JP3828835B2 - Antenna impedance matching adjustment circuit for small radio - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small wireless device, and more particularly to an antenna impedance matching adjustment circuit thereof.
[0002]
[Prior art]
Conventionally, an antenna tuner or the like has been used for impedance matching between a transceiver of a radio and an antenna.
[0003]
[Problems to be solved by the invention]
Helical antennas and loop antennas that are generally used for radio equipment, depending on the antenna system and the frequency of transmission and reception, exhibit maximum performance when a sufficiently large ground is provided for the size of the antenna. However, a small wireless device cannot take a sufficiently large ground. In this specification, a mobile radio device that can be connected to a mobile phone or the like having a metal casing or ground larger than its own device is referred to as a small radio device.
[0004]
In the case of a small wireless device, if antenna impedance matching is performed while connected to a mobile phone, communication can be performed satisfactorily in that state, but when using a small wireless device alone, the ground area relative to the antenna and Since the positional relationship changes, there is a problem that the resonance frequency of the antenna changes and communication cannot be performed satisfactorily.
[0005]
The present invention has been made in view of the above points, and its object is to automatically perform impedance matching with an antenna when connected to a mobile phone or the like and when used alone. An object of the present invention is to provide an antenna impedance matching adjustment circuit for a small wireless device.
[0006]
[Means for Solving the Problems]
Antenna impedance matching adjustment circuit of the small radio of the present invention, in an electronic device which can be connected small radios, and digital adjustment data when the digital adjustment data and single when connected to a specific electronic apparatus Non-volatile memory for storing, detection means for detecting that the small wireless device is connected to the specific electronic device, and a characteristic value is changed by an electrical signal obtained by converting the adjustment data into an analog signal. An adjustment circuit that performs impedance matching with an antenna including an element, and the adjustment corresponding to each of when the small wireless device is connected to the specific electronic device and when the single wireless device is connected by an output from the detection unit Adjustment is automatically performed based on the data .
[0007]
The antenna impedance matching adjustment circuit is configured to download adjustment data when connected to the specific electronic device via the Internet.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a connection state when making an initial setting of a small radio according to an embodiment of the present invention. As shown in FIG. 1, in a state where the mobile phone 401 is connected to the wireless device A301 and the portable information terminal 501 is connected to the wireless device B302, the wireless device A301 and the wireless device B302 are in a communication state, and the mobile information terminal 501 Adjustment data of the adjustment circuit 102 for antenna impedance matching of the wireless device A301 is initialized.
[0009]
FIG. 1 shows the main parts of the radio device A301 and the radio device B302. In the wireless device A301, the transmission / reception circuit 103 transmits / receives from the antenna 101 via the adjustment circuit 102 for antenna impedance matching. The adjustment circuit 102 (shown in FIG. 2) will be described later.
[0010]
The microcomputer 104 controls the entire apparatus. Further, after the connection with the mobile phone 401 is initialized, the microcomputer 104 is used when the wireless device A301 is connected to the mobile phone 401 and when the wireless device A301 is used alone. Sometimes the impedance of the adjustment circuit 102 is set optimally.
[0011]
That is, the wireless device A301 is connected to the mobile phone 401 via the connection connector 108 to the interface 107, but the attachment / detachment detection circuit 106 detects whether the connection connector 108 is connected, and the microcomputer 104 is connected to the attachment / detachment detection circuit 106. Based on the signal, the impedance of the adjustment circuit 102 is set by data stored in the nonvolatile memory 105.
[0012]
In the wireless device B302, the transmission / reception circuit 203 transmits and receives via the antenna 201. The microcomputer 204 controls the entire apparatus, and further, a portable information terminal 501 is connected via an interface 207 and a connection connector 208. In addition, a nonvolatile memory 205 is connected to the microcomputer 204.
[0013]
As shown in FIG. 1, the portable information terminal 501 stores impedance setting data in the nonvolatile memory 105 of the wireless device A301 in the connected state. At this time, the portable information terminal 501 is a wireless device B302, are connected to the radio A301 and the portable telephone 401 support site on the Internet via (specific URL on the WEB), is downloaded configuration data.
[0014]
As shown in FIG. 3, setting data is stored in a support site on the Internet for each wireless device model and each portable device connected thereto. The portable information terminal 501 downloads the setting data by designating the model of the wireless device A301 and the mobile phone 401 (mobile 1) connected thereto. The downloaded data (AB, CD) is first stored in the nonvolatile memory 205 of the wireless device B302 or stored in the portable information terminal 501 and then wirelessly written into the nonvolatile memory 105 of the wireless device A301. .
[0015]
After the initialization as described above, when the mobile phone 401 is connected to the wireless device A301, the microcomputer 104 uses the data (AB, CD) stored in the nonvolatile memory 105 to determine the impedance of the adjustment circuit 102. When the cellular phone 401 is not connected to the wireless device A301, the impedance of the adjustment circuit 102 is set based on data stored in the nonvolatile memory 105 when used alone.
[0016]
That is, the microcomputer 104 has a built-in D / A converter, converts the digital data read from the nonvolatile memory 205 into a voltage, and outputs the voltage to the connection terminal T2 of the adjustment circuit 102 shown in FIG.
[0017]
In the adjustment circuit 102, a capacitor C2, a variable capacitance diode VC, and a capacitor C1 are connected in series between the connection terminal T1 of the antenna 101 and the transmission / reception circuit 103, and between the connection point of the capacitor C2 and the variable capacitance diode VC and the ground. The coil L1 is connected, and a resistor R1 is connected between a connection point between the variable capacitance diode VC and the capacitor C1 and the connection terminal T2. The impedance of the adjustment circuit 102 can be set by changing the capacitance of the variable capacitance diode VC according to the voltage at the connection terminal T2.
[0018]
The embodiment is configured as described above, but the invention is not limited to this. For example, the present invention is also applicable when a wireless device is connected to a desktop personal computer, a notebook personal computer, a PDA, a measuring instrument, a home appliance, or the like. Applicable.
[0019]
In addition, when a device to be connected can be specified from the connected connector, it is possible to perform optimum impedance matching for the connected device when a plurality of devices are selected and connected.
[0020]
Furthermore, when the device to which the wireless device is connected is specified in advance, adjustment data may be set in advance without connecting to the Internet.
[0021]
【The invention's effect】
According to the antenna impedance matching adjustment circuit of the small radio device of the present invention, for example, by initializing the small radio device by the control terminal, it is possible to use the radio device without requiring a special operation from the user. The optimum wireless communication can be realized by automatically automatically adjusting the impedance matching with the antenna according to the situation.
[0022]
Also, even if the shape of the antenna or mobile phone to which a small radio is connected is added or changed, the case of the radio itself can be opened to replace parts, and programs and data memory can be written. It can be handled by simply changing the database on the Internet without changing it.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a part of the configuration of the embodiment.
FIG. 3 is a configuration diagram illustrating setting of adjustment data according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 Antenna 102 Adjustment circuit 103 Transmission / reception circuit 104 Microcomputer 105 Non-volatile memory 106 Desorption detection circuit 107 Interface 108 Connection connector 201 Antenna 203 Transmission / reception circuit 204 Microcomputer 205 Non-volatile memory 207 Interface 208 Connection connector 301 Radio A
302 Radio B
401 mobile phone 501 portable information terminal C1, C2 capacitor R1, resistor L1, coil VC, variable capacitance diode T1, T2 connection terminal

Claims (2)

In a small-sized radio that can be connected to an electronic device, a non-volatile memory that stores digital adjustment data when connected to a specific electronic device and digital adjustment data when a single device is connected, and the small-sized radio sets the specific radio Detecting means for detecting that the electronic device is connected, and an adjusting circuit for performing impedance matching with an antenna including an element whose characteristic value is changed by an electric signal obtained by converting the adjustment data into an analog signal ; And the configuration is such that adjustment is automatically performed by the corresponding adjustment data when the small wireless device is connected to the specific electronic device and when it is a single unit, based on the output from the detection means. An antenna impedance matching adjustment circuit for a small radio. 2. The antenna impedance matching adjustment circuit for a small radio according to claim 1, wherein adjustment data when connected to the specific electronic device is downloaded via the Internet.

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