes a control signal and is supplied to the ASK modulation unit 60 via the control signal input terminal 21.

  Thus, even when the amplitude of the data signal input to the data input terminal 51 varies from a predetermined value due to a loss of wiring or the like, the variation is absorbed by the amplitude limiting amplifier 53. Therefore, a data signal having a constant amplitude is input to the control signal input terminal 21 of the ASK modulation unit 60.

  Therefore, a stable modulation degree can be realized, so that a stable communication state can be ensured. Note that the desired amplitude may be determined according to the design, in order to realize a stable degree of modulation.

  In addition, the operating point (bias point) of the high-frequency transistor 24 in the ASK modulator 60 can be adjusted by superimposing the DC signal from the DC voltage supply circuit 62 on the data signal at the time of passing through the capacitor 56. Become. Therefore, it is possible to adjust the on / off ratio and reduce the insertion loss in the ASK modulation circuit 50.

  In addition, the ASK modulation circuit 50 according to the present embodiment is configured to include the data signal supply circuit 61 and the DC voltage supply circuit 62. It can be set as a suitable structure.

[Embodiment 5]
The following will describe another embodiment of the present invention with reference to the drawings. Configurations other than those described in the present embodiment are the same as those in the first to fourth embodiments. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 4 are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 12 is a block diagram illustrating a configuration example of the transmission device 70 according to the present embodiment.

  As shown in FIG. 12, the transmission device 70 according to the present embodiment includes an oscillation circuit 71, a frequency multiplication circuit 72, an ASK modulation circuit 73, a filter circuit 74, an amplification circuit 75, and an antenna 76.

  The oscillation circuit 71 may have any configuration that can output a signal having a constant frequency and amplitude. For example, a DRO (Dielectric Resonator Oscillator) can be used.

  The ASK modulation circuit 73 supplies a data signal to the ASK modulation circuits 10, 30, 40, and 50 of the first to fourth embodiments and the ASK modulation circuit 10, 30, or 40 of the first to third embodiments. A circuit or the like further comprising means is used.

  According to the above configuration, the signal generated by the oscillation circuit 71 is multiplied by the frequency multiplication circuit 72 to generate a carrier wave signal. The carrier signal is modulated by the data signal input in the ASK modulation circuit 73, and unnecessary signals are removed by the filter circuit 74. The modulated signal that has passed through the filter circuit 74 is amplified by the amplifier circuit 75 and transmitted by the antenna 76.

  Thus, by providing the ASK modulation circuit 73, it is possible to perform ASK modulation with reduced passage loss even in the millimeter wave band.

  Further, since the ASK modulation circuit 73 has a simple configuration, the configuration circuits (such as the oscillation circuit 71, the frequency multiplication circuit 72, and the filter circuit 74) adjacent to the ASK modulation circuit 73 in the transmission device 70 are integrated with the ASK modulation circuit. Even in this case, it is possible to suppress an increase in chip area. Therefore, the transmission device 70 can be reduced in size.

  Further, the frequency multiplier circuit 72 may have a function of multiplying the signal generated from the oscillation circuit 71 and further amplifying it.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  The present invention can be applied to an ASK modulation circuit in which the amplitude of a high-frequency signal is changed based on a data signal by a switch circuit, but is not limited to this and can be applied to other fields. For example, the present invention can also be applied to a circuit that switches between passing / reflecting a signal by switching a switch circuit on and off by supplying a control signal.

It is a circuit diagram which shows one Embodiment of the ASK modulation circuit in this invention. It is a circuit diagram which shows the structure of the high frequency circuit in the said ASK modulation circuit. 3 is a Smith chart showing reflection characteristics corresponding to the configuration of FIG. 2. It is a circuit diagram which shows the structure of the high frequency circuit in the said ASK modulation circuit, and a front-end | tip open transmission line. It is a Smith chart which shows the reflective characteristic corresponding to the structure of FIG. It is a graph which shows the passage characteristic and reflection characteristic in the said ASK modulation circuit. It is a graph which shows the passage characteristic and reflection characteristic in the said ASK modulation circuit. It is a circuit diagram which shows other embodiment of the ASK modulation circuit in this invention. It is a graph which shows the passage characteristic in the said ASK modulation circuit. It is a circuit diagram which shows other embodiment of the ASK modulation circuit in this invention. It is a block diagram which shows other embodiment of the ASK modulation circuit in this invention. It is a block diagram which shows one Embodiment of the transmitter in this invention. It is a circuit diagram which shows the structure of the conventional switch circuit.

Explanation of symbols

10, 30, 40, 50 ASK modulation circuit 11 Input terminal 12 Output terminal 13, 13a, 13b First transmission line 14 Second transmission line 15, 15a, 15b Open-ended transmission line 16, 16a, 16b Connection point 20, 20a, 20b High-frequency circuit 21 Control signal input terminal 22, 22a, 22b Resistor 23, 23a, 23b Third transmission line (first transmission line)
24, 24a, 24b High-frequency transistors (nonlinear elements)
25, 25a, 25b Fourth transmission line 26, 26a, 26b Inductance 41a, 41b Fifth transmission line (second transmission line)
42a, 42b Capacitors (capacitance elements)
51 Data input terminal 52 Capacitor (blocking means)
53 Amplitude limiting amplifier (amplifying means)
54 Low-pass filter (extraction means)
55 Attenuator (Attenuation means)
60 ASK modulation unit (ASK modulation circuit)
61 Data signal supply circuit (control signal supply means, data signal supply means)
62 DC voltage supply circuit (control signal supply means, DC voltage supply means)
70 Transmission Device 73 ASK Modulation Circuit S11 Reflection Characteristic S21 Passage Characteristic

Claims (6)

A high-frequency circuit having a first transmission line and a non-linear element provided in this order from the main transmission line side between a point on the main transmission line that transmits a high-frequency signal and the ground is provided as a control signal. An ASK modulation circuit that changes the amplitude of the high-frequency signal by switching the operation state of the nonlinear element based on
At the connection point where the main transmission line and the high-frequency circuit are connected, an open-ended transmission line is provided ,
The nonlinear element is a high-frequency transistor,
A second transmission line having a length of approximately a quarter wavelength of the high-frequency signal, one terminal connected to the control terminal of the high-frequency transistor, and the other terminal grounded via a capacitive element;
Data signal supply means for supplying a data signal to the other terminal of the second transmission line;
DC voltage supply means for supplying a DC voltage to the other terminal of the second transmission line . A high-frequency circuit having a first transmission line and a non-linear element provided in this order from the main transmission line side between a point on the main transmission line that transmits a high-frequency signal and the ground is provided as a control signal. An ASK modulation circuit that changes the amplitude of the high-frequency signal by switching the operation state of the nonlinear element based on
The high-frequency circuit is provided at a plurality of positions separated by a predetermined interval on the main transmission line,
A plurality of connection points to which the main transmission line and the high frequency circuits provided at the plurality of positions are connected, respectively, are provided with open-ended transmission lines, respectively .
The nonlinear element is a high-frequency transistor,
A second transmission line having a length of approximately a quarter wavelength of the high-frequency signal, one terminal connected to the control terminal of the high-frequency transistor, and the other terminal grounded via a capacitive element;
Data signal supply means for supplying a data signal to the other terminal of the second transmission line;
DC voltage supply means for supplying a DC voltage to the other terminal of the second transmission line . The first transmission line has one terminal connected to one point on the main transmission line, the other terminal connected to the first conduction terminal of the high-frequency transistor,
3. The ASK modulation circuit according to claim 1, wherein the high-frequency transistor has the control signal supplied to a control terminal and the second conduction terminal is grounded. 4.   3. The ASK modulation circuit according to claim 2, wherein the predetermined interval is a length of approximately a quarter wavelength of an operating frequency. The data signal supply means includes:
Blocking means for blocking the DC component of the input data signal;
Amplifying means for making the amplitude of the data signal output from the blocking means constant;
Extraction means for removing unnecessary signal components of the data signal output from the amplification means;
3. The ASK modulation circuit according to claim 1, further comprising attenuation means for setting the amplitude of the data signal output from the extraction means to a predetermined value. A transmission device that includes an ASK modulation circuit that performs ASK modulation on a high-frequency signal, and that transmits a modulation signal output from the ASK modulation circuit.
The ASK modulation circuit, the transmission device, characterized in that the ASK modulation circuit according to any one of claims 1-5.

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