JP2002171196A - High-frequency module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency module which can bring out the characteristics of a semiconductor element for high frequency used for a power amplifying section to the maximum even when the power amplifying section is integrated with a coupler and can be improved in efficiency. SOLUTION: This high-frequency module has the power amplifying section AMP which amplifies high-frequency input signals, and the coupler COP which is used for monitoring the output of the amplifying section AMP. The amplifying section AMP and coupler COP are matched to each other with an impedance of <=50 Ω.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-frequency module, and more particularly to a high-frequency module having a power amplifier for amplifying a high-frequency input signal and a coupler for monitoring an output from the power amplifier. .

[0002]

2. Description of the Related Art In recent years, the spread of mobile phones has been remarkable, and the functions and services of mobile phones have been improved. As a new mobile phone, a dual-band mobile phone has been proposed. This dual-band mobile phone handles two transmission / reception systems while a normal mobile phone handles only one transmission / reception system.
As a result, the user can select and use a convenient transmission / reception system.

In recent years in Europe, a GSM / DCS dual-band mobile phone having a plurality of transmission / reception systems having different pass bands has been studied.

FIG. 7 shows a circuit block diagram of the GSM / DCS dual band system. GSM / DC shown in FIG.
In the case of the S dual band system, at the time of transmission,
After being amplified by the power amplifier AMP100 or AMP200 on the Tx side, the coupler COP100 or COP200 is amplified.
, A radio wave is transmitted from the antenna ANT via the high-frequency switch module ASM1 including a high-frequency switch and a demultiplexing circuit.

On the other hand, at the time of reception, a radio wave is received from the antenna ANT and the high-frequency switch module ASM
1 and is sent to the power amplifier AMP300 or AMP400 on the receiving circuit (Rx) side.

Conventionally, in the above-mentioned dual-band portable telephone, parts dedicated to respective transmission / reception systems have been used.
That is, a circuit is configured using the couplers COP100 and COP200, and the power amplifiers AMP100 and AMP200. Since these components are matched with an impedance of 50Ω, the circuit is simply connected to the dedicated components. Could be configured.

[0007] By the way, conventionally, dedicated components have been used, which has led to an increase in size and cost of the equipment. It is advantageous to use a common part as much as possible for common parts, to reduce the size and cost of the device. For this reason, it is expected that further miniaturization and weight reduction will be progressed while further improving the functions.

[0008]

However, in the related art, although some modules are typified by, for example, a dual-band high-frequency switch module, each of a high-frequency switch module, a coupler, and a power amplifier is used. Since the components are mounted on the printed wiring board, there is a problem that it is difficult to further reduce the size and weight.

Therefore, in recent years, it has been proposed to modularize a power amplifier, a coupler for distributing the output power of the power amplifier, a high-frequency switch for separating a transmission / reception signal of a high-frequency signal, and the like.

In the conventional case in which the above-described components of the high-frequency switch module, the coupler and the power amplifier are mounted on a printed wiring board, each is designed and commercialized independently, so that each of the characteristics is satisfied. Normally, each component is designed with an impedance of 50Ω to perform the design, and the components of the coupler and the power amplifier are matched with 50Ω, so even when the power amplifier, coupler, high-frequency switch, etc. are modularized, 50Ω is used. Matching is conceivable.

FIG. 8 shows the impedance matching of the conventional high-frequency switch module, coupler, and power amplifier. As can be understood from FIG. 8, the impedance at both ends of the power amplifier AMP is 5%.
0Ω, and 50Ω at both ends of the high-frequency switch module ASM1 and the coupler COP.

That is, the coupler COP and the power amplifier AMP
After the connection, a matching circuit is added between the coupler and the power amplifier so as to satisfy the characteristics of the coupler COP and the power amplifier AMP, such as output power, current consumption, and insertion loss. The line length of the matching circuit and the constants of chip capacitors and chip inductors were adjusted.

Looking at the power amplifier AMP in detail,
As shown in FIG. 9, the power amplifier AMP includes an input matching circuit, a high-frequency semiconductor device MMIC, and an output matching circuit. Normally, the power amplifier AMP outputs an output from a3 between the high-frequency semiconductor device MMIC and the output matching circuit. The impedance seen from the matching circuit side, that is, the load of the high-frequency semiconductor element MMIC is several Ω, and the impedance seen from b3 to the output side is 50Ω because the power amplifier AMP is designed to be 50Ω.

However, in spite of the fact that the impedance seen from a3 is several ohms, in order to design a 50 ohm power amplifier AMP alone, it must be set to 50 ohms at b3, and the load in the output matching circuit of the power amplifier AMP. Due to large fluctuations, a narrow band design is required, the insertion loss in the output matching circuit is increased, and the characteristics of the high-frequency semiconductor element MMIC used for the power amplifier AMP cannot be maximized, and the efficiency cannot be further improved. was there.

Moreover, the coupler COP and the power amplifier AM
When modularizing P, 50
It is sufficient to design Ω, and there is no need to design 50Ω alone.

An object of the present invention is to provide a high-frequency module capable of maximizing the characteristics of a high-frequency semiconductor element used in a power amplification section and achieving high efficiency even when the power amplification section and the coupler are integrated. Aim.

[0017]

According to the present invention, there is provided a high-frequency module comprising a high-frequency semiconductor element, a power amplifier for amplifying a high-frequency input signal, and a coupler for monitoring an output from the power amplifier. And the power amplifier and the coupler are matched with an impedance lower than 50Ω.

According to the high-frequency module of the present invention, the impedance matching between the coupler and the power amplifying unit is 5
Since the matching is performed with an impedance lower than 50Ω instead of the 0Ω design, the load fluctuation is reduced in the output matching circuit of the power amplifying unit. As a result, a wide band design is possible, and the insertion loss of the output matching circuit is reduced. Therefore, the characteristics of the high-frequency semiconductor element used in the power amplifier can be maximized.In the conventional case where the coupler and the power amplifier are individually combined, the coupler and the power amplifier are designed with 50Ω each. Further miniaturization and higher efficiency can be achieved as compared with the integrated high-frequency module.

Further, the high-frequency module of the present invention desirably has a high-frequency switch for switching between a transmission system and a reception system while separating a plurality of transmission / reception systems having different pass bands into respective transmission / reception systems.

[0020]

FIG. 1 is a block diagram showing a high-frequency module according to the present invention. The high-frequency module according to the present invention includes a branching circuit DIP1 for dividing a plurality of transmission / reception systems having different pass bands into transmission / reception systems, a low-pass filter LPF2 for removing a harmonic signal, and a transmission system and a reception system for each of the transmission / reception systems. Multiband high-frequency switch SW having diode switch circuits SW1 and SW2 for switching, amplifying units AMP1 and AMP2, and amplifying unit AM
In order to monitor the outputs of P1 and AMP2, they are connected to the Tx terminals of the diode switch circuits SW1 and SW2,
Couplers COP1 and COP corresponding to each pass frequency
And 2.

The high-frequency switch SW is a GSM / D
In the CS dual-band mobile phone, for switching the connection between the transmission circuit Tx corresponding to each system and the demultiplexing circuit DIP1 which is a common circuit, and the connection between the reception circuit Rx and the demultiplexing circuit DIP1 which is a common circuit. Used for

The couplers COP1 and COP on the Tx side
Reference numeral 2 plays a role in extracting a part of the transmission signal amplified by each of the amplifiers AMP1 and AMP2 and transmitting a feedback signal to the APC circuit.

FIG. 2 shows a specific configuration of the high-frequency switch SW of FIG. 1 and the couplers COP1 and COP2. The first port P1 of the diode switch circuit SW1 connected to the coupler COP1 on the Tx side has a diode D
It is connected to the anode of AG1. The anode of the diode DAG1 is grounded via the inductor LAG2 and the capacitor CAG4.

Further, a connection point between the inductance LAG2 and the capacitor CAG4 is connected to a control terminal VG1 via a control resistor RG1. Also, the diode DA
The cathode of G1 is connected to the second port P2 of the branching circuit DIP1.
It is connected to the.

The transmission line STL is connected to the second port P2.
1 is connected to the other end of the transmission line STL1.
It is connected to a third port P3 which is an Rx signal output terminal. The other end of the transmission line STL1 is connected to a diode DA.
It is connected to the anode of G2, and the cathode of diode DAG2 is grounded via capacitor CAG2 and inductor LAG1. Here, the parallel resonance circuit formed by the capacitor CAG2 and the inductor LAG1 has a role of controlling the isolation between the first port P1 and the third port P3.

Similarly, the coupler COP2 on the Tx side is connected to a fourth port P4 of a low-pass filter LPF2 for removing a harmonic signal. The other end of the low-pass filter LPF2 is connected to the anode of the diode DAD1 of the diode switch circuit SW2.

The anode of the diode DAD1 is
It is grounded via the inductor LAD2 and the capacitor CAD4. Further, a connection point between the inductor LAD2 and the capacitor CAD4 is connected to the control terminal VD1 via the control resistor RD1. Also, the diode DA
The cathode of D1 is connected to the fifth port P5 of the branching circuit DIP1.
It is connected to the.

Further, the fifth port P5 has a transmission line S
One end of TL2 is connected, and the other end of the transmission line STL2 is connected to a sixth port P6 which is an Rx signal output terminal. The other end of the transmission line STL2 is connected to the anode of the diode DAD2, and the cathode of the diode DAD2 is connected to the capacitor CAD2 and the inductor LAD1.
Grounded. Here, the capacitor CAD2,
The parallel resonance circuit formed by the inductor LAD1 has a role of controlling the isolation between the port P4 and the port P6.

The antenna terminal ANT is connected to a demultiplexing circuit DI.
The second port P2 and the fifth port P5 via P1
It is connected to the. This demultiplexing circuit DIP1 has two different
It has a role of separating the transmission / reception signal of the 900 MHz band and the transmission / reception signal of the 1800 MHz band of two systems.

Here, the demultiplexing circuit DIP1 is, for example, 180
A high-pass filter HPF1 for passing a 0 MHz band;
It is composed of a capacitor C2, an inductor L2, a low-pass filter LPF1 that allows the 900 MHz band to pass, a capacitor C1, and an inductor L1.

Then, the demultiplexing circuit DIP1, the diode switch circuits SW1, SW2, the low-pass filter LPF
2, and at least a part of the couplers COP1 and COP2 are built in the substrate. For example, the demultiplexing circuit DIP1
, A low-pass filter LPF1 for removing harmonics, and transmission lines STL1, STL2, and a coupler COP1, which constitute a diode switch circuit.
COP2 is incorporated in a substrate formed by laminating an electrode pattern and a dielectric layer. Also, a chip element such as a diode, which constitutes a part of the demultiplexing circuit DIP1, the diode switch circuits SW1 and SW2, the low-pass filter LPF2, and the couplers COP1 and COP2, is mounted on the substrate.

FIG. 3 shows the amplifiers AMP1 and AMP2 of FIG.
FIG. 4 shows a specific configuration of FIG.

For example, G which is a mobile phone system in Europe
In the dual system of the SM / DCS, one is a high-frequency power amplifier AMP1 for GSM and the other is a high-frequency power amplifier AMP2 for DCS, and these are combined to form an amplifier AMP.

The amplifying unit AMP includes high-frequency semiconductor elements (hereinafter, also referred to as high-frequency MMICs) 3a and 3b.
Input matching circuits 2a and 2b connected to these high-frequency MMICs 3a and 3b for matching input impedance of high-frequency input signals;
and output matching circuits 5a and 5b connected to voltage supply lines 6a and 6b for supplying voltages to a and 3b, respectively, for matching desired output characteristics.

Each of the input matching circuits 2a and 2b has a capacitor, an inductor, and the like.

On the other hand, the output matching circuits 5a and 5b have output side microstrip line lines 7 and 10 for transmitting different signals. The output side direct current blocking capacitor C is connected between them. The output terminals 12 and 15 are connected to the Tx terminals in FIGS.

The output side microstrip line line 7,
Numeral 10 is used to optimize impedance matching with an external circuit connected to the output terminals 12 and 15 and to achieve matching so as to satisfy desired output characteristics, for example, output power and current consumption singly or simultaneously. The output side microstrip line lines 7 and 10 are grounded via output matching capacitors C21a and C31a.

Further, voltage supply lines 6a, 6b for applying a voltage to the high frequency MMICs 3a, 3b are connected to the output side microstrip line lines 7, 10, respectively. stub)
17a and 17b are connected in parallel with the voltage supply lines 6a and 6b.

The amplifying section AMP of the present invention is described in detail in FIG.
As shown in (2), the two amplifying units AMP1 and AMP2 are formed on a dielectric substrate having a specific dielectric constant of a predetermined value. Specifically, GSM /
In the DCS dual system, the lower part between A and B is GSM
High-frequency power amplifier AMP1 and the upper part between A and B is DC
This is the S high frequency power amplifier AMP2.

The amplification unit AMP is connected to the high frequency MMIC 3 (3
a, 3b), an input matching circuit 2 for matching input impedance of a high-frequency input signal, a bias circuit 4, and an output matching circuit 5 for matching desired output characteristics. I have. The input matching circuit 2 is connected with a capacitor, an inductor, and the like.

In the output matching circuit 5, the high frequency MM
The output side microstrip line lines 7 and 10 which are distributed constant lines are connected to the IC 3 in order to achieve matching so as to satisfy desired output characteristics, for example, output power and current consumption singly or simultaneously. These output side microstrip line lines 7, 10 are grounded via output matching capacitors C21a, C31a.

Further, open-ended distributed constant lines 17a and 17b are connected to the output side microstrip lines 7 and 10, respectively.

The frequency of the DCS high-frequency power amplifier AMP2 at the upper part between A and B is 1800 MHz, which is twice the frequency of 900 MHz of the GSM high-frequency power amplifier AMP1. The harmonics on the GSM side, especially the second harmonic, are DCS
There is a possibility that the 1800 MHz harmonic signal, which is the fundamental wave on the side, may be affected by interference. However, in the present invention, the output side microstrip line lines 7 and 10 are provided with open-ended distributed constant lines 17a and 17b to provide higher harmonics. Can be reduced.

In the output matching circuits 5a and 5b, the output microstrip line line 7 on the DCS side is used.
And output side microstrip line 10 on the GSM side
Between them, a GND line 9 and a GND line 18 are arranged to reduce interference between the output microstrip lines 7 and 10 on the DCS side and the GSM side. This G
The ND lines 9 and 18 are formed in parallel, and are connected to GND by a plurality of via-hole conductors.

The line lengths of the voltage supply lines 6a and 6b and the open-ended distributed constant lines 17a and 17b are shorter than １ ／ of the wavelength of the fundamental wave in the high-frequency input signal. Since the line length is not fixed to 1/4 wavelength of the fundamental wave but shorter than 1/4 wavelength, the phase of harmonics can be adjusted, and non-conjugate matching should be performed at any spurious frequency between the coupler and the amplifier. And a small high-frequency module can be obtained.

In the present invention, as shown in FIG.
The power amplifier AMP and the coupler COP are designed to be matched with an impedance lower than 50Ω, and FIG. 5 shows a case where a 20Ω design is performed.

The power amplifier AMP and the coupler COP1 are impedance-matched at 20 to 30 Ω from the viewpoint that a few Ω which is a load at the end of the high-frequency semiconductor element MMIC in the power amplifier is matched with the coupler with little load fluctuation. Desirably. In order to match with such an impedance lower than 50Ω, the power amplifier AM
The matching may be achieved by shortening the line length of the microstrip lines 7 and 10 on the output side of P.

In the high-frequency module as described above, the matching between the power amplifier AMP and the coupler COP is designed to be 20 Ω, so that the impedance of several Ω viewed from a3 in FIG. It can be set to 20 Ω lower than 50 Ω, and the load variation in the output matching circuit of the power amplifier is smaller than in the conventional case of the 50 Ω design. The characteristics of the device can be maximized.

Therefore, further miniaturization and higher efficiency can be realized as compared with the conventional case where the coupler and the power amplifying unit are combined as a single unit, and the module product where the coupler and the power amplifying unit are each integrated with a 50Ω design. .

The high-frequency module of the present invention is not limited to these, and various modifications can be made without departing from the gist of the present invention.

The present inventor integrated the above-described power amplifier AMP shown in FIG. 3 with the coupler COP and the high-frequency switch SW as shown in FIG.
As shown in FIGS. 5 and 8, when the matching between the power amplifying unit and the coupler is 50Ω and 20Ω, the S11 and S21 characteristics of the output matching circuit of the power amplifying unit are examined by circuit simulation. Is shown in FIG. In the case of 20Ω matching, the line length of the output side microstrip line is made shorter than that in the case of 50Ω matching,
The capacitors C21a and C31a were finely adjusted to achieve matching.

As a result, when matching between the power amplifier and the coupler is set to 20Ω, the coupler and the power amplifier are set to 5Ω.
It was confirmed that the return loss was improved by about 10 dB, the low-loss portion near 1 GHz was wide, and the band was widened, as compared with the comparative example matched at 0Ω. Furthermore, the insertion loss in the output matching circuit was also reduced, and it was confirmed that further miniaturization and higher efficiency could be realized.

[0053]

According to the high-frequency module of the present invention, the impedance matching between the coupler and the power amplifying unit is not designed to be 50 Ω, but is matched with an impedance lower than 50 Ω. , Load fluctuation is reduced, and as a result, the insertion loss of the output matching circuit is reduced, so that the characteristics of the high-frequency semiconductor element used in the power amplifier can be maximized, and further miniaturization and higher efficiency can be achieved. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the concept of a high-frequency module according to the present invention.

FIG. 2 is a circuit diagram of a high-frequency switch and a coupler in the high-frequency module of FIG. 1;

FIG. 3 is a circuit diagram of an amplification unit of the high-frequency module according to the present invention.

FIG. 4 is a pattern layout diagram of FIG. 3;

FIG. 5 is a block diagram of a transmission / reception unit in a communication device when the impedance matching between the coupler and the power amplification unit is set to 20Ω.

FIG. 6 is a graph showing S11 and S21 characteristics when the impedance matching between the coupler and the power amplifier is set to 50Ω and 20Ω.

FIG. 7 is a block diagram of a transmission / reception system having a conventional high-frequency switch, coupler, and power amplifier.

FIG. 8 is a block diagram of a transmission / reception unit in a communication device when the impedance matching between the coupler and the power amplification unit is set to 50Ω.

FIG. 9 is a block diagram of a power amplifier.

[Explanation of symbols]

 AMP1, AMP2: Power amplification unit COP1, COP2: Coupler SW: High frequency switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J067 AA01 AA04 AA41 CA36 CA75 CA92 FA00 HA19 HA25 HA29 HA33 HA39 KA00 KA12 KA13 KA29 KA42 KA68 KS01 KS11 LS12 QS04 SA13 TA01 5J091 AA01 AA04 AA29 CA33 KA00 KA12 KA13 KA29 KA42 KA68 SA13 TA01 5J092 AA01 AA04 AA41 CA36 CA75 CA92 FA00 HA19 HA25 HA29 HA33 HA39 KA00 KA12 KA13 KA29 KA42 KA68 SA13 TA01 5K011 BA03 BA04 DA21 DA23 JA01 KA00

Claims (2)

[Claims] A power amplifier for amplifying a high-frequency input signal; and a coupler for monitoring an output from the power amplifier. Characterized in that they are matched with an impedance lower than 50Ω. 2. The high-frequency module according to claim 1, wherein a plurality of transmission / reception systems having different pass bands are separated into transmission / reception systems, and a high-frequency switch for switching between a transmission system and a reception system is provided.