JPH05110454A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To obtain a best matching state at all times independently of a change in a transmission power by providing an impedance matching circuit to the communication equipment to select the matching state. CONSTITUTION:The impedance matching circuit 4 is adjusted so that the matching is maximized when the transmission power of an amplifier processing section 2 is large (e.g., 1W). Moreover, the impedance matching circuit 4 is adjusted so that the matching is best when the transmission power of the amplifier processing section 2 is small (e.g., 63mW). When the transmission power is large, changeover switches 3, 6 are controlled to be thrown to the position of the impedance matching circuit 4 and when the transmission power is small, the changeover switches 3, 6 are controlled to be thrown to the position of the impedance matching circuit 5. The proper matching state is obtained by allowing the user to operate the changeover switches 3,6, a loss to be caused in a conventional equipment is eliminated and the efficiency is improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a wireless communication device, and more particularly to a wireless communication device capable of controlling transmission power.

[0002]

2. Description of the Related Art Generally, as a wireless communication device of this type,
When wireless communication is performed between a base and a mobile device, there is a device provided on the mobile device side. Then, as shown in FIG. 3, the conventional wireless communication device includes a transmitter 1
An impedance matching circuit 4 is provided for the amplifier 2 and the antenna 7. In addition, 1 is a local transmission part.

Next, the structure will be described. In this conventional wireless communication device, the impedance matching circuit 4 is adjusted so that the matching state is best under certain conditions when the amplifying unit 6 and the antenna 7 are matched.

However, in this conventional wireless communication device, the impedance changes when the collector current flowing through the transistor element in the amplification section 2 changes. Therefore, when the transmission power is significantly changed, the matching state between the antenna 7 and the amplification unit 2 is displaced, so that the amount of attenuation between the antenna and the amplification unit is increased. Therefore, in order to obtain a predetermined transmission power, an extra amount is required. There is a drawback that it requires electric power and impairs efficiency.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to provide a wireless communication apparatus which does not impair the efficiency even when the transmission power is changed. is there.

[0006]

According to the present invention, there is provided a radio communication device in which an amplification section for amplifying a signal to be transmitted to a predetermined transmission power, an antenna for transmitting the amplified signal by radio, and impedances of the amplification section and the antenna. A matching circuit that matches
Means for controlling the matching state in the matching circuit according to the transmission power value in the amplifier.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of a wireless communication apparatus according to the present invention, and the same portions as those in FIG. 3 are designated by the same reference numerals. The wireless communication device shown in FIG. 1 has a configuration of a transmitter in the wireless communication device in which the transmission power can be controlled in two ways, high power and low power, as an example. In the figure, the impedance matching circuit 4 and the impedance matching circuit 5 are connected to the local transmitter 1 and the amplifier 2 via the changeover switch 3, and the impedance matching circuit 4 and the impedance matching circuit 5 are further connected via the changeover switch 6. Is connected to the antenna 7. As a result, the impedance matching circuits 4 and 5 can be switched by the changeover switches 3 and 6.

Next, the operation of the apparatus of this example having such a configuration will be described. First, the impedance matching circuit 4
Adjusts the maximum matching when the transmission power of the amplification unit 2 is high (for example, 1 W). Further, the impedance matching circuit 5 performs adjustment so that the matching is best when the transmission power of the amplification unit 2 is low (for example, 63 mW). When the transmission power is high, the changeover switch 3
The changeover switch 6 is connected to the impedance matching circuit 4, and the changeover switch 3 and the changeover switch 6 are controlled to be connected to the impedance matching circuit 5 when the transmission power is small.

In other words, when the user operates the changeover switches 3 and 6, a proper matching state can be obtained, the loss which has been conventionally caused is eliminated, and the efficiency is improved.

Next, a specific internal configuration example of the matching circuits 4 and 5 will be described with reference to FIG. 2, parts equivalent to those in FIGS. 1 and 3 are indicated by the same reference numerals.

The matching circuit 4 is, as shown in the figure,
It is composed of coils L1 and L3 and a capacitor C1. The matching circuit 5 is composed of coils L2 and L4 and a capacitor C2. And the coil L1
And L2 are connected to a predetermined power source.

Here, the characteristic impedance of the antenna 7 is 50Ω, the characteristic impedance of the amplifier 2 when the transmission power is 1 W (30 dBm) is 5 Ω, and the transmission power is 63 mW.
If the characteristic impedance of the amplifier 2 at (18 dBm) is 20Ω and the transmission frequency is 1 GHz, the coil L1
= 100 nH (choke coil), coil L2 = 100 nH (choke coil), coil L3 = 1.6 nH, coil L4
= 0.8 nH, capacitor C1 = 2PF, capacitor C2
If = 1 PF, two types of transmission power values can be supported.

That is, when the transmission power is high (1 W), the impedance matching circuit 4 is selected by the changeover switches 3 and 6, and when the transmission power is low (63 mW), the impedance matching circuit 4 is selected by the changeover switches 3 and 6. If 5 is selected, the correct matching state is obtained and the efficiency is improved. Therefore, when the wireless communication device transmits, if the user operates the changeover switch according to the transmission power value, power loss can be reduced.

When the transmission power value changes in three or more stages, the number of impedance matching circuits may be increased according to the number of stages. In this case, the inductance value of the coil and the capacitance value of the capacitor may be appropriately adjusted so that the matching state can be obtained.

Further, when an impedance matching circuit is provided between the amplification section 2 and the transmission section 1, or the amplification section 2
It is clear that the same effect can be obtained when it is provided in the preceding stage or the latter stage, and also when it is applied to the transmission circuit on the base side.

Furthermore, in the above example, the matching state is adjusted stepwise, but if only one matching circuit using a variable inductance or a variable capacitor is provided and impedance is continuously changed, all transmissions are performed. Obviously, it can correspond to the power value.

[0018]

As described above, according to the present invention, the impedance matching circuit is provided and the matching state is switched, so that the best matching state can always be obtained regardless of the change in the transmission power value. There is an effect that the electric power for obtaining the electric power can be minimized and the efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wireless communication device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration example of an impedance matching circuit of FIG.

FIG. 3 is a block diagram showing a configuration of a conventional wireless communication device.

[Explanation of symbols]

 1 Local oscillator 2 Amplifying unit 3,6 Changeover switch 4,5 Impedance matching circuit 7 Antenna

Claims (2)

[Claims] 1. An amplification unit for amplifying a signal to be transmitted to a predetermined transmission power, an antenna for wirelessly transmitting the amplified signal, a matching circuit for impedance matching between the amplification unit and the antenna, and And a means for controlling a matching state in the matching circuit according to a transmission power value in the amplification section. 2. An amplification section for amplifying a signal to be transmitted to a predetermined transmission power, an antenna for wirelessly transmitting the amplified signal, and a plurality of types of matching circuits for impedance matching between the amplification section and the antenna. And a switching unit that controls switching of the plurality of types of matching circuits according to the transmission power value in the amplification unit.