JP2009135619A - Gunn diode voltage-controlled oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Gunn diode voltage-controlled oscillator keeping an excellent linear characteristic, and having a large modulated width. <P>SOLUTION: This Gunn diode voltage-controlled oscillator includes at least two varactor diode modulation circuits; one-side varactor diode modulation circuit has a modulation characteristic where a modulation increase width is increased as an applied modulation voltage is increased; and the other-side varactor diode modulation circuit has a modulation characteristic where the modulation increase width is decreased as the applied modulation voltage is increased. An oscillation frequency is modulated by applying modulation voltages to the respective varactor diode modulation circuits independently and simultaneously. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oscillator using a microwave or millimeter-wave Gunn diode, and more particularly to a Gunn diode voltage controlled oscillator which has a wide modulation width and an improved linearity of modulation characteristics.

  FIG. 8 shows a surface view (a) and a cross-sectional view (b) of a gallium arsenide (GaAs) surface-mount type Gunn diode 200 having a mesa structure used for a microwave or millimeter wave band oscillator. A first semiconductor layer 23 made of high-concentration n-type GaAs, an active layer 24 made of low-concentration n-type GaAs, and a high-concentration n-type GaAs are formed on a semiconductor substrate 22 made of high-concentration n-type GaAs by MBE or MOCVD. The second semiconductor layer 25 made of is sequentially stacked, and has a mesa structure in order to reduce the area of the electron travel space. 26 is an insulator, 27 is an anode electrode, 28 is a cathode electrode, 29 is an anode bump formed by conductive protrusions, and 30 is a cathode bump formed by conductive protrusions. The insulator 26 is formed in a cylindrical shape by boron implantation from the upper surface to the boundary between the active layer 24 and the first semiconductor layer 23, and the anode electrode 27 is separated from the cathode electrode 28, and the inner side surrounded by the insulator 26 is formed. A functional part of a Gunn diode is formed by the active layer 24 and the second semiconductor layer 25. In FIG. 8, six cylindrical portions surrounded by the insulator 26 are formed, and Gunn diode function portions are formed under the six anode electrodes 27, respectively. The anode bumps 29 are formed on all the upper surfaces of the six anode electrodes 27, respectively, and the cathode bumps 30 are three on one side so that a group of anode bumps 29 are sandwiched from both sides of the upper surface of the cathode electrode 28. A total of six are formed. This type of surface-mount type Gunn diode is disclosed in Patent Document 1.

  In addition to the surface-mount type Gunn diode as described above, it has a Gunn diode functional part composed of the first semiconductor layer 23, the active layer 24 and the second semiconductor layer 25, and the cathode electrode on the semiconductor substrate side. In some cases, the Gunn diode element is formed and assembled into a pill type package and used as a pill type Gunn diode.

  FIG. 9 is a partial cross-sectional view of a Gunn diode voltage controlled oscillator configured by mounting the Gunn diode 200 of FIG. 8 on the oscillation circuit 100 formed of a microstrip line. FIG. 10 is an overall perspective view of a Gunn diode voltage controlled oscillator composed of a microstrip line. In the oscillation circuit 100, an output signal line 12 constituted by a microstrip line and an open stub line 17 constituting a resonator are formed on the upper surface of a dielectric substrate 11, and the open stub line 17 is sandwiched from both sides. The surface ground electrode 13 for two Gunn diodes is formed, and the back surface ground electrode 14 is formed on the back surface, and each surface ground electrode 13 and the back surface ground electrode 14 are electrically connected by the via hole 15 penetrating the dielectric substrate 11. It has been made. On the output signal line 12, a Gunn diode bias electrode 16 for supplying power to the Gunn diode 200 is formed. The Gunn diode 200 is mounted such that the central anode bump 29 is connected to the signal line 12 and the open stub line 17, and the cathode bumps 30 on both sides are connected to the surface ground electrodes 13 for the Gunn diodes on both sides.

In the varactor diode 300, an anode bump (not shown) connected to the anode is installed in the vicinity of the open stub line 17, and a cathode bump (connected to the cathode) is connected to the transmission line 18 coupled to the open stub line 17 in high frequency. (Not shown) is mounted so as to be connected to the back-open stub line 21 installed in the vicinity of the transmission line 18. A surface ground electrode 19 for varactor diode is formed on the transmission line 18, and a bias electrode 20 for varactor diode is formed on the back-open stub line 21. A modulation voltage is applied to the bias electrode 20, and the oscillation frequency is modulated by changing the capacitance value of the varactor diode 300, thereby constituting a Gunn diode voltage controlled oscillator. This type of voltage-controlled Gunn diode oscillation circuit is disclosed in Patent Document 2. Reference numeral 31 denotes a heat dissipation base, which is not shown in FIG.
JP 2003-152246 A Japanese Patent Laid-Open No. 2002-9551

  Such a conventional Gunn diode voltage controlled oscillator has a problem that a sufficient modulation width and good linearity cannot be obtained. An object of the present invention is to provide a Gunn diode voltage controlled oscillator having a wide modulation width while maintaining good linearity.

  In order to achieve the above object, according to the first aspect of the present invention, a Gunn diode and a varactor diode are mounted on a conductor circuit provided on a dielectric substrate, and the conductor circuit includes a line on the upper surface of the dielectric substrate. A Gunn diode comprising a varactor diode modulation circuit which is composed of a microstrip line having a back surface ground electrode on the entire back surface of the dielectric substrate, and modulates the oscillation frequency by applying a modulation voltage to the varactor diode connected to the line. In the voltage controlled oscillator, at least two varactor diode modulation circuits are provided, and one of the varactor diode modulation circuits has a modulation characteristic in which the modulation increase width increases as the applied modulation voltage increases, and the other varactor diode modulation circuit. Is a modulation characteristic in which the modulation increase width decreases as the applied modulation voltage increases. , The varactor diode modulation circuit, each independently, and by applying a modulation voltage simultaneously, characterized by modulating the oscillation frequency.

  The invention according to claim 2 of the present application mounts a Gunn diode and a varactor diode on a conductor circuit provided on a dielectric substrate, and the conductor circuit is formed on a signal electrode on the upper surface of the dielectric substrate, and on the signal electrode. A continuous open stub line; a surface ground electrode connected to a back ground electrode through a via hole penetrating the dielectric substrate; a transmission line connected in high frequency with the open stub line; and a back open stub line. It is composed of a microstrip line having the back surface ground electrode on the entire back surface of the dielectric substrate, and the Gunn diode connects either the anode or the cathode to the open stub line, and either the cathode or the anode. Is connected to the surface ground electrode, and the varactor diode is connected in front of either the anode or the cathode. A Gunn diode voltage having a varactor diode modulation circuit that is connected to a transmission line, has either a cathode or an anode connected to the back open stub line, and applies a modulation voltage to the back open stub line to modulate the oscillation frequency. The controlled oscillator includes at least two varactor diode modulation circuits. One of the varactor diode modulation circuits has a modulation characteristic in which the modulation increase width increases as the modulation voltage to be applied increases, and the other varactor diode modulation circuit has The modulation characteristics are such that the modulation increase width decreases as the applied modulation voltage increases, and the oscillation frequency is modulated by applying the modulation voltage independently and simultaneously to the varactor diode modulation circuit. And

  The invention according to claim 3 of the present application is characterized in that, in the Gunn diode voltage controlled oscillator according to claim 2, the width of the transmission line coupled to the open stub line at a high frequency is different for each varactor diode modulation circuit. To do.

  The invention according to claim 4 of the present application is the Gunn diode voltage controlled oscillator according to any one of claims 1 to 3, wherein the varactor diode modulation circuit has a modulation increase width that increases as the modulation voltage applied increases. When the modulation voltage to be applied is increased, the modulation characteristic becomes smaller in modulation increase width, and the one varactor diode modulation circuit has a voltage range in which the modulation increase width increases as the modulation voltage applied increases. A modulation voltage is applied, and the other varactor diode modulation circuit modulates the oscillation frequency by applying the modulation voltage in a voltage range in which the modulation increase width decreases as the modulation voltage applied increases. It is characterized by that.

  The Gunn diode voltage controlled oscillator of the present invention includes at least two varactor diode modulation circuits, and combines the modulation characteristics of one varactor diode modulation circuit with the modulation characteristics of the other varactor diode modulation circuit, thereby providing one varactor diode modulation circuit. Compared with the case of providing only one, it is possible to obtain characteristics with a wide modulation width while maintaining linearity.

  The modulation characteristics of the varactor diode modulation circuit can be easily adjusted by changing the degree of coupling with the open stub electrode by changing the width of the transmission line on which the varactor diode is mounted. Also, using two varactor diodes with almost equal characteristics, one is used as a varactor diode modulation circuit that is used in a voltage range with a small applied voltage, and the other is combined as a varactor diode modulation circuit that is used in a voltage range with a large applied voltage. Can be easily adjusted.

  Hereinafter, the Gunn diode voltage controlled oscillator of the present invention will be described in detail.

  FIG. 1 is an explanatory diagram of a first embodiment of a Gunn diode voltage controlled oscillator according to the present invention using a surface mount Gunn diode 200. As shown in FIG. 8, the Gunn diode 200 is a surface-mounted Gunn diode in which an anode bump 29 is protruded at the center of the bottom surface, and a cathode bump 30 is formed on both sides. The Gunn diode 200 is an output diode composed of a microstrip line. The signal line 12 is mounted as described later.

The oscillation circuit has a good semi-insulating property with a specific resistance of 10 ⁶ Ω · cm or more and a thermal conductivity of 140 W / mK or more such as aluminum nitride (AlN), silicon (Si), silicon carbide (SiC), diamond, etc. This substrate is a dielectric substrate 11, and a gun for supplying power to the output signal line 12, the surface ground electrode 13 for the Gunn diode, the open stub line 17, and the Gunn diode 200 on the surface of the dielectric substrate 11. A bias electrode 16 for the diode is formed. The transmission line 18A coupled to the open stub line 17 in high frequency, the back open stub line 21A installed near the transmission line 18A, the bias electrode 20A for varactor diode for applying a modulation voltage to the varactor diode 300A, and the varactor A surface ground electrode 19A for the diode is formed. Furthermore, a transmission line 18B coupled to the open stub line 17 in a high frequency manner, a back open stub line 21B installed in the vicinity of the transmission line 18B, a bias electrode 20B for a varactor diode for applying a modulation voltage to the varactor diode 300B, A surface ground electrode 19B for the varactor diode is formed. Each front surface ground electrode 13, 19 </ b> A, 19 </ b> B is connected to the back surface ground electrode 14 through a via hole 15 penetrating the dielectric substrate 11.

  The Gunn diode 200 is mounted such that the central anode bump 29 is connected to the signal line 12 and the open stub line 17, and the cathode bumps 30 on both sides are connected to the surface ground electrodes 13 for the Gunn diodes on both sides. The varactor diode 300A is mounted such that an anode bump (not shown) connected to the anode is connected to the transmission line 18A, and a cathode bump (not shown) connected to the cathode is connected to the back-open stub line 21A. 1 varactor diode modulation circuit. Further, the varactor diode 300B is mounted such that an anode bump (not shown) connected to the anode is connected to the transmission line 18B, and a cathode bump (not shown) connected to the cathode is connected to the back-open stub line 21B. A second varactor diode modulation circuit is configured.

  In the Gunn diode voltage controlled oscillator having such a configuration, a bias voltage is applied to the Gunn diode 200 via the Gunn diode bias electrode 16, and a bias voltage is applied to the varactor diode 300A via the varactor diode bias electrode 20A. At the same time, by applying a bias voltage to the varactor diode 300B via the varactor diode bias electrode 20B, the oscillation frequency of the output signal of the Gunn diode 200 can be modulated by the two varactor diode modulation circuits.

  In this embodiment, the modulation voltage applied to one varactor diode modulation circuit and the modulation voltage applied to the other varactor diode modulation circuit are set as follows.

  FIG. 2 shows a first varactor diode modulation circuit (displayed as a first modulation circuit) mounted with a varactor diode 300A and a second varactor diode modulation circuit (displayed as a second modulation circuit) mounted with a varactor diode 300B. It is a graph which shows a modulation characteristic. As can be seen from FIG. 2, the oscillation frequency changes as the modulation voltage applied to the varactor diode increases. As the modulation voltage is gradually increased from 0 V, the modulation increase width (the oscillation frequency width that changes when the voltage is increased from a predetermined voltage to a constant width) gradually increases as the modulation voltage increases. It can be seen that there is a region where the modulation increases, and when the modulation voltage increases to some extent, there is a region where the modulation increase width gradually decreases as the modulation voltage increases.

  The present invention provides a Gunn diode voltage controlled oscillator having good linearity and a wide modulation width by using a combination of varactor diode modulation circuits having different modulation characteristics with different modulation increase widths. is doing. As an example, in the case of the varactor diode modulation circuit having the modulation characteristics shown in FIG. 2, the range of 0 to 10V is a region where the modulation increase width gradually increases, and the range of 10 to 15V is the modulation increase width gradually. This is a smaller area. Therefore, a configuration is adopted in which a modulation voltage of 0 to 10 V is applied to the first varactor diode modulation circuit, and a modulation voltage of 10 to 15 V is simultaneously applied to the second varactor diode modulation circuit. Specifically, when a modulation voltage of 0, 1, 2, 3,... 10 V is applied to the first varactor diode modulation circuit, 10.0, 10.5, The modulation voltages were applied independently and simultaneously so as to be 11.0, 11.5.

  FIG. 3 is a graph showing the modulation characteristics of the Gunn diode voltage controlled oscillator when the two varactor diode modulation circuits shown in FIG. 2 are used. In FIG. 3, the modulation voltage indicates the modulation voltage applied to the first varactor diode modulation circuit. As shown in FIG. 3, when the modulation voltage is changed in the range of 0 to 10 V (the modulation voltage of the second varactor diode modulation circuit is changed in the range of 10 to 15 V), the modulation width is 210 MHz, linearity The result was 0.95%. For comparison, when only the first varactor diode modulation circuit shown in FIG. 1 is used (modulation voltage 0 to 10 V), the modulation width is 122 MHz and the linearity is 7.4%. Similarly, the second varactor diode is used. When only the modulation circuit is used (modulation voltage 0 to 10 V), the modulation width is 159 MHz and the linearity is 7.5%, which clearly shows that the characteristics of the present invention are excellent.

  In the present embodiment, the number of varactor diode modulation circuits is not limited to two. By increasing the number of varactor diode modulation circuits, the modulation width can be improved, the linearity can be improved, and the oscillation frequency can be finely adjusted. Become. The modulation voltage to be applied is appropriately set so as to obtain a desired frequency characteristic. For example, in the case of a configuration including two varactor diode modulation circuits, the modulation voltage to be applied is described later. If the condition is set so that the straight line of the modulation characteristic intersects almost half of the distance, the adjustment can be easily made. The varactor diode modulation circuit is not limited to one having different modulation characteristics as shown in FIG. 2, and may have substantially the same modulation characteristics, and the modulation voltage to be applied is desired according to the modulation characteristics. What is necessary is just to set suitably so that the frequency characteristic of this can be obtained.

  FIG. 4 is an explanatory diagram of a second embodiment of the Gunn diode voltage controlled oscillator of the present invention using the surface mount type Gunn diode 200. As in the first embodiment, the Gunn diode 200 is a surface-mounted Gunn diode in which the anode bump 29 is formed at the center of the bottom surface and the cathode bumps 30 are formed on both sides as shown in FIG. Is mounted on the output signal line 12 configured as described below.

As described with reference to FIG. 1, the oscillation circuit has a specific resistance of 10 ⁶ Ω · cm or more, such as aluminum nitride (AlN), silicon (Si), silicon carbide (SiC), diamond, etc., and a thermal conductivity of 140 W / cm. A dielectric substrate 11 is an excellent semi-insulating substrate of mK or more, and an output signal line 12, a surface ground electrode 13 for a Gunn diode, an open stub line 17, and a Gunn diode 200 are formed on the surface of the dielectric substrate 11. A bias electrode 16 for a Gunn diode for supplying power to is formed. Also, a transmission line 18C coupled to the open stub line 17 in high frequency, a back open stub line 21C installed in the vicinity of the transmission line 18C, a bias electrode 20C for varactor diode for applying a modulation voltage to the varactor diode 300C, and a varactor A surface ground electrode 19C for the diode is formed. Further, in the present embodiment, a narrow transmission line 18D coupled to the open stub line 17 in high frequency, a back open stub line 21D installed near the transmission line 18D, and a varactor for applying a modulation voltage to the varactor diode 300D. A bias electrode 20D for the diode and a surface ground electrode 19D for the varactor diode are formed. The transmission line 18 </ b> C and the transmission line 18 </ b> D are formed so as to have different widths, so that the degree of coupling with the open stub line 17 is different. Each of the front surface ground electrodes 13, 19 </ b> C, 19 </ b> D is connected to the back surface ground electrode 14 through a via hole 15 penetrating the dielectric substrate 11.

  The Gunn diode 200 is mounted such that the central anode bump 29 is connected to the signal line 12 and the open stub line 17, and the cathode bumps 30 on both sides are connected to the surface ground electrodes 13 for the Gunn diodes on both sides. The varactor diode 300C is mounted such that an anode bump (not shown) connected to the anode is connected to the transmission line 18C, and a cathode bump (not shown) connected to the cathode is connected to the back-open stub line 21C. This constitutes a varactor diode modulation circuit. Furthermore, the varactor diode 300D is mounted such that an anode bump (not shown) connected to the anode is connected to the transmission line 18D, and a cathode bump (not shown) connected to the cathode is connected to the back-open stub line 21D. A fourth varactor diode modulation circuit is configured.

  In the Gunn diode voltage controlled oscillator having such a configuration, a bias voltage is applied to the Gunn diode 200 through the Gunn diode bias electrode 16, and a bias voltage is applied to the varactor diode 300C through the Varactor diode bias electrode 20C. In addition, by applying a bias voltage to the varactor diode 300D via the varactor diode bias electrode 20D, the oscillation frequency of the output signal of the Gunn diode 200 can be modulated by the two varactor diode modulation circuits.

  In particular, in this embodiment, the modulation voltage applied to one varactor diode modulation circuit and the modulation voltage applied to the other varactor diode modulation circuit are set as follows, and the oscillation frequency is changed by changing the shape of the transmission line. It is a great feature to adjust the modulation of.

  FIG. 5 shows the modulation increase widths of the third varactor diode modulation circuit on which the varactor diode 300C is mounted and the fourth varactor diode modulation circuit on which the varactor diode 300D is mounted. As described above, the modulation increase width is represented by a frequency width that changes when each modulation voltage is increased from a constant voltage. As shown in FIG. 5, it can be seen that both the third varactor diode modulation circuit and the fourth varactor diode modulation circuit have the maximum modulation increase when the modulation voltage is 10V. It can also be seen that the modulation width of the fourth varactor diode modulation circuit in which the width of the transmission line 18D is formed narrower than that of the third varactor diode modulation circuit.

  By using a combination of varactor diodes having different modulation increase widths as described above, a Gunn diode voltage controlled oscillator having a good linearity and a wide modulation width can be configured as in the first embodiment.

  Next, a method for adjusting the modulation characteristics using the varactor diode modulation circuit having the characteristics shown in FIG. 5 will be described. In FIG. 6, a modulation voltage of 10 to 15 V is applied to the third varactor diode modulation circuit (denoted as the third modulation circuit), and the fourth varactor diode modulation circuit (denoted as the fourth modulation circuit) is applied. Indicates a modulation increase width when a modulation voltage of 1 to 10 V is applied. In this case, as shown in FIG. 5, the modulation voltage is about 3 V and the straight lines intersect. On the other hand, in FIG. 7, a modulation voltage of 0 to 10 V is applied to the third varactor diode modulation circuit (denoted as the third modulation circuit), and the fourth varactor diode modulation circuit (denoted as the fourth modulation circuit). Shows the modulation increase width when a modulation voltage of 10 to 15 V is applied. In the case shown in FIG. 6, the modulation voltage is about 5V and the straight lines intersect. As a result of examining the modulation characteristics of the Gunn diode voltage controlled oscillator using such a varactor diode modulation circuit, the linearity was 2.63% when the varactor diode modulation circuit shown in FIG. 6 was used. On the other hand, when the varactor diode modulation circuit shown in FIG. 7 was used, the linearity was 0.95%. Generally, by adjusting so that the modulation characteristic where the modulation increase width increases to the right and the modulation characteristic which decreases conversely are crossed at almost half of the change width of the modulation voltage to be set. It was found that an excellent Gunn diode voltage controlled oscillator can be obtained. The slope of the straight line indicating the modulation characteristic may be adjusted by changing the modulation voltage width to be applied.

  As mentioned above, although the Example of this invention was described, it cannot be overemphasized that this invention is not limited to the said Example. For example, the shape of the conductor line and the modulation voltage applied to the varactor diode may be set as appropriate in order to obtain desired oscillation characteristics. Further, the Gunn diode 200 is not limited to the surface mount type, such as using a pill type Gunn diode assembled in a pill type package by forming an anode electrode and a cathode electrode on opposite sides so as to sandwich the Gunn diode functional part. . When a pill type Gunn diode is used, the surface ground electrode 13 is not necessarily required. The varactor diode is not limited to the surface mount type.

It is explanatory drawing of the Gunn diode voltage control oscillator which is the 1st Example of this invention. It is a figure explaining the modulation | alteration characteristic of the varactor diode modulation circuit of the 1st Example of this invention. It is a figure explaining the modulation characteristic of the Gunn diode voltage controlled oscillator which is the 1st example of the present invention. It is explanatory drawing of the Gunn diode voltage control oscillator which is the 2nd Example of this invention. It is a figure explaining the modulation characteristic of the varactor diode modulation circuit of the 2nd Example of this invention. It is a figure explaining the adjustment method of the modulation characteristic of the Gunn diode voltage controlled oscillator of the present invention. It is a figure explaining the adjustment method of the modulation characteristic of the Gunn diode voltage controlled oscillator of the present invention. It is explanatory drawing of the conventional Gunn diode. It is a partial sectional view of a conventional Gunn diode voltage controlled oscillator. It is explanatory drawing of the conventional Gunn diode voltage control oscillator.

Explanation of symbols

100: Oscillator circuit, 200: Gunn diode, 300A, 300B, 300C: Varactor diode, 11: Dielectric substrate, 12: Signal line, 13: Surface ground electrode for Gunn diode, 14: Back surface ground electrode, 15: Via hole , 16: bias electrode for Gunn diode, 17: open stub line, 18, 18A, 18B, 18C: transmission line, 19, 19A, 19B, 19C: surface ground electrode for varactor diode, 20, 20A, 20B, 20C : Bias electrode for varactor diode, 21, 21A, 21B, 21C: back-open stub line, 22: semiconductor substrate, 23: first semiconductor layer, 24: active layer, 25: second semiconductor layer, 26: insulation 27: anode electrode, 28: cathode electrode, 29: anode bump, 30: cathode van , 31: radiator base

Claims (4)

A Gunn diode and a varactor diode are mounted on a conductor circuit provided on a dielectric substrate,
The conductor circuit comprises a microstrip line having a line on the top surface of the dielectric substrate and a back ground electrode on the entire back surface of the dielectric substrate, and applies a modulation voltage to a varactor diode connected to the line. In a Gunn diode voltage controlled oscillator with a varactor diode modulation circuit that modulates the oscillation frequency by
Comprising at least two varactor diode modulation circuits;
One varactor diode modulation circuit has a modulation characteristic that increases the modulation increase width as the applied modulation voltage increases, and the other varactor diode modulation circuit increases the modulation increase width as the applied modulation voltage increases. The modulation characteristics become smaller,
A Gunn diode voltage controlled oscillator characterized by modulating an oscillation frequency by applying a modulation voltage to each of the varactor diode modulation circuits independently and simultaneously. A Gunn diode and a varactor diode are mounted on a conductor circuit provided on a dielectric substrate,
The conductor circuit has a signal electrode on the top surface of the dielectric substrate, an open stub line continuous to the signal electrode, a surface ground electrode connected to a back ground electrode through a via hole penetrating the dielectric substrate, A transmission line that is connected to the open stub line at a high frequency, and a back open stub line, and is configured by a microstrip line that includes the back surface ground electrode on the entire back surface of the dielectric substrate,
The Gunn diode has either an anode or a cathode connected to the open stub line, and either a cathode or an anode connected to the surface ground electrode,
The varactor diode has either an anode or a cathode connected to the transmission line, and either a cathode or an anode connected to the back-open stub line,
In a Gunn diode voltage controlled oscillator including a varactor diode modulation circuit that modulates an oscillation frequency by applying a modulation voltage to the back-open stub line,
Comprising at least two varactor diode modulation circuits;
One varactor diode modulation circuit has a modulation characteristic that increases the modulation increase width as the applied modulation voltage increases, and the other varactor diode modulation circuit increases the modulation increase width as the applied modulation voltage increases. The modulation characteristics become smaller,
A Gunn diode voltage controlled oscillator characterized by modulating an oscillation frequency by applying a modulation voltage to each of the varactor diode modulation circuits independently and simultaneously. The Gunn diode voltage controlled oscillator according to claim 2,
A Gunn diode voltage controlled oscillator, wherein a width of the transmission line coupled to the open stub line at a high frequency is different for each varactor diode modulation circuit. The Gunn diode voltage controlled oscillator according to any one of claims 1 to 3,
The varactor diode modulation circuit has a modulation characteristic that the modulation increase width increases as the applied modulation voltage increases, and the modulation increase width decreases when the applied modulation voltage is further increased.
The one varactor diode modulation circuit applies the modulation voltage in a voltage range in which the modulation increase width increases as the modulation voltage applied increases, and the other varactor diode modulation circuit applies the modulation applied. A Gunn diode voltage controlled oscillator, wherein the oscillation frequency is modulated by applying the modulation voltage in a voltage range in which the modulation increase width decreases as the voltage increases.

Images