JP2001244710A - High frequency device and mobile radio using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized high frequency device. SOLUTION: A distributed constant line 103, whose electrical length is shorter than the quarter wavelength and that is branched into two ways from an input terminal 102 is employed for wiring used for the high-frequency device and a capacitive element 105 is connected to the distributed constant line 103. Even when the line length of the distributed constant line 103 is shorter than quarter wavelength, by adding the parallel capacitive element 105 to the distributed constant line 103 becomes about quarter wavelength is obtained in terms of the electrical length, so as to make the high frequency device small in size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave power amplifier, and more particularly to a high-frequency high-power device suitable for a mobile radio and a base station transmitter in a mobile radio system.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. Sho 61-26302 discloses a microwave power distributor shown in FIG.
An electric length of about 1/4 wavelength is disclosed. FIG. 2 also shows a different wiring layout,
Also disclosed is one having an electric length of about 1/4 wavelength. Japanese Unexamined Patent Publication (Kokai) No. 63-197346 discloses that, for each unit transistor block divided in multiple parallel,
It is disclosed that the internal matching circuit is multiplex-divided to correspond to each, and that the matching circuit is mainly configured by a strip line. Further, related technologies relating to the high-frequency semiconductor device are disclosed in JP-A-6-6151, JP-A-62-292007, and JP-A-60-2832.
03, JP-A-3-250807, JP-A-4-250
JP-A-361404, JP-A-5-235666, JP-A-4-154311, JP-A-5-298
No. 51, JP-A-1-122606, JP-A-5
-37212, JP-A-63-246002, JP-A-6-61760 and JP-A-6-33.
No. 4054.

[0003]

However, Japanese Patent Application Laid-Open No.
In Japanese Patent Application Laid-Open No. 1-26302, the actual length of the wiring is uniquely determined by the shape and material of the wiring and the like, and no consideration is given to shortening the wiring. Also,
In JP-A-63-197346, FIG. 1 shows a conceptual diagram of a high-frequency semiconductor device, and FIG. 3 shows a specific configuration thereof. However, as is clear from FIG. 3,
It is not disclosed that the shape of the distributed constant line is symmetrical when viewed from the distribution element.

On the other hand, in order to constitute a high-output amplifier in the microwave band, it is necessary to increase the saturation output of the amplifier. MOSFET (Metal O
In the case of using the xideSemiconductor Field Effect Transistor, the saturation output could be increased by increasing the gate width. But one
MOSFET used in frequency band exceeding GHz
In the case of, the saturation output Pout does not increase in proportion to the increase in the gate width Wg, as shown in FIG.
It was found that the decrease in dd was large. According to this result, when the gate width Wg is 8 mm, the saturation output Pout is 0.5 W and the power addition efficiency ηadd is 49%. However, when the gate width is 4 times and 32 mm, 4 times the saturation output 2 W is obtained. In this case, only 1.4 W can be obtained, and the power added efficiency also drops to 33%. It is known that this is caused by a common impedance and a thermal mutual interference effect generated by using a large amplifying element integrated on the same chip. In order to suppress these mutual interference effects, it is effective to block large amplifying elements into a plurality of blocks and separate and arrange them. It is necessary to distribute the power uniformly, amplify, and combine the outputs uniformly.

[0005] This type of device includes a Wilkinson power divider / synthesizer, but in order to construct an optimum matching circuit, the electric length of a plurality of distributed constant lines used here is four.
It is necessary to make it to one-half wavelength.

In the case of the Wilkinson power divider / synthesizer, if a distributed constant line formed on a dielectric substrate having a relative dielectric constant of 10 is used, a quarter at 1.75 GHz is used.
The wavelength is about 17 mm, and if a pair is provided for each of the input and output of a plurality of amplifying elements obtained by blocking this, the size of the high-frequency amplifier becomes excessively large with this alone. This is a serious problem particularly when the operating frequency is low because the wavelength is long. On the other hand, the length of the distributed
If the wavelength is shorter than one-half wavelength, an optimum matching circuit cannot be formed as it is, so that there is a problem that high output and high efficiency amplification characteristics are remarkably reduced.

[0007] The present invention has as its main object to provide a small high-frequency device, and further provides a small, high-efficiency, high-frequency high-power device used for a mobile radio and a base station transmitter in a mobile radio system. Is to do.

[0008]

Therefore, according to the present invention, a wiring having only an electrical length shorter than 1/4 wavelength is used.
In addition, by connecting a capacitance element to the wiring, the electrical length is set to about １ ／ wavelength.

In order to further reduce the size of the capacitive element, the connecting position of the capacitive element when a semiconductor element is connected to one end of the wiring is set to a position closer to the other end of the wiring. (About 0.02 wavelength).

More specifically, in FIG. 1 showing a high-frequency high-power device according to the present invention, reference numeral 1 denotes a dielectric substrate;
Reference numerals 101, 102, 103, 104, and 105 denote thin film conductors formed on the surface of the dielectric substrate 1. 101 is a common ground, 102 is an input terminal, 103 is the input terminal 1
A plurality of distributed constant lines branched from line 02 are formed, and each terminal is connected to an input terminal of a semiconductor amplifying element.
105 is an output terminal, 104 is the output terminal 105
A plurality of branched distributed constant lines are formed, and each terminal is connected to an output terminal of a semiconductor amplifying element. Here, the plurality of distributed constant lines 103 are arranged symmetrically with respect to the input terminal 102, each length is shorter than a quarter wavelength, and each is grounded via at least one capacitor. The plurality of distributed parameter lines 104 are arranged symmetrically with respect to the output terminal 105, each of the lengths is shorter than a quarter wavelength, and
The object of the present invention is achieved by grounding via the individual capacitors.

Further, the object of the present invention is achieved not only by forming the thin film conductor on a dielectric substrate but also by forming the thin film conductor on the same semiconductor substrate as the semiconductor amplifying element.

[0012]

The semiconductor amplifying device has a gate oxide film thickness of 35 nm, a gate length of 0.8 μm, and a gate width of 16 mm.
When a MOSFET having the following specifications is used, the capacitance Cx and the position Lxc on the distributed constant line 103 for realizing the input impedance Zin viewed from the input terminal 102 are as shown in FIG. Here, a case is shown in which the operating frequency is 1.75 GHz and the length of the distributed constant line 103 is shortened to 0.04 to 0.1 wavelength (3 to 7 mm). It has been found that the output impedance of the pre-stage MOSFET required to drive this is in the range of 15 to 25 Ω, and from FIG. 2 it can be seen that the length of the distributed constant line required to achieve the input impedance Z in Lx, capacitance Cx and its position Lxc can be determined. In this case, the length Lx of the distributed constant line is set to 0.0.
7 wavelengths, capacitance Cx of 3.6 to 2.9 pF, position Lxc of 0.0
If the wavelength is set to 33 to 0.017, an optimum input matching circuit can be formed.

Also, a plurality of MOSFETs having the above specifications
Load impedance Zou that can be driven by
FIG. 3 shows the capacitance Cy on the distributed constant line 104 for realizing t and the connection position Lyc. Here, the operating frequency is 1.75 GHz, and the length Ly of the distributed constant line 104 is 0.04.
This shows a case where the wavelength is shortened to 0.07 wavelength (2.8 to 5 mm). From this result, the matching load impedance Zout
Becomes 12.5 to 25Ω, the length Ly, the capacitance Cy, and the position Lyc of the distributed constant line can be obtained. In this case, the length Ly of the distributed constant line is set to 0.04 wavelength,
The capacitance Cy is 4.4 to 3.2 pF, and the position Lyc is 0.029 to
If the wavelength is 0.09 (2 to 0.63 mm), an optimal output matching circuit can be configured.

As described above, according to the present invention, an optimum matching circuit is formed even if the length of the distributed constant line is shortened from one third to one sixth of the conventional quarter wavelength line. It becomes possible. Although the case where the operating frequency is 1.75 GHz is shown here, the same result can be obtained in a wide range in the UHF band, and the matching circuit for a plurality of MOSFETs arranged in parallel is reduced in size. Can be configured.

FIG. 6 shows the effect of the present invention. This result shows that a MOSFET having a gate width Wg of 32 mm is
It is divided into two SFET blocks and operated in parallel according to the present invention, and shows the results of six prototypes. According to this, the saturation power is reduced from 1.4 W according to the prior art to 1.7 W,
The power added efficiency has increased from 33% to 42%. This result is twice the saturation output of the MOSFET having a gate width of 16 mm, and indicates that there is almost no decrease in power added efficiency.

As described above, according to the present invention, it is possible to provide a compact, high-efficiency, high-frequency high-power device.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 4 shows an output section of a printed wiring board for UHF band power amplification. 1 is a ceramic substrate, 21 to
24 is a ground wiring, 3 and 4 are distributed constant lines, 5 to 8 are wiring metal pads, and Q01 and Q02 are power MOSs.
An FET (power MOSFET) chip. here,
103 and 104 are distributed constant lines according to the present invention;
01 to C04 are impedance matching capacitors. FIG.
Is the circuit configuration of the UHF band power amplification output unit. Q01
And Q02 use a power MOSFET having a gate length of 0.8 μm and a gate width of 16 mm. Here, the lengths of the distributed constant lines 103 and 104 in the present invention are 5 mm, C01 and C02 are each 5 pF, and C03 and C04 are each 3 pF. 9 ~
12 is the inductance of the bonding wire, which is about 1n
H.

The feature of this structure is that the parallel connection of the power MOSFETs is formed using a distributed constant line, the length of the distributed constant line is shorter than a quarter wavelength of the electrical length at the operating frequency, and the distributed constant The point is that at least one capacitor is connected to the line and impedance matching is performed.

The effect of the present invention will be described with reference to FIG. FIG. 6 shows the relationship between the power added efficiency and the saturation output in the UHF band power amplification output circuit using power MOSFETs having different sizes (gate widths). The operating conditions are operating frequency 1.
75 GHz, drain power supply voltage 4.8V. In general, when the size of the power MOSFET, that is, the gate width is increased, the saturation output of the power MOSFET is greatly reduced as the saturation output increases, as shown in the conventional example. In contrast, the power MOSFET according to the present invention
When the parallelization of T is applied, it is possible to improve the saturation output while minimizing the decrease in the power added efficiency. According to the present embodiment, two power MOSFET chips are used, and 1.7 is used.
At 5 GHz, a result of a saturated output of 2 W and a power added efficiency of 40% or more was obtained.

FIG. 7 and FIG. 8 show a second embodiment of the present invention.

FIG. 7 shows a module configuration of the UHF band power amplifier. A high-gain power amplifier module including a driver unit in the output unit shown in the first embodiment is formed on a printed wiring board. FIG. 8 shows the circuit configuration.
The driver section has two power MOSFETs, Q1 and Q
2 and two capacitors Ca and Cb are integrated on one chip to achieve miniaturization. Output part is two power MOSF
ET, Q31 and Q32 are connected in parallel,
Each is connected to vertically symmetric distributed constant lines 31 and 41, and one end of each is grounded via capacitors C8 to C11. According to this embodiment, the saturation output is 2 W at 1.75 GHz and the power supply voltage is 4.8 V, and the power gain is 30 d.
B: A total efficiency of 45% is obtained. This high-frequency power amplifier is suitable for application to a transmission unit of a portable terminal for a cellular telephone.

FIG. 9 shows a third embodiment of the present invention.

FIG. 9 shows an output section of a printed wiring board for power amplification in the UHF band. 41 is a ceramic substrate, 42, 43
Is a ground wiring, 44 to 49 are distributed constant lines, and Q41 to Q4
4 is a power MOSFET chip. Also R41-4
6 is an isolation resistor, and C41 to C48 are impedance matching capacitors. Here, Q41 to Q44 are power MOSFETs each having a gate length of 0.8 μm and a gate width of 16 mm. Each of the resistors R41 to R46 is 2
0Ω, C41 to C44 are each 6 pF, and C45
To C48 are each 4 pF. The distributed constant lines 44 and 45 and 46 and 47 functioning as power distributors are respectively arranged symmetrically and connected to the distributed constant lines 48 and 49 of the input / output circuit unit. According to the present embodiment, using four power MOSFET chips, in a 1.9 GHz band and a power supply voltage of 8 V, a saturation output of 30 W and a power added efficiency of 5 are used.
0% or more is obtained. This is suitable for application to a transmission power amplifier of a cordless telephone base station.

In the above embodiment, the MOSFEs connected in parallel
Although the number of T chips has been described by taking two and four as an example,
Further, the same effect can be obtained with a large number. Further, the semiconductor amplifying element is not limited to the MOSFET described above, but can be applied to a high-frequency high-power device using an insulated gate type, a Schottky junction type field effect transistor, and a bipolar transistor.

As described above, the parallel connection of the field effect transistors can be efficiently performed at the UHF band frequency.
A power amplification module having high output and high efficiency characteristics can be provided.

[0026]

According to the present invention, the wiring used for the high-frequency device is formed by using only the wiring 103 having an electrical length shorter than 1/4 wavelength and connecting the capacitive element 105 to the wiring 103. Even if the length is short, the electrical length is about 1/4
Wavelength, which reduces the size of the high-frequency device.

[Brief description of the drawings]

FIG. 1 is a diagram showing the concept of the present invention.

FIG. 2 is a diagram illustrating the operation and effect of the present invention.

FIG. 3 is a diagram illustrating the operation and effect of the present invention.

FIG. 4 is an output section of a UHF band power amplification printed wiring board according to the first embodiment of the present invention.

FIG. 5 is a UHF band power amplifier circuit of the present invention.

FIG. 6 is a graph showing the relationship between the power added efficiency and the saturation output in the UHF band power amplification output circuit showing the effect of the present invention.

FIG. 7 is a UHF band power amplification printed wiring board module according to a second embodiment of the present invention.

FIG. 8 is a UHF band power amplification module circuit diagram.

FIG. 9 is an output section of a UHF band power amplification printed wiring board according to a third embodiment of the present invention.

[Explanation of symbols]

1, 41: dielectric substrate 21 to 24, 42, 43, 101: wiring for ground 3, 4, 44 to 49, 102, 103, 104, 10
5: Distributed constant line 5-8: Metal chip for wiring 9-12, 17-20: Inductance Q01, Q02, Q1, Q2, Q31, Q32, Q41
To Q44, 109, 110: MOSFET chips.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01P 5/19 H01L 23/12 B H03F 3/60 23/14 SR (72) Inventor Kenji Sekine Tokyo 1-280 Higashi Koigakubo, Kokubunji City, Hitachi, Ltd. Central Research Laboratory, Ltd. (72) Inventor Joh Nagata 1-280 Higashi Koigabo, Kokubunji City, Tokyo, Hitachi, Ltd. Central Research Laboratory, Ltd.

Claims (14)

[Claims] A dielectric substrate or a semiconductor substrate; a plurality of semiconductor elements formed on the dielectric substrate or the semiconductor substrate; a thin-film conductor formed on the dielectric substrate or the semiconductor substrate; An input-side distributed constant line that is formed by a part of the thin-film conductor, branches into two from the input terminal, and forms a symmetrical shape when viewed from a branch point; and an output terminal that is formed by a part of the thin-film conductor. A distributed constant line on the output side, which is more branched into two and has a symmetrical shape when viewed from the branch point; a terminal of the distributed constant line on the input side is connected to an input terminal of the semiconductor element; The terminal of the distributed constant line is connected to the output terminal of the semiconductor element, and one electrode is provided on the distributed constant line at a predetermined position in the intermediate portion between the input-side and output-side distributed constant lines. Connect to The other electrode of the capacitive element to be connected is connected, and the electrical length from the branch point to the position where each of the capacitive elements is connected is substantially equal to each other on the input side and substantially equal to each other on the output side. High frequency device. 2. The intermediate portions of the input-side and output-side distributed constant lines have distances Lxc and Lxc from respective branch points to positions to which the respective capacitive elements are connected.
The ratios Lxc / Lx and Lyc / Ly of yc to the line lengths Lx and Ly of the input and output distributed constant lines.
The high-frequency device according to claim 1, wherein? 3. An input terminal of the input-side distributed constant line terminates another input-side distributed constant line having a branch pattern similar to that of the input-side distributed constant line; The output terminal of the line terminates another output-side distributed constant line with a branch pattern similar to that of the output-side distributed constant line, and each of the other input-side and output-side distributed constant lines has a branch. 3. The high-frequency device according to claim 1, wherein the high-frequency device has a shape that is repeated one or more times. 4. The high frequency device according to claim 1, wherein said semiconductor element is an insulated gate field effect transistor or a Schottky junction field effect transistor. 5. The high-frequency device according to claim 1, wherein the operating frequency is in a UHF band. 6. The high-frequency device according to claim 1, wherein a length from the input terminal to the terminal of the distributed constant line is less than a quarter wavelength. 7. A high-frequency amplifier comprising the high-frequency device according to claim 1. 8. A mobile radio comprising the high-frequency device according to claim 1. 9. A printed circuit board comprising a driver section and an output section, wherein the driver section includes a plurality of power MOSFETs integrated on one chip, and wherein the output section comprises two power MOSFETs. A distributed constant line on the input side that branches off from the input terminal into two and forms a symmetrical shape when viewed from the branch point, and a distribution on the output side that branches off from the output terminal into two and forms a symmetrical shape when viewed from the branch point One end of the distributed constant line on the input side is connected to the input terminal of one of the two power MOSFETs, and the other end of the distributed constant line on the input side is One end of the distributed constant line on the output side is connected to an input terminal of the other power MOSFET of the two power MOSFETs. The other end of the distributed constant line on the output side is connected to the output terminal of the other power MOSFET of the two power MOSFETs, and the distribution on the input side and the output side is connected to the output terminal of one power MOSFET. On the distributed constant line at a predetermined position in each intermediate portion of the constant line, the other electrode of the capacitive element having one electrode connected to the ground wiring is connected, and the capacitive elements are connected from the branch point. A high-frequency device, wherein the electrical length up to a certain position is substantially equal to each other on the input side and substantially equal to each other on the output side. 10. The intermediate portions of the input-side and output-side distributed constant lines include distances Lxc and Lyc from each branch point to a position where each of the capacitive elements is connected, and the input side and the output side. Lxc / Lx and Lyc /
The high-frequency device according to claim 9, wherein Ly is in a range of 0.2 or more and 0.8 or less. 11. An input terminal of the distributed constant line on the input side terminates another distributed constant line on the input side having a branch pattern similar to that of the distributed constant line on the input side, and the distributed constant on the output side. The output terminal of the line terminates another output-side distributed constant line with a branch pattern similar to that of the output-side distributed constant line, and each of the other input-side and output-side distributed constant lines has a branch. The high-frequency device according to claim 9, wherein the high-frequency device has a shape repeated one or more times. 12. An input terminal which is formed on an insulating substrate.
A distributed constant line on the input side that branches into two and forms a symmetrical shape when viewed from the branch point; and an output side that is formed on the insulating substrate and branches into two from the output terminal and forms a symmetrical shape when viewed from the branch point. And a semiconductor element connected to the input-side and output-side distributed constant lines, wherein a predetermined position of an intermediate portion of each of the input-side and output-side distributed constant lines is provided. The other electrode of the capacitive element, one electrode of which is connected to the ground wiring, is connected on the distributed constant line, and the electrical length from the branch point to the position where each of the capacitive elements is connected is an input side. A high-frequency device characterized by being substantially equal to each other and substantially equal to each other at an output side. 13. The intermediate portions of the input-side and output-side distributed constant lines include distances Lxc and Lyc from respective branch points to positions where the respective capacitive elements are connected, and the input side and output side. Lxc / Lx and Lyc /
13. The high-frequency device according to claim 12, wherein Ly is in a range from 0.2 to 0.8. 14. An input terminal of the distributed constant line on the input side terminates another distributed constant line on the input side with a branch pattern similar to that of the distributed constant line on the input side, and the distributed constant on the output side. The output terminal of the line terminates another output-side distributed constant line with a branch pattern similar to that of the output-side distributed constant line, and each of the other input-side and output-side distributed constant lines has a branch. 14. The high-frequency device according to claim 12, wherein the high-frequency device has a shape repeated one or more times.