JPH088448B2 - Microwave oscillator circuit - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oscillation circuit that can be used in equipment using microwaves such as sanitary communication equipment.

2. Description of the Related Art In recent years, research and development of new wireless communication systems typified by satellite communication have been actively conducted. Many of these new wireless communication systems use microwaves. Further, research and development of microwave oscillating circuits, which play an important role in microwave devices, are being actively conducted.

Hereinafter, an example of a conventional microwave oscillation circuit will be described with reference to the drawings.

FIG. 13 shows a configuration diagram of a conventional microwave oscillation circuit. In FIG. 13, 51 is a field effect transistor (hereinafter abbreviated as FET), 52 is a drain terminal, 55 is a first open-ended strip line, 56, 58 and 67 are low pass filters, and 57 and 62 are strip lines. , 59 and 68 are resistors, 60 is an interdigital DC blocking circuit, 61 is a load resistor, 63 is a dielectric resonator, 64 is a terminating resistor, 65 is a second open-ended strip line, and 66 is a power supply terminal. .

The operation of the conventional microwave oscillation circuit configured as described above will be described below.

First, the drain terminal 52 of the FET 51 is connected to a first open strip line 55, and the microwave impedance at the drain terminal 52 is adjusted by the first open strip line 55. Also,
The low-pass filter 56 connected to the drain terminal 52 prevents the oscillated microwave from leaking to the power supply terminal 66. Next, a strip line 57 is connected to the source terminal 53 of the FET 51, and an oscillation output is taken out from the strip line 57 and supplied to the load resistor 61. In addition, the low-pass filter 58 connected to the source terminal 53
Prevents the oscillated microwave from leaking to the resistor 59. The resistor 59 is a bias resistor for the source terminal 53. Next, the strip line 6 is connected to the gate terminal 54 of the FET 51.
2 is connected, and a dielectric resonator 63 is electromagnetically coupled to this strip line 62. This dielectric resonator
63 has a very high Q and is intended to stabilize the oscillation frequency. Further, the other end of the strip line 62 is connected to a strip line 65 having a second open end through a terminating resistor 64. The resistance value of this terminating resistor 64 is the strip line 65.
Is designed to have the same characteristic impedance as, and the second open strip line 65 is designed to have a length of 1/4 of the wavelength of the oscillation frequency, so that the strip line 62 at a frequency near the oscillation frequency. The reflected wave at the terminal on the side to which the several-end resistor 64 is connected is suppressed.
Further, the low-pass filter 67 connected to the strip line 62 blocks the oscillated microwave from leaking to the resistor 68. The resistor 68 is a resistor for biasing the gate terminal 54 and a resistor for preventing parasitic oscillation at frequencies other than the oscillation frequency, and its resistance value is designed to be the same as the characteristic impedance of the strip line 65 (for example, (Kaisho 56-47107).

However, in the configuration as described above, the resistance value of the resistor 68 cannot be freely designed, and normally the resistance value must be set to a low value, so that an excessive current flows in the gate of the FET 51. There was a problem that the FET 51 was destroyed by the flow.

In view of the above problems, the present invention provides a microwave oscillation circuit capable of preventing parasitic oscillation at frequencies other than the oscillation frequency to stabilize oscillation, and further preventing destruction of active elements to improve reliability. It is provided.

Means for Solving the Problems In order to solve the above problems, the microwave oscillation circuit of the present invention aims to stabilize the frequency with a dielectric resonator and terminates a stripline for electromagnetically coupling the dielectric resonator. A circuit includes a first terminating resistor, a first open-ended strip line connected to the first terminal of the first terminating resistor, and a first terminal connected to the second terminal of the first terminating resistor.
Choke circuit, a second terminating resistor and a capacitor connected in series between the first choke circuit and ground, and a first resistor connected in parallel with the second terminating resistor and the capacitor. It uses a circuit equipped with.

With the above-described structure, the present invention suppresses reflection at the end of the strip line at a frequency near the oscillation frequency by the first terminating resistor and the first open-ended strip line, and the oscillating frequency by the second terminating resistor. It is possible to suppress reflected waves at frequencies other than those to prevent parasitic oscillation, and to design the bias current of the active element to an arbitrary optimum value by the first resistor.

Example Hereinafter, a microwave oscillation circuit according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a stripline termination circuit for electromagnetically coupling a dielectric resonator of a microwave oscillation circuit according to a first embodiment of the present invention. In FIG. 1, 14
Is a first terminating resistor, 15 is a first open-ended strip line, 18 is a first choke circuit, 19 is a capacitor, 20 is a second terminating resistor, 21 is a first resistor, and 30 is a terminal. . The terminal 30 is connected to the first open-ended strip line 15 via the first terminating resistor 14, and is also connected to the first choke circuit 18. And the choke circuit 18
Is connected to the ground via the capacitor 19 and the second terminating resistor 20, and is also connected to the ground via the first resistor 21. Then, the terminal 30 is connected to the end of a strip line for electromagnetically coupling the dielectric resonator.

The operation of the microwave oscillation circuit configured as described above will be described below with reference to FIG.

In FIG. 1, the first open-ended strip line
15 is designed to have a length of 1/4 of the wavelength λ _g of the oscillation frequency fraction _O. That is, the terminal 30 is grounded via the first terminating resistor 14 at the oscillation frequency _O. Therefore, if the resistance value of the first terminating resistor 14 is made equal to the characteristic impedance of the strip line for electromagnetically coupling the dielectric resonator, the dielectric resonator is electromagnetically coupled at a frequency near the oscillation frequency _O. It is possible to suppress the reflected wave at the end of the strip line where the terminal 30 is connected. Further, the choke circuit 18 connected to the terminal 30 is designed to have high impedance at the oscillation frequency _O , and the capacitance value of the capacitor 19 is designed to have low impedance at high frequencies. Further, since the resistance value of the second terminating resistor 20 is designed to be equal to the characteristic impedance of the strip line that electromagnetically couples the dielectric resonator, like the first terminating resistor 14, parasitic resistance at frequencies other than the oscillation frequency _O is set. Oscillation can be prevented. Then, the first resistor 21 designs the bias current of the active element to an arbitrary optimum value to prevent the breakdown of the active element.

As described above, according to the present embodiment, the first terminating resistor 14, the first open-ended strip line 15, and the first choke circuit 18 are provided in the strip line terminating circuit for electromagnetically coupling the dielectric resonator. Capacitor 19 and second terminating resistor 20
And the first resistor 21 prevent parasitic oscillation other than oscillation due to the resonance frequency of the dielectric resonator and prevent destruction of the active element due to excessive current flow. be able to.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a configuration diagram of a stripline termination circuit for electromagnetically coupling the dielectric resonator of the microwave oscillation circuit according to the second embodiment of the present invention. In FIG. 2, 22 is a thin strip line, 23 to 26 are second to fifth open-ended strip lines, and 27 is a first resistor. The thin stripline 22 is connected to the terminal 30 and the first resistor 27 is connected between the thin stripline 22 and ground. The second to fifth open-ended strip lines 23 to 26 are designed to have arbitrary lengths and are connected to arbitrary positions of the thin strip line 22. Then, the terminal 30 is connected to the end of a strip line for electromagnetically coupling the dielectric resonator.

The operation of the microwave oscillation circuit configured as described above will be described below with reference to FIG.

In FIG. 2, the first terminating resistor 14 and the first open-ended strip line 15 perform the same operations as in the first embodiment. Thin stripline 22
Operates as a choke coil. Further, the second to fifth open-ended strip lines 23 to 26 connected to the arbitrary positions of the thin strip line 22 reflect at a frequency near a frequency having a wavelength four times the length of each strip line. Suppress the waves. Here, the second and third open-ended strip lines 23 and 24
Is designed to have a length of 1/4 of the wavelength of the oscillation frequency _O where suppression of reflected waves is important, and a thin stripline 2
2 may be connected at intervals of a length of 1/4 of the wavelength of the resonance frequency _O. Then, the first resistor 27 designs the bias current of the active element to an arbitrary optimum value to prevent the destruction of the active element.

As described above, according to this embodiment, the first terminating resistor 14, the first open-ended strip line 15, the thin strip line 22, and the second strip line 22 are provided in the strip line termination circuit for electromagnetically coupling the dielectric resonator. To the fifth open-ended strip lines 23 to 26 and the first resistor 27, parasitic parasitic oscillation other than oscillation due to the resonance frequency of the dielectric resonator is prevented, and excessive current flows to the active element. It is possible to prevent the active element from flowing and being destroyed.

A third embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram of a stripline termination circuit for electromagnetically coupling a dielectric resonator of a microwave oscillator circuit according to a third embodiment of the present invention. In FIG. 3, 31 is a third open-ended strip line,
It is designed to have a length different from that of the second open-ended strip line 23, and is connected to the thin strip line 22 at the same position as the second open-ended strip line 23.

A fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 4 is a configuration diagram of a stripline termination circuit for electromagnetically coupling a dielectric resonator of a microwave oscillator circuit according to a fourth embodiment of the present invention. In FIG. 4, the thin strip line 22 is connected to the terminal 30, and the capacitor 19 and the second terminating resistor 20 are connected in series between the thin strip line 22 and the ground. The first resistor 21 is also connected between the thin strip line 22 and the ground. Further, the second and third open-ended strip lines 23 and 31 are connected to arbitrary positions of the thin strip line 22. And terminal 30
Is connected to the end of a strip line that electromagnetically couples the dielectric resonator.

The operation of the microwave oscillation circuit configured as described above will be described below with reference to FIG.

In FIG. 4, the first terminating resistor 14, the first open-ended strip line 15, the capacitor 19, the second terminating resistor
20 and the first resistor 21 perform the same operations as the respective operations in the first embodiment. The thin strip line 22 operates similarly to a choke coil. Further, the second and third open-ended striplines 23 and 31 connected at arbitrary positions of the thin stripline 22 reflect at frequencies near the frequency having a wavelength four times the length of the respective striplines. Suppress the waves. Here, the second or third open-ended strip line 23 or 24
Is designed to have a length of 1/4 of the wavelength of the oscillation frequency _O where suppression of reflected waves is important, and a thin stripline 2
It may be connected at a position separated from the second terminal 30 and the capacitor 19 by a length of 1/4 of the wavelength of the resonance frequency _O.

As described above, according to this embodiment, the first terminating resistor 14, the first open-ended strip line 15, the thin strip line 22, and the second strip line 22 are provided in the strip line termination circuit for electromagnetically coupling the dielectric resonator. By providing the third open-ended strip lines 23 and 31, the capacitor 19, the second terminating resistor 20, and the first resistor 21, parasitic oscillation other than oscillation due to the resonance frequency of the dielectric resonator is prevented. At the same time, it is possible to prevent the active element from being destroyed due to excessive current flowing through the active element.

A fifth embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a block diagram of a stripline termination circuit for electromagnetically coupling a dielectric resonator of a microwave oscillator circuit according to a fifth embodiment of the present invention. In FIG. 5, 28 is a capacitor and 29 is a first resistor. The thin slip line 22 is connected to terminal 30 and
28 and the first resistor 29 are connected in parallel between the thin strip line 22 and ground. Further, the strip line 23 having the second open end is connected to an arbitrary position of the thin strip line 22. Then, the terminal 30 is connected to the end of a strip line for electromagnetically coupling the dielectric resonator.

The operation of the microwave oscillation circuit configured as described above will be described below with reference to FIG.

In FIG. 5, the first terminating resistor 14 and the first open-ended strip line 15 perform the same operations as those in the first embodiment. Thin stripline 22
Operates as a choke coil. Further, the second open-ended strip line 23 connected to an arbitrary position of the thin strip line 22 suppresses a reflected wave at a frequency in the vicinity of a frequency having a wavelength four times the length of the strip line. Further, the capacitor 28 suppresses a reflected wave at a frequency according to its capacitance value and frequency characteristics.
Then, the first resistor 29 designs the bias current of the active element to an arbitrary optimum value to prevent the breakdown of the active element. Here, the second open strip line 23 is designed to have a length of 1/4 of the wavelength of the oscillation frequency _O where suppression of reflected waves is particularly important, and the terminal 30 of the thin strip line 22 is designed.
Alternatively, the capacitor 19 may be connected to a place separated from the capacitor 19 by a length of 1/4 of the wavelength of the resonance frequency _O.

As described above, according to this embodiment, the first terminating resistor 14, the first open strip line 15, the thin strip line 22 and the second strip line 22 are provided in the strip line terminating circuit for electromagnetically coupling the dielectric resonator. By providing the open-ended stripline 23, the capacitor 28, and the first resistor 29, parasitic oscillation other than oscillation due to the resonance frequency of the dielectric resonator is prevented, and excessive current flows in the active element, It is possible to prevent the active element from being destroyed.

A sixth embodiment of the present invention will be described below with reference to the drawings. FIG. 6 is a configuration diagram of a stripline termination circuit for electromagnetically coupling a dielectric resonator of a microwave oscillator circuit according to a sixth embodiment of the present invention. In FIG. 6, reference numeral 21 is a third open end spline, which is connected to an arbitrary position of the thin strip line 22, and its length is different from the length of the second open end strip line 23. . Then, the terminal 30 is connected to the end of a strip line for electromagnetically coupling the dielectric resonator.

The operation of the microwave oscillation circuit configured as described above will be described below with reference to FIG.

In FIG. 6, a first terminating resistor 14, a first open-ended strip line 15, a thin strip line 22, a second
The open-ended strip line 23, the capacitor 28, and the first resistor 29 perform the same operations as those in the fifth embodiment. Further, the third open-ended strip line 31 connected to an arbitrary position of the thin strip line 22 suppresses a reflected wave at a frequency near a frequency having a wavelength four times the length of the strip line.

As described above, according to the present embodiment, in the stripline termination circuit for electromagnetically coupling the dielectric resonator, the first terminating resistor 14, the first open stripline 15, the thin stripline 22, the second stripline 22, and the second stripline 22 are provided. Third open-ended strip lines 23 and 31, capacitor 28 and first resistor 29
In addition to the effect of the fifth embodiment, the reflection wave at a frequency near the frequency having a wavelength four times the length of the third open-ended stripline 31 can be suppressed at the same time. Therefore, it is possible to prevent parasitic oscillation other than oscillation due to the resonance frequency of the dielectric resonator, and to prevent destruction of the active element due to excessive current flowing in the active element.

Hereinafter, seventh to twelfth embodiments of the present invention will be described with reference to the drawings. 7 to 12 show the seventh embodiment of the present invention.
14 is a configuration diagram of a microwave oscillation circuit according to a twelfth embodiment. In FIGS. 7 to 12, 1 is an active three-terminal element, 2 to 4 are first to third terminals of the active three-terminal element 1, 5 is an open-ended strip line, 6 and 8 are choke circuits, 7 11, 11 and 12 are strip lines, 9 is a resistor, 10 is a direct current blocking circuit, 13 is a dielectric resonator, 16 is a power supply terminal, and 17 is an output terminal. A strip line 5 having an open end and a choke circuit 6 are connected to the first terminal 2 of the active three-terminal element 1. A strip line 7 and a choke circuit 8 are connected to the second terminal 3 of the active three-terminal element 1. A resistor 9 is connected between the choke circuit 8 and the ground, and a strip line 11 is connected to the strip line 7 via a DC blocking circuit 10. A stripline 12 is connected to the third terminal 4 of the active three-terminal element 1, and the dielectric resonator 13 is electromagnetically coupled to the stripline 12.

The operation of the microwave oscillation circuit configured as described above will be described below with reference to FIGS. 7 to 12.

In FIG. 7 to FIG. 12, a strip line 5 having an open tip adjusts the impedance of microwaves at the active three-terminal element 1 and the first terminal 2. Further, the choke circuit 6 connected to the first terminal 2 prevents the oscillated microwave from leaking to the power supply terminal 16. next,
A strip line 7 is connected to the first and second terminals 3 of the active three-terminal element, and an oscillation output is taken out from the strip run-in 7 to the output terminal 17 via the DC blocking circuit 10 and the strip line 11. There is. The choke circuit connected to the second terminal 3 prevents the oscillated microwave from leaking to the resistor 9. The resistor 9 is a bias resistor for the second terminal 3. Next, the strip line 12 is connected to the third terminal 4 of the active three-terminal element 1, and the dielectric resonator is connected to the strip line 12.
13 are electromagnetically coupled. This dielectric resonator 13 has a very high Q and stabilizes the oscillation frequency. The terminal circuits 30 of the stripline 12 are connected to the termination circuits having the configurations shown in the first to sixth embodiments to prevent parasitic oscillation other than oscillation due to the resonance frequency of the dielectric resonator and to activate the active element. It prevents the active element from being destroyed due to excessive current flowing through it.

As described above, according to the seventh to twelfth embodiments, it is possible to realize a stable and highly reliable microwave oscillation circuit with a very simple structure.

In the first to twelfth embodiments, the first open-ended strip line 15 has the wavelength λ _g of the oscillation frequency _O.
Although the rectangular shape having a length of 1/4 is used, the strip line 15 having an open end may have any length and shape depending on the mounting state of the first terminating resistor 14.

Further, in the first to twelfth embodiments, the resistance values of the first and second terminating resistors 14 and 20 are the strip line 15
However, it is not necessary that the resistance values of the first and second terminating resistors 14 and 20 exactly match the characteristic impedance of the strip line 15.

Also, in the first, fourth, seventh and tenth embodiments, the connection order of the capacitor 19 and the second terminating resistor 20 may be reversed.

In addition, in the first, fourth, seventh and tenth embodiments, the capacitance value of the capacitor 19 can be designed arbitrarily according to the oscillation frequency _O.

Further, in the second to sixth and eighth to twelfth embodiments, the number and shape of the open strip lines connected to the thin strip line 22 and the position where the open strip line is connected to the thin strip line 22. Can be designed arbitrarily.

Further, in the fifth, sixth, eleventh and twelfth embodiments, the capacitance value of the capacitor 28 can be arbitrarily designed according to the frequency of the reflected wave to be suppressed.

Further, the choke circuits 6, 8 and 18 in the first and seventh to twelfth embodiments are constituted by repeating thin strip lines having a length of 1/4 of the wavelength λ _g of the arbitrary frequency _O and stubs. It is possible to use the above-mentioned one or the one including a choke coil and a capacitor.

In addition, in the second, third, fifth, sixth, eighth, ninth, eleventh and twelfth embodiments, when the bias current of the active three-terminal element does not matter, the resistance of the resistor 27 or 29 is used. The value may be the same as the characteristic impedance of the strip line 15.

Also, in the seventh to twelfth embodiments. DC blocking circuit
As the capacitor 10, it is possible to use a thin strip line having a length of 1/4 of the wavelength of the oscillation frequency _{O of} an interdigital type or a capacitor.

Further, in the seventh to twelfth embodiments, FETs and transistors can be used as the active three-terminal element, and when the FET is used as the active three-terminal element, the first
Can be used as the drain, the second terminal as the source, and the third terminal as the gate.

Further, as the active element serving as the oscillation source, a two-terminal element such as a diode can be used in addition to the three-terminal element.

EFFECTS OF THE INVENTION As described above, according to the present invention, the frequency is stabilized by the dielectric resonator, and the first terminating resistor and the first terminating resistor are provided in the stripline terminating circuit for electromagnetically coupling the dielectric resonator. A first open-ended stripline connected to the first terminal of the first terminating resistor and a second of the first terminating resistor.
A first choke circuit connected to the terminal of the
Second connected in series between the choke circuit and ground
By providing the terminating resistor and the capacitor and the first resistor connected in parallel with the second terminating resistor and the capacitor, parasitic oscillation other than oscillation due to the resonance frequency of the dielectric resonator is prevented and It is possible to prevent the active element from being destroyed due to excessive current flowing through the active element.

[Brief description of drawings]

1 to 6 are block diagrams of a stripline termination circuit for electromagnetically coupling the dielectric resonators of the microwave oscillation circuit in the first to sixth embodiments of the present invention, respectively, and FIGS. FIGS. 13A and 13B are block diagrams of microwave oscillating circuits according to the seventh to twelfth embodiments of the present invention, and FIG. 13 is a block diagram of a conventional microwave oscillating circuit. 1 ... Active three-terminal element, 2 ... First terminal of active three-terminal element, 3 ... Second terminal of active three-terminal element, 4 ... Third terminal of active three-terminal element, 5,15 , 23,24,25,26,31 …… Strip line with open tip, 6,8,18 …… Choke circuit,
7,11,12 …… Stripline, 9,21,27,29 …… Resistance, 1
0 …… DC blocking circuit, 13 …… Dielectric resonator, 14,20 …… Terminal resistor, 16 …… Power supply terminal, 17 …… Output terminal, 19,28 ……
Capacitor, 22 ...... Thin strip line, 30 …… Terminal, 51 …… Field effect transistor, 52 …… Drain terminal, 53 …… Source terminal, 54 …… Gate terminal, 55, 65 ……
Strip line with open tip, 56,58,67 …… Low pass filter, 57,62 …… Strip line, 59,68 …… Resistance,
60 …… Interdigital DC blocking circuit, 61 …… Load resistance, 63 …… Dielectric resonator, 64 …… Terminal resistance, 66 …… Power supply terminal.

Claims (8)

[Claims] 1. A first termination resistor and a first termination resistor of the first termination resistor in a stripline termination circuit for stabilizing the frequency with a dielectric resonator and electromagnetically coupling the dielectric resonator. A first open-ended strip line connected to the terminal and a first choke circuit connected to the second terminal of the first terminating resistor, the first choke circuit, and the first choke circuit are connected in series. A second terminating resistor and a capacitor,
A microwave oscillating circuit comprising a circuit comprising the second terminating resistor and a first resistor connected in parallel with a capacitor. 2. A first terminating resistor and a first terminating resistor of the first terminating resistor are provided in a strip line terminating circuit for stabilizing the frequency with a dielectric resonator and electromagnetically coupling the dielectric resonator. A first open strip line connected to a terminal, a thin strip run-in connected to a second terminal of the first terminating resistor, and at least two thin line run-in connected to arbitrary positions of the thin strip line. A microwave oscillating circuit using a circuit including the above-described open-ended strip lines having different lengths and a first resistor connected between the thin strip line and the ground. 3. A dielectric resonator for stabilizing the frequency, and a first terminating resistor and a first terminating resistor in a stripline terminating circuit for electromagnetically coupling the dielectric resonator. A first open-ended strip line connected to a terminal, a thin strip line connected to a second terminal of the first terminating resistor, and a capacitor connected in series between the thin strip line and ground. And a second terminating resistor, a first resistor connected in parallel with the capacitor and the second terminating resistor, and at least two or more lengths connected to arbitrary positions of the thin strip line. A microwave oscillating circuit characterized by using a circuit having different open-ended strip lines. 4. A first termination resistor and a first termination resistor of the first termination resistor in a stripline termination circuit for stabilizing the frequency with a dielectric resonator and electromagnetically coupling the dielectric resonator. A first open-ended strip line connected to a terminal, a thin slip line connected to a second terminal of the first terminating resistor, and a resistor connected in parallel between the thin strip line and ground. And a capacitor and a second connected to any position of the thin slip line
A microwave oscillating circuit using a circuit having a stripline whose tip is open. 5. The microwave oscillating circuit according to claim 4, wherein a terminating circuit is used in which at least two strip lines having different open ends are connected to arbitrary positions of the thin strip line. 6. A microwave oscillation circuit according to claim 2, 3 or 5, wherein a terminating circuit in which two strip lines having different open ends are connected to arbitrary same positions of a thin strip line is used. circuit. 7. An active three-terminal element, another open-ended strip line connected to the first terminal of the active three-terminal element, a second choke circuit, and a second one of the active three-terminal elements.
A first strip line and a third choke circuit connected to the terminal of the first line, a DC blocking circuit connected to the first strip line, and a second DC line connected to the DC blocking circuit.
Strip line and a second resistor connected between the third choke circuit and ground, and electromagnetically coupled to the dielectric resonator to the third terminal of the active three-terminal element. 7. The microwave oscillating circuit according to claim 1, 2, 3, 4, 5, or 6, wherein strip lines are connected. 8. The micro according to claim 7, wherein a field effect transistor is used as the active three-terminal element, a drain is used as the first terminal, a source is used as the second terminal, and a gate is used as the third terminal. Wave oscillator circuit.