JP2002359530A - High frequency amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect a via hole sufficiently away from a terminal to be grounded without connecting a capacitor to a terminal to be grounded of the transistor, and to connect a terminal to be grounded of the transistor in a DC manner. Provided is a high-frequency amplifier having a high yield and excellent high-frequency characteristics that can be grounded in an AC manner. SOLUTION: A base terminal 14B of a transistor 14 and a ground are directly connected via a via hole 16. One end of the open transmission line 17 is connected to the base terminal 14B of the transistor 14. The electrical length of the transmission line 17 having the open end is approximately 1/4 wavelength at the operating frequency. In this way, the base terminal 14B of the transistor 14 is equivalently grounded at the operating frequency, thereby preventing a decrease in gain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency amplifier for amplifying a signal in a microwave band (including a millimeter wave band) such as a grounded base amplifier and a cascode amplifier.

[0002]

2. Description of the Related Art Conventionally, as a high frequency amplifier, as shown in FIG. 6, there is a grounded base type amplifier using a bipolar transistor. In this grounded base amplifier, the base terminal of NPN transistor 214 is grounded, the emitter terminal is connected to input terminal 211 via input matching circuit 213, and the collector terminal is connected to output terminal 212 via output matching circuit 215. ing. In this case, the transistor is operated by applying a negative voltage to the emitter terminal to ground the base terminal.

As another high-frequency amplifier, there is a cascode amplifier in which a base terminal of a transistor is AC grounded. This cascode amplifier has an emitter terminal
The collector terminal (or drain terminal) of the first transistor whose (or source terminal) is grounded and the base terminal (or gate terminal) are AC grounded by a MIM (Metal Insulator Metal) capacitor, etc. An emitter terminal (or a source terminal) of the second transistor, and a collector terminal (or a drain terminal) of the first transistor and an emitter terminal (or a source terminal) of the second transistor forming an interstage circuit. DC connection. The cascode-type amplifier having the above-described configuration can provide a gain equivalent to a two-stage amplifier with a chip area of approximately one stage amplifier and has excellent high-frequency characteristics.
(30 to 300 GHz).

[0004] FIG. 7 is a diagram showing an example of the IEEE MICROWAVE.
AND GUIDED WAVELETTERS (V
OL. 8, No. 12, DECEMBER 1998) ", a coplanar HEMT (High Electron
Mobility Transistor: Electron mobility transistor) MMI
FIG. 2 is an equivalent circuit diagram of a C (Monolithic Microwave Integrated Circuit) cascode amplifier. As shown in FIG. 7, a first transistor 313 having a gate terminal connected to the input terminal 311 and a source terminal connected to the ground, and an interstage circuit 314 having a transmission line connected to the drain terminal of the first transistor 313. , The source terminal of which is connected through the second transistor 31 and the base terminal of which is connected to the bias terminal 317.
5 and an MIM capacitor 316 connected between the second transistor 315 and the ground.
The output terminal 312 is connected to the drain terminal of the second transistor 315. In the cascode amplifier, the drain terminal of the first transistor 313 and the source terminal of the second transistor 315 are DC-connected via the interstage circuit 314, and the gate terminal of the second transistor 315 is connected to the MIM capacitor 316. Is grounded alternately.

[0005]

In the cascode amplifier, which is the high-frequency amplifier, the MMIC is formed by using a coplanar line on the compound semiconductor substrate. When mounting on a ceramic substrate, it is necessary to connect the ground on the surface of the MMIC substrate and the ground on the ceramic substrate by connecting means such as bonding wires. However, in the millimeter wave band, a parasitic element of an inductance component of a bonding wire or the like becomes a problem, and it is difficult to connect the ground on the surface of the MMIC substrate and the ground of the ceramic substrate to obtain a stable ground.
Therefore, it is preferable to configure the MMIC using a microstrip line whose back surface is the ground.

When the grounded base amplifier is formed on the MMIC substrate by a microstrip line, the ground is on the back surface of the MMIC substrate. Therefore, a via hole reaching the back surface of the compound semiconductor substrate is provided near the terminal to be grounded of the transistor. It is necessary to ground both DC and AC. When the cascode amplifier is formed on the MMIC substrate by a microstrip line, the first
DC and AC grounding of the emitter terminal of the transistor is performed by connecting to the ground metal provided on the back surface of the MMIC substrate via holes, and the base terminal of the second transistor is located near the base terminal. It is necessary to provide an MIM capacitor and a via hole and ground them alternately.

However, in the above-mentioned common base amplifier and cascode amplifier, when the operating frequency is increased, the parasitic components of the MIM capacitor and the via hole become a problem.

FIG. 8 is a circuit diagram of a grounded-base amplifier, in which an emitter terminal of an NPN transistor 415 is connected to an input terminal 411 via an input matching circuit 413, and an output matching circuit is connected to a collector terminal of the transistor 415. It is connected to the output terminal 412 via 415. The transistor 415 is connected to the ground terminal via a via hole 416. The via hole 416 has a parasitic inductance L4.

FIG. 9 is a circuit diagram of a cascode amplifier, in which a first transistor 5 is connected to an input terminal 511.
13 is connected to the first transistor 513.
Is connected to the ground via a via hole 514. The second terminal is connected to the drain terminal of the first transistor 513 via an interstage circuit 515 including a transmission line.
Of the transistor 516 is connected. The ground terminal is connected to the gate terminal of the second transistor 516 via the MIM capacitor 517 and the via hole 518, and the bias terminal 519 is connected to the gate terminal of the second transistor 516. The output terminal 51 is connected to the drain terminal of the second transistor 516.
2 are connected.

[0010] In the grounded base amplifier shown in FIG.
Due to the influence of the inductance component and the like of the via hole, the base terminal of the grounded-base amplifier cannot be sufficiently grounded in an AC manner, and the characteristics of the high-frequency amplifier deteriorate. Further, in the cascode amplifier shown in FIG. 9, the source terminal of the first transistor of the cascode amplifier cannot be sufficiently grounded in an AC manner due to the influence of the inductance component of the via hole and the like. Deteriorates.

FIG. 10 is a circuit diagram showing the characteristics of M at an operating frequency of 60 GHz when an inductance is added to the ground terminals of the common emitter transistor and the common base transistor.
Changes in SG (Maximum Stable Gain) and stabilization coefficient K (“K factor” in FIG. 10) are shown. In FIG. 10, the horizontal axis represents the ground connection inductance, and the vertical axis represents the MSG and the stabilization coefficient K. As is apparent from FIG. 10, the gain of the common-base amplifier is larger than that of the common-emitter amplifier when the ground terminal of the transistor is not sufficiently AC-grounded.

Further, the base terminal of the second transistor of the cascode amplifier cannot be sufficiently grounded in terms of AC because of the influence of the characteristics of the MIM capacitor.
The gain of the high-frequency amplifier decreases. In particular, in the millimeter wave band, the influence of the via hole parasitic component is large,
Further, since the characteristics of the MIM capacitor also deviate from the ideal capacitor characteristics, sufficient grounding cannot be performed, and it is difficult to obtain a desired gain.

As described above, in a common-base amplifier, it is necessary to provide a via hole near the base terminal of a transistor. In a cascode amplifier,
It is necessary to provide a via hole near the source terminal of the first transistor, provide an MIM capacitor and a via hole near the base terminal of the second transistor, and connect them. However, a step of opening a via hole in the vicinity of the base terminal of a common base transistor or in the vicinity of the source terminal of the first transistor of the cascode amplifier, or in the vicinity of the gate terminal of the second transistor in the cascode amplifier, Forming a via hole; forming a via hole;
For example, a process of connecting the IM capacitor and the via hole must be performed. For this reason, transistors, in particular,
In a vertical semiconductor device, M
In some cases, failure such as deterioration of withstand voltage due to abnormal film quality of the insulating film constituting the IM capacitor and abnormal shape of the via hole may occur, resulting in a problem that the yield is reduced.

Further, since a process margin such as the amount of side etching is required in the step of opening the via hole by etching, the via hole cannot be provided sufficiently close to the terminal to be grounded of the transistor. Therefore, it is difficult to sufficiently ground the terminal of the transistor in the millimeter wave band. In the case where the gate terminal of the second transistor of the cascode amplifier is AC grounded, a process for connecting the MIM capacitor and the via hole is required near the gate terminal. Since a process margin is required,
It is difficult to provide the gate terminal and the MIM capacitor and the MIM capacitor and the via hole sufficiently close to each other. Therefore, it is difficult to sufficiently ground the gate terminal of the second transistor in the cascode amplifier in an AC manner.

An object of the present invention is to connect a via hole sufficiently away from a terminal to be grounded without connecting a capacitor to the terminal to be grounded, and to connect a terminal to be grounded of the transistor with a direct current. It is an object of the present invention to provide a high-frequency amplifier having high yield and excellent high-frequency characteristics which can be grounded in an AC manner.

[0016]

In order to achieve the above object, a high frequency amplifier according to a first aspect of the present invention comprises a transistor having a base terminal or a gate terminal to be grounded, and a ground conductor connected to the base terminal or the gate terminal of the transistor. At least one via hole to be connected, and at least one open-ended transmission line having one end connected to a base terminal or a gate terminal of the transistor are provided.

According to the high-frequency amplifier having the above configuration, for example, when a grounded base amplifier is formed using a bipolar transistor, the base terminal of the transistor and the ground conductor are connected by at least one via hole to connect the base terminal. DC grounded. Also, by connecting one end of at least one open-ended transmission line to the base terminal of the transistor and adjusting the length of the open-ended transmission line, AC grounding of the base terminal can be performed well. It becomes possible. Therefore, a via hole for connecting the terminal to the ground conductor can be provided at a place sufficiently distant from the terminal without providing a capacitor for grounding the base terminal of the transistor in an alternating current manner, and the transistor can be provided with a via hole. It is possible to realize a high-yield high-frequency amplifier with high yield and high-frequency characteristics, in which the base terminal can be easily grounded in a DC and AC manner. The same applies to the case where a grounded-gate amplifier is formed using a field-effect transistor.

According to a second aspect of the present invention, there is provided a high-frequency amplifier having a transistor whose emitter terminal or source terminal is to be grounded, an input circuit for connecting a ground conductor to the emitter terminal or source terminal of the transistor, and a base terminal of the transistor. Alternatively, there is provided a bias supply line having one end connected to the gate terminal, and at least one open-ended transmission line having one end connected to the base terminal or the gate terminal of the transistor.

According to the high-frequency amplifier having the above-described configuration, for example, when a common-base amplifier is formed using a bipolar transistor, the emitter terminal of the transistor is DC-grounded through an input circuit, and at least the base terminal of the transistor is connected to the base terminal of the transistor. By connecting one end of one open transmission line and adjusting the length of the open transmission line, AC grounding of the base terminal can be performed satisfactorily. Further, by adjusting the length of the transmission line having the open end, it is possible to compensate for the inductance component of the base electrode and the base lead wiring inside the transistor and to add feedback, thereby stabilizing the grounded base amplifier. Can be realized. Accordingly, a via hole for connecting the emitter terminal of the transistor to the ground conductor can be provided at a place sufficiently distant from the terminal, and a capacitor and a via hole for ac grounding the base terminal are provided near the element. Thus, a high-frequency amplifier having a high yield and excellent high-frequency characteristics can be realized in which the base terminal can be easily grounded in an AC manner. The same applies to the case where a grounded-gate amplifier is formed using a field-effect transistor.

The high-frequency amplifier according to a third aspect of the present invention includes a first transistor having an emitter terminal or a source terminal grounded, an interstage circuit having one end connected to a collector terminal or a drain terminal of the first transistor. A second transistor having an emitter terminal or a source terminal connected to the other end of the inter-stage circuit, a bias supply line having one end connected to a base terminal or a gate terminal of the second transistor, Means for grounding the base terminal or the gate terminal of the transistor in an AC manner.

According to the high-frequency amplifier having the above-described configuration, for example, when a cascode amplifier is configured using bipolar transistors as the first and second transistors, the collector terminal of the first transistor whose emitter terminal is grounded and the second terminal And the emitter terminal of the second transistor is connected via the inter-stage circuit, one end of a bias supply wiring is connected to the base terminal of the second transistor, and the base terminal of the second transistor is AC grounded. . In this cascode type amplifier, by providing means for grounding the base terminal of the second transistor in an alternating manner, it is possible to satisfactorily ground the base terminal of the second transistor in an alternating manner. Note that the same applies to the case where a cascode amplifier is configured using a field effect transistor.

In one embodiment of the present invention, the AC grounding means includes at least one open-ended transmission line.

According to the high-frequency amplifier of the above embodiment, the base terminal (or gate terminal) of the second transistor
By adjusting the length of the open-ended transmission line provided in the above, it is possible to easily add feedback to the amplifier.

In one embodiment, the high-frequency amplifier includes at least one open-ended transmission line having one end connected to the emitter terminal or the source terminal of the first transistor.

According to the high-frequency amplifier of the above-described embodiment, the open-ended transmission line provided at the emitter terminal (or source terminal) of the first transistor is made capacitive at the operating frequency. Emitter electrode (or source electrode)
(Or the source lead-out wiring) can be compensated for, thereby improving the gain and stabilizing the operation.

In one embodiment of the high-frequency amplifier according to the first to third aspects of the present invention, at least one of the open-ended transmission lines has an electrical length of approximately 1/4 wavelength at an operating frequency. It is characterized by having.

According to the high-frequency amplifier having the above configuration, in the high-frequency amplifier according to the first and second aspects of the present invention, in the grounded-base amplifier in which the base terminal of the transistor is connected to the ground conductor via the via hole, By making the electrical length of the open-ended transmission line, one end of which is connected to the terminal, approximately 波長 wavelength at the operating frequency, the base terminal is not affected by parasitic elements such as inductance at the operating frequency, Better grounding can be achieved as compared to the case where grounding is performed using an MIM capacitor and via holes. In the high-frequency amplifier according to the third aspect of the present invention, in the cascode amplifier in which the collector terminal of the first transistor whose emitter terminal is grounded and the emitter terminal of the second transistor are connected via an interstage circuit, By setting the electrical length of the open-ended transmission line connected to the base terminal to be grounded at a high frequency of the second transistor functioning as the grounding transistor to be approximately 波長 wavelength at the operating frequency, the base terminal can operate at the operating frequency. In this case, a better grounding can be obtained as compared with the case where the grounding is performed by using the MIM capacitor and the via hole without being affected by a parasitic element such as an inductance. Further, by setting the electrical length of the open-ended transmission line connected to the emitter terminal of the first transistor of the cascode amplifier to be approximately 1/4 wavelength at the operating frequency, the emitter terminal can be operated at a high frequency at the operating frequency. It is possible to be grounded, and it is possible to suppress the influence of a parasitic component such as an inductance component of the via hole connected to the emitter terminal, thereby preventing a gain reduction of the amplifier. The same applies to the case where the above-mentioned grounded base amplifier and cascode amplifier are formed using field effect transistors.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a high-frequency amplifier according to the present invention will be described in detail with reference to the illustrated embodiments.

(First Embodiment) FIG. 1 is a circuit diagram of a grounded-base amplifier as a high-frequency amplifier according to an embodiment of the present invention. As shown in FIG. 1, the input terminal 11 is connected to the emitter terminal of an NPN transistor 14 via an input matching circuit 13, and the collector terminal of the transistor 14 is connected to the output terminal 12 via an output matching circuit 18. I have.
One end of the transmission line 15 is connected to the base terminal of the transistor 14, and the ground is connected to the other end of the transmission line 15 via the via hole 16. Further, the open transmission line 17 is connected to the base terminal of the transistor 14.
Are connected at one end. Transmission line 17 with open end
Consists of a microstrip line having an electrical length of approximately 1/4 wavelength at the operating frequency. Further, a parasitic inductance L1, which is a main parasitic element of the via hole 16, is connected between the base terminal of the transistor 14 and the ground. The base terminal of the transistor 14 is DC-grounded by the via hole 16, and an open-ended transmission line 17 composed of a microstrip line having an electrical length of approximately 波長 wavelength at the operating frequency is connected to the base terminal of the transistor 14. By doing so, the base terminal is AC grounded at the operating frequency.

FIG. 2 shows an operation frequency of 60 V at the base terminal of the transistor 14 in the grounded base amplifier shown in FIG.
When one end of an open transmission line having an electrical length of 1/4 wavelength at GHz is connected, changes in MSG and stabilization coefficient K at 60 GHz with respect to ground connection inductance of via hole 16 and the like connected to the base terminal are shown. I have. By providing an open-ended transmission line at the base terminal of the transistor, even when an inductance component is added to the ground terminal of the transistor, as shown in FIG. 2, the MSG of the transistor does not decrease and is stable. The value of the conversion coefficient K can also be prevented from lowering.

FIG. 3 shows characteristics (S11 is an input return loss, S22 is an output return loss, and S21 is a gain) when the grounded base amplifier shown in FIG. 1 is formed as an MMIC on a compound semiconductor substrate. As shown in FIG. 3, the base terminal of the transistor 14 is equivalently grounded by the open-ended transmission line 17 near the operating frequency of 60 GHz, so that the base terminal is not provided with the open-ended transmission line 17. Gain is 3dB compared to
Improved.

The via hole 16 is provided in the transmission line 1.
5, it is not necessary to provide a via hole near the base terminal 14B of the transistor, and the yield can be improved.

Further, by setting the length of the open-ended transmission line 17 so that the open-ended transmission line 17 composed of the microstrip line becomes capacitive at the operating frequency, the feedback to the grounded base type amplifier is achieved. Plus
Operation can be stabilized. In the common base amplifier of the present invention, the base terminal 14B of the transistor 14
The amount of feedback can be easily adjusted by adjusting the length of the open transmission line 17 connected to the
Since an IM capacitor or the like is not used, there is no influence of a parasitic component and the reproducibility is excellent.

In the first embodiment, one transmission line 17 having an electric length of approximately 1/4 wavelength at the operating frequency is provided at the base terminal 14B of the transistor 14, but more preferably two transmission lines 17 are provided. Grounding the transmission line with the open end allows the base terminal to be reliably grounded.

Although the first embodiment has been described using a bipolar transistor, the field effect transistor is used by replacing the emitter terminal with the source terminal, replacing the base terminal with the gate terminal, and replacing the collector terminal with the drain terminal. A similar effect can be obtained even when a common-gate amplifier is configured.

(Second Embodiment) FIG. 4 is a circuit diagram of a grounded-base amplifier as a high-frequency amplifier according to a second embodiment of the present invention.

As shown in FIG. 4, an NPN is connected to an input terminal 21 via a transmission line 25 composed of a microstrip line.
The emitter terminal of the transistor 26 is connected.
One end of a transmission line 23 composed of a microstrip line is connected to the input terminal 21, and the other end of the transmission line 23 is connected to ground via a via hole 24. The output terminal 22 is connected to the collector terminal of the transistor 26 via an output matching circuit 36. Also, one end of an open-ended transmission line 27 made of a microstrip line is connected to the base terminal 26B of the transistor 26, and the transmission line 28, the resistor 29, the transmission line 30, and the via hole 31 are connected to the base terminal 26B of the transistor 26.
Is connected to the ground. Further, the transmission line 32 and the resistor 3 are connected to the base terminal 26B of the transistor 26.
3 and the bias terminal 3 via the bias supply wiring 34.
5 are connected.

The transmission line 23, via hole 24 and transmission line 25 constitute an input matching circuit.
By connecting one end of the transmission line 25 on the input terminal 21 side to the ground with the via hole 24, the emitter terminal of the transistor 26 is DC-grounded.

The via holes 24 and 31 have parasitic inductances L21 and L22, which are main parasitic elements, respectively. Further, the electrical length of the transmission line 27 having the open end is set to approximately 1/4 wavelength at the operating frequency.

According to the grounded-base amplifier of the second embodiment, the emitter terminal of the transistor 26 is DC-grounded via the via hole 24 provided at one end of the transmission line 23 constituting the input matching circuit. At the operating frequency, the transistor 26 is grounded by the open transmission line 27 provided at the base terminal 26B of the transistor 26. Thus, a bias can be applied to the base terminal, so that a negative power supply is not required.

The open-ended transmission line 27 made of the microstrip line has a base electrode and a base lead wire inside the base-grounded transistor 26 having inductance values of 5 ph to 30 ph. It is more preferable that the electrical length of the transmission line 27 be equal to or more than ５ wavelength and equal to or less than ４ wavelength at the operating frequency.

Although the second embodiment has been described using a bipolar transistor, the field effect transistor can be replaced by replacing the emitter terminal with the source terminal, replacing the base terminal with the gate terminal, and replacing the collector terminal with the drain terminal. The same effect can be obtained even when a common-gate amplifier is configured by using the same.

(Third Embodiment) FIG. 5 is a circuit diagram of a cascode type amplifier as a high frequency amplifier according to a third embodiment of the present invention.

As shown in FIG. 5, an NPN type first transistor 44 is connected to an input terminal 41 via an input matching circuit 43.
And one end of an open-ended transmission line 45 made of a microstrip line is connected to the emitter terminal 44E of the first transistor 44. further,
The ground is connected to the emitter terminal 44E of the first transistor 44 via a via hole 46. The NPN type second transistor is connected to the collector terminal of the first transistor 44 via an inter-stage circuit 47 composed of a microstrip line.
Of the transistor 48 is connected. One end of an open-ended transmission line 49 made of a microstrip line is connected to the base terminal 48B of the second transistor 48, and a bias terminal 51 is connected to the base terminal 48B of the second transistor 48 via a bias supply wiring 50. Are connected. And the second transistor 4
The output terminal 42 is connected to the collector terminal 8 via an output matching circuit 52.

The via hole 46 has a parasitic inductance L3 which is a main parasitic element. Further, the electrical length of the transmission lines 45 and 50 is set to approximately 1 /
It has four wavelengths.

Here, the base terminal 48B of the second transistor 48 is connected to the bias terminal 50 in terms of direct current, and at the operating frequency, the electrical length provided at the base terminal 48B is approximately 波長 wavelength. Is grounded by the transmission line 49 having the open end, the second transistor 48
Functions as a base-grounded transistor whose base terminal 48B is grounded at its operating frequency.

At the operating frequency, the base terminal 48B of the second transistor 48 is grounded at a high frequency by the transmission line 49 whose upper end is open.
As compared with the case where the MIM capacitor and the via hole are formed in the vicinity of B and grounded, the influence of the parasitic element is small, so that good grounding is possible. Therefore, at the operating frequency, the gain of the high-frequency amplifier can be improved as compared with the case where the MIM capacitor and the via hole are grounded.

Further, there is no need to provide an MIM capacitor for grounding the base terminal 48 B of the second transistor 48, and a via hole can be provided at a place sufficiently distant from the second transistor 48. The yield can be improved.

Further, the emitter terminal 44E of the first transistor 44 is grounded by a via hole 46 in terms of DC, and the emitter terminal 44E
E is grounded at a high frequency by an open transmission line 45 having an electric length of approximately 1/4 wavelength at the operating frequency. In this manner, the via hole 46 for grounding the emitter terminal 44E of the first transistor 44 can be provided at a place sufficiently distant from the transistor 44, and the yield is improved.

Since the emitter terminal 44E of the first transistor 44 is AC grounded at the operating frequency by the open-ended transmission line 45 made of a microstrip line, the parasitic inductance L of the via hole 46 is reduced.
3 can prevent gain deterioration.

The transmission line 45 having the open end has an inductance of the emitter electrode and the emitter lead wire inside the first transistor 44 of 5 ph to 30 ph.
In order to compensate for these, the electrical length of the transmission line 45 having the open end is set to 1/5 at the operating frequency.
More preferably, the wavelength is equal to or longer than the wavelength and equal to or shorter than the quarter wavelength.

Further, by using a radial stub as the transmission line having the open end, it is possible to widen the frequency range of AC grounding.

In the third embodiment, one end of one open transmission line 49 is connected to the base terminal 48B of the second transistor 48. However, a plurality of terminals connected to the base terminal of the second transistor 48 are connected. By providing the open transmission line, the base terminal 48B of the second transistor 48 can be more reliably grounded in an AC manner.

Further, when a cascode amplifier is configured using a microstrip line having a ground metal on the back surface of the MMIC substrate and the MMIC substrate is mounted on a ceramic substrate, the ground on the surface of the MMIC substrate and the ground on the ceramic substrate are not connected. Since direct connection is possible, excellent grounding at high frequencies is possible.

Although the third embodiment has been described using a bipolar transistor, the field effect transistor is used by replacing the emitter terminal with the source terminal, replacing the base terminal with the gate terminal, and replacing the collector terminal with the drain terminal. A similar effect can be obtained even when a cascode amplifier is configured.

(Fourth Embodiment) FIG. 11 is a circuit diagram of a cascode type amplifier as a high frequency amplifier according to a fourth embodiment of the present invention.

As shown in FIG. 11, an NPN first transistor 6 is connected to an input terminal 61 via an input matching circuit 64.
6 are connected to the ground, and the emitter terminal 66E of the first transistor 66 is connected to the ground via a transmission line 73a made of a microstrip line and a via hole 72a. Further, the ground is connected to the emitter terminal 66E of the first transistor 66 via a transmission line 73b composed of a microstrip line and a via hole 72b. The emitter terminal of an NPN-type second transistor 67 is connected to the collector terminal of the first transistor 66 via an interstage circuit 68 composed of a microstrip line. An open-ended transmission line 69 composed of a microstrip line having an approximately 1/4 wavelength at the operating frequency is connected to the base terminal 67B of the second transistor 67.
a and 69b are connected to one end respectively. The ground is connected to the base terminal 67B of the second transistor 67 via a transmission line 70a composed of a microstrip line, an MIM capacitor 71a, and a via hole 72c. Further, a transmission line 7 composed of a microstrip line is connected to the base terminal 67B of the second transistor 67.
0b, and a bias terminal 63 is connected to the other end of the transmission line 70b. The other end of the transmission line 70b is connected to ground via a MIM capacitor 71b and a via hole 72d. The output terminal 62 is connected to the collector terminal of the second transistor 67 via the output matching circuit 65.

In FIG. 11, L61 to L64 denote via holes 72a, 72b,
It represents a parasitic inductance which is a main parasitic element included in 72c and 72d. The emitter terminal 66E of the first transistor 66 has two via holes 72a and 72b.
Are grounded in a DC and AC manner. The collector terminal of the first transistor 66 is DC-connected to the emitter terminal of the second transistor 67 via an interstage circuit 68.

Here, the base terminal 67B of the second transistor 67 is DC-connected to the bias terminal 63, and the base terminal 67B at the operating frequency.
B is grounded by two open microstrip lines 69a and 69b each having an electric length of about 1/4 wavelength, and the base terminal 67B of the second transistor 67 is grounded at the operating frequency. Functions as a base-grounded transistor.

As described above, the second transistor 67
The base terminal 67B is grounded at a high frequency at the operating frequency by the two open transmission lines 69a and 69b. Can be wider. In addition, two open transmission lines 69a, 69
Since b can be arranged on both sides of the element, the layout is also easy.

Further, the emitter terminal 66E of the first transistor 66 is connected via the transmission lines 73a and 73b to the second terminal 66E.
Although grounded by the two via holes 72a and 72b, the two via holes 72a and 72b can be arranged on both sides of the device. Also, the emitter terminal 66E
The transmission lines 73a and 73b provided between the first and second via holes 72a and 72b have the same effect as the ground inductance, and degrade the gain of the transistor. However, the deterioration of the gain due to the increase of the ground inductance is more gradual in the common emitter transistor than in the common base transistor. Therefore, if there is a margin for the desired gain, by providing a transmission line between the emitter terminal 66E and the via holes 72a and 72b, although the gain is slightly reduced, the operation of the cascode amplifier is further stabilized. And the distance between the via holes 72a, 72b and the transistor 66 is increased,
The yield is improved. Here, in order to stabilize the cascode amplifier, the transmission line 73a,
Although the two via holes 72a and 72b are connected via the 73b, the emitter terminal 66E and the via hole 72a are connected to each other.
If a and 72b are arranged close to each other, the gain can be improved.

Although the fourth embodiment has been described using a bipolar transistor, the field effect transistor is used by replacing the emitter terminal with the source terminal, replacing the base terminal with the gate terminal, and replacing the collector terminal with the drain terminal. A similar effect can be obtained even when a cascode amplifier is configured.

[0063]

As is clear from the above, according to the high-frequency amplifier of the first invention, in the base-grounded (gate-grounded) amplifier in which the base terminal (gate terminal) is connected to the bias supply wiring, By providing at least one open transmission line at the (gate terminal), it is possible to satisfactorily perform AC grounding of the base terminal (gate terminal).

According to the high-frequency amplifier of the second invention,
In a base-grounded (gate-grounded) amplifier in which an emitter terminal (or a source terminal) is DC-grounded through an input circuit and a base terminal (gate terminal) is connected to a bias supply wiring, the base terminal (gate terminal) By providing at least one open-ended transmission line on the base terminal, it is possible to satisfactorily perform AC grounding of the base terminal (gate terminal).

Further, in the high frequency amplifiers according to the first and second aspects of the present invention, the MIM capacitor for grounding the base terminal (gate terminal) in an AC manner is not required, and the base terminal is not required.
Since the via hole can be provided at a position sufficiently distant from the (gate terminal), the yield can be improved. Further, by adjusting the length of the transmission line with the open end, it is possible to compensate for the inductance component of the base electrode (gate electrode) or the base lead-out wiring (gate lead-out wiring) of the transistor or to apply feedback. It is possible, and the operation of the common base amplifier can be stabilized.

According to the high-frequency amplifier of the third invention,
The collector terminal (or drain terminal) of the first transistor whose emitter terminal (or source terminal) is grounded, and the emitter terminal (or source terminal) of the second transistor whose base terminal (gate terminal) is connected to the bias supply wiring )
In a cascode amplifier in which DC and DC are connected through an interstage circuit, the base terminal of the second transistor
By connecting one end of the transmission line having the open end to the (gate terminal), the AC terminal of the base terminal (gate terminal) of the second transistor can be satisfactorily grounded. Also,
By adjusting the length of the open-ended transmission line having one end connected to the base terminal (gate terminal) of the second transistor, feedback can be easily applied to the amplifier.

Further, by providing an open transmission line at the emitter terminal (or source terminal) of the first transistor of the cascode amplifier, the emitter terminal
(Or source terminal) can be grounded in an alternating manner at the operating frequency, and the influence of parasitic components such as inductance component of the via hole connected to the emitter terminal (or source terminal) is suppressed, and the gain of the amplifier is reduced. The drop can be prevented. Further, the stub line (open transmission line) provided at the emitter terminal (or source terminal) of the first transistor is made capacitive in the operating frequency band, so that the emitter terminal inside the transistor can be formed.
(Or a source terminal) and a parasitic inductance component of an emitter lead-out wiring (source lead-out wiring) can be compensated to improve the gain of the amplifier and to stabilize the operation.

In the high-frequency amplifier according to the first to third aspects of the present invention, at least one of the open-ended transmission lines has an electrical length substantially equal to a quarter wavelength at an operating frequency, so that an operation is performed. At the frequency, the terminal to be grounded of the transistor can be grounded at a high frequency.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a grounded-base amplifier as a high-frequency amplifier according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a change in characteristics with respect to a ground connection inductance in the grounded base amplifier.

FIG. 3 is a diagram comparing the characteristics of the above-mentioned common base amplifier with the characteristics of a conventional common base amplifier.

FIG. 4 is a circuit diagram of a grounded-base amplifier as a high-frequency amplifier according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of a cascode amplifier as a high-frequency amplifier according to a third embodiment of the present invention.

FIG. 6 is a circuit diagram of a conventional grounded base amplifier.

FIG. 7 is a circuit diagram of a conventional cascode amplifier.

FIG. 8 is a circuit diagram of a conventional grounded base amplifier.

FIG. 9 is a circuit diagram of a conventional cascode amplifier.

FIG. 10 is a diagram comparing changes in characteristics with respect to ground inductance in a common-emitter amplifier and a common-base amplifier.

FIG. 11 is a circuit diagram of a cascode amplifier as a high-frequency amplifier according to a fourth embodiment of the present invention.

[Explanation of symbols]

 11 input terminal, 12 output terminal, 13 input matching circuit, 14 transistor, 14B base terminal, 15 transmission line, 16 via hole, 17 open transmission line, 18 output matching circuit, L1 ... Parasitic inductance, 21: input terminal, 22: output terminal, 23: transmission line, 24: via hole, 25: transmission line, 26: transistor, 27: transmission line with open end, 28: transmission line, 29: resistance, 30 ... Transmission line, 31: Via hole, 32: Transmission line, 33: Resistance, 34: Bias supply wiring, 35: Bias terminal, 36: Output matching circuit, L21, L22: Parasitic inductance, 41: Input terminal, 42: Output terminal, 43: input matching circuit, 44: first transistor, 44E: emitter terminal, 45: open transmission line, 46: viahole 47, an interstage circuit, 48, a second transistor, 48B, a base terminal, 49, a transmission line with an open end, 50, a bias supply wiring, 51, a bias terminal, 52, an output matching circuit, L3, a parasitic inductance, Reference numeral 61 denotes an input terminal, 62 denotes an output terminal, 63 denotes a base terminal of a transistor, 64 denotes an input matching circuit, 65 denotes an output matching circuit, 66 denotes a first transistor, 66E denotes an emitter terminal, 67 denotes a second transistor, and 67B denotes a transistor. Base terminal, 68: Interstage circuit, 69a, 69b: Open transmission line, 70a, 70b: Transmission line, 71a, 71b: MIM capacitor, 72a, 72b, 72c, 72d: Via hole, L61 to L64: Parasitic inductance, 73a, 73b: transmission line, 211: input terminal, 212: output terminal, 213: input matching circuit, 214 ... Transistors, 215 ... output matching circuit, 311 ... input terminal, 312 ... output terminal, 313 ... first transistor, 314 ... interstage circuit, 315 ... second transistor, 316 ... MIM capacitor, 317 ... bias terminal.

Continued on front page F-term (reference) 5J067 AA01 AA04 CA00 CA61 FA16 HA02 HA09 HA25 HA29 HA33 KA29 KA68 KS11 LS12 MA04 MA17 MA21 TA02 TA03 5J092 AA01 AA04 CA00 CA61 FA16 HA02 HA09 HA25 HA29 HA33 KA29 KA68 MA03 TA21 MA21

Claims (6)

[Claims] 1. A transistor whose base terminal or gate terminal is to be grounded, at least one via hole connecting a ground conductor to the base terminal or gate terminal of the transistor, and one end connected to the base terminal or gate terminal of the transistor. And a transmission line having an open end. 2. A transistor having an emitter terminal or a source terminal to be grounded, an input circuit connecting a ground conductor to the emitter terminal or the source terminal of the transistor, and one end connected to a base terminal or a gate terminal of the transistor. A high-frequency amplifier comprising: a bias supply wiring; and at least one open-ended transmission line having one end connected to a base terminal or a gate terminal of the transistor. 3. A first transistor having an emitter terminal or a source terminal grounded; an interstage circuit having one end connected to a collector terminal or a drain terminal of the first transistor; A second transistor to which an emitter terminal or a source terminal is connected, a bias supply wiring having one end connected to a base terminal or a gate terminal of the second transistor, and a base terminal or a gate terminal of the second transistor, A high frequency amplifier comprising: means for electrically grounding. 4. The high-frequency amplifier according to claim 3, wherein said AC grounding means includes at least one open-ended transmission line. 5. The high-frequency amplifier according to claim 3, further comprising at least one open-ended transmission line having one end connected to an emitter terminal or a source terminal of said first transistor. High frequency amplifier. 6. The high-frequency amplifier according to claim 1, wherein at least one of the open-ended transmission lines has an electrical length of approximately ４ wavelength at an operating frequency. High frequency amplifier.