JP2010081167A - Antenna apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To switch and use two-loop antennas without havng to use a high-frequency switch, and to lower the manufacturing cost for an antenna apparatus. <P>SOLUTION: The two-loop antennas 10a and 10b of the antenna apparatus 1 comprise a part of conductive patterns 3a and 3b and antenna elements 4a and 4b, respectively and are connected with a radio circuit section 12 by a common signal line 8 respectively. A changeover switch 15, having a cover plate 17 which is a conductor, is disposed close to the loop antennas 10a and 10b; a user operates the changeover switch 15 so that the cover plate 17 is close to the loop antenna 10a or 10b which is not used. Matching of one loop antenna 10a or 10b to be used for transmitting and receiving radio signals is attained, matching of the other loop antenna 10b or 10a is shifted, and the antennas can be switched. <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, this antenna device has a problem that the circuit configuration becomes complicated because a diode and a circuit for applying a bias voltage to the diode must be provided on the circuit board.
Japanese Patent Publication No. 7-44492

  The present invention has been made in view of the above-described problems, and can be used by completely switching between two loop antennas without using a high-frequency switch with a simple circuit configuration, and the manufacturing cost can be reduced. It is an object to provide a simple antenna device.

  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. Using 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, and one of the two loop antennas In the antenna device including a radio circuit unit that transmits and / or receives radio signals and a control unit that controls the operation of the radio circuit unit, the two loop antennas are signals common to the radio circuit unit, respectively. It has a plate-like member that is connected via a wire and made of a conductor, and changes the positional relationship between the plate-like member and each loop antenna. The antenna circuit means further comprises an antenna cover means configured to be used by the radio circuit unit for transmitting and / or receiving radio signals by changing the positional relationship between the plate-like member and the loop antenna by the antenna cover means. The loop antenna can be switched.

  According to the invention of claim 1, by changing the positional relationship between the plate-like member and the loop antenna by the antenna cover means, the inductance of the loop antenna can be changed, and the matching state of each loop antenna can be changed. Therefore, by using the antenna cover means to match one loop antenna used for transmitting and receiving a radio signal and not matching the other loop antenna, the radio signal can be transmitted or received reliably. The loop antenna can be switched so that it can be received. 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 antenna circuit configuration can be simplified. The manufacturing cost of the apparatus can be reduced.

  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 this is done, a lighting signal is generated using these as a trigger. 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 configured to switch between two loop antennas based on an operation by the user and to transmit or receive signals. 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.

  4 and 5 show the configuration of the antenna device 1. The antenna device 1 is configured by housing, for example, a substantially rectangular circuit board 2 inside a 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. In addition, illustration of the front panel 51 is abbreviate | omitted in FIG. 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. A changeover switch (antenna cover means) 15 is provided above the antenna device 1. The structure of the changeover switch 15 will be described later. First, the structure of the antenna portion of the antenna device 1 will be described.

  In the upper left 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. In addition, at the upper right part of the circuit board 2, both ends are electrically connected to the second conductive pattern 3b formed on the circuit board 2 and both ends of a part of the second conductive pattern 3b. Thus, the substantially U-shaped 2nd antenna element 4b mounted on the circuit board 2 similarly to the 1st antenna element 4a is provided. 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 such that their loop surfaces are located on substantially the same plane. Therefore, for example, when transmitting or receiving a radio signal using one loop antenna 10a, 10b, it is possible to prevent the occurrence of noise due to the induction of current in the other loop antenna 10b, 10a. Radio signals can be transmitted and received properly. 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 the loop surfaces are located on the same plane.

  On the circuit board 2, a capacitor 5a and a capacitor 5b, which are respectively inserted into a part of the first conductive pattern 3a and the second conductive pattern 3b constituting the loop antennas 10a and 10b, respectively, and the circuit board 2 The wireless circuit unit 12 and the control unit 13 mounted on the above 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 between the capacitors 5a and 5b of the conductive patterns 3a and 3b and one end of the antenna elements 4a and 4b, and a direction substantially perpendicular to the loop surface of the loop antennas 10a and 10b. It is extended to become. 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. In the two loop antennas 10a and 10b, the arrangement order of the capacitors 5a and 5b, the ground line 7, and the signal line 8 is opposite to each other.

  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, and the capacitors 5a and 5b. 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.

  FIG. 6 shows a circuit configuration of the antenna portion of the antenna device 1. For simplification of the drawing, the arrangement order of the circuit elements is appropriately modified in the drawing. 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 composed of a capacitor 5a and a ground line 7. Further, the impedance adjustment of the second loop antenna 10b is performed by a second matching circuit unit (matching means) 11b composed of the capacitor 5b and the ground line 7. Specifically, the resonant frequencies of the first loop antenna 10a and the second loop antenna 10b are adjusted by appropriately selecting the capacitance values in the capacitors 5a and 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. 6).

  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. At this time, the circularly polarized swirl direction is the same as that of the first loop antenna 10a. It is configured to be in the opposite direction to that used when radiating and receiving. That is, in this antenna device 1, by switching which one of the first loop antenna 10a and the second loop antenna 10b is used for transmission / reception of a radio signal as described later, for example, right-handed circular polarization and left-handed circular polarization It is comprised so that the effect of the polarization diversity which switches can be acquired.

  Next, the changeover switch 15 will be described. As shown in FIG. 5, the changeover switch 15 is connected to the handle 16 for the user to operate and the handle 16, and close to the loop antennas 10 a and 10 b on the upper side of the loop antennas 10 a and 10 b of the antenna device 1. And a cover plate (plate member) 17 arranged so as to do. In the present embodiment, as shown in FIG. 4, a slide rail 51 a is formed on the upper portion of the front panel 51 so that the left and right sides are in the longitudinal direction along the upper portions of the loop antennas 10 a and 10 b. . Around the slide rail 51a, for example, a recess 51b is provided which is stepped down from the surface of the housing 50, and the handle 16 is disposed on the recess 51b so as to be slidable right and left along the slide rail 51a. .

  The cover plate 17 is a plate-like member made of a conductor such as iron or aluminum, and is substantially parallel to the loop surfaces of the loop antennas 10a and 10b behind the handle 16 inside the housing 50. It is arranged with a proper posture. The cover plate 17 is connected to the handle 16. Therefore, for example, when the user slides the handle 16 left and right, the cover plate 17 is displaced together with the handle 16 inside the housing 50. In the present embodiment, the cover plate 17 is formed in a substantially rectangular shape that can almost cover one loop surface of the loop antennas 10a and 10b when viewed from a direction perpendicular to the loop surface. That is, the antenna device 1 is configured so that the positional relationship between the cover plate 17 and the loop antennas 10a and 10b can be changed by sliding the handle 16. In the slide rail 51a, the first loop antenna 10a is substantially covered by the cover plate 17 when the handle 16 is slid to the left most, and the second loop antenna 10b is covered by the cover plate when the handle 16 is slid to the most right. It is formed so as to be substantially covered.

  In the present embodiment, the user operates the changeover switch 15 to change the positional relationship between the cover plate 17 and the loop antennas 10a and 10b, so that either the first loop antenna 10a or the second loop antenna 10b is a radio signal. It is possible to switch whether to use for transmission / reception. FIGS. 7A and 7B show the antenna device 1 when the loop antennas 10a and 10b are switched. Also in FIG. 7, illustration of the front panel 51 is omitted. For example, when the first loop antenna 10a is used for transmission / reception of a radio signal, as shown in FIG. 7A, the user operates the handle 16 to set the changeover switch 15 to the right of the antenna device 1, that is, the second. Slide in the direction in which the loop antenna 10b is arranged. By operating the changeover switch 15 in this manner, the cover plate 17 is positioned so as to be close to the second loop antenna 10b and cover the loop surface, so that the inductance of the second loop antenna 10b is reduced and the matching is shifted. It becomes a state. On the other hand, since the cover plate 17 is not close to the first loop antenna 10a, the first loop antenna 10a is matched. 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 not performed from the second loop antenna 10b. No radio waves are emitted, and radio waves are emitted only from the matched first loop antenna 10a.

  For example, in order to switch the antenna used for radio signal transmission / reception from the first loop antenna 10a to the second loop antenna 10b, the user operates the changeover switch 15 as shown in FIG. Is moved to the left, that is, in the direction in which the first loop antenna 10a is disposed. Thereby, the first loop antenna 10a can be covered with the cover plate 17, the matching of the first loop antenna 10a can be shifted, and the matching of the second loop antenna 10b can be taken. 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, the matching state of the loop antennas 10a and 10b can be changed by changing the positional relationship between the cover plate 17 and the loop antennas 10a and 10b. Therefore, by matching the loop antennas 10a and 10b used for transmission and reception of radio signals and shifting the matching of the other loop antennas 10b and 10a with a simple operation, it is possible to reliably transmit or receive radio signals. The loop antennas 10a and 10b can be switched as possible. In addition, 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. . Furthermore, in this embodiment, since the positional relationship between the cover plate 17 and the loop antennas 10a and 10b is changed mechanically by a user operation, the configuration of the antenna circuit of the antenna device 1 can be simplified. The manufacturing cost of the antenna device 1 can be further reduced.

  In the present embodiment, the configuration of the changeover switch 15 is not limited to the above, and a mechanism for displacing the cover plate 17 can be changed as appropriate. Further, for example, a total of two cover plates 17 may be provided so as to correspond to each of the loop antennas 10a and 10b. Furthermore, a mechanism using a motor or the like that displaces the cover plate 17 by electric power may be provided so that the cover plate 17 can be displaced. In this case, the loop antennas 10a and 10b may be automatically switched under the control of the control unit 13 without any user operation.

  In the present embodiment, the two loop antennas are L-shaped or T-shaped when the two loop antennas are viewed so that their loop surfaces are substantially perpendicular to each other and in the intersecting direction of the mutual loop surfaces. You may arrange | position so that. In that case, by providing two cover plates so that each one corresponds to each loop antenna, the loop antenna can be switched in the same manner as described above. Adopting such an arrangement of two loop antennas makes it difficult for magnetic flux generated in each loop antenna to interfere with other loop antennas, making it difficult for the loop antennas to be coupled together as described above. At this time, instead of the circularly polarized wave as described above, radio waves of vertically polarized waves and horizontally polarized waves can be transmitted and received by the loop antenna, and polarization diversity may be realized.

  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 that case, space diversity, directivity diversity, and the like can be realized by switching and using two loop antennas. Furthermore, the cover plate may cover a part of the loop surface of the loop antenna that is not used for transmitting and receiving radio signals. Thus, even if a part of the loop surface of the loop antenna is covered, the matching of the loop antenna can be shifted, and the loop antenna can be switched.

  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 configuration of the antenna device, the manufacturing cost of the transmitter, the remote control device, the control device, or the like can be reduced and communication can be reliably performed.

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 perspective view which shows an example of the antenna apparatus used for the said illumination control system. The perspective view which shows the inside of the said antenna apparatus. The figure which shows the circuit structure of the said antenna apparatus. (A) is a perspective view which shows the time of using the 1st loop antenna of the said antenna apparatus, (b) is a perspective view which shows the time of using the 2nd loop antenna of the same antenna apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 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 (matching means) )
11b Second matching circuit section (matching means)
12 wireless circuit part 13 control part 15 changeover switch (antenna cover means)
17 Cover plate (plate-like member)

Claims (1)

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;
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,
An antenna cover means having a plate-like member made of a conductor, and configured to be able to change the positional relationship between the plate-like member and each of the loop antennas;
By changing the positional relationship between the plate-like member and the loop antenna by the antenna cover means, the radio circuit unit is configured to be able to switch a loop antenna used for transmission and / or reception of a radio signal. An antenna device.

Images