WO2017208328A1

WO2017208328A1 - High-frequency amplifier

Info

Publication number: WO2017208328A1
Application number: PCT/JP2016/065980
Authority: WO
Inventors: 純神岡; 政毅半谷; 山中　宏治
Original assignee: 三菱電機株式会社
Priority date: 2016-05-31
Filing date: 2016-05-31
Publication date: 2017-12-07
Also published as: JP6289678B1; JPWO2017208328A1

Abstract

A high-frequency amplifier is configured such that a second harmonic processing circuit (8) that is a resonant circuit that resonates at a second harmonic of a high-frequency signal includes: an overlying electrode (9) of which one end is connected to a gate electrode (2) of an FET (1) and which has two or more bend sections (9a); a underlying electrode (10) having one end that is grounded; and a dielectric member (11) arranged between the overlying electrode (9) and the underlying electrode (10). This makes it possible to reduce circuit size, and expand the frequency band in which a high-efficiency operation can be expected.

Description

High frequency amplifier

This invention relates to a high frequency amplifier for amplifying a high frequency signal.

For example, a high-frequency amplifier that amplifies a high-frequency signal is mounted on a wireless communication device, a radar device, or the like.
Some high-frequency amplifiers use, for example, field-effect transistors (FETs) with a common source.

High frequency amplifiers are required to have high efficiency characteristics. In order to increase the efficiency of the high-frequency amplifier, a method of short-circuiting the reflection phase of the second harmonic wave from the gate electrode in anticipation of the matching circuit on the input side is known.
Non-Patent Document 1 below discloses a high-frequency amplifier that short-circuits the reflection phase of the second harmonic by providing a second harmonic processing circuit including a tip release stub.

Since the conventional high-frequency amplifier is configured as described above, high efficiency can be achieved by providing a second harmonic processing circuit including a tip release stub. However, since the second harmonic processing circuit including the tip release stub is large in size, it is difficult to be integrated in the immediate vicinity of the transistor, and it is necessary to connect to the transistor via a lead-out transmission line or a bonding wire. is there. As a result, there is a problem that the circuit is increased in size.
In addition, since the lead-out transmission line and the bonding wire have an inductance component, there is a problem that a frequency band in which high-efficiency operation can be expected is narrowed.

The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a high-frequency amplifier capable of reducing the size of a circuit and expanding a frequency band in which high-efficiency operation can be expected. .

A high-frequency amplifier according to the present invention includes a transistor that amplifies a high-frequency signal input from an input electrode and outputs an amplified high-frequency signal from an output electrode, and a resonance circuit that resonates with a second harmonic of the high-frequency signal, A resonant circuit is disposed between the upper electrode and the lower electrode, one upper electrode connected to the transistor input electrode and having two or more bent portions, the lower electrode grounded at one end And having a dielectric.

According to this invention, a resonant circuit that resonates with a second harmonic of a high-frequency signal has one end connected to the input electrode of the transistor, the upper electrode having two or more bent portions, and one end grounded. Since it is configured to have a base electrode and a dielectric disposed between the top electrode and the base electrode, it is possible to reduce the size of the circuit and to provide a frequency band that allows high-efficiency operation. There is an effect that can be spread.

1 is a configuration diagram showing a high-frequency amplifier according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view taken along line A-A ′ of a second harmonic processing circuit 8 in the high frequency amplifier of FIG. 1. It is a perspective view which shows the upper electrode 9 and the lower electrode 10 of the high frequency amplifier by Embodiment 2 of this invention. It is a block diagram which shows the high frequency amplifier by Embodiment 3 of this invention. It is a block diagram which shows the high frequency amplifier by Embodiment 4 of this invention.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a high frequency amplifier according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view taken along line AA ′ of a second harmonic processing circuit 8 in the high frequency amplifier of FIG.
1 and 2, FET 1 is a transistor that amplifies a high-frequency signal input from an input electrode and outputs an amplified high-frequency signal from an output electrode.
In the first embodiment, it is assumed that the FET 1 is a grounded field effect transistor, and the FET 1 has a gate electrode 2 as an input electrode and a drain electrode 4 as an output electrode. The source electrode 3 of the FET 1 is grounded via via

holes

7a and 7b.

However, the FET 1 is not limited to a source grounded field effect transistor, and may be, for example, a drain grounded field effect transistor.
The bonding pad 5 a is a pad for inputting a high-frequency signal, and is connected to the gate electrode 2 of the FET 1 through the transmission line 6.
The bonding pad 5b is a pad for outputting a high frequency signal, and is connected to the drain electrode 4 of the FET1.
The transmission line 6 is a line connecting the bonding pad 5 a and the gate electrode 2 of the FET 1, and transmits a high-frequency signal input from the bonding pad 5 a to the gate electrode 2 of the FET 1.
The

via holes

7a and 7b are composed of a hole connecting the front surface and the back surface of the substrate, and pads provided around the upper end of the hole. Pads provided around the upper ends of the

via holes

7a and 7b are connected to the source electrode 3 of the FET 1, and the lower ends of the

via holes

7a and 7b are connected to the ground applied to the back surface of the substrate. In addition, a hole middle portion in the via hole 7 a is connected to the base electrode 10.

The second harmonic processing circuit 8 is a resonance circuit that resonates with a second harmonic of a high frequency signal.
The second harmonic processing circuit 8 includes a MIM (Metal Insulator Metal) capacitor, and the MIM capacitor includes an upper electrode 9, a lower electrode 10, and a dielectric 11.
One end of the upper electrode 9 is connected to the gate electrode 2 of the FET 1 via the transmission line 6 and has a meander shape. That is, the upper electrode 9 has a shape having two or more bent portions 9a. In the example of FIG. 1, it has seven bending parts 9a.
Since the upper electrode 9 has a meander shape, it has a large inductance component.
One end of the base electrode 10 is grounded via the via hole 7 a, and the base electrode 10 is disposed below the upper electrode 9.
A dielectric 11 is disposed between the upper electrode 9 and the lower electrode 10.
For example, silicon nitride can be used as the dielectric 11.

Next, the operation will be described.
A high-frequency signal input from the bonding pad 5 a is input to the gate electrode 2 of the FET 1 through the transmission line 6.
The high frequency signal input from the gate electrode 2 is amplified by the FET 1, and the high frequency signal amplified by the FET 1 is output from the drain electrode 4 of the FET 1 to the bonding pad 5b.

Here, a second harmonic processing circuit 8 which is a series resonance circuit that resonates with a second harmonic of a high frequency signal is formed by the inductance components of the upper electrode 9, the lower electrode 10, and the via hole 7a and the capacitance component of the MIM capacitor. ing.
The second harmonic processing circuit 8 is disposed in the immediate vicinity of the gate electrode 2 of the FET 1, and the upper electrode 9 is shunt-connected to the transmission line 6.
For this reason, the impedance at the second harmonic of the high-frequency signal looking into the input side from the gate electrode 2 of the FET 1 is short-circuited, and a highly efficient high-frequency amplifier is realized.

In the second harmonic processing circuit 8, since the upper electrode 9 having a large inductance component and the MIM capacitor having a large capacitance component are integrated, a second harmonic processing circuit including a tip release stub, a transmission line, and an MIM capacitor are provided. Compared to a series resonant circuit connecting the two, a small resonant circuit can be realized.

As apparent from the above, according to the first embodiment, the resonance circuit that resonates with the second harmonic of the high-frequency signal has one end connected to the gate electrode 2 of the FET 1 and has two or more bent portions 9a. The upper electrode 9 is grounded, the ground electrode 10 is grounded at one end, and the dielectric 11 is disposed between the ground electrode 9 and the ground electrode 10. There is an effect that the size can be reduced and the frequency band in which high-efficiency operation can be expected can be expanded.

In the first embodiment, the parasitic reactance of the transmission line 6 and the FET 1 can be ignored. However, when the parasitic reactance of the transmission line 6 and the FET 1 cannot be ignored, the resonance frequency of the second harmonic processing circuit 8 is high. By selecting the specifications of the second harmonic processing circuit 8 so as to deviate from the second harmonic of the signal, the impedance at the second harmonic of the high frequency signal is shorted at the gate end face of the FET 1. An efficient high frequency amplifier is realized.

Embodiment 2. FIG.
In the first embodiment, the base electrode 10 has a plate shape and only the upper electrode 9 has a meander shape. However, in the second embodiment, the base electrode 10 also has a top shape. Similar to the electrode 9, a meander-shaped one will be described.

FIG. 3 is a perspective view showing the upper electrode 9 and the lower electrode 10 of the high-frequency amplifier according to Embodiment 2 of the present invention.
In FIG. 3, the base electrode 10 has a meander shape. That is, the base electrode 10 has a shape having two or more bent portions 10a.
In FIG. 3, the dielectric 11 is not drawn for simplification of the drawing, but the dielectric 11 is disposed between the upper electrode 9 and the lower electrode 10.

As apparent from the above, according to the second embodiment, since the base electrode 10 has a shape having two or more bent portions 10a, the inductance component is larger than that of the first embodiment. For this reason, when obtaining a series resonance circuit having the same resonance frequency, there is an effect that the size can be reduced as compared with the first embodiment.

Embodiment 3 FIG.
In the first and second embodiments, one double harmonic processing circuit 8 is disposed between the transmission line 6 and the via hole 7a. However, two second harmonic processing circuits 8 are disposed. It may be a high frequency amplifier.

4 is a block diagram showing a high frequency amplifier according to Embodiment 3 of the present invention. In FIG. 4, the same reference numerals as those in FIG.
The second harmonic processing circuit 8a is a second harmonic processing circuit similar to the second harmonic processing circuit 8 in the first embodiment, and includes an upper electrode 9 having one end connected to the gate electrode 2 of the FET 1, and one end Has a base electrode 10 grounded through a via hole 7a, and an upper electrode 9 and a dielectric 11 disposed between the base electrode 10.
The second harmonic processing circuit 8b is a second harmonic processing circuit similar to the second harmonic processing circuit 8a, but one end of the base electrode 10 in the second harmonic processing circuit 8b is grounded via a via hole 7b.
The base electrode 10 in the second

harmonic processing circuits

8a and 8b may have a meander shape as in the second embodiment.

When the second harmonic processing circuit 8a is loaded on the via hole 7a side and the second harmonic processing circuit 8b is loaded on the via hole 7b side, the reflection coefficient in the impedance at the second harmonic of the high frequency signal is the above-described first embodiment. , 2 is closer to 1, so that it is less affected by the input side circuit, and a more efficient high-frequency amplifier is realized.

Embodiment 4 FIG.
In the first to third embodiments, the upper electrode 9 has a meander shape. However, the upper electrode 9 only needs to have a shape having two or more bent portions 9a. 9 may be shaped like a spiral inductor.

FIG. 5 is a block diagram showing a high-frequency amplifier according to Embodiment 4 of the present invention. In FIG. 5, the same reference numerals as those in FIG. The upper electrode 9 has a shape like a spiral inductor.
Here, an example is shown in which the upper electrode 9 is shaped like a spiral inductor, but the underlying electrode 10 may also be shaped like a spiral inductor.
Even in a shape like a spiral inductor, the inductance component becomes large as in the meander shape.

In the first to fourth embodiments, the example in which the transistor is the FET 1 is shown. However, the present invention is not limited to this. For example, the transistor may be a bipolar transistor.

In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

The present invention is suitable for a high-frequency amplifier that amplifies a high-frequency signal.

1 FET (transistor), 2 gate electrode (input electrode), 3 source electrode, 4 drain electrode (output electrode), 5a, 5b bonding pad, 6 transmission line, 7a, 7b via hole, 8, 8a, 8b double wave processing Circuit (resonant circuit), 9 upper electrode, 9a bent portion, 10 lower electrode, 10a bent portion, 11 dielectric.

Claims

A transistor that amplifies the high-frequency signal input from the input electrode and outputs the amplified high-frequency signal from the output electrode;
A resonance circuit that resonates at a second harmonic of the high-frequency signal,
The resonant circuit is:
An upper electrode having one end connected to the input electrode of the transistor and having two or more bent portions;
A ground electrode having one end grounded;
A high-frequency amplifier comprising: a dielectric disposed between the upper electrode and the lower electrode.
The high-frequency amplifier according to claim 1, wherein the base electrode has two or more bent portions.
2. The high-frequency amplifier according to claim 1, comprising two resonance circuits.