JP2005333203A - Antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna capable of performing optimum impedance matching by making a feeding point position arbitrarily variable in order to select more resonance frequency bands or an arbitrary frequency band without requiring an extra installation area, and also, capable of conducting high-speed impedance switching. <P>SOLUTION: A ribbon-shaped spring structure 17 is composed of two kinds or more of metal layers having different thermal expansion coefficients, generates heat by energization, performs deformation motion, and is constituted to the feeding point side of a feeder line 15A. One end of the ribbon-shaped spring structure 17 comes into contact with the feeding point position in a prescribed frequency band on a patch antenna 13. The optimum impedance matching is performed by the deformation motion of the ribbon-shaped spring structure 17 generated by energization during the transmission and reception of a wireless signal in the prescribed frequency band of the patch antenna 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna used for a wireless LAN, a mobile phone, and the like.

  In recent years, wireless LAN has begun to spread to offices and homes, and is becoming an important information infrastructure. In a wireless LAN, it is often connected to a PC or a mobile device via a wireless LAN card, and it is important to make the antenna smaller and lower in posture than a mobile phone. In addition, antennas have a wide range of commonly used radio frequency bands, and are required to have a configuration that enables communication in a plurality of frequency bands such as a 2 GHz band and a 5 GHz band so that they can be interconnected.

Patch antennas are often used as small and low-profile antennas. For example, in order to match the impedance of the rectangular patch antenna with the feed line, the following conditions must be considered.
That is, as shown in FIG. 19, the wavelength in the free space of radio waves input to and output from the rectangular patch antenna Pa on the dielectric di is λ ₀ , the characteristic admittance of the patch antenna Pa as a line is Y ₀ , and the patch antenna The length of Pa is L (x direction), the width is W (y direction), the position of the feeding point is Lf from the patch end, the distance (thickness) between the patch antenna Pa and the ground plane Gr is h, the patch antenna Pa and the ground plane Assuming that the dielectric constant of the dielectric di provided between Gr is εr, the following equation needs to be satisfied in order for the patch antenna Pa to resonate.

[Equation 1]
L = λg / 2
λg = λ ₀ / sqrt (εr)

  In addition, the input admittance Yin of the patch antenna Pa at resonance is expressed by the following equation (reference: Hiroyuki Arai, “New Antenna Engineering”, General Electronic Publisher, p63).

[Equation 2]
Yin = (2G) / {cos ^ 2 (β · Lf)
+ (G / Y ₀ ) ^ 2 · sin ^ 2 (β · Lf)}
G = (W / λ ₀ ) ^ 2/90
Y ₀ = (sqrt (εr) · h) / (120π · W)
β = 2π / λg

That is, in order to make Yin equal to the admittance Yf of the feed line (impedance matching) so that no signal reflection occurs at the patch antenna Pa, the position Lf of the feed point is adjusted according to the resonance wavelength λ ₀ . Of course, if λ ₀ that is the wavelength used by the patch antenna Pa changes, the position Lf of the feed point must also change. Even when the shape of the patch antenna Pa is other than rectangular, there is no substitute for changing to an optimum feeding point according to the wavelength used.

That is, when trying to communicate a plurality of frequency bands using the same patch antenna Pa, a plurality of feeding points must be prepared.
In such a conventional example, a plurality of feeding points are provided in one patch antenna, and power distribution and combination is performed by the power distribution and combination circuit 17, so that a plurality of resonance states can be selected by one patch antenna and directivity can be selected. A patch antenna device that performs control is known (for example, see Patent Document 1).

  In addition, although not a patch antenna, an internal multiband antenna is known which can resonate in a plurality of frequency bands by preparing three types of radiating elements (antennas) according to the frequency band and switching the antennas. (For example, refer to Patent Document 2).

JP 2000-312112 A JP 2003-124730 A

  However, in the conventional example described in Patent Document 1, since the position of the feeding point is fixed in advance, there is a problem that the resonating frequency band is fixedly limited to the preset frequency band.

  Further, in the conventional example described in Patent Document 2, since a plurality of radiating elements (antennas) are prepared in advance, there is a problem that the installation area is increased correspondingly, which is contrary to the demand for downsizing.

  On the other hand, if a wideband antenna such as a discone antenna is used, a plurality of frequency bands can be transmitted and received. However, wideband antennas are often three-dimensional and difficult to lower. For this reason, there is a demand for a patch antenna that is a planar antenna that can be lowered and miniaturized, and that the impedance can be made variable so that impedance matching can be achieved in a plurality of frequency bands.

  As an example, there is an attempt to change the impedance by moving a movable feeding point that is electromagnetically coupled, change the feeding phase and feeding power to the array antenna, and perform directivity control. Considering motors for movement, there is a problem that high-speed impedance switching cannot be expected and the size becomes large.

As already described, in the patch antenna, the input impedance changes depending on the feeding position. Since there is only one optimum feeding position that matches the feeding line according to the frequency of the input / output signal, if the feeding position is fixed, the input impedance of the antenna varies due to the change in the frequency of the input / output signal.
It is good if the frequency change is small, but if there is a large frequency change in the input / output signal (wireless signal), for example, the fundamental frequency is doubled, the input impedance of the patch antenna will fluctuate and impedance matching with the feeder line will occur. There is a problem that radio waves (wireless signals) cannot be efficiently transmitted and received from the patch antenna.

  In addition, the patch antenna must be easy to manufacture including the feeding line and feeding point, and feeding is required to be stable and reliable. Moreover, it is desirable that the patch antenna itself be a “smart antenna” that can select an appropriate impedance in accordance with the frequency.

  The present invention solves the above-mentioned problems of the prior art, and in order to select more frequency bands to resonate or any frequency band to resonate, the feed point position can be arbitrarily varied to achieve optimum impedance matching. It is an object of the present invention to provide an antenna that can be used, and that does not require an extra installation area, does not hinder downsizing, and also enables high-speed impedance switching.

  To achieve the above object, according to the present invention, a patch antenna capable of transmitting and receiving radio signals in a plurality of frequency bands is contacted with a feed line that can mechanically change a feed point position, and the feed line is mechanically connected. By performing a deformation motion, optimum impedance matching is performed when transmitting and receiving radio signals in a predetermined frequency band of the patch antenna.

  In addition, the present invention has a ribbon-like spring structure that is composed of two or more types of metal layers having different thermal expansion coefficients on the feeding point side of the feeder line and generates heat and deforms when energized. One end is in contact with a feeding point position of a predetermined frequency on the patch antenna, and optimal impedance matching is performed when the patch antenna transmits / receives a radio signal of a predetermined frequency band by deformation movement of the ribbon-like spring structure by energization. Features.

  In addition, the present invention provides a feed line that includes a dielectric layer and a first electrostatic electrode layer and can be mechanically deformed and can change a feed point position with respect to a patch antenna capable of transmitting and receiving radio signals of a plurality of frequencies. And a second electrostatic electrode layer is provided adjacent to the patch antenna on the same surface on which the patch antenna is placed, and a voltage applied between the first and second electrostatic electrode layers is provided. The feeding line is deformed and moved by an induced electrostatic force to perform optimum impedance matching when transmitting and receiving a radio signal in a predetermined frequency band of the patch antenna.

  Further, the present invention is characterized in that a ribbon-like spring structure including the first electrostatic electrode layer capable of mechanically deforming with the electrostatic force is configured with respect to a feeding point side of the feeding line. To do.

  Further, according to the present invention, the feeding point side of the feeding line or the feeding point side of the ribbon-like spring structure is joined in advance to the feeding point position of a predetermined frequency band on the patch antenna with a conductive binder. It is characterized by that.

  Further, the present invention is characterized in that a high frequency cut coil is provided in an energization circuit for supplying the voltage between the first and second electrostatic electrode layers.

  Further, the present invention is optimal for transmitting and receiving radio signals in a predetermined frequency band of the patch antenna by applying pressure to the movable contact of the patch antenna from the feeder line or the ribbon-like spring structure of the feeder line. Impedance matching is performed.

  Further, the present invention is characterized in that the feeding line or the ribbon-like spring structure of the feeding line and the movable contact of the patch antenna are capacitively coupled through an insulating film having low adhesion.

  Further, the present invention provides a frequency determination circuit for determining a frequency of a radio signal to be received or transmitted between the power supply line and the receiver and the transmitter, and the frequency determination circuit and the power supply line or the The position of the feeding point by controlling the deformation motion of the feeding line or the ribbon-like spring structure of the feeding line based on the frequency determined by the frequency judgment circuit with respect to the ribbon-like spring structure of the feeding line Therefore, there is provided a feed position control circuit that performs optimum impedance matching when transmitting and receiving radio signals in a predetermined frequency band of the patch antenna.

  According to the present invention, in order to select more frequency bands to resonate or to select any frequency band to resonate, it is possible to arbitrarily change the feeding point position to achieve optimum impedance matching, and to install an extra installation. It does not require an area, does not hinder downsizing, and enables high-speed impedance switching.

  That is, by changing the impedance using a feed line that can move the feed point, the input impedance of the patch antenna can be matched to the feed line even if the operating frequency band of the patch antenna changes. Band radio waves can be transmitted and received.

  In addition, since the feeding point position of the patch antenna is changed using a ribbon-like spring structure that has an arch shape and deforms and moves with a difference in thermal expansion coefficient, the feeding point moving mechanism is made monolithic. An inexpensive patch antenna suitable for mass production can be realized.

  In addition, when using a ribbon-like spring structure that moves (deforms) by electrostatic force, the feed point moving mechanism is monolithic, so that an inexpensive patch antenna suitable for mass production can be realized.

  In addition, since the movable feeding point is brought into contact by applying pressure, contact of the feeding point is ensured, so that a stable patch antenna having a characteristic with little change with time can be realized.

  In addition, since the movable feeding point is capacitively coupled through an insulating film with low adhesion, the feeding point is prevented from coming into close contact, so that a patch antenna having a long life can be realized.

  In addition, the ribbon-shaped spring structure is automatically variably moved (deformation motion) to a position that matches the input impedance of the patch antenna in accordance with the reception frequency band (transmission frequency band) determined by the frequency determination circuit. Since impedance is automatically matched for each frequency band (transmission frequency band), a patch antenna capable of transmitting and receiving a plurality of frequency bands can be configured.

  Hereinafter, the antennas according to the first to sixth embodiments of the present invention will be sequentially described.

  First, although not shown in detail, the antenna according to the first embodiment (corresponding to claim 1) of the present invention is a radio of a plurality of frequency bands formed (placed) on the dielectric di on the ground plane Gr. A patch antenna capable of transmitting and receiving signals (for example, radio waves) is configured to contact a feed line that can mechanically change the feed point position.

  For example, the power supply line deforms by heat generation due to energization or application of pressure based on driving of a predetermined pressure application means, and mechanically changes the position of the power supply point.

  By changing the feeder line mechanically, the input impedance of the patch antenna is changed to an optimum value according to the frequency band in which the radio signal to be transmitted and received resonates. In other words, optimal impedance matching is possible by mechanically changing the feeder line.

  In other words, if the position of the feed point on the patch antenna can be moved mechanically (variable movement), the input impedance can be changed, so that the resonance condition of the patch antenna itself may change due to changes in the input / output frequency of the radio signal, Even if the impedance of the feeder line varies, impedance matching between the feeder line and the patch antenna can be achieved. Note that the patch shape of the patch antenna may be rectangular, circular, or any other shape.

  Next, an antenna according to a second embodiment (corresponding to claim 2) of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a main configuration of an antenna 11 according to the present embodiment.

  As shown in FIG. 1, the antenna 11 of the present example is formed by forming a dielectric di on the ground plane Gr, and forming (installing) a patch antenna 13 having a predetermined planar shape at a predetermined position on the dielectric di. Although not shown in detail, the patch antenna 13 has a configuration capable of transmitting and receiving radio signals (for example, radio waves) in a plurality of frequency bands. The patch shape of the patch antenna 13 may be any of a rectangular shape, a circular shape, and any other shape.

  A feeding line 15A is formed (installed) at another predetermined position on the dielectric di, that is, at a position along, for example, a central axis (not shown) of the patch antenna 13. The feed line 15A is made of, for example, Al on the dielectric di. A ribbon-like spring structure 17 that can be deformed by energization, which will be described later, is configured at one end of the power supply line 15 (one end on the power supply point side). The oscillator 18 that outputs a high-frequency signal is connected between the ground plane Gr and the feeder line A15.

  As shown in FIG. 2, the ribbon strip spring structure (hereinafter referred to as ribbon structure) 17 is formed of two or more kinds of thin metal layers having different coefficients of thermal expansion, and generates heat that is deformed like a bimetal by heat generated by energization. The body is formed in an arch shape. In the ribbon structure 17, for example, the lowermost thin film layer 21 is made of Al, the upper thin film layer 23 is made of SiN, and the uppermost thin film layer 25 is made of Pt as a heating element. The power supply line 15A is also Al, for example, and is integrally formed with the lowermost thin film layer (Al) 21 in advance.

  The ribbon structure 17 has an arch shape and straddles the separation width between the feeding line 15 </ b> A and the patch antenna 13, and the lowermost thin film layer (Al) 21 at the tip thereof contacts a predetermined feeding point position on the patch antenna 13. (It may be fixed).

  On the other hand, as shown in FIG. 3, the uppermost thin film layer (Pt) 25 is laminated on the thin film layer 23 of an intermediate layer with a so-called U-shape, and one end of both U-shapes. Is directed to the feeder line 15A side. As shown in FIGS. 2 and 3, an energization circuit 31 including a DC power supply 27 and a switch 29 is connected to one end of both. When the uppermost thin film layer (Pt) 25 generates heat by energization, the generated heat heats the lower thin film layers 23 and 21.

  When the ribbon structure 17 is not energized, as shown in FIG. 4, the tip of the ribbon structure 17 is kept in contact with, for example, the center of the patch antenna 13, that is, the feeding point position farthest from the feeding line 15 </ b> A. Yes. Further, when the ribbon structure 17 is energized (during heat generation), as shown in FIG. 5, the uppermost thin film layer (Pt) 25 is warped and lower due to the difference in thermal expansion coefficient of each thin film layer 21, 23, 25. The thin film layers 23 and 21 are curved inward (deformation movement), and the position of the feeding point at the tip is slidably moved (displacement movement) on the patch antenna 13 in the direction toward the inner end side, that is, toward the feeding line 15A.

  The ribbon structure 17 can freely perform a so-called deformation motion that widens the curve and a deformation motion that narrows the curve by turning on and off the switch 29, thereby enabling the patch antenna 13 to wirelessly operate in a plurality of more predetermined frequency bands. It is possible to perform optimum impedance matching when transmitting / receiving a signal or a radio signal of an arbitrary predetermined frequency band.

  On the other hand, when a high frequency signal is supplied to the patch antenna 13, the oscillator 18 shown in FIG. 2 is driven to apply the high frequency signal between the ground plane Gr and the feeder line A (Al) 15. At this time, when the deformation motion of the ribbon structure 17 is controlled to perform optimum impedance matching, the direct current from the energizing circuit 31 is applied between the two ends forming the U-shaped shape of the uppermost thin film layer (Pt) 25. To supply. When the switch 29 is turned on and a direct current is passed through the uppermost thin film layer (Pt) 25, the thin film layer (Pt) 25 generates heat, and the intermediate thin film layer (SiN) 23 and the uppermost thin film layer (Pt) 25. Due to the difference in thermal expansion coefficient, the thin film layer (Pt) 25 side of the uppermost layer of the ribbon structure 17 extends and warps. Then, the contact position of the ribbon structure 17 and the patch antenna 13 changes, that is, the position of the feeding point to the patch antenna 13 changes.

  In the present embodiment, when transmitting and receiving a high-frequency signal (wireless signal), the ribbon structure 17 can be deformed by heat so that the position of the feeding point can be arbitrarily changed to achieve optimum impedance matching. In addition, no extra installation area is required, that is, miniaturization is not hindered, and high-speed impedance switching is possible.

  Instead of using the switch 29, a duty ratio control circuit for controlling the ON / OFF duty ratio in accordance with the resonant frequency band may be used.

  Next, an antenna according to a third embodiment of the present invention (corresponding to claims 3, 4, 5 and 6) will be described with reference to FIGS.

  As an outline, the antenna 41 of this example includes a ribbon structure 45 composed of an insulating layer and a first electrostatic electrode layer on the front end side of a feed line that supplies power to the patch antenna 13, and one end of the ribbon structure 45 is connected to the patch antenna 13. A voltage applied between the first and second electrostatic electrode layers with a second electrostatic electrode provided adjacent to the same plane (dielectric) on which the patch antenna 13 is placed, in contact with or fixed thereon The ribbon structure 45 is deformed toward the second electrostatic electrode layer by the electrostatic force induced by, and the contact position (feeding point position) between the ribbon structure 45 and the patch antenna 13 is changed by the deformation movement of the ribbon structure 45. Thus, the grounding position (feeding point position) between the patch antenna 13 and the feeding line 15B is changed.

  Hereinafter, a specific configuration of the antenna according to the present embodiment will be described with reference to FIGS. FIG. 6 is a perspective view showing the configuration of the antenna according to the present embodiment. In FIG. 6, the same parts as those shown in FIG.

As shown in FIG. 6, the antenna 41 of this example has a ribbon structure configured by a patch antenna 13 and a feeder line 15 </ b> B capable of transmitting and receiving radio signals in a plurality of frequency bands on a dielectric di having a ground plane Gr on the back surface. An electrostatic electrode layer (second electrostatic electrode layer) 47 for driving (deformation motion) 45 is provided apart from each other. As shown in FIG. 7, an insulating layer 48 made of, for example, SiO ₂ is laminated on the upper surface of the electrostatic electrode layer 47.

  On the other hand, on the dielectric di, at a position having a predetermined separation width from the patch antenna 43 and the electrostatic electrode layer 47, a dielectric di2 for a feed line for forming (mounting) the feed line 15B is stacked in a trapezoidal shape. The power supply line 15B is disposed along this line. That is, the dielectric di2 is used as a spacer that provides a height difference (deformation motion region) between the electrostatic electrode layer 47 and the ribbon structure 45. As shown in FIG. 8, an oscillator 18 that outputs a high-frequency signal is connected between the feeder line 15B and the ground plane Gr.

As shown in FIG. 7, the ribbon structure 45 is formed by laminating an insulating layer 50 made of, for example, SiO ₂ on a lower electrostatic electrode layer (first electrostatic electrode layer) 49 made of a metal such as Al. Has been. As shown in FIGS. 8 and 9, the ribbon structure 45 has its tip bonded to a predetermined feeding point position on the patch antenna 13 with, for example, a conductive adhesive (conductive bonding material: solder or the like) gl. Thus, a so-called gentle arch shape that curves downward from the height of the feeder line 15B is maintained by the coupling of the tips (see FIG. 10). The electrostatic electrode layer 49 of the ribbon structure 45 is made of the same material as that of the power supply line 15A and is integrated with the power supply line 15 in advance.

  Between the electrostatic electrode layer 49 of the ribbon structure 45 and the electrostatic electrode layer 47 on the dielectric di, an energization circuit including a high frequency cut coil 51, a DC power source 53, and a switch 55 is provided as shown in FIG. 57 is connected. When the switch 55 is turned on, as shown in FIGS. 9 and 11, an electrostatic force that acts as an attractive force is generated between the electrostatic electrode layer 49 of the ribbon structure 45 and the electrostatic electrode layer 47 on the dielectric di. The attractive force causes the ribbon structure 45 to bend (bend) in the direction of the electrostatic electrode layer 47, that is, to deform as much as possible into a so-called concave shape until contacting the electrostatic electrode layer 47. The deformation movement of the ribbon structure 45 is continuously performed from the position where the feeding point on the patch antenna 13 of the ribbon structure 45 is moved toward the inner end on the patch antenna 13, that is, one end in the direction approaching the feeding line 15. The feeding point position will be changed.

  The ribbon structure 45 can be arbitrarily switched between an undeformed state and a deformed state by an electrostatic force, that is, can be controlled, whereby the position of the feeding point moves away from the feeding line 15B or the feeding line 15B. It is possible to arbitrarily change the direction approaching. Since the ribbon structure 45 is driven by an electrostatic force accompanying voltage application, an electrode (electrostatic electrode layer 47) is required on the dielectric di, but since no heat is used, the amount of warping (deformation momentum) depends on the ambient temperature. Hard to do.

Next, a more detailed structure of the ribbon structure 45 will be described. First, as shown in FIG. 7, an Al film is laminated on a dielectric di having a ground plate Gr on the back surface, and is patterned so that a part becomes a patch antenna 13 and a part becomes an electrostatic electrode layer 47. Next, an insulating film 48 made of, for example, SiO ₂ is laminated on the electrostatic electrode layer 47. A power supply line dielectric di2 is laminated on the dielectric di, and a power supply line 15B including an electrostatic electrode layer 49 made of Al and an insulating layer 50 made of SiO ₂ is provided in a bowl shape. The hook-shaped portion becomes the ribbon structure 45. As shown in FIG. 8, the tip of the ribbon structure 45 is fixed on the patch antenna 13 with a conductive adhesive gl. Normally, this fixed end functions as a feeding point. The high frequency signal fed to the patch antenna 13 is applied between the ground plane Gr and the electrostatic electrode layer 49 of the feed line 15B. The high frequency cut coil 51 of the energization circuit 57 is inserted so that a high frequency signal is not applied between the electrostatic electrode layer 47 and the high frequency cut coil 51.

  By applying a DC voltage between the electrostatic electrode layer 49 and the electrostatic electrode layer 47 of the ribbon structure 45, an electrostatic force is generated between them, and the ribbon structure 45 causes the electrostatic electrode layer 47 to be generated by this electrostatic force. The contact position (feeding point position) between the electrostatic electrode layer 49 of the ribbon structure 45 and the patch antenna 13 moves, and as a result, the feeding point position can be variably controlled by the voltage applied to the electrostatic electrode layer 47. become.

  In the present embodiment, when transmitting and receiving a high-frequency signal (wireless signal), the ribbon structure 45 is deformed and moved by an electrostatic force, so that the position of the feeding point can be arbitrarily changed without depending on the ambient temperature. Impedance matching can be achieved, and an extra installation area is not required, that is, miniaturization is not hindered, and high-speed impedance switching is possible.

  Instead of the switch 55, a control circuit for controlling the ON / OFF duty ratio may be used.

  Next, an antenna according to a fourth embodiment (corresponding to claim 7) of the present invention will be described with reference to FIGS.

  As an outline, the antenna 61 of this example is characterized in that contact is made between the feeding point of the ribbon structure 63 formed on the feeding line 15 </ b> C and the movable contact of the patch antenna 13 by applying pressure.

  Even if the front end portion (ribbon structure) of the feeding line 15C is not fixed on the patch antenna 13, the pressure caused by the spring force of the ribbon structure 63 is pressed against the movable contact on the patch antenna 13 to bring them into contact with each other. The separation distance is always zero, and stable power feeding is possible. For example, if the patch antenna 13 itself is made of gold and the electrode surface of the ribbon structure 63 is also made of gold, the contact becomes resistant to rust.

  Hereinafter, a specific configuration of the antenna according to the present embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 is a side view showing the configuration of the antenna according to the present embodiment. In addition, the same code | symbol is attached | subjected to the part same as the part shown in FIG. 2, and detailed description is abbreviate | omitted.

As shown in FIG. 12, the antenna 61 of this example forms the following multilayer structure when a curved ribbon structure 63 is formed at the tip of the feeder line 15C. First, the patch antenna 13 made of an Al layer is laminated on the dielectric di, and an antenna pattern is formed by etching. Next, for example, a part made of SiO ₂ is laminated on the movable contact on the patch antenna 13, that is, the sliding contact region of the ribbon structure 63, and the other part forms the feed line 15 C on the dielectric di A sacrificial layer 65 that is stacked up to the position reaching the tip is formed, and etched to a shape corresponding to the lateral width of the feeder line 15C. Next, a feeding line 15 </ b> C made of an Al layer is formed on the dielectric di, and a part of the Al layer 67 is laminated on the sacrificial layer 65. Similarly, a SiN layer 69 is sequentially stacked on the Al layer 67 and a Pt layer 71 is stacked on the SiN layer 69.

When the Al layer 67, the SiN layer 69, and the Pt layer 71 are formed, the internal stress is provided to each layer by controlling the film formation conditions, and the ribbon structure 63 itself is warped from the beginning and is in contact with the patch antenna 13 Make a. Control of internal stress during film formation is generally performed by a MEMS process or the like, and is not difficult. Finally, when the sacrificial layer 65 of SiO ₂ is removed, a ribbon structure 63 having a shape as shown in FIG. 13 is obtained. However, the ribbon structure 63 is caused by internal stress of the Al layer 67, the SiN layer 69, and the Pt layer 71. A curve (arch shape) as shown in FIG. 2 occurs, and the tip of the ribbon structure 63 is pressed against the movable contact on the patch antenna 13 by the pressure accompanying this curve. The control of the deformation motion of the ribbon structure 63 is the same as that in the second embodiment, and detailed description thereof is omitted.

  In the present embodiment, the ribbon structure 63 can be manufactured monolithically. Therefore, the manufacturing is easy, and contact between the tip (Al layer 67) of the ribbon structure 63 and the patch antenna 13 is achieved by applying internal stress. It becomes possible to keep good, and it becomes possible to make impedance matching favorable.

  Next, with reference to FIGS. 14 and 17, an antenna according to a fifth embodiment (corresponding to claim 8) of the present invention will be described.

  As an outline, the antenna 81 of this example is characterized by capacitive coupling via an insulating film having low adhesion between the feeding point and the movable contact of the patch antenna 13.

If the metal surface of the patch antenna 13 and the metal of the ribbon structure 83A (83B) of the feeder line 15D (15E) are pressed at the same position for a long time, they may come into close contact with each other and cannot be separated. Therefore, in order to avoid adhesion, one or both of the contact points between the patch antenna 13 and the ribbon structure 83A (83B) are covered with an insulating film such as SiN or SiO _{2 having} low adhesion. The patch antenna 13 and the feeding line 15D (15E) are capacitively coupled by being covered with an insulating film, but if the capacity is sufficiently small, there is no influence on the feeding of a high-frequency signal. The capacitance can be controlled by the material and thickness of the insulating film.

  Hereinafter, an aspect of a specific configuration of the antenna according to the present embodiment will be described with reference to FIGS. FIG. 14 is a perspective view showing an aspect of the configuration of the antenna according to this embodiment. In addition, the same code | symbol is attached | subjected to the part same as the part shown in FIG. 2, and detailed description is abbreviate | omitted.

In one embodiment of the antenna 81 of this example, as shown in FIG. 14, when the curved ribbon structure 83A is formed at the tip of the feeder line 15D, the following multilayer structure is formed. First, the patch antenna 13 made of an Al layer is laminated on the dielectric di, and an antenna pattern is formed by etching. Next, for example, a part made of SiO ₂ is partially laminated on the movable contact on the patch antenna 13, that is, the sliding contact region of the ribbon structure 83A, and the other part is a position where the feeding line 15D is formed on the dielectric di. A sacrificial layer 85 that is stacked up to the position reaching the tip of the film is formed and etched into a shape corresponding to the lateral width of the feeder line 15D. Next, the SiN layer 87 is laminated on the dielectric di and the sacrificial layer 85, and the Al layer 89 constituting the feeder 15D is laminated on the SiN layer 87. Similarly, the SiN layer 91 is laminated on the Al layer 89 corresponding to the region constituting the ribbon structure 83A, and the Pt layer 93 is laminated on the SiN layer 91.

When the SiN layer 87, the Al layer 89, the SiN layer 91, and the Pt layer 93 are formed, internal stress is provided to each layer by controlling the film formation conditions, and the ribbon structure 83A itself warps from the beginning and the patch antenna 13 Make a contact state. Internal stress control at the time of film formation is also generally performed by a MEMS process or the like, and is not difficult. Finally, when SiO ₂ which is the sacrificial layer 85 is removed, a ribbon structure 83A having a shape as shown in FIG. However, the ribbon structure 83A has a curve (arch shape) as shown in FIG. 2 due to the internal stress of the Al layer 89, the SiN layer 91, and the Pt layer 93, and the pressure associated with this curve causes the ribbon structure 83A to The tip is pressed against the movable contact on the patch antenna 13. The control of the deformation motion of the ribbon structure 83A may be the same as that in the second embodiment, and detailed description thereof is omitted.

  Next, with reference to FIGS. 16 and 17, another aspect of the specific configuration of the antenna according to the present embodiment will be described. FIG. 16 is a side view showing another aspect of the configuration of the antenna according to this embodiment. In addition, the same code | symbol is attached | subjected to the part same as the part shown in FIG. 2, and detailed description is abbreviate | omitted.

On the other hand, in another aspect of the antenna 81 of this example, as shown in FIG. 16, when the curved ribbon structure 83B is formed at the tip of the feeder line 15E, the following multilayer structure is formed. First, the patch antenna 13 made of an Al layer is stacked on the dielectric di, an antenna pattern is formed by etching, and then an SiN layer 84 is formed on the patch antenna 13. Next, for example, a part made of SiO ₂ is laminated on the movable contact on the SiN layer 84 of the patch antenna 13, that is, the sliding contact region of the ribbon structure 83 B, and the other part is fed on the dielectric di and the feed line 15 E. A sacrificial layer 85 is formed up to a position reaching the tip of the film, and is etched into a shape corresponding to the lateral width of the feeder line 15E. Next, an Al layer 89 constituting the feeder 15E is laminated on the dielectric di and the sacrificial layer 85. Similarly, the SiN layer 91 is laminated on the Al layer 89 corresponding to the region constituting the ribbon structure 83B, and the Pt layer 93 is laminated on the SiN layer 91.

When the Al layer 89, the SiN layer 91, and the Pt layer 93 are formed, internal stress is provided to each layer by controlling the film formation conditions, and the ribbon structure 83B itself is warped from the beginning and is in contact with the patch antenna 13 Make a. Internal stress control at the time of film formation is also generally performed by a MEMS process or the like, and is not difficult. Finally, when SiO ₂ which is the sacrificial layer 85 is removed, a ribbon structure 83B having a shape as shown in FIG. However, the ribbon structure 83B has a curve (arch shape) as shown in FIG. 2 due to the internal stress of the Al layer 89, the SiN layer 91, and the Pt layer 93, and the pressure associated with the curve causes the ribbon structure 83B. The tip is pressed against the movable contact on the SiN layer 84 of the patch antenna 13. The control of the deformation motion of the ribbon structure 83B may be the same as in the second embodiment, and detailed description thereof is omitted.

  In the present embodiment, since an insulating film having low adhesion is used for both or one of the metal surface of the patch antenna 13 and the metal of the ribbon structure 83 of the feeder line, the patch antenna 13 and the ribbon structure 83 are located at the same position. Even if it is pressed for a long time at the (feeding point position), it does not come in close contact with each other, and this effectively prevents the occurrence of control failure due to close contact when transmitting and receiving radio signals in multiple frequency bands. can do.

  Next, with reference to FIG. 18, an antenna according to a sixth embodiment (corresponding to claim 9) of the present invention will be described. FIG. 18 is a block diagram showing a configuration of the antenna according to the present embodiment. The same parts as those shown in FIG.

  The antenna of this example is provided with a frequency determination circuit 103 and a feeding position control circuit 105 with respect to the antenna 11 shown in FIG.

  That is, the antenna 11 shown in FIG. 1, the frequency determination circuit 103, and the feeding position control circuit 105 are provided. The transmitter 107 according to the reception frequency band determined by the frequency determination circuit 105 at the time of reception and at the time of transmission. The feeding position control circuit 105 moves (controls) the feeding point position of the ribbon structure 17 to a position where impedance matching with the feeding line 15A can be obtained.

  As shown in FIG. 18, the frequency determination circuit 103 is connected between the power supply line 15 </ b> A and the RF switch 111 connected to the transmitter 107 and the receiver 109. The RF switch 111 is switched by, for example, a control signal from a control unit such as a baseband processing circuit (not shown) at the time of transmission / reception of a radio signal, and either the transmitter 107 or the receiver 109 is connected to the frequency determination circuit 103. To connect. The transmitter 107 outputs the frequency signal to the frequency determination circuit 103 when transmitting a radio signal.

  The frequency determination circuit 103 determines the frequency at the time of transmission / reception of a radio signal, and outputs a control signal corresponding to the frequency to the power feeding position control circuit 105. The feeding position control circuit 105 supplies a voltage and current (feeding position control signal) for controlling the feeding point position of the ribbon structure to a feeding point position where optimum impedance matching can be obtained based on the control signal from the frequency determination circuit 103. Is output.

  For example, if the frequency determination circuit 103 for determining the frequency is provided in the variable impedance patch antenna 13, the frequency can be known at the time of reception. If the feeding point position for impedance matching in the frequency band is obtained in advance, the impedance matching is automatically performed according to the frequency used by moving the feeding point position to the position for matching with the power from the feeding position control circuit 105. be able to. Since the frequency is known at the time of transmission, impedance matching is automatically performed when the information (control signal) is sent to the feeding position control circuit 105. Since the antenna itself performs impedance matching according to the operating frequency by the displacement movement of the ribbon structure 17, it becomes a kind of “smart antenna”.

  In this embodiment, since the frequency determination circuit 103 and the feeding position control circuit 105 are provided, impedance matching can be performed with higher accuracy when transmitting and receiving radio signals.

  The frequency determination circuit 103 and the feeding position control circuit 105 may be applied to the antenna 41 of the third embodiment shown in FIG. 6 or the antennas 61 and 81 of the fourth and fifth embodiments. Of course.

It is a perspective view which shows the principal part structure of the antenna which concerns on the 2nd Embodiment of this invention. It is a side view which shows the whole structure of the antenna which concerns on 2nd Embodiment. It is a top view which shows the upper surface structure of the antenna which concerns on 2nd Embodiment. It is a side view which shows the state at the time of the non-operation of the antenna which concerns on 2nd Embodiment. It is a side view which shows the state at the time of operation | movement (at the time of heat_generation | fever) of the antenna which concerns on 2nd Embodiment. It is a perspective view which shows the principal part structure of the antenna which concerns on the 3rd Embodiment of this invention. It is a side view which shows the side view principal part structure at the time of the front-end | tip non-fixation of the antenna which concerns on 3rd Embodiment. It is explanatory drawing explaining the whole structure at the time of the front-end | tip fixation of the antenna which concerns on 3rd Embodiment. It is a side view which shows the state at the time of operation | movement of the antenna which concerns on 3rd Embodiment (at the time of electrostatic force application). It is a side view which shows the state at the time of the non-operation of the antenna which concerns on 3rd Embodiment. It is a side view which shows the state at the time of the operation | movement of the antenna which concerns on 3rd Embodiment. It is explanatory drawing explaining the manufacture process of the front | former stage of the antenna which concerns on the 4th Embodiment of this invention. It is explanatory drawing explaining the manufacture process of the middle stage of the antenna which concerns on 4th Embodiment. It is explanatory drawing explaining the manufacturing process of the front | former stage in the one aspect | mode of the antenna which concerns on the 5th Embodiment of this invention. It is explanatory drawing explaining the manufacture process of the middle stage in the one aspect | mode of the antenna which concerns on 5th Embodiment. It is explanatory drawing explaining the manufacturing process of the front | former stage in the other one aspect | mode of the antenna which concerns on the 5th Embodiment of this invention. It is explanatory drawing explaining the manufacture process of the middle stage in the other one aspect | mode of the antenna which concerns on 5th Embodiment. It is a block diagram explaining the whole structure of the antenna which concerns on the 6th Embodiment of this invention. It is explanatory drawing explaining the prior art.

Explanation of symbols

11, 41, 61, 81 Antenna 13 Patch antenna 15A, 15B, 15C, 15D, 15E Feed line 17, 45, 63, 83A, 83B Ribbon spring structure (ribbon structure)
18 Transmitter 21, 23, 25 Thin film layer 27, 53 DC power supply 29, 55 Switch 31, 57 Current-carrying circuit 47 Electrostatic electrode layer (second electrostatic electrode layer)
48, 50 Insulating layer 49 Electrostatic electrode layer (first electrostatic electrode layer)
51 High-frequency cut coil 65, 85 Sacrificial layer 67, 89 Al layer 69, 84, 87, 91 SiN layer 71, 93 Pt layer 103 Frequency determination circuit 105 Feed position control circuit 107 Transmitter 109 Receiver 111 RF switch Gr Ground plane di , Di2 dielectric gl conductive adhesive

Claims (9)

A patch antenna that can send and receive radio signals in multiple frequency bands is contacted with a feed line that can change the feed point position mechanically.
An antenna characterized in that optimal impedance matching is performed when a radio signal in a predetermined frequency band of the patch antenna is transmitted and received by mechanically deforming the feeder line. It has a ribbon-like spring structure that consists of two or more types of metal layers having different thermal expansion coefficients on the feeding point side of the feeding line and generates heat and deforms when energized,
One end of the ribbon-shaped spring structure is in contact with a feeding point position of a predetermined frequency on the patch antenna,
The antenna according to claim 1, wherein optimal impedance matching is performed when a radio signal in a predetermined frequency band of the patch antenna is transmitted and received by deformation movement of the ribbon-shaped spring structure by energization. A patch antenna that can transmit and receive radio signals of a plurality of frequencies is in contact with a feed line that consists of an insulating layer and a first electrostatic electrode layer and can be mechanically deformed and can change the feed point position.
Providing a second electrostatic electrode layer adjacent to the patch antenna on the same surface on which the patch antenna is placed;
The feeder line is deformed and moved by an electrostatic force induced by a voltage applied between the first and second electrostatic electrode layers, and optimum impedance matching is performed when the patch antenna transmits and receives a radio signal in a predetermined frequency band. An antenna characterized by that.   4. The ribbon-like spring structure including the first electrostatic electrode layer capable of mechanically deforming with the electrostatic force with respect to a feeding point side of the feeding line is configured. 5. Antenna.   The feeding point side of the feeding line or the feeding point side of the ribbon-like spring structure is previously joined to a feeding point position in a predetermined frequency band on the patch antenna with a conductive binder. Item 5. The antenna according to Item 3 or 4.   The antenna according to any one of claims 3 to 5, wherein a high-frequency cut coil is provided in an energization circuit that supplies the voltage between the first and second electrostatic electrode layers.   By applying pressure to the movable contact of the patch antenna from the feeder line or the ribbon-like spring structure of the feeder line, optimal impedance matching is performed when transmitting and receiving radio signals in a predetermined frequency band of the patch antenna. The antenna according to any one of claims 1 to 5, characterized in that:   8. The capacitive coupling of claim 1, wherein the feed line or the ribbon-like spring structure of the feed line and the movable contact of the patch antenna are capacitively coupled via an insulating film having low adhesion. Antenna described in. A frequency determination circuit for determining the frequency of a radio signal to be received or transmitted is provided between the feeder and the receiver and the transmitter,
And, between the frequency determination circuit and the power supply line or the ribbon-like spring structure of the power supply line, the power supply line or the ribbon shape of the power supply line based on the frequency determined by the frequency determination circuit A feed position control circuit is provided that controls the deformation movement of the spring structure to control the feed point position, and thus performs optimum impedance matching when transmitting and receiving radio signals in a predetermined frequency band of the patch antenna. The antenna according to any one of claims 1 to 8.

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