JP2010081161A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To finely adjust matching and to reduce manufacturing costs, without using a high-frequency switch for switching two loop antennas in an antenna device. <P>SOLUTION: The antenna device 1 is constituted of a part for respective conductive patterns 3a, 3b and antenna elements 4a, 4b, and has the two-loop antennas 10a, 10b each of which is connected to a wireless circuit part 12 by a common signal line 8. To the loop antennas 10a, 10b, varicaps 15a, 15b, and control lines 9a, 9b for connecting their positive electrode sides to a control part 13 are connected, respectively. The control part 13 transmits a PWM signal to change the capacitance values of the varicaps 15a, 15b; takes matching of one of loop antennas 10a, 10b used for transmission and reception of a radio signal; shifts matching of the other of loop antennas 10b, 10a; and switches the two-loop antennas 10a, 10b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna device that transmits or receives a signal using a loop antenna, and particularly relates to an antenna device that includes two loop antennas.

  As a load control system for turning on / off a load such as illumination, a radio signal transmitted from a transmitter is received by a switch disposed on a construction surface such as a wall surface, and the illumination device is based on a signal received by the switch Some of them are configured to perform an opening / closing operation. In such a load control system, by using wireless communication, for example, a highly functional switch can be replaced with an existing switch without performing wiring work with other parts of the load control system. Or it can newly arrange | position easily.

  In such a load control system using wireless communication, depending on the application, it may be more desirable to transmit and receive signals between the transmitter and the switch by wireless communication using radio waves than to transmit and receive by infrared light. This is because wireless communication has advantages such as a wider transmitter area that allows signals to be transmitted to the switch due to radio wave transmission and diffraction than with infrared light. . In a small switch or transmitter used in a load control system, a minute loop antenna is usually preferable as an antenna for transmitting and receiving signals by wireless communication. The micro loop antenna has a feature that the total length is as small as 1/10 or less of the transmission wavelength, and that it is more resistant to a noise electric field than a micro dipole antenna.

  By the way, in such an antenna device that radiates and receives radio waves, two loop antennas having different conditions are provided to be switchable with each other so that radio waves can be radiated and received more reliably. In some cases, the diversity effect is used. In order to switch between the two antennas, it is necessary to provide a high-frequency switch in the signal transmission line connecting the antenna and the radio circuit. However, the high frequency switch used in the high frequency transmission line is expensive, and there is a problem that the manufacturing cost of the antenna device increases. In addition, there is a problem that high-frequency loss occurs in the switch. Furthermore, when two loop antennas are used close to each other in the same antenna device, in order to transmit or receive radio waves reliably with one antenna, in order to prevent coupling between the antennas, There is a problem that the matching of the other antenna must be shifted.

Here, in Patent Document 1, a diode is connected in series to a capacitor provided in a loop antenna, and the movement of the loop antenna is controlled by shifting matching according to the presence or absence of the bias current of the diode, An antenna device that switches a loop antenna is disclosed. However, since this antenna device uses a diode, there is a problem in that it is difficult to control the capacitance value and the matching of the loop antenna cannot be finely adjusted.
Japanese Patent Publication No. 7-44492

  The present invention has been made in view of the above-described problems, and it is possible to finely adjust the matching, and it is not necessary to use a high-frequency switch for switching between two loop antennas, thereby reducing the manufacturing cost. An object of the present invention is to provide an antenna device capable of performing the above.

  In order to achieve the above object, an invention according to claim 1 is an antenna formed of a circuit board, a part of the conductive pattern formed on the circuit board, and a conductor, and arranged to correspond to the conductive pattern. Two loop antennas each having an element, two matching means provided to respectively correspond to the two loop antennas, and adjusting matching of the loop antennas by changing a capacitance value; In the antenna device including a radio circuit unit that transmits and / or receives a radio signal using one of the two loop antennas and a control unit that controls the operation of the radio circuit unit, the two loop antennas are Are connected to the radio circuit unit via a common signal line, and the control unit sends a predetermined control signal to the two matching means. And the matching means changes the capacitance value based on the control signal, so that the radio circuit unit is configured to be able to switch a loop antenna used for transmission and / or reception of a radio signal. is there.

  According to a second aspect of the present invention, in the first aspect of the invention, the predetermined control signal is different for each matching means.

  According to a third aspect of the present invention, in the first aspect of the invention, the predetermined control signal is configured to be transmitted in common to the two matching means, and the two sets of loop antennas and matching circuits are: They are configured differently so that only one of the loop antennas can be matched when the predetermined identical control signal is transmitted.

  According to the first aspect of the present invention, since each matching unit changes the capacitance value based on a predetermined control signal, the matching state of each loop antenna can be finely adjusted. Therefore, it is possible to accurately match one loop antenna used for radio signal transmission and reception, and not to match the other loop antenna, so that the radio signal can be reliably transmitted or received. Can be switched. In addition, since the two loop antennas are connected to the radio circuit unit via a common signal line, an expensive high-frequency switch is unnecessary, and the manufacturing cost of the antenna device can be reduced.

  According to the invention of claim 2, since each matching means can be controlled by transmitting a different control signal for each matching means, a matching means corresponding to the loop antenna is provided depending on the configuration and use of each loop antenna. Easy to configure and adjust.

  According to the invention of claim 3, since the same control signal can be transmitted to control each matching means, the circuit configuration of the control unit can be further simplified, and the manufacturing cost of the antenna device can be further reduced. be able to.

  FIG. 1 shows an illumination control system using an antenna device according to an embodiment of the present invention. The lighting control system 101 includes a lighting device 150, a transmitter (antenna device) 151 that transmits a radio signal, a power source 153 that is a commercial AC power source, and a switch that is a control device that is connected in series to the lighting device 150 via electric wires. (Antenna device) A load control system including 152 and the like. The switch 152 has an operation handle 152a that can be operated by the user from the outside. The switch 152 turns on or off the illumination device 150 in accordance with the operation of the operation handle 152a or a wireless signal transmitted from the transmitter 151. The transmitter 151 is provided with operation buttons (not shown) that can be operated by the user. Here, the illumination device 150 made of an incandescent lamp is illustrated as a load. However, the present invention is not limited to this, and other loads such as a fluorescent lamp and a fluorescent lamp electronic ballast, and a load other than the illumination load. Also good.

  FIG. 2 shows a block configuration of the transmitter 151. The transmitter 151 includes a sensor unit 151a, a control unit 151b that generates a control signal such as a lighting signal for lighting the lighting device 150, a wireless circuit unit 151c that modulates and amplifies the control signal, and will be described later. A signal transmission unit 151d having a loop antenna, a switch circuit unit 151e, and a power supply unit 151f. For example, the transmitter 151 is configured in a box shape in which each unit is housed in a housing, and is used by being mounted on a wall surface, for example. The transmitter 151 is an antenna device that can transmit a radio signal.

  The sensor unit 151a includes a human sensor that detects the presence or absence of a person in the detection area by detecting a heat ray radiated from a human body by a pyroelectric element, and an illuminance that detects ambient brightness by a photoelectric conversion element or a solar cell. A sensor for detecting the brightness of the surroundings detected by the illuminance sensor and the presence / absence of the person detected by the human sensor. The control unit 151b is configured by a microcomputer or the like. When the sensor unit 151a detects that the surrounding brightness is darker than the reference value and the human body exists, an operation signal described later is input. When it is done, it generates a lighting signal. The lighting signal is modulated and amplified by the wireless circuit unit 151c, and then transmitted as a wireless signal from the signal transmission unit 151d. The switch circuit unit 151e sends an operation signal to the control unit 151b when the user operates the operation button. That is, the user can forcibly turn on or off the lighting device 150 by operating the operation button regardless of the presence or absence of a person detected by the sensor unit 151a. The power supply unit 151f supplies operation power to each unit using, for example, a battery as a power source.

  FIG. 3 shows a block configuration of the switch 152. The switch 152 includes a control unit 152b, a load control circuit unit 152c, a signal receiving unit 152d that receives a radio signal, a radio circuit unit 152e that demodulates and amplifies the signal received by the signal receiving unit 152d, and a display unit 152f. , A switch input unit 152g and a power supply circuit unit 152h. The switch 152 is formed in a two-module size, for example, a wide handle type continuous switch (see JIS C 8304) having a rectangular box-shaped body made of synthetic resin, and is attached to a mounting frame or the like conforming to the standard. And placed in a switch box embedded in the wall surface. The switch 152 is an antenna device that can receive a radio signal.

  The load control circuit unit 152c includes a switching element (for example, a triac) that opens and closes a power feeding path from the power source 153 to the lighting device 150. The control unit 152b is configured by a microcomputer or the like, and controls switching of the switching element of the load control circuit unit 152c. As will be described later, the signal receiving unit 152d is configured to be able to receive a radio signal by a loop antenna. The display unit 152f includes, for example, a light emitting element such as a light emitting diode, and displays a control state such as control validity / invalidity by the transmitter 151 based on control of the control unit 152b. The switch input unit 152g has a tact switch that is pressed by the operation handle 152a, and sends an operation signal to the control unit 152b when the tact switch is turned on. That is, whenever the operation handle 152a is pushed and an operation signal is sent from the switch input unit 152g, the switching element of the load control circuit unit 152c is switched by the control of the control unit 152b, and the lighting device 150 is turned on. The light is switched off. The power supply circuit unit 152h supplies operating power to the control unit 152b and the like. In the switch 152, when the load control circuit unit 152c opens a power feeding path to the lighting device 150, the power circuit unit 152h charges the capacitor to generate an operating power source for the switch 152. On the other hand, when the load control circuit unit 152c closes the power supply path from the power source 153 to the lighting device 150, the load control circuit unit 152c periodically feeds the power supply path within a range that does not affect the lighting state of the lighting device 150. Is opened for a predetermined time to charge the capacitor of the power supply circuit unit 152h, and when closed outside the predetermined time, the capacitor is discharged to generate an operating power supply. Thereby, the switch 152 can connect the power supply 153 and the illumination device 150 in series with two lines. Since this type of power supply circuit unit 152h is conventionally known (see, for example, Japanese Patent Laid-Open No. 2000-357443, etc.), illustration and description of a detailed configuration and operation are omitted.

  By the way, in this embodiment, the transmitter 151 and the switch 152 are each configured to be able to transmit or receive signals by switching two loop antennas. Hereinafter, for the sake of simplification, instead of describing the configuration of the transmitter 151 or the switch 152, it is used for the transmitter 151 or the switch 152, and the loop antenna can be switched in the same manner as described above. A configuration of the antenna device 1 capable of transmitting or receiving a radio signal will be described. The antenna apparatus 1 includes the control units 151b and 152b, the radio circuit units 151c and 152e, the signal transmission unit 151d, the signal reception unit 152d, and the like out of the transmitter 151 and the switch 152 described above. Other parts that are not directly related to wireless transmission, such as the operation handle 152a, the sensor unit 151a, and the load control circuit unit 152c, are not shown and described below.

  FIG. 4 shows the configuration of the antenna device 1. FIG. 5 shows a circuit configuration of the antenna portion of the antenna device 1. The antenna device 1 is configured by housing, for example, a substantially rectangular circuit board 2 inside a box-shaped housing 50. The housing 50 is made of, for example, a synthetic resin, and is configured by joining a front panel 51 on the front side of the antenna device 1 and a base member 52 on the back side of the antenna device 1. The circuit board 2 is mounted on the base member 52 by, for example, screwing a screw (not shown) penetrating the circuit board 2 onto a boss (not shown) provided on the base member 52. ing.

  On the upper part of the circuit board 2, a first conductive pattern 3a formed on the circuit board 2 and both ends of the first conductive pattern 3a are electrically connected to both ends of the first conductive pattern 3a. For example, a substantially U-shaped first antenna element 4a mounted substantially vertically on the circuit board 2 using solder (not shown) or the like is provided. Further, at the lower part of the circuit board 2, both ends are electrically connected to the second conductive pattern 3 b formed on the circuit board 2 and both ends of a part of the second conductive pattern 3 b. In addition, a substantially U-shaped second antenna element 4b mounted on the circuit board 2 is provided in the same manner as the first antenna element 4a. The first conductive pattern 3a and the first antenna element 4a constitute a rectangular first loop antenna 10a. Further, the second conductive pattern 3b and the second antenna element 4b constitute a rectangular second loop antenna 10b in the same manner as the first loop antenna 10a. In the present embodiment, the first loop antenna 10a and the second loop antenna 10b are arranged so that their loop surfaces are parallel to each other. The first antenna element 4a and the second antenna element 4b do not have to be fixed to the circuit board 2. For example, each conductive element is configured to form a loop antenna via a conductor such as another conductive wire. It may be connected to the patterns 3a and 3b. Further, the first loop antenna 10a and the second loop antenna 10b may not be arranged so that their loop surfaces are parallel to each other.

  On the circuit board 2, a first capacitor circuit 5a and a second capacitor circuit respectively inserted into a part of each of the first conductive pattern 3a and the second conductive pattern 3b constituting the loop antennas 10a and 10b. 5b and a wireless circuit unit 12 and a control unit 13 mounted on the circuit board 2 are provided. Further, on the circuit board 2, a ground pattern 6 which is a so-called solid pattern and a part of the first conductive pattern 3a and the second conductive pattern 3b, which are the first loop antenna 10a and the second loop antenna 10b. There are provided two ground lines 7 that connect the ground pattern 6 to each other, a signal line 8 that is a feed line for supplying signals from the radio circuit unit 12 to the first loop antenna 10a and the second loop antenna 10b, and the like. Yes. The ground line 7 has a longitudinal direction that is substantially perpendicular to the loop surfaces of the loop antennas 10a and 10b between the capacitor circuits 5a and 5b and one end of the antenna elements 4a and 4b of the conductive patterns 3a and 3b. It is extended so that it may become a direction. The signal line 8 is connected between a portion of the conductive patterns 3a and 3b to which the ground line 7 is connected and one end of the antenna elements 4a and 4b. In the present embodiment, the signal line 8 is connected to the conductive patterns 3a and 3b so as to branch the common transmission line connected to the wireless circuit unit 12. That is, the two loop antennas 10 a and 10 b are connected to the radio circuit unit 12 via the common signal line 8. Among the parts of the transmitter 151 and the switch 152, the control units 151b and 152b correspond to the control unit 13 of the antenna device 1, and the radio circuit units 151c and 152e, the signal transmission unit 151d, and the signal reception unit 152d are This corresponds to the radio circuit unit 12, the first loop antenna 10a and the second loop antenna 10b, the capacitor circuits 5a and 5b, and the like. In the antenna device 1, the radio circuit unit 12 is configured to be able to switch between signal transmission and reception. However, the present invention is not limited to this, and only one of transmission and reception is possible. You may be comprised so that it can perform.

  Assuming that the frequency of the wireless communication performed by the antenna device 1 is f, the wireless circuit unit 12 outputs a signal of the frequency f when transmitting a wireless signal. The width and height of the first loop antenna 10a and the second loop antenna 10b are designed so that the total length of one loop is about 1/10 or less of the transmission wavelength λ. The impedances of the first loop antenna 10a and the second loop antenna 10b are adjusted so that the loss is minimized at the frequency f (= 2π / λ) (decrease in the antenna gain is reduced). The impedance adjustment of the first loop antenna 10a is performed by a first matching circuit unit (matching means) 11a configured by the first capacitor circuit 5a and the ground line 7. The impedance adjustment of the second loop antenna 10b is performed by a second matching circuit unit (matching means) 11b configured by the second capacitor circuit 5b and the ground line 7. Specifically, the resonance frequency of the first loop antenna 10a and the second loop antenna 10b is adjusted by appropriately selecting the capacitance value in the first capacitor circuit 5a and the second capacitor circuit 5b, respectively. Further, assuming that the resonance frequency of the first loop antenna 10a and the second loop antenna 10b is a desired frequency, each conductive pattern 3a, 3b is connected to the ground line 7 from the connection point with the signal line 8. The antenna input impedance can be adjusted by adjusting the distance to the connection point (indicated by dimension lines D1 and D2 in FIG. 5).

  For example, when a radio signal is transmitted using the first loop antenna 10a, a high-frequency current is excited in the antenna device 1 when a high-frequency signal output from the radio circuit unit 12 is output. This high-frequency current flows along the conductive path constituting the first loop antenna 10a and contributes to radiation as the first loop antenna 10a (loop mode current), and in the longitudinal direction of the ground line 7 on the circuit board 2. It can be divided into two types of currents (dipole mode currents) that flow and contribute to radiation as a dipole antenna. The loop mode current excites a radio wave (horizontal polarization component) having a polarization parallel to the loop surface in a direction parallel to the rectangle formed by the first loop antenna 10a. On the other hand, the dipole mode current excites a polarized wave (vertical polarization component) parallel to the longitudinal direction of the ground line 7 in a direction perpendicular to the circuit board 2. For example, the antenna device 1 is configured to be able to radiate and receive circularly polarized radio waves obtained by combining radio waves of polarization components in these two directions. Similarly, when the second loop antenna 10b is used, the antenna device 1 can radiate and receive circularly polarized radio waves, and the first loop antenna 10a and the second loop antenna 10b as described later. By switching which one is used for transmission / reception of radio signals, for example, the effect of polarization diversity that switches between right-handed circularly polarized wave and left-handed circularly polarized wave can be obtained.

  Here, as shown in FIG. 5, the first capacitor circuit 5a includes a capacitor 14a and a varicap 15a. The second capacitor circuit 5b includes a capacitor 14b and a varicap 15b. The capacitor 14a and the capacitor 14b have the same specifications, for example, and the varicap 15a and the varicap 15b have, for example, the same specifications. A control line 9a for inputting a control signal from the control unit 13 is connected to the anode side of the varicap 15a. A control line 9b for inputting a control signal from the control unit 13 is connected to the anode side of the varicap 15b. In the circuit of the antenna device 1, elements such as a capacitor having a capacitance that does not affect the high-frequency signal are provided for cutting the direct current, but these elements are not shown. ing.

  In the present embodiment, the control unit 13 transmits two different types of control signals to the first capacitor circuit 5a and the second capacitor circuit 5b through the control lines 9a and 9b, respectively. It is possible to switch which of the two loop antennas 10b is used for transmission / reception of radio signals. As the control signal, for example, a PWM signal can be used.

  For example, when the first loop antenna 10a is used for transmission / reception of a radio signal, the control unit 13 sets the capacitance value of the varicap 15a so that the matching of the first loop antenna 10a can be obtained. A PWM signal having a predetermined duty ratio is transmitted through the control line 9a. On the other hand, the control unit 13 outputs a PWM signal having a duty ratio different from that transmitted to the control line 9a so that the capacitance value of the varicap 15b becomes a value such that the matching of the second loop antenna 10b is shifted. And transmitted through the control line 9b. When the PWM signal is transmitted from the control unit 13, the capacitance values of the varicaps 15a and 15b change according to each PWM signal, the first loop antenna 10a is matched, and the second loop antenna 10b Matching is out of place. Therefore, at the time of signal transmission, for example, the same high frequency signal is input from the radio circuit unit 12 to the loop antennas 10a and 10b via the common signal line 8, but the matching is shifted from the second loop antenna 10b. Hardly emits radio waves, and radio waves are radiated only from the matched first loop antenna 10a. Since the PWM signal is transmitted as the control signal in this way, the control unit 13 can easily and finely control the capacitance values of the varicaps 15a and 15b. The control signal may be a constant voltage signal.

  For example, in order to switch the antenna used for transmission / reception of a radio signal from the first loop antenna 10a to the second loop antenna 10b, the control unit 13 transmits a PWM signal to be transmitted to the first capacitor circuit 5a and the second capacitor circuit 5b. Change it. In particular, in the present embodiment, capacitors 14a and 14b and varicaps 15a and 15b having the same specifications are used, so that the control unit 13 transmits PWM signals to the first capacitor circuit 5a and the second capacitor circuit 5b. May be replaced with each other. That is, by transmitting the PWM signal in this way, the capacitance values of the varicaps 15a and 15b are changed based on the PWM signal, the matching of the first loop antenna 10a is shifted, and the second loop antenna 10b matching can be obtained. Therefore, it is possible to reliably operate the second loop antenna 10b while preventing the first loop antenna 10a from operating.

  As described above, in the antenna device 1, since the matching state of each loop antenna 10a, 10b can be finely adjusted, the matching of the loop antennas 10a, 10b used for radio signal transmission and reception is accurately performed, and The matching of the other loop antennas 10b and 10a is shifted, and the loop antennas 10a and 10b can be switched so that radio signals can be reliably transmitted or received. Since the two loop antennas 10a and 10b are connected to the radio circuit unit 12 via the common signal line 8 without using an expensive high-frequency switch, the manufacturing cost of the antenna device 1 can be reduced. Further, since it is possible to control the first matching circuit unit 11a and the second matching circuit unit 11b by transmitting different control signals to the capacitor circuits 5a and 5b, depending on the configuration and application of each loop antenna 10a and 10b, Matching circuit portions 11a and 11b corresponding to the loop antennas 10a and 10b can be easily configured and adjusted. In particular, in the present embodiment, capacitors 14a and 14b and varicaps 15a and 15b having the same specifications are used, so that the manufacturing cost can be further reduced.

  The control unit 13 may be configured to transmit the same control signal to the capacitor circuits 5a and 5b. FIG. 6 is a circuit diagram of the antenna device 31 configured as described above. The antenna device 31 includes capacitor circuits 5a and 5b provided with capacitors 34a and 34b having different capacitance values and varicaps 35a and 35b having different capacitance values with respect to a bias voltage. In addition, the same control line 39 branched from the control unit 13 and extending in place of the control line 9a and the control line 9b is connected to the anode side of each varicap 35a, 35b. The other parts of the capacitor circuits 5a and 5b are the same as the configuration of the antenna device 1 described above, and thus description thereof is omitted.

  In the antenna device 31, the control unit 13 transmits the first loop antenna 10a and the second loop signal to the same control line 39 by transmitting one of the first PWM signal and the second PWM signal having different duty ratios as the control signal. One of the loop antennas 10b corresponding to the transmitted PWM signal can be selected as an antenna that can be used for transmission / reception of a radio signal. For example, when the first PWM signal having a duty ratio larger than that of the second PWM signal is transmitted and the capacitance value of the varicap 35a is changed, the first capacitor circuit 5a can match the first loop antenna 10a and perform comparison. The capacitor 34a and the varicap 35a selected in consideration of matching adjustment are configured so that the matching of the first loop antenna 10a is shifted when the second PWM signal having a small target duty ratio is transmitted. In addition, the second capacitor circuit 5b causes the matching of the second loop antenna 10b to be shifted when the first PWM signal is transmitted and the capacitance value of the varicap 35b is changed, and when the second PWM signal is transmitted, the second capacitor circuit 5b is second. In order to achieve matching of the loop antenna 10b, the capacitor 34b and the varicap 35b selected in consideration of matching adjustment are used.

  As described above, the antenna device 31 is configured to be able to switch between the first loop antenna 10a and the second loop antenna 10b by transmitting the same control signal. Can be systematic. Therefore, the circuit configuration of the control unit 13 can be further simplified, and the manufacturing cost of the antenna device 31 can be further reduced. It should be noted that such a configuration in which the two loop antennas 10a and 10b can be switched by the same control signal cannot be realized only by adjusting the configuration of the capacitor circuits 5a and 5b. For example, the impedances of the two loop antennas 10a and 10b are made different by adjusting the impedances of the antenna elements 4a and 4b and the position of the ground line 7 using the capacitor circuits 5a and 5b having the same configuration. As described above, the loop antennas 10a and 10b can be switched by the same control signal as described above.

  In addition, this invention is not limited to the structure of the said embodiment, A various deformation | transformation is possible suitably in the range which does not change the meaning of invention. For example, the loop antenna is not limited to a rectangle, and may have another shape. In addition, the antenna device may be configured to be able to transmit and receive radio waves of horizontal polarization or vertical polarization simply by the loop antenna. The arrangement of the loop antennas is different from the above, and the two loop antennas have different directivities. The radio wave may be radiated / received. In this case, space diversity, directivity diversity, and the like can be realized by switching between two loop antennas.

  Also, arrange the two loop antennas so that the loop surfaces of each loop are substantially vertical, and the two loop antennas are L-shaped or T-shaped when viewed in the direction of the line of mutual loop surfaces. May be. Adopting such an arrangement of two loop antennas makes it difficult for the magnetic flux generated in each loop antenna to interfere with other loop antennas, making it difficult for the loop antennas to be coupled to each other. Therefore, for example, when transmitting and receiving a radio signal using one loop antenna, it is possible to prevent the generation of noise due to the induction of current in the other loop antenna, and more appropriately the radio signal. Can send and receive. Further, the two loop antennas may be arranged so that their loop surfaces are located in substantially the same plane. In this case as well, similarly, it is possible to make it difficult to couple the loop antennas together, and to transmit and receive radio signals more appropriately.

  In addition to the illumination control system that controls the on / off of the illumination load as described above, the antenna device is an air conditioning system, a hot water supply system, or a transmitter that is turned on / off according to a signal transmitted from the transmitter. It can also be used in a load control system used for other purposes, such as a security system that receives a predetermined signal transmitted from the terminal and performs a notification operation. That is, a transmitter or a remote control device used to remotely control the operation of the load control system by transmitting a radio signal, or a control device such as a switch that receives such a radio signal is described above. By using the structure of the antenna device, the manufacturing cost of the transmitter, the remote control device, the control device, or the like can be reduced.

The figure which shows an example of the illumination control system using the antenna device which concerns on one Embodiment of this invention. The block diagram which shows the structure of the switch of the said illumination control system, and an illuminating device. The block diagram which shows the structure of the transmitter of the said illumination control system. The disassembled perspective view which shows an example of the antenna device used for the said illumination control system. The figure which shows the circuit structural example of the said antenna apparatus. The figure which shows the circuit structural example of the antenna apparatus which concerns on the modification of the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,31 Antenna apparatus 2 Circuit board 3a 1st conductive pattern 3b 2nd conductive pattern 4a 1st antenna element 4b 2nd antenna element 8 Signal line 10a 1st loop antenna 10b 2nd loop antenna 11a 1st matching circuit part ( Alignment means)
11b Second matching circuit section (matching means)
12 wireless circuit unit 13 control unit

Claims (3)

A circuit board;
Two loop antennas each having a part of a conductive pattern formed on the circuit board and an antenna element formed of a conductor and arranged to correspond to the conductive pattern;
Two matching means provided to respectively correspond to the two loop antennas, and adjusting matching of the loop antennas by changing capacitance values;
A radio circuit unit that transmits and / or receives a radio signal using one of the two loop antennas;
In an antenna device comprising a control unit for controlling the operation of the radio circuit unit,
The two loop antennas are respectively connected to the radio circuit unit via a common signal line,
The control unit transmits a predetermined control signal to the two matching units, and the matching unit changes a capacitance value based on the control signal, whereby the radio circuit unit transmits and / or transmits a radio signal. Alternatively, an antenna device characterized in that a loop antenna used for reception can be switched.   2. The antenna apparatus according to claim 1, wherein the predetermined control signal is different for each matching unit. The predetermined control signal is configured to be transmitted in common to the two matching means,
The two sets of loop antennas and matching circuits are different from each other so that only one of the loop antennas can be matched when the predetermined identical control signal is transmitted. Item 2. The antenna device according to Item 1.

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