JP2008294748A - Radio equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio equipment capable of improving an antenna characteristic more when switching and using a loop antenna and a monopole antenna. <P>SOLUTION: The radio equipment switches a first mode for making an antenna element formed in a loop shape operate as a monopole antenna and a second mode for making the antenna element operate as a loop antenna. In addition, the antenna element has a first end point and a second end point, and the radio equipment contains a first switch that short-circuits the first end point and the second end point in the first mode and does not short-circuit the first end point and the second end point in the second mode, and a second switch that makes switching to a first path for feeding the power to the antenna element with the first end point as a feed point in the first mode and makes switching to a second path for feeding the power to the antenna element with the first end point and the second end point as feed points in the second mode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radio apparatus that transmits and receives radio signals by switching between a first mode in which an antenna element formed in a loop shape operates as a monopole antenna and a second mode in which the antenna element operates as a loop antenna.

  2. Description of the Related Art Conventionally, there has been proposed a radio apparatus using a diversity system that switches between receiving an electric field component included in a radio signal or receiving a magnetic field component in accordance with the reception status of the radio signal (for example, Patent Document 1). reference).

  In the wireless device disclosed in Patent Document 1, wireless signals are transmitted and received by a diversity method using one antenna element. Specifically, in such a wireless device, a feeding point is provided at one end of an antenna element formed in a loop shape, and a switch for switching between grounding and opening is provided at the other end. Further, in such a wireless device, when the switch is opened, the antenna element operates as a monopole antenna having high sensitivity of the electric field included in the wireless signal, and when the switch is grounded, the loop having high magnetic field sensitivity. Operates as an antenna.

Therefore, in such a wireless device, it is possible to switch between antenna characteristics with high electric field sensitivity and antenna characteristics with high magnetic field sensitivity by using one antenna element. Further, since each antenna characteristic is different, a higher diversity effect can be obtained.
JP 2001-326514 A

  However, in the wireless device having the above-described configuration, for example, when one end of an antenna element is used as a feeding point and the other end is opened and operated as a single wavelength monopole antenna, the current distribution from the feeding point to the middle point of the antenna element is The current distribution from the midpoint to the open point (the other end) is in reverse phase.

  In addition, since the antenna element described above is formed in a loop shape, in such a wireless device, the current distribution from the feeding point to the middle point of the antenna element and the current distribution from the middle point to the open point (the other end) May cancel each other, and the antenna characteristics as a monopole antenna may be greatly degraded.

  As described above, in the wireless device described above, it is possible to switch between the loop antenna and the monopole antenna. However, even if the antenna is switched, the antenna characteristics may deteriorate, and sufficient diversity is achieved. There was a problem that the effect could not be obtained.

  Therefore, the present invention has been made in view of the above points, and an object of the present invention is to provide a radio apparatus capable of further improving antenna characteristics when switching between a loop antenna and a monopole antenna.

  The first feature of the present invention is that radio signals are transmitted and received by switching between a first mode in which an antenna element formed in a loop shape operates as a monopole antenna and a second mode in which the antenna element operates as a loop antenna. The antenna element has a first end point and a second end point, short-circuits the first end point and the second end point in the first mode, and the second end point. A first switch that does not short-circuit the first end point and the second end point in the mode; and a first path that feeds power to the antenna element using the first end point as a feed point in the first mode; And a second switch that switches to a second path that feeds power to the antenna element using the first end point and the second end point as feed points in two modes. It is.

  According to such a feature, the wireless device short-circuits the first end point and the second end point of the antenna element in the first mode that operates as a monopole antenna. In the wireless device, the first end point is used as a feeding point to switch to the first path that feeds the antenna element. That is, when operating the antenna element as a monopole antenna, the antenna element is fed in phase from the first end point. Therefore, since the current excited in the antenna element flows from the first end point in the clockwise direction of the antenna element and from the first end point in the counterclockwise direction of the antenna element, these currents are combined and strengthened. The antenna characteristics when operating as a monopole antenna are improved. Thus, according to such a radio apparatus, it is possible to further improve the antenna characteristics when switching between the loop antenna and the monopole antenna.

  The second feature of the present invention relates to the first feature, and is summarized in that the antenna element is fed in phase with the first mode.

  A third feature of the present invention relates to the first feature or the second feature, further comprising a converter for converting an unbalanced signal from a power feeding side into a balanced signal, wherein the second path includes the first end point and the first end point. This is a path for feeding power to the second end point via the converter, and the gist of the antenna element is balanced feeding in the second mode.

  According to such a feature, in the wireless device, in the second mode in which the antenna element operates as a loop antenna, the antenna element is switched to the first endpoint and the second path that feeds power to the second endpoint via the converter. The balanced power is supplied. Therefore, a balanced signal having a symmetrical current distribution is fed to each of the first end point and the second end point, so that, for example, an excess current is prevented from flowing to the ground side of the housing, etc. The antenna characteristics during operation can be improved.

  The fourth feature of the present invention is that a radio signal is switched by switching between a first mode in which an antenna element formed in a loop shape operates as a monopole antenna and a second mode in which the antenna element operates as a loop antenna. A wireless device for transmitting and receiving, wherein the antenna element has a first end point where a feeding point is provided and a second end point, and the first end point and the second end point in the first mode. The gist of the invention is to include a switch that short-circuits the end point and grounds the second end point in the second mode.

  According to this feature, in the first mode in which the wireless device operates as a monopole antenna, the first end point and the second end point are short-circuited instead of opening the second end point as in the prior art. . Further, in the first mode, the wireless device supplies in-phase power to the antenna element from the first end point. Therefore, since the current excited in the antenna element flows from the first end point in the clockwise direction of the antenna element and from the first end point in the counterclockwise direction of the antenna element, these currents are combined and strengthened. The antenna characteristics when operating as a monopole antenna are improved. Thus, according to such a radio apparatus, it is possible to further improve the antenna characteristics when switching between the loop antenna and the monopole antenna.

 According to the characteristics of the present invention, it is possible to provide a radio apparatus capable of further improving antenna characteristics when switching between a loop antenna and a monopole antenna.

(Configuration of the terminal device according to the first embodiment of the present invention)
A first embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic. The configuration of the terminal device 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows an overall schematic configuration of a terminal device 1 according to the present embodiment. The terminal device 1 is assumed to be a device that receives or transmits a radio signal, such as a television, a radio, a mobile phone, or a PDA.

  As illustrated in FIG. 1, the terminal device 1 according to the present embodiment includes an antenna element A, a wireless device 10, a transmission / reception circuit 40, and a control circuit 50. In addition, although the terminal device 1 is provided with other devices, such as a power supply device, the description regarding the other device is abbreviate | omitted in this embodiment. Further, the wireless device 10, the transmission / reception circuit 40, and the control circuit 50 may be provided on the substrate 100.

  The antenna element A is composed of a conductor formed in a loop shape. In the present embodiment, it is assumed that the electrical length of the antenna element A is about one wavelength of the frequency used in the radio signal. Note that the electrical length of the antenna element A is not limited to this.

  The wireless device 10 transmits and receives wireless signals via the antenna element A. The radio apparatus 10 outputs a signal from the antenna element A to the control circuit 50 and outputs a signal from the control circuit 50 to the antenna element A. Further, the radio apparatus 10 switches between a first mode in which the antenna element A operates as a monopole antenna and a second mode in which the antenna element A operates as a loop antenna in response to a switching control signal from the control circuit 50. The wireless signal is transmitted and received through the antenna element A. The operation of the wireless device 10 in the first mode and the second mode will be described in detail later.

  Further, in the terminal device 1, the antenna element A is controlled to function as a monopole antenna or a loop antenna by the function of the wireless device 10, and wireless signals are transmitted / received by a diversity method.

  The transmission / reception circuit 40 inputs or outputs a transmission / reception signal to / from the wireless device 10. Here, the transmission / reception signal indicates a signal received by the antenna element A or a signal transmitted from the antenna element A. The transmission / reception circuit 40 executes the wireless signal processing of the transmission / reception circuit 40 and the like.

  The control circuit 50 outputs a switching control signal to the wireless device 10 according to the quality of the transmission / reception signal received by the transmission / reception circuit 40. Here, the switching control signal is a signal instructing switching to the first mode in which the antenna element A operates as a monopole antenna, or instructing switching to the second mode in which the antenna element A operates as a loop antenna. is there. The control circuit 50 periodically monitors the reception quality such as the reception level and bit error rate of the transmission / reception signal received by the transmission / reception circuit 40. Then, the control circuit 50 provides a switching control signal for instructing switching to the other mode when the reception quality decreases below the threshold value when using either the first mode or the second mode. Transmit to the wireless device 10.

(Configuration of the wireless device 10 according to the first embodiment)
Next, the configuration of the wireless device 10 will be described with reference to the drawings. Hereinafter, portions related to the present invention will be mainly described. Therefore, it should be noted that the radio apparatus 10 may have a function that is not shown or a description that is omitted in order to realize a function of switching between a loop antenna and a monopole antenna.

  Here, FIG. 2A shows the configuration of the wireless device 10 in the first mode in which the antenna element A operates as a monopole antenna, and FIG. 2B shows the antenna element A as a loop antenna. The structure of the radio | wireless apparatus 10 in the 2nd mode which operate | moves as is shown. Hereinafter, the configuration of the wireless device 10 will be described with reference to FIGS. In the figure, the vertical direction is assumed to be the vertical direction, and the horizontal direction is assumed to be the horizontal direction.

  As illustrated in FIGS. 2A and 2B, the wireless device 10 includes a power feeding unit 12, a changeover switch 14, a changeover switch 18, and a balanced / unbalanced converter 16. The antenna element A has an end point Q1 (first end point) and an end point Q2 (second end point). Note that the end point Q1 and the end point Q2 are provided symmetrically from the center of the antenna element A.

  The power feeding unit 12 functions as a connection terminal connected to the transmission / reception circuit 40. In addition, the power feeding unit 12 outputs a reception signal from the antenna element A to the transmission / reception circuit 40 side, and outputs a transmission signal from the transmission / reception circuit 40 to the antenna element A side. In the present embodiment, the case where the power feeding unit 12 is electrically connected to the antenna element A will be described as power feeding.

  The changeover switch 14 is a switch that can be electrically opened and closed, and for example, a PIN diode switch or the like may be used. The changeover switch 14 switches to the first path for feeding power to the antenna element A with the end point Q1 as a feeding point in the first mode, and feeds the antenna element with the end points Q1 and Q2 as feeding points in the second mode. Switch to.

  Specifically, when a switching control signal instructing switching to the first mode is input to the wireless device 10, the switching switch 14 is connected to the connection point b1 as illustrated in FIG. In addition, when the changeover switch 14 is connected to the connection point b1, power is supplied from the power supply unit 12 to the end point Q1 of the antenna element A. As described above, the path from the power feeding unit 12 to the end point Q1 via the changeover switch 14 is the first path.

  Further, when a switching control signal instructing switching to the second mode is input to the wireless device 10, the switching switch 14 is connected to the connection point b2, as shown in FIG. Further, when the changeover switch 14 is connected to the connection point b2, power is supplied from the power supply unit 12 to the end points Q1 and Q2 of the antenna element A via the balanced / unbalanced converter 16. As described above, the path that feeds power from the power feeding unit 12 to the end points Q1 and Q2 is the second path. In the present embodiment, the changeover switch 14 constitutes a second switch.

  The changeover switch 18 is an electrically switchable switch, and for example, a PIN diode switch or the like may be used. The changeover switch 18 short-circuits the end point Q1 and the end point Q2 in the first mode, and does not short-circuit the end point Q1 and the end point Q2 in the second mode.

  Specifically, when a switching control signal instructing switching to the first mode is input to the wireless device 10, the switching switch 18 is connected to the connection point a as illustrated in FIG. Moreover, the end point Q1 and the end point Q2 of the antenna element A are short-circuited when the changeover switch 18 is connected to the connection point a. In this way, the wireless device 10 short-circuits the end point Q1 and the end point Q2, and supplies power to the antenna element A by supplying power with the end point Q1 as a feeding point.

  Further, when a switching control signal for instructing switching to the second mode is input to the wireless device 10, the switching switch 18 opens from the connection point a as shown in FIG. In this way, the wireless device 10 opens the end point Q1 and the end point Q2, and feeds power from the power feeding unit 12 through the balanced / unbalanced converter 16 as the feeding points to the antenna element A. Power is fed to the balance. In the present embodiment, the changeover switch 18 constitutes a first switch.

  The balanced / unbalanced converter 16 converts an unbalanced signal from the power supply side into a balanced signal. Specifically, in the wireless device 10, an unbalanced signal is output from the power feeding unit 12 side. In the second mode in which the antenna element A operates as a loop antenna, the end point Q1 and the end point Q2 are symmetrical with respect to the antenna element A and are electrically balanced. Therefore, if unbalanced power is supplied to the end point Q1 and the end point Q2 in the second mode, excess current flows through the ground-side casing and the magnetic field sensitivity of the antenna element A is reduced. Therefore, in the wireless device 10, by supplying balanced power to the end point Q1 and the end point Q2, it is possible to prevent an excess current from flowing through the ground-side casing and to improve the magnetic field sensitivity of the antenna element A. A balun or the like is assumed as an example of the balanced / unbalanced converter 16. In the present embodiment, the balanced / unbalanced converter 16 constitutes a converter.

(Operation / Effect of Wireless Device 10 according to First Embodiment)
According to the wireless device 10 according to the present embodiment, the end point Q1 and the end point Q2 of the antenna element are short-circuited in the first mode that operates as a monopole antenna. Further, the wireless device switches to the first path for feeding power to the antenna element with the end point Q1 as a feeding point. That is, in the wireless device, in-phase power feeding is performed to the end point Q1 of the antenna element A when the antenna element is operated as a monopole antenna.

  Here, when the wireless device 10 operates in the first mode, as shown in FIG. 2A, a current 31 flows from the end point Q1 in the counterclockwise direction of the antenna element A to the antenna element A. A current 32 flows in the clockwise direction of the antenna element A. Further, in such a radio apparatus 10, since the in-phase power is supplied to the antenna element A, the current distributions of the currents 31 to 32 are combined and strengthened, and the combined current CV equivalent to the case where two half-wave monopole antennas are provided. Can be generated in the vertical direction. Thereby, in this radio | wireless apparatus 10, since the sensitivity of the electric field of the antenna element A can be improved, the antenna characteristic at the time of operating the antenna element A as a monopole antenna can be improved.

  Further, according to the wireless device 10, the end point Q1 and the end point Q2 of the antenna element are opened in the second mode in which the antenna element A operates as a loop antenna. Further, the wireless device 10 switches to the second path that supplies power to the end point Q1 and the end point Q2 via the balanced / unbalanced converter 16. That is, in the wireless device 10, balanced power is supplied to the end point Q1 and the end point Q2 of the antenna element A.

  Here, when the wireless device 10 operates in the second mode, as shown in FIG. 2B, a current 41 flows in the antenna element A from the right end in the counterclockwise direction of the antenna element A, and the antenna element starts from the right end. A current 42 flows in the clockwise direction of A. Further, in the wireless device 10, the balanced power is supplied to the end point Q1 and the end point Q2, thereby preventing excess current from flowing to the ground-side casing, strengthening the current distribution of each of the currents 41 to 42, and combining the combined currents. CH can be generated in the horizontal direction. Thereby, in this radio | wireless apparatus 10, since the sensitivity of the magnetic field of the antenna element A can be improved, the antenna characteristic at the time of making the antenna element A operate | move as a loop antenna can be improved.

  As described above, according to the wireless device 10, the antenna characteristics (including the directivity characteristics and the polarization characteristics) when the one antenna element A is switched to the monopole antenna or the loop antenna are used. Can do. Moreover, the diversity effect in the terminal device 1 can be further improved by improving the antenna characteristics when the antenna element A operates as a monopole antenna and a loop antenna.

(Modification 1)
The present invention is not limited to the above-described embodiments, and various modifications can be made. In the wireless device 10 according to the present embodiment, in the first mode that operates as a monopole antenna, in-phase power is supplied to the antenna element A, and balanced power is supplied to the antenna element A in the second mode that operates as a loop antenna. Although it is the same as that of 1st Embodiment, the structure of the changeover switch provided in the radio | wireless apparatus 10 differs.

  Specifically, in the wireless device 10 according to the present embodiment, as illustrated in FIGS. 3A to 3B, the changeover switch 14 is not provided, but a changeover switch 20 is provided instead. Here, FIG. 3A shows the configuration of the wireless device 10 in the first mode in which the antenna element A operates as a monopole antenna, and FIG. 3B shows the antenna element A in a loop. The configuration of the wireless device 10 in the second mode that operates as an antenna is shown.

  For example, in the wireless device 10, when a switching control signal instructing switching to the first mode is input, as illustrated in FIG. 3A, the switching switch 18 is connected to the connection point a <b> 1 and the antenna element is connected. The end point Q1 and the end point Q2 are short-circuited. The changeover switch 20 is connected to the connection point c and grounded. With this configuration, in the wireless device 10, power is supplied from the power supply unit 12 to the end point Q <b> 1 via the balanced / unbalanced converter 16. At this time, in the wireless device 10, since the changeover switch 20 is connected to the connection point c and grounded, the antenna element A is supplied with unbalanced power. In the wireless device 10, the antenna element A is set with the end point Q1 as the feeding point. Are fed in phase.

  Further, for example, in the wireless device 10, when a switching control signal instructing switching to the second mode is input, as illustrated in FIG. 3B, the switch 18 is connected to the connection point a2. Moreover, the changeover switch 20 opens with the connection point c. With this configuration, the wireless device 10 supplies balanced power to the antenna element A from the power feeding unit 12 via the balanced / unbalanced converter 16 with the end points Q1 and Q2 as feeding points.

  In the present embodiment, the changeover switch 18 constitutes a first switch that does not short-circuit or short-circuit the end point Q1 and the end point Q2. In the present embodiment, the changeover switch 20 constitutes a second switch that switches between a first path having the end point Q1 as a feeding point and a second path having the end point Q1 and the end point Q2 as feeding points.

  As described above, also in the wireless device 10 according to the present embodiment, the same effects as those of the wireless device 10 according to the first embodiment described above can be obtained.

(Modification 2)
The present invention is not limited to the above-described embodiments, and various modifications can be made. Here, FIG. 4A shows a configuration of the wireless device 10 in the first mode in which the antenna element A operates as a monopole antenna in the present embodiment, and FIG. A configuration of the wireless device 10 in the second mode in which the antenna element A operates as a loop antenna is shown.

  For example, in the wireless device 10, when a switching control signal instructing switching to the first mode is input, as illustrated in FIG. 4A, the switching switch 18 is connected to the connection point a <b> 1 and the antenna element is connected. The end point Q1 and the end point Q2 are short-circuited. The changeover switch 14 is connected to the connection point b1 and supplies power to the end point Q1 of the antenna element. With this configuration, the wireless device 10 supplies the antenna element A with the in-phase power from the power feeding unit 12 via the changeover switch 14 with the end point Q1 as a power feeding point.

  For example, in the wireless device 10, when a switching control signal for instructing switching to the second mode is input, as illustrated in FIG. 4B, the switch 18 is connected to the connection point a2. The changeover switch 14 is connected to the connection point b2. With this configuration, the wireless device 10 supplies balanced power to the antenna element A from the power feeding unit 12 via the balanced / unbalanced converter 16 with the end point Q1 as a feeding point.

  In the present embodiment, the changeover switch 18 constitutes a first switch that does not short-circuit or short-circuit the end point Q1 and the end point Q2. In the present embodiment, the changeover switch 14 constitutes a second switch that switches between the first route and the second route.

  As described above, also in the wireless device 10 according to the present embodiment, the same effects as those of the wireless device 10 according to the first embodiment described above can be obtained.

(Modification 3)
The present invention is not limited to the above-described embodiments, and various modifications can be made. In the wireless device 10 according to the present embodiment, a phase shifter 26 is provided instead of the balanced / unbalanced converter 16 as shown in FIGS.

  The phase shifter 26 is configured to shift (delay) the phase of the input signal by a half wavelength (π). In the wireless device 10, the phase shifter 26 outputs the phase of the input signal shifted by a half wavelength, so that the signal input to the end point Q <b> 2 is out of phase with the signal input to the end point Q <b> 1. . As a result, the wireless device 10 can perform balanced power feeding to the end point Q1 and the end point Q2. The phase shifter 26 may be configured to shift the phase by an odd multiple of a half wavelength (π). Further, when the electrical length of the antenna element A is set to one wavelength, the phase can be shifted by using a line having a length that is an odd multiple of a half wavelength of the electrical length. In the present embodiment, the phase shifter 26 constitutes a converter.

  Here, FIG. 5A shows a configuration of the wireless device 10 in the first mode in which the antenna element A operates as a monopole antenna in the present embodiment, and FIG. A configuration of the wireless device 10 in the second mode in which the antenna element A operates as a loop antenna is shown.

  For example, in the wireless device 10, when a switching control signal instructing switching to the first mode is input, as illustrated in FIG. 5A, the switching switch 18 is connected to the connection point a <b> 1 and the antenna element is connected. The end point Q1 and the end point Q2 are short-circuited. At this time, the changeover switch 14 is opened. With this configuration, the wireless device 10 supplies the antenna element A with the same phase power by supplying power to the antenna element A from the power supply unit 12 via the changeover switch 14 with the end point Q1 as a power supply point.

  For example, in the wireless device 10, when a switching control signal instructing switching to the second mode is input, as illustrated in FIG. 5B, the switch 18 is connected to the connection point a2. At this time, the changeover switch 14 is connected to the connection point b. With this configuration, the wireless device 10 supplies balanced power to the antenna element A from the power feeding unit 12 through the changeover switch 14 and the phase shifter 26 with the end points Q1 and Q2 as feeding points.

  In the present embodiment, the changeover switch 18 constitutes a first switch that does not short-circuit or short-circuit the end point Q1 and the end point Q2. In the present embodiment, the changeover switch 14 constitutes a second switch that switches between the first route and the second route.

  Even if the phase shifter 26 is used as in the wireless device 10 according to the present embodiment, the same effects as those of the wireless device 10 according to the first embodiment described above can be obtained.

(Modification 4)
The present invention is not limited to the above-described embodiments, and various modifications can be made. In the wireless device 10 according to the present embodiment, a phase shifter 26 is provided as shown in FIGS. Moreover, in the radio | wireless apparatus 10 which concerns on this embodiment, the structure of the selector switch provided differs.

  Here, FIG. 6A shows a configuration of the wireless device 10 in the first mode in which the antenna element A operates as a monopole antenna in the present embodiment, and FIG. A configuration of the wireless device 10 in the second mode in which the antenna element A operates as a loop antenna is shown.

  For example, in the wireless device 10, when a switching control signal instructing switching to the first mode is input, as illustrated in FIG. 6A, the switching switch 18 is connected to the connection point a1, and the switching switch 14 is connected. Is connected to the connection point b1. In the wireless device 10, the end point Q1 and the end point Q2 of the antenna element are short-circuited. With this configuration, the wireless device 10 supplies the antenna element A with the common mode power supply from the power supply unit 12 using the end point Q1 as a power supply point.

  Further, for example, in the wireless device 10, when a switching control signal instructing switching to the second mode is input, as illustrated in FIG. 6B, the switch 18 is connected to the connection point a2. The changeover switch 14 is connected to the connection point b2. With this configuration, in the wireless device 10, balanced power is supplied from the power feeding unit 12 to the antenna element A through the changeover switch 14, the phase shifter 26, and the changeover switch 18 with the end points Q 1 and Q 2 as feed points.

  In the present embodiment, the changeover switch 18 and the changeover switch 14 constitute a first switch and a second switch.

  Even if the phase shifter 26 is used as in the wireless device 10 according to the present embodiment, the same effects as those of the wireless device 10 according to the first embodiment described above can be obtained.

(Configuration of radio apparatus according to second embodiment of the present invention)
Next, the configuration of the wireless device 10 according to the second embodiment of the present invention will be described with reference to the drawings. Hereinafter, portions related to the present invention will be mainly described. Therefore, it should be noted that the radio apparatus 10 may have a function that is not shown or a description that is omitted in order to realize a function of switching between a loop antenna and a monopole antenna.

  Here, FIG. 7A shows the configuration of the wireless device 10 in the first mode in which the antenna element A operates as a monopole antenna, and FIG. 7B shows the antenna element A in a loop. The configuration of the wireless device 10 in the second mode that operates as an antenna is shown. Hereinafter, the configuration of the wireless device 10 will be described with reference to FIGS. In the figure, the vertical direction is assumed to be the vertical direction, and the horizontal direction is assumed to be the horizontal direction.

  As illustrated in FIGS. 7A to 7B, the wireless device 10 includes a power feeding unit 12 and a changeover switch 18. The antenna element A has an end point Q1 (first end point) and an end point Q2 (second end point). In the present embodiment, in the wireless device 10, a feeding point is provided at the end point Q1. Note that the end point Q1 and the end point Q2 are provided symmetrically from the center of the antenna element A.

  The power feeding unit 12 functions as a connection terminal connected to the control circuit 50. In addition, the power feeding unit 12 outputs a reception signal from the antenna element A to the transmission / reception circuit 40 side, and outputs a transmission signal from the transmission / reception circuit 40 to the antenna element A side. In the present embodiment, the case where the power feeding unit 12 is electrically connected to the antenna element A will be described as power feeding.

  The changeover switch 18 is an electrically switchable switch, and for example, a PIN diode switch or the like may be used. The changeover switch 18 short-circuits the end point Q1 and the end point Q2 in the first mode, and grounds the end point Q2 in the second mode.

  Specifically, when a switching control signal instructing switching to the first mode is input to the wireless device 10, the switching switch 18 is connected to the connection point a1 as illustrated in FIG. Moreover, the end point Q1 and the end point Q2 of the antenna element A are short-circuited when the changeover switch 18 is connected to the connection point a1. As described above, in the first mode in which the antenna element A operates as a monopole antenna, the wireless device 10 short-circuits the end point Q1 and the end point Q2 and supplies power using the end point Q1 as a feeding point, thereby providing the antenna element A with the same phase. Supply power.

  In addition, when a switching control signal instructing switching to the second mode is input to the wireless device 10, the switching switch 18 is connected to the connection point a2 as illustrated in FIG. 7B. Further, the end point Q2 of the antenna element A is grounded by connecting the changeover switch 18 to the connection point a2. Thus, in the second mode in which antenna element A operates as a loop antenna, radio apparatus 10 opens end point Q1 and end point Q2, and feeds power to antenna element A using end point Q1 as a feed point.

(Operation / Effect of Wireless Device According to Second Embodiment)
According to the wireless device 10 according to the present embodiment, the end point Q1 and the end point Q2 are short-circuited instead of opening the end point Q2 in the first mode of operating as a monopole antenna as in the prior art. Therefore, when the antenna element A is operated as a monopole antenna, in-phase power is supplied from the end point Q1 to the antenna element A. Therefore, the current excited in the antenna element flows from the end point Q1 in the clockwise direction of the antenna element and from the end point Q1 in the counterclockwise direction of the antenna element. A combined current equivalent to the case of providing two monopole antennas can be generated in the vertical direction. Thereby, in this radio | wireless apparatus 10, since the sensitivity of the electric field of the antenna element A can be improved, the antenna characteristic at the time of operating the antenna element A as a monopole antenna can be improved. As described above, according to the wireless device 10, it is possible to further improve the antenna characteristics when switching between the loop antenna and the monopole antenna.

(Other embodiments)
As described above, the contents of the present invention have been disclosed through one embodiment of the present invention. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments will be apparent to those skilled in the art. For example, in the above-described embodiment, the changeover switch 14 illustrated in FIG. 5 may be provided between the phase shifter 26 and the connection point a <b> 2 of the changeover switch 18. Thus, in the above-described embodiment, the changeover switch can be variously changed.

  In addition, the operation and effect of each embodiment and each modification are merely a list of the most preferable operations and effects resulting from the present invention, and the operation and effect according to the present invention are described in each embodiment and each modification. It is not limited to the ones. As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a schematic block diagram which shows the structure of the terminal device which concerns on 1st Embodiment of this invention. (A) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on 1st Embodiment of this invention as a monopole antenna. (B) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on 1st Embodiment of this invention as a loop antenna. (A) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 1 of this invention as a monopole antenna. (B) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 1 of this invention as a loop antenna. (A) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 2 of this invention as a monopole antenna. (B) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 2 of this invention as a loop antenna. (A) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 3 of this invention as a monopole antenna. (B) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 3 of this invention as a loop antenna. (A) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 4 of this invention as a monopole antenna. (B) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on the modification 4 of this invention as a loop antenna. (A) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on 2nd Embodiment of this invention as a monopole antenna. (B) It is a figure which shows the structure at the time of operating the radio | wireless apparatus which concerns on 2nd Embodiment of this invention as a loop antenna.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Terminal device, 10 ... Radio | wireless apparatus, 12 ... Power feeding part, 14 ... Changeover switch, 16 ... Balance / unbalance converter, 18 ... Changeover switch, 20 ... Changeover switch, 26 ... Phase shifter, 31-32 ... Current 41-42 ... current, 40 ... transmission / reception circuit, 50 ... control circuit, 100 ... substrate, A ... antenna element, CH ... composite current, CV ... composite current, Q1 ... end point, Q2 ... end point, a ... connection point, a1 ... connection point, a2 ... connection point, b ... connection point, b1 ... connection point, b2 ... connection point, c ... connection point,

Claims (4)

A radio apparatus for transmitting and receiving radio signals by switching between a first mode in which an antenna element formed in a loop shape operates as a monopole antenna and a second mode in which the antenna element operates as a loop antenna,
The antenna element has a first end point and a second end point;
A first switch that short-circuits the first end point and the second end point in the first mode, and that does not short-circuit the first end point and the second end point in the second mode;
In the first mode, the first end point is used as a feeding point to switch to a first path that feeds the antenna element. In the second mode, the first end point and the second end point are used as feeding points to the antenna element. A wireless device comprising: a second switch that switches to a second path for feeding power. The radio apparatus according to claim 1, wherein the antenna element is fed in-phase in the first mode. A converter for converting an unbalanced signal from the power supply side into a balanced signal;
The second path is a path that feeds power to the first end point and the second end point via the converter,
The radio apparatus according to claim 1, wherein the antenna element is balancedly fed in the second mode. A radio apparatus for transmitting and receiving radio signals by switching between a first mode in which an antenna element formed in a loop shape operates as a monopole antenna and a second mode in which the antenna element operates as a loop antenna,
The antenna element has a first end point where a feeding point is provided, and a second end point,
A radio apparatus comprising: a switch that short-circuits the first end point and the second end point in the first mode and grounds the second end point in the second mode.

Images