JPH06310916A - Microwave integrated circuit - Google Patents

Abstract

PURPOSE:To attain matching without using an open stub circuit taking a chip area when the microwave integrated circuit is matched on a semi-insulation board. CONSTITUTION:Open stub circuits 3, 6 are formed by using series elements comprising lamination capacitors 30, 32 and equivalent inductors 31, 33 of a throughhole penetrated through the semi-insulation board. Thus, the circuit is matched with a required input output impedance of a FET 1. As a result, the chip area of the matching circuit is reduced and the matching for power combination is easily attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave integrated circuit, and more particularly to a matching circuit for FETs on the microwave integrated circuit.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing an amplifier of an FET by a conventional open stub circuit used in a microwave integrated circuit, and FIG. 7 is a structure of an amplifier in which power is combined in the amplifier as shown in FIG. It is a figure. In FIG. 6, 1
Is an FET, 2 is a transmission line for converting the gate side input impedance, 3 is a matching open stub at the input end 4, 5 is a transmission line for converting the drain side output impedance, and 6 is a matching open stub at the output end 7. . In FIG. 7, 10a and 10b are FET amplifiers 11a, 11b, 11a, 11b having the configuration of FIG.
Reference numerals 13a and 13b are high-frequency signal composite transmission lines, 12 is an absorption resistor for absorbing a reflected signal due to mismatching, 14 is a transmission line, 15 is an input terminal of a composite amplifier, and 16a and 16 are provided.
b, 18a, and 18b are high-frequency signal composite transmission lines, 17 is an absorption resistor for the same purpose as the absorption resistor 12, 19 is a transmission line,
Reference numeral 20 is an output terminal of the combined amplifier.

Next, the operation will be described. When the input / output impedance of the FET 1 is capacitive, it can be converted into an inductive impedance by the transmission lines 2 and 5 and matching can be achieved with the ground component of the open capacitance of the open stubs 3 and 6 in the required band. . Such an amplifier is shown in FIG.
It is possible to operate as a power amplifier by combining two (10a, 10b) as shown in Fig. 7, and in this case, as shown in Fig. 7, the line lengths of the transmission lines 11, 13 and 16, 18 are changed. By making the a side and the b side equal, the phases of the high frequency signals at the corresponding positions of both FET amplifier circuits are adjusted to be in phase. At this time, the absorption resistors 12 and 17 that absorb the reflected signals at the connecting portions between the input terminals 15 and the output terminals 20 and the transmission lines 13 and 18 are used.

[0004]

Since the conventional microwave integrated circuit uses the matching circuit as described above, the length of the open stubs 3 and 6 becomes long depending on the frequency band. Therefore, on the semi-insulating substrate. It was necessary to take a large chip area. Further, in the case of synthesizing as a power amplifier, there is a problem that the transmission line necessary for this synthesizing becomes long and the chip area becomes large.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a microwave integrated circuit in which the matching circuit can be downsized and the chip area can be kept small. To do.

[0006]

In a microwave integrated circuit according to the present invention, an open stub forming a matching circuit is connected to a multilayer capacitor and a multilayer capacitor on the front surface side of a substrate, and this is grounded to the back surface of the substrate. It is equivalently replaced by a through hole.

Further, according to the present invention, a plurality of multilayer capacitors among circuits equivalent to the above-mentioned open stub are provided, and by selecting them, the conversion amount of the impedance of the FET can be adjusted according to the change of the characteristics of the FET. It is the one.

Further, according to the present invention, when the power combining is performed using the matching circuit, the impedance matched by each unit amplifier is set to the impedance matched by the power combiner.
When it is set to twice as high as this and is parallelized, the impedance can be matched at the input / output terminals of the parallelized circuit.

[0009]

In the microwave integrated circuit according to the present invention, the equivalent open stub is constituted by the multilayer capacitor formed on the semi-insulating substrate and the through hole for grounding the multilayer capacitor on the substrate to the back surface of the substrate. The area can be reduced and the matching circuit can be downsized.

By forming a large number of the above multilayer capacitors and selecting them, the matching impedance can be adjusted.

Further, by doubling the impedance of the unit amplifier of the power combiner, it is possible to shorten the transmission line of the matching circuit of the unit amplifier at the time of power combination, and to downsize the power amplifier. You can

[0012]

EXAMPLES Example 1. FIG. 1 shows a microwave integrated circuit according to an embodiment of the present invention, which constitutes an FET amplifier using an open stub circuit. In FIG. 1, reference numerals 1, 2, 4, 5, and 7 are the same as those in FIG. 6, and in the figure, 30 and 32 are equivalent capacitances of multilayer capacitors formed on the surface of a semi-insulating substrate, and 31, 33. Is an equivalent inductor having a through hole that is connected to the multilayer capacitor on the front surface side of the substrate and grounds the capacitor, and that penetrates from the front surface to the back surface of the semi-insulating substrate.

Next, the operation will be described. If the input / output impedance of the FET1 is capacitive, it can be converted by the transmission lines 2, 5 in order to make this impedance inductive. The multilayer capacitors 30 and 32 provided at the ends of the transmission lines 2 and 5 are grounded to the ground plane on the back surface of the substrate through the through holes 31 and 33. The grounded multilayer capacitors 30 and 32 and the through holes 31 and 33 equivalently form a series element of a capacitor and an inductor. Therefore, the inductive impedance of the FET converted by the transmission lines 2 and 5 as described above can be converted into the matching impedance by adjusting the series element so as to exhibit the capacitive impedance.

In the microwave integrated circuit of the first embodiment, the multilayer capacitor 3 formed on the semi-insulating substrate is used.
0 and 32 and the through holes 31 and 33 for grounding the multilayer capacitor on the substrate to the back surface of the substrate constitute an equivalent open stub, so that the chip area can be reduced and the matching circuit can be miniaturized. To be

Example 2. FIG. 2 shows a microwave semiconductor device according to the second embodiment of the present invention. Example 1 of FIG. 1 above
In the circuit of (1), if the characteristics such as the S parameter of the FET1 change for some reason, the impedance cannot be matched with the FET1, which is a problem.

The second embodiment of the present invention addresses this problem. As shown in FIG. 2, a transmission line corresponding to the transmission lines 2 and 5 of the first embodiment for converting input / output impedance. Are provided as 42, 41, 40, 50, 51, 52, and a plurality of multilayer capacitors 48, 47, 46, 56, 57, 58 are provided on the input and output sides, respectively, and normally the terminals 44, 54 are provided. Closed, other terminals 45, 43,
With 53 and 55 open, the multilayer capacitors 47 and 57,
The impedance of FET1 is matched at the center frequency of the FET1 amplifier by the open stub composed of the inductors 49 and 59 by the through holes, and the FET1
For the impedance deviation of the terminals 43, 44,
The desired one of the 45, 50, 51, 52 is closed and the desired multilayer capacitor 46, 47, 48, 56, 57,
By using 58, impedance matching can be achieved.

In the second embodiment as described above, even if the characteristics such as the S parameter of the FET1 amplifier change for some reason, the impedance matching with the FET1 can be achieved by appropriately selecting the multilayer capacitor to be used. Therefore, there is an effect that a stable operation of the microwave semiconductor device can be obtained.

Example 3. FIG. 3 shows a microwave semiconductor device according to a third embodiment of the present invention, which is an example of a patterned matching circuit of the FET amplifier of the first or second embodiment. In FIG. 3, 70
Is a FET, 71, 72, 73 and 78 are transmission lines, 74,
75 is a multilayer capacitor, 77 is a through hole for grounding, 76
Is a pad, and 79a and 79b are the boundaries of the transmission lines following 71 and 72, and the boundaries of the transmission lines following 72 and 73, respectively.

Next, the operation and action will be described. FE
T70 is the transmission line 71, 72 to the multilayer capacitor 74.
Is grounded through the through hole 77. At this time, FET70
If the impedance of is as designed, at the end face 79a,
That is, matching can be achieved without the transmission line 73. However, when the impedance of the FET 70 changes to the high impedance side, the pad 76 and the line 72 are further
By connecting and with a wire, the multilayer capacitor 75 can also be used for the matching circuit via the pad 76,
This makes it possible to adjust the matching circuit.

The above is the adjustment method for increasing the capacitance connected to the line 72. However, in order to reduce the capacitance connected to the line 72, the multilayer capacitor 74 is laser-trimmed to be removed from the transmission line 72. By disconnecting and connecting the multilayer capacitor 75 having a smaller capacity than the multilayer capacitor 74 to the transmission line 72 via the pad 76, it is possible to adjust the matching circuit in the direction of reducing the capacity. The transmission line 73 in FIG. 3 is a transmission line for transmitting the signal from the FET 1 to another place.

Example 4. FIG. 4 shows a microwave semiconductor device according to a fourth embodiment of the present invention. It is also possible to construct a power amplifier by performing power combining using a single amplifier composed of one FET of the above-mentioned first embodiment, and the fourth embodiment shown in FIG. 4 has the same high frequency performance. 1 shows an amplifier configured to combine power by using the amplifiers in parallel. Figure 4
4A is a circuit diagram of the amplifier of the fourth embodiment, and FIG. 4B is an equivalent circuit diagram thereof. In the figure, 80 is the same as the single amplifier of the first embodiment, 81 is an input terminal, 82 is an output terminal, 90 is an equivalent circuit when the single amplifier 80 is matched, and 91 is the single amplifier 80. The input impedance at the time of matching, that is, the impedance seen from the terminal 81, and 92 is the output impedance of the single amplifier 80 at the time of matching, that is, the impedance seen from the terminal 82.

Next, the operation will be described. In the matching circuit of the fourth embodiment, the input / output impedance (91, 92) for matching the single amplifier 80 is set to the single amplifier 8
Impedance matching when 0 is combined into a power amplifier, that is, 2 of input / output impedance of the power amplifier
If, for example, 100Ω is set, the input / output impedance of the entire power amplifier configured by paralleling the two becomes 50Ω and matches the high-frequency signal source of the input terminal 81 and the load impedance of the output terminal 82. It is possible to take In this case, the matching circuit of the single amplifier 80 having a high impedance of double (100Ω) shortens the line length by increasing the wavelength shortening rate of the transmission line and can reduce the chip area. It is a thing.

In this fourth embodiment, one FET is used.
It becomes possible to construct a power amplifier by using a single amplifier consisting of, and at that time, there is an effect that the chip area can be reduced.

Example 5. FIG. 5 shows a power amplifier according to a fifth embodiment of the present invention, which is a multi-stage configuration of the power amplifier shown in FIG. That is,
In the figure, 100a and 100b have the configuration of the first embodiment, a single amplifier having an input / output impedance of 100Ω, and 101a, 101b, 101c, and 101d have the configuration of the first embodiment and an input / output impedance of 2
It is a single amplifier of 00Ω and has an input / output impedance of 10
Input / output impedance matching (100Ω) is performed by each of the 0Ω single amplifiers 100a and 100b and the two single input / output impedance 200Ω single amplifiers 101a and 101b or 101c and 101d. 100a and 100b) are combined in parallel in two stages, and the input terminal 102 and the output terminal 103 are matched in input / output impedance to 50Ω.

In the microwave integrated circuit according to the fifth embodiment as described above, there is an effect that a power amplifier having multiple stages and a large amplification degree can be configured.

[0026]

As described above, according to the microwave integrated circuit of the present invention, the open stub circuit is composed of the multilayer capacitor on the front surface of the substrate and the through hole penetrating from the front surface to the back surface of the substrate. Since the equivalent capacitor and the inductor are replaced, the size of the matching circuit can be reduced.

Further, by providing a plurality of equivalent capacitors composed of the above-mentioned multilayer capacitors, it is possible to adjust the impedance of the FET.

Further, it is possible to obtain an effect such that matching can be easily performed when a FET combiner having a matching circuit is combined to form a power combiner.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a single amplifier according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a single amplifier provided with an adjusting multilayer capacitor according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a layout of a matching circuit of an FET amplifier according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a power-combined single amplifier according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a multistage amplifier according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a single amplifier using a conventional open stub circuit.

FIG. 7 is a diagram showing a configuration of a single amplifier in the case of conventional power combining.

[Explanation of symbols]

1 Field Effect Transistor (FET) 2 Transmission Line for Input Impedance Conversion 5 Transmission Line for Output Impedance Conversion 30, 32 Equivalent Capacitance of Multilayer Capacitor 31, 33 Equivalent Inductor 40 of Through Hole Penetrating from Top to Back of Semi-insulating Substrate 41 Input impedance conversion transmission line 44, 45, 46 Between terminals 53, 54, 55 Between terminals 46 to 48 Equivalent capacitance of adjustment multilayer capacitor 50, 51 Output impedance conversion transmission line 56 to 58 Equivalent capacitance of adjustment multilayer capacitor 70 FET cell 74, 75 multilayer capacitor pattern

Claims (4)

[Claims] 1. A microwave integrated circuit in which a field effect transistor (hereinafter referred to as FET) and a matching circuit thereof are formed on a semi-insulating or semiconductor substrate, wherein the matching circuit is a transmission line of a constituent of the microwave integrated circuit. The microwave impedance is set to a desired impedance value depending on the length, and one end of the transmission line is grounded by a multilayer capacitor and a through hole that penetrates the substrate and is connected to the back surface of the substrate. circuit. 2. The microwave integrated circuit according to claim 1, wherein a plurality of the multilayer capacitors are provided in parallel, and by selecting them, the amount of impedance conversion by the matching circuit can be adjusted in accordance with changes in the characteristics of the FET. Characteristic microwave integrated circuit. 3. The microwave integrated circuit according to claim 1 or 2, wherein two power amplifiers each having the FET are provided in parallel to form a power amplifier, and each FET amplifier having a matching circuit comprises: A microwave integrated circuit having an input / output matching impedance that is twice the input / output impedance of the power amplifier in a required band. 4. The microwave integrated circuit according to claim 3, wherein the two FET amplifiers forming the power amplifier are set as a unit, and the FET amplifiers are formed in multiple stages.