JP2005354502A - Antenna matching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the power loss caused by impedance mismatching by resolving impedance mismatching occurring at the approach of a human body or the like in a short time even in a radio communication machine for transmission and reception like a mobile phone. <P>SOLUTION: An adaptive control part 109 measures a detection value of a reflected power outputted from a reflected power detection part 103 and reads out a phase angle and a capacity value from a storage part 110 as initial values on the basis of a measurement result and adaptively controls the phase angle and variable capacitance capacitors Cp and Cs so as to minimize the reflected power. As a result of control, a phase angle and a capacity value of a reception frequency corresponding to the most suitable value of a transmission frequency are read out from the storage part 110 and taken as initial values, and a detection value of a reception signal outputted from a reception power detection part 104 is measured, and variable capacitance capacitors Cp and Cs are adaptively controlled on the basis of a measurement result. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna matching device, and is suitable for application to a wireless communication device such as a mobile phone.

  FIG. 7 shows a simplified block diagram of the internal configuration of a mobile phone equipped with an antenna element 705 as a conventional example. The antenna element 705 is connected to the wireless transmission unit 701 or the wireless reception unit 702 via the matching circuit unit 704 and the changeover switch 703. Normally, the matching circuit unit 704 is set so that the antenna element 705 is in an impedance matching state at a use frequency in free space.

FIG. 8 shows a call state in which the user holds the casing 802 of the mobile phone. When the human body is in the proximity state, the input impedance of the antenna element 801 is greatly changed unlike the state in which the human body is placed in free space, impedance mismatch occurs, and power loss increases. In order to suppress this power loss, there are devices and algorithms that automatically match the input impedance of the antenna element 801. Japanese Patent Laid-Open No. 2004-228561 discloses the contents of automatically matching the input impedance, and discloses that impedance matching between the antenna and the receiver is performed by phase shift by the phase shifter and capacitance change by the variable reactance element. ing.
JP 2003-318689 A

  However, in Patent Document 1, it takes time until the impedance matching state is reached. In a wireless communication device that alternately performs transmission and reception of a mobile phone or the like in a short time, if the impedance greatly deviates, the impedance matching state is reached. There is a problem that the call quality is greatly deteriorated without being in time and inconsistent state.

  The object of the present invention is to solve the above-mentioned problems, and even in a wireless communication device that performs transmission / reception of a mobile phone or the like, the impedance mismatch that occurs when the human body is approaching is eliminated in a short time, and the power loss due to the impedance mismatch is reduced. An object of the present invention is to provide an antenna matching device that can be reduced.

  An antenna matching device of the present invention includes a phase adjusting unit connected to an antenna element for adjusting a phase, a variable matching unit connected to the phase adjusting unit for adjusting impedance, and phase information of the phase adjusting unit. Storage means for storing a set value table for control information of the variable matching means; and first detection means for detecting any of a signal reflected when the antenna element is fed, a reflection coefficient, and a voltage standing wave ratio; The second detection means for detecting either the received power or the reception sensitivity of the received signal from the antenna element, and the value detected by the first detection means is minimized, and the value detected by the second detection means Adaptive control using the phase information and control information read from the setting value table of the storage means when the phase adjustment means and the variable matching means are adaptively controlled so as to maximize Taking a control unit that, the configuration with.

  According to this configuration, the first detection means and the second detection means detect whether the impedance is matched or mismatched. When the impedance is mismatched, the phase information and control read from the storage means are controlled. By adaptively controlling the phase adjustment means and the variable matching means using information, the impedance matching state can be set in a short time regardless of the impedance, and power loss due to impedance mismatching can be reduced. it can.

  In the antenna matching apparatus of the present invention, the control means completes adaptive control processing of the detection value detected by either the first detection means or the second detection means, and the phase information and control information at that time are obtained. A configuration is adopted in which the detection value detected by the other detection means is adaptively controlled based on the phase information and control information read from the storage means.

  In the antenna matching device of the present invention, the storage means includes phase information and control information in which the antenna element is in an impedance matching state in free space, phase information and impedance information in a representative state other than free space, and Control information is stored in advance, and the control means employs a configuration in which adaptive control processing is started using any phase information and control information stored in the storage means as initial control information.

  According to these configurations, the adaptive control process is started in a state where the deviation of the impedance is small, and the time required to obtain the impedance matching state can be shortened.

  The antenna matching apparatus of the present invention employs a configuration in which the control means includes an input means that allows the user to input information on what state the antenna element is in.

  According to this configuration, it is not necessary to provide a circuit for judging the state of the antenna element by providing an input means for inputting information on the state of the antenna element by the user. It can be configured.

  The antenna matching apparatus of the present invention employs a configuration in which the variable matching means is a variable capacitor and control information is a capacitance value of the variable capacitor.

  The antenna matching apparatus of the present invention employs a configuration in which the variable matching means is a variable capacitance diode, and control information is a control voltage applied to the variable capacitance diode.

  According to these configurations, the variable matching means can be a variable capacitance capacitor or a variable capacitance diode, and can be brought into an impedance matching state by being controlled by a capacitance value or a control voltage.

The antenna matching apparatus according to the present invention employs a configuration in which the variable matching means includes a plurality of capacitors having different capacities and a switch means for selectively switching the plurality of capacitors.
According to this configuration, an impedance matching state can be achieved by selectively switching a plurality of capacitors having different capacitances.

  The antenna matching apparatus according to the present invention employs a configuration in which the phase adjustment unit includes a plurality of phase shifters having different phase angles and a switch unit that selectively switches the plurality of phase shifters.

  In the antenna matching apparatus of the present invention, the phase adjustment means includes a plurality of phase circuits having different phase angles, each including an inductor and a capacitor, and a switch means for selectively switching the plurality of phase circuits. Take.

  The antenna matching device of the present invention employs a configuration in which the phase adjusting unit includes a plurality of transmission lines having different lengths and a switch unit that selectively switches the plurality of transmission lines.

  According to these configurations, an optimum phase angle can be obtained by switching with a switch, and an impedance matching state can be obtained at any impedance.

  According to the present invention, a phase adjustment unit connected to the antenna element and a variable matching unit for impedance adjustment are provided, and information for controlling the phase adjustment unit and the variable matching unit to be in an impedance matching state is transmitted to free space or a call. Phase information prepared in advance in a table corresponding to the state of time, etc., and after performing adaptive control processing at the time of transmission or reception, the other control information corresponding to the control information at that time is read from the table, and the read phase information By using the control information and the other adaptive control, the antenna matching device mounted on the mobile phone or the like eliminates the impedance mismatch caused by various conditions in a short time, and the power due to the impedance mismatch Loss can be reduced.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIG. 1, FIG. 2, and FIG.

  FIG. 1 is a block diagram showing a configuration of an antenna matching apparatus according to Embodiment 1 of the present invention. In this figure, the antenna element 108 is connected to the changeover switch 105 via the phase adjustment unit 107 and the variable matching unit 106. The change-over switch 105 is wirelessly received via the reflected power detection unit 103 (corresponding to the first detection means) during transmission to the wireless transmission unit 101 and is received via the reception power detection unit 104 (corresponding to the second detection means) during reception. The unit 102 is switched and connected.

  Here, the variable matching unit 106 has a configuration in which a variable capacitor Cp is connected in parallel to the signal line, and a variable capacitor Cs is interposed in series with the signal line.

  The phase adjustment unit 107 includes a plurality of stages of phase circuits including inductors and capacitors, and a switch that selectively switches the phase circuits. Here, the phase circuit is a π-type circuit including a capacitor C and an inductance L, and includes a plurality of stages of phase angle control circuits including transmission side elements Ct and Lt and reception side elements Cr and Lr.

  The wireless transmission unit 101 is a part that performs transmission processing such as encoding, modulation, and D / A conversion on a signal transmitted to a communication partner. Then, the signal after the transmission processing from the wireless transmission unit 101 is transmitted from the antenna element 108 via the reflected power detection unit 103 and the changeover switch 105, the variable matching unit 106, and the phase adjustment unit 107. It is transmitted as an ft radio wave.

  When the reflected power detection unit 103 in the next stage of the wireless transmission unit 101 causes impedance mismatch for the antenna element 108 during transmission, reflection occurs in the mismatched part, and the power of the reflected signal This is the part that detects The value detected by the reflected power detection unit 103 is output to the adaptive control unit 109.

  On the other hand, in the reception system, the reception power detection unit 104 connected to the variable matching unit 106 detects the power of the signal of the reception frequency fr received by the antenna element 108 and adapts the detected value (detection value). Output to the control unit 109.

  The wireless reception unit 102 performs reception processing such as A / D conversion, demodulation, and decoding on the signal having the reception frequency fr received by the antenna element 108.

  The storage unit 110 stores in advance a phase angle (phase information) for impedance matching and a capacitance value (control information) of a variable capacitor in a typical state such as a free space state or a call by a user. . The initial value of the phase angle and the initial values of the variable capacitors Cp and Cs are also stored.

  The adaptive control unit 109 measures the detection value of the reflected power output from the reflected power detection unit 103, and based on the measurement result, the reflected power is minimized with the phase angle and the capacitance value from the storage unit 110 as initial values. Thus, the phase angle and the variable capacitors Cp and Cs are adaptively controlled. Further, the detection value of the reception signal output from the reception power detection unit 104 is measured, and the phase angle and the variable capacitors Cp and Cs are adaptively controlled based on the measurement result. That is, the adaptive control unit 109 is connected to the variable matching unit 106 to perform capacitance control of the variable capacitors Cp and Cs, and is connected to the phase adjustment unit 107 to selectively switch the switch. Thus, impedance matching can be achieved for the antenna element 108.

  Here, the phase adjustment unit 107 will be further described. FIG. 2 is a diagram illustrating the impedance of the antenna element 108 on the Smith chart. When the impedance of the antenna element 108 in a certain state at the transmission frequency ft is At, the impedance in a different state is Bt, the impedance of the antenna element 108 in a certain state at the reception frequency fr is Ar, and the impedance in a different state is Br, the variable capacitance By controlling the capacitors Cp and Cs and adjusting the phase angle of the phase adjusting unit 107, the impedance is shifted to an impedance that enables an impedance matching state. In FIG. 2, At, Ar, Bt, and Br are moved to At ′, Ar ′, Bt ′, and Br ′, respectively, by phase adjustment.

  Here, the storage unit 110 will be described more specifically. FIG. 3 is a diagram illustrating a table stored in the storage unit 110. At the transmission frequency ft, the phase angle for impedance matching and the capacitance value of the variable capacitor are stored in correspondence with a typical state such as a state where a user is talking in a free space or a user's phone call. ing. Similarly, at the reception frequency fr, the phase angle for impedance matching and the capacitance value of the variable capacitor are stored in advance.

Next, a processing procedure in the adaptive control unit 109 will be described.
(1) At the time of transmission, the transmission initial value is read from the storage unit 110, and the phase circuit and the variable capacitors Cp and Cs are set.
(2) In this state, the detection value detected by the reflected power detection unit 103 is measured, and the value is sent to the adaptive control unit 109.
(3) The adaptive control unit 109 sets the variable capacitors Cp and Cs by changing the capacitance value of the variable capacitor.
(4) By repeating the above (2) to (3), the adaptive control unit 109 performs control processing so that the detection value detected by the reflected power detection unit 103 is minimized.
(5) Next, the phase adjustment unit 107 is switched to a different phase circuit, and control is performed so that the detection value detected by the reflected power detection unit 103 is minimized as in (4) above.
(6) The above (5) is repeated, and finally the phase angle and capacitance value at which the detection value is minimized are set.
(7) The adaptive control process at the transmission frequency ft at the time of transmission is completed. At this time, the impedance matching state is established at the transmission frequency ft. From FIG. 3, there are states corresponding to the optimum phase angle and optimum capacity value at the transmission frequency ft. On the other hand, at the time of reception, the phase angle and the capacitance value at the reception frequency fr in that state are read, and the phase angle and the variable capacitors Cp and Cs are set as reception initial values.
(8) In this state, the detection value detected by the reception power detection unit 104 is measured, and the detection value is sent to the adaptive control unit 109.
(9) The adaptive control unit 109 sets the variable capacitors Cp and Cs by changing the capacitance value of the variable capacitor.
(10) By repeating the above (8) to (9), the adaptive control unit 109 performs control processing so that the detection value detected by the reception power detection unit 104 is maximized. Further, the same control processing in the adaptive control unit 109 is performed by switching the phase angle of the phase circuit.
(11) The adaptive control process at the reception frequency fr at the time of reception is completed. At this time, the impedance matching state is established at the reception frequency fr.

  As described above, by performing the processing in the adaptive control unit 109, the impedance matching state is achieved at the time of transmission and at the time of reception. As a result, during a call or the like, it is possible to correct an impedance shift in a short time, reduce power loss due to mismatch loss, and ensure good communication quality. Furthermore, by setting the phase angle and the capacitance value at the reception frequency fr corresponding to the phase angle and the capacitance value at the transmission frequency ft to be the initial value of the adaptive control processing at the time of reception, The time required to do so can be shortened.

  In the above description, the adaptive control process at the time of reception is performed after the adaptive control process at the time of transmission. Conversely, the adaptive control process at the time of transmission is performed after the adaptive control process at the time of reception. May be performed.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a configuration of an antenna matching apparatus according to the second embodiment of the present invention. 4 is generally the same as the block configuration shown in FIG. 1, and includes an antenna element 408, a phase adjustment unit 407, a variable matching unit 406, a changeover switch 405, a reflected power detection unit 403 (corresponding to the first detection means), There are a wireless transmission unit 401, a reception power detection unit 404 (corresponding to the second detection means), a wireless reception unit 402, an adaptive control unit 409, and a storage unit 410. The internal circuit of the variable matching unit 406, the adaptive control unit 409 The presence of the control voltage terminal and the input unit 411 is different from that in FIG. In FIG. 4, the variable matching unit 406 includes a variable capacitance diode VDp in parallel with the signal line, a variable capacitance diode VDs in series with the signal line, and high frequency blocking inductors L1, L2, L3, and L4. DC voltage blocking capacitors C1, C2, and C3 are provided. The high frequency blocking inductors L1 and L3 are connected to the output terminals of the control voltages Vp and Vs of the adaptive control unit 409, respectively. Here, the control voltage corresponds to the control information described above. In addition, an input unit 411 that allows the user to input the current state is connected to the adaptive control unit 409.

  The input unit 411 includes a switch, a button, and the like. When the user switches the switch, the adaptive control unit displays a current state such as a state where the user is placed in a free space or a state where the user is talking on the metal plate. 409 is notified. Thereby, it is not necessary to provide a circuit for determining in which state the antenna element is in the adaptive control unit 409, and a simple circuit configuration can be obtained.

  The storage unit 410 stores, as initial values, a phase angle and a control voltage that are in an impedance matching state in a free space or a state such as when a user is talking. Further, a table in which the capacitance value shown in FIG. 3 is associated with the control voltage is stored.

  The adaptive control unit 409 reads the phase angle and control voltage stored in the storage unit 410 according to the content notified from the input unit 411, and uses the read phase angle and control voltage as initial values for adaptive control. The processing in the adaptive control unit 409 is the same as in the first embodiment except that the capacitance value described in the first embodiment is changed to a control voltage and the phase circuit does not need to be switched by the transmission side control. Detailed description thereof is omitted.

  As a result, the difference between the phase angle and the control voltage when the impedance matching state is achieved by adaptive control and the initial value can be reduced, and the time required to reach the impedance matching state can be shortened. . For this reason, stable communication quality can be ensured.

  As described above, according to the present embodiment, the phase angle and the control voltage that are in the impedance matching state in the typical state of the antenna element are prepared in advance as initial values, the initial value is selected according to the state, and the selected initial value is selected. By performing the adaptive control process using the value, it is possible to shorten the time required to reach the impedance matching state and to ensure stable communication quality.

<Embodiment 3>
A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing an antenna matching apparatus according to Embodiment 3 of the present invention. 5 is different from FIG. 1 in that the variable matching unit 506 is changed to a capacitance switching unit including a plurality of capacitors and a changeover switch.

  Capacitance switching units 512 and 513 serving as matching means include a plurality of capacitors having different capacitance values Cp1 to CpN and Cs1 to CsN, respectively, and the capacitors to be connected are switched by controlling the changeover switch.

  The capacity switching units 512 and 513 are controlled by the adaptive control unit as described in the above embodiment.

  The processing in the adaptive control unit is the same as in the first embodiment except that the capacitance value described in the first embodiment is changed to a switch that is turned on.

  As described above, according to the present embodiment, the changeover switch is adaptively controlled, and an impedance matching state can be obtained by switching a capacitor to be connected, so that stable communication quality can be ensured.

<Embodiment 4>
Another embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing an antenna matching apparatus according to another embodiment of the present invention. FIG. 6 differs from FIG. 1 in that the phase adjustment unit 607 has changed a plurality of phase circuits composed of inductors and capacitors to a plurality of transmission lines having different lengths.

  The processing in the adaptive control unit is merely changing the phase circuit described in the first embodiment to a transmission line, and the other processing is the same as in the first embodiment.

  In each of the embodiments described above, the reflected power detection unit detects the power of the reflected signal. However, the present invention is not limited to this, and any one of the reflected signal, the reflection coefficient, and the voltage standing wave ratio is detected. It may be.

  Further, in each of the above-described embodiments, the power of the received signal is detected at the time of reception. However, the present invention is not limited to this, and either the received signal or the reception sensitivity may be detected.

  The antenna matching device according to the present invention is suitable for application to a wireless communication device such as a mobile phone.

Configuration diagram of antenna matching apparatus shown in Embodiment 1 of the present invention The figure which shows the effect of the phase adjustment section The figure which shows the table memorize | stored in the memory | storage part. Configuration diagram of antenna matching apparatus shown in embodiment 2 of the present invention Configuration diagram of antenna matching apparatus shown in Embodiment 3 of the present invention Configuration diagram of antenna matching apparatus shown in Embodiment 4 of the present invention Configuration of conventional antenna matching device Diagram showing the state during a call

Explanation of symbols

101, 401, 701 Wireless transmission unit 102, 402, 702 Wireless reception unit 105, 405, 505, 703 Changeover switch 704 Matching circuit unit 108, 408, 705, 801 Antenna element 103, 403 Reflected power detection unit 104, 404 Received power Detection unit 109, 409 Adaptive control unit 110, 410 Storage unit 106, 406, 506 Variable matching unit 107, 407, 607 Phase adjustment unit 411 Input unit 512 Parallel capacity switching unit 513 Series capacity switching unit

Claims (10)

A phase adjusting means connected to the antenna element for adjusting the phase;
Variable matching means connected to the phase adjusting means for adjusting impedance;
Storage means for storing a set value table of phase information of the phase adjustment means and control information of the variable matching means;
First detection means for detecting any one of a signal reflected when power is supplied to the antenna element, a reflection coefficient, and a voltage standing wave ratio;
Second detection means for detecting either received power or received sensitivity of a received signal from the antenna element;
When adaptively controlling the phase adjustment unit and the variable matching unit so that the value detected by the first detection unit is minimized and the value detected by the second detection unit is maximized, the setting of the storage unit An antenna matching apparatus comprising: control means for adaptively controlling using phase information and control information read from a value table.   The control means completes adaptive control processing of the detection value detected by either the first detection means or the second detection means, and reads out the phase information and control information at that time from the storage means 2. The antenna matching apparatus according to claim 1, wherein the detection value detected by the other detection means is adaptively controlled based on the phase information and the control information. The storage means stores in advance phase information and control information in which the antenna element is in an impedance matching state in free space, and phase information and control information in an impedance matching state in a representative state other than free space,
The antenna matching apparatus according to claim 1, wherein the control unit starts an adaptive control process using any one of phase information and control information stored in the storage unit as initial control information.   The antenna matching according to any one of claims 1 to 3, wherein the control means includes an input means that allows a user to input information on what state the antenna element is in. apparatus.   5. The antenna matching apparatus according to claim 1, wherein the variable matching unit is a variable capacitor, and the control information is a capacitance value of the variable capacitor.   5. The antenna matching device according to claim 1, wherein the variable matching means is a variable capacitance diode, and control information is a control voltage applied to the variable capacitance diode.   5. The antenna matching according to claim 1, wherein the variable matching unit includes a plurality of capacitors having different capacities and a switch unit that selectively switches the plurality of capacitors. 6. apparatus.   8. The phase adjusting unit according to claim 1, further comprising: a plurality of phase shifters having different phase angles; and a switch unit that selectively switches the plurality of phase shifters. Antenna matching device.   2. The phase adjusting means comprises a plurality of phase circuits having different phase angles, each comprising an inductor and a capacitor, and switch means for selectively switching the plurality of phase circuits. The antenna matching apparatus according to claim 7.   The said phase adjustment means is equipped with the several transmission line from which length differs, and the switch means which selectively switches these transmission lines, The any one of Claims 1-7 characterized by the above-mentioned. Antenna matching device.

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