JP4627295B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device, and more particularly to an antenna device for emitting or receiving circularly polarized waves.

  Conventionally, as shown in Patent Document 1, a broadband planar antenna for emitting or receiving circularly polarized waves is known.

An antenna (antenna device) shown in Patent Document 1 is disposed on a substrate, a conductive layer (conductive layer) having a plurality of grooved openings disposed on one surface of the substrate, and a back surface of the conductive layer disposed surface of the substrate. And a transmission line (feed line) for feeding power to the grooved opening as the antenna element. The plurality of grooved openings are spirally provided with the same antenna axis. Further, in the planar direction of the substrate, the transmission line is provided so as to overlap with the vicinity of the inner peripheral end portion of each of the plurality of slots via the substrate. That is, it is configured such that by electromagnetic coupling, power is fed from the transmission line to the spiral grooved opening from the inner peripheral side, whereby circularly polarized waves can be emitted or received.
Special table 2003-507915 gazette

  By the way, the transmission line has a connection portion with the outside (connector) at one end, and a termination resistor at the other end. It also has a matching section for impedance matching. Thus, the transmission line has a predetermined length, and a predetermined area is required for arrangement. Therefore, if the transmission line is arranged on the inner peripheral side of the grooved opening in the plane direction of the substrate, the transmission line has a great influence on the size of the antenna in the plane direction. It is difficult to reduce the size of the antenna in the plane direction while ensuring the positional relationship.

  In view of the above problems, an object of the present invention is to provide a miniaturized antenna device.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of spiral slots penetrating in the plate thickness direction of the conductive member as antenna elements are provided for the flat conductive member with the same antenna axis. An antenna device including a conductive layer and a feed line that is disposed at a predetermined distance from the conductive layer via a dielectric, and feeds power to the slot. Each slot is provided so as to overlap the vicinity of the outer peripheral end of each slot via a dielectric, and among the conductive members, the inner peripheral side portion with respect to the slot and the outer peripheral side portion with respect to the slot are connected differently from the conductive member. It is electrically connected by a wire.

  As described above, according to the present invention, since the spiral slot is provided in the conductive member as the antenna element, circularly polarized waves can be emitted or received. In addition, since the antenna axis is the same and a plurality of such slots are provided, the antenna characteristics can be improved (the directivity of circular polarization can be improved).

  In addition, since a power supply line is provided so that power is supplied from the vicinity of the outer peripheral end of each slot, the size of the power supply line is smaller than that of the configuration in which power is supplied from the inner peripheral side of the slot. The influence on the size of the direction can be reduced. That is, the physique of the antenna device can be made smaller than before. In addition, the vicinity of the outer peripheral end means the outer peripheral end of the slot or a portion in the vicinity of the end.

  The conductive member functions as GND. If the size of the antenna device is reduced in the planar direction of the conductive layer, the inner peripheral portion of the conductive member with respect to the slot is smaller than the outer peripheral portion of the slot. It is conceivable that the potential at the peripheral portion becomes unstable in terms of high frequency. On the other hand, in this invention, since the inner peripheral part and outer peripheral part of an electrically-conductive member are electrically connected by the connecting wire different from an electrically-conductive member, an antenna characteristic can be stabilized.

  In the first aspect of the present invention, as described in the second aspect, in the planar direction of the conductive layer, the connecting portion between the connecting wire and the outer peripheral portion of the conductive member is a feeder line and the outside (for example, a connector). It is good to set it as the structure made into the connection part vicinity.

  According to this, as compared with the configuration in which the connecting portion between the connecting wire and the outer peripheral portion of the conductive member is located away from the connecting portion between the feeder line and the outside, the connecting portion and the outer peripheral portion from the inner peripheral portion. Since the transmission distance in the direction of the connecting portion between the feeder line and the outside in the outer peripheral side portion of the current that has escaped to the outside is short, the antenna characteristics can be further improved.

  In the invention described in claim 1 or 2, as described in claim 3, the dielectric is a flat dielectric substrate, and a conductive layer is provided on one side of the dielectric substrate. A feed line is provided on the back side of the surface provided with the connecting line, the connecting line penetrates the dielectric substrate, and is electrically connected to the inner peripheral side portion of the conductive member and the conductive member. It is preferable to include an outer peripheral side through portion electrically connected to the outer peripheral side portion and a connection portion that electrically connects the inner peripheral side through portion and the outer peripheral side through portion on the back surface side of the dielectric substrate.

  When a flat dielectric substrate is employed as the dielectric as described above, the relative positions of the conductive layer, the feed line, and the connecting line are determined and easily held. Further, the configuration can be simplified.

  In the invention according to any one of claims 1 to 3, it is preferable that the plurality of slots include a plurality of at least two types of slots having different electrical lengths.

  Accordingly, it is possible to radiate or receive a plurality of circularly polarized waves having different wavelengths in one antenna device. In each case, the antenna characteristics can be improved.

  In the invention described in claim 4, as described in claim 5, the slot having the same electrical length (slot length) among the plurality of slots in the planar direction of the conductive layer is centered on the antenna axis. And a configuration provided in a rotationally symmetric manner. According to this, the symmetry is improved and the antenna characteristics can be further improved.

  In the invention according to any one of claims 1 to 5, as described in claim 6, the plurality of slots change the direction from the vicinity of the spiral portion and the end portion on the outer periphery side of the spiral portion to the outer periphery. It is preferable to have a configuration in which an extending portion extending in the direction is provided so that the feeder line overlaps with the extending portion of the slot. According to this, power can be supplied to the slot without making the power supply line complicated.

  In the invention according to any one of claims 1 to 6, as described in claim 7, the dielectric constant is higher than that of the dielectric so as to cover at least a part of the slot on the conductive layer. It is preferable that the high dielectric member is arranged in contact with the conductive layer.

  According to this, the electrical length of the slot for a desired frequency can be shortened by the wavelength shortening effect of the high dielectric member. That is, the size of the antenna device can be further reduced. In addition, it is possible to emit or receive circularly polarized waves having a lower frequency than the configuration without the high dielectric member at the same electrical length.

  In the invention described in claim 7, as described in claim 8, it is preferable that the slot is entirely covered with a high dielectric member. As the coverage of the slot with the high dielectric member increases, the influence of the wavelength shortening effect increases. Therefore, if the configuration is such that all the slots are covered, the size of the antenna device can be made smaller than the configuration in which the slots are partially covered.

  In the invention according to any one of claims 1 to 8, as described in claim 9, the radio wave reflecting member or the radio wave absorber disposed at a predetermined distance with respect to the conductive layer so as to sandwich the feeder line therebetween. It is good also as a structure provided with a member. According to this, by the radio wave reflecting member or the radio wave absorbing member, it is possible to reduce circularly polarized radiation radiated to the dielectric arrangement side of the conductive layer or reception from the dielectric arrangement side of the conductive layer. Therefore, the radiation or reception direction of circularly polarized waves can be defined on the side opposite to the dielectric arrangement side of the conductive layer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a plan view of the antenna device according to the first embodiment of the present invention as viewed from the conductive layer side. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a plan view of the antenna device as viewed from the power feeding pattern side. In FIG. 1, in order to show the positional relationship between the slot and the power supply pattern, the power supply pattern is shown by a broken line.

  As shown in FIG. 2, the antenna device 100 according to this embodiment includes a conductive layer 140 in which a plurality of spiral slots 144 are provided on a flat plate (planar circular) conductive member 142 as a main part, The power supply pattern 160 is disposed at a predetermined distance from the conductive layer 140 via the dielectric 120, and supplies a high-frequency current to the slot 144 by electromagnetic coupling.

  As the dielectric 120, a resin substrate (contains at least a resin, for example, a concept including a glass epoxy resin), a ceramic substrate, a glass substrate, or the like can be employed. Preferably, the dielectric 120 can hold the conductive layer 140 and the power supply pattern 160 on the surface thereof. In this embodiment, a dielectric substrate 120 made of a resin having a conductive foil (for example, a copper foil) attached to both opposing surfaces is employed as the dielectric 120. The conductive foils are patterned to form conductive layers 140 and power supply patterns 160, respectively. When such a configuration is employed, a known printed board manufacturing method can be applied. In addition, for example, a glass substrate may be employed as the dielectric 120, and the conductive layer 140 and the power supply pattern 160 may be configured by vapor deposition on the substrate surface. In addition, a gas layer (for example, an air layer) can be adopted as the dielectric 120, but a support member is necessary to hold the conductive layer 140 and the power feeding pattern 160 in a positioned state. When the flat dielectric substrate 120 is employed as the dielectric 120 in this manner, the relative positions of the conductive layer 140, the power feeding pattern 160, and the connecting pattern 172 are determined and easily held. Further, the configuration can be simplified. Hereinafter, a dielectric 120 and a dielectric substrate 120 are shown.

  The conductive layer 140 is provided with a plurality of spiral slots 144 that penetrate the conductive member 142 in the plate thickness direction as antenna elements, with the antenna shaft 102 being the same. In the present embodiment, the conductive foil as the conductive member 142 attached to the entire surface of the dielectric substrate 120 is etched to form grooves in the conductive foil to form a plurality of slots 144. Further, as shown in FIG. 1, the plurality of slots 144 include a plurality of two types of slots 146 and 148 having different electrical lengths (resonance lengths). More specifically, the electrical length is set so that the slot 146 resonates at a frequency of 1.575 GHz, and the electrical length of the slot 148 is set so as to resonate at a frequency of 1.227 GHz. That is, the antenna device 100 according to the present embodiment is configured as an antenna device for RTK-GPS (Real Time Kinematic GPS). As described above, when a plurality of at least two types of slots 144 (146, 148) having different electrical lengths are included, each antenna device 100 can radiate or receive a plurality of circularly polarized waves having different wavelengths. it can. In each case, the antenna characteristics can be improved.

  The two types of slots 146 and 148 have the same antenna shaft 102. From the outer peripheral side end of the spiral portions 146a and 148a and the left-handed spiral portions 146a and 148a spiraling counterclockwise around the antenna shaft 102, respectively. In addition, extending portions 146b and 148b extending radially outward from the antenna shaft 102 are provided. The spiral portions 146a and 148a are Archimedean spirals in which the interval between the adjacent spiral portions 146a and 148a is constant, and the lengths thereof are set to lengths that resonate at a predetermined frequency. The length that resonates at a predetermined frequency is a length of n · λ / 4 (n is a natural number) excluding the wavelength shortening effect by the dielectric substrate 120, where λ is the predetermined frequency. In the present embodiment, the dielectric substrate 120 has a small relative dielectric constant, and the lengths of the spiral portions 146a and 148a are set to about one wavelength (n = 4). Further, the extending portions 146b and 148b are set to have the same length, and are arranged so as to overlap the power supply pattern 160 in the planar direction of the conductive layer 140 as shown in FIGS. . That is, the extending portions 146b and 148b function as portions to which a high-frequency current is supplied from the power supply pattern 160 by electromagnetic coupling in the slots 146 and 148. As described above, the plurality of slots 144 (146, 148) have the extending portions 146b, 148b extending from the vicinity of the outer peripheral ends of the spiral portions 146a, 148a and extending in the outer peripheral direction, and the power feeding pattern 160 is If the extension portions 146b and 148b are provided so as to overlap with each other, the power can be supplied to the slot 144 (146 and 148) even if the power supply pattern 160 is not complicated.

  In addition, four slots 146 and 148 are provided, and in the plane direction of the conductive layer 140, the spiral portions 146a and 148a are alternately arranged from the outer peripheral side, and each of the four slots 146 and 148 has the antenna shaft 102. Are provided in a rotationally symmetric manner with respect to each other. As described above, in the planar direction of the conductive layer 140, among the plurality of slots 144, the slots 144 (146, 148) having the same electrical length are symmetrically provided with the antenna axis 102 as the center. The antenna characteristics (directivity of circular polarization) can be further improved. In the present embodiment, in each slot 144 (146, 148), the connecting portions of the spiral portions 146a, 148a and the extending portions 146b, 148b are on the same circumference with the antenna shaft 102 as the center. . Accordingly, as shown in FIGS. 1 and 2, the spiral portion 148a of the slot 148 having a long electrical length is provided continuously on the inner peripheral side without interposing the spiral portion 146a in view of the electrical length. .

  In the conductive layer 140, the conductive member 142 functions as GND. Hereinafter, in the conductive member 142, the outer peripheral side portion 142a is located on the outer peripheral side of the spiral portions 146a and 148a of the slot 144 (146, 148), and the inner peripheral side portion 142b is provided on the inner peripheral side relative to the spiral portions 146a and 148a. A portion between the portions 146a and 148a is defined as an inter-spiral region 142c. In addition, the area of the outer peripheral side part 142a is larger than the area of the inner peripheral part 142b, and is set to an area sufficient to function as GND. With such a configuration, the physique of the antenna device 100 in the planar direction of the dielectric substrate 120 (conductive layer 140) is larger than the configuration in which the area of the inner peripheral portion 142b is increased and the function as the GND is exhibited. Can be miniaturized.

  The power supply pattern 160 is a power supply line (corresponding to a power supply line described in claims) for supplying a high-frequency signal to the slot 144 (146, 148), and is on the outer peripheral side with respect to the slot 144 (146, 148). In order to supply power from the vicinity of the end portion of the dielectric substrate 120, the conductive substrate 142 is not overlapped with the inner peripheral portion 142b in the planar direction of the dielectric substrate 120 (conductive layer 140), and is provided so as to overlap at least the outer peripheral portion 142a. Yes. In this embodiment, the conductive foil adhered to the back surface of the dielectric substrate 120 on which the conductive layer 140 is formed is etched to form a predetermined pattern so that all overlap with the outer peripheral portion 142 a of the conductive member 142. A power supply pattern 160 is configured.

  Here, it is assumed that the power supply patterns 160 having the same length are provided in the inner peripheral portion 142b and the outer peripheral portion 142a of the conductive member 142, respectively. When a circle centered on the antenna shaft 102 is considered, the longer the distance from the center, the longer the circumference becomes proportionally. Therefore, in the arrangement in the inner peripheral portion 142b, the power supply pattern 160, which should be a quadruple spiral, for example, may be a single spiral in the outer peripheral portion 142a. That is, in the planar direction of the dielectric substrate 120 (the conductive layer 140), the size of the antenna device 100 is reduced when the feeding pattern 160 is disposed in the outer peripheral portion 142a than in the inner peripheral portion 142b. be able to.

  More specifically, as shown in FIG. 3, the power supply pattern 160 includes an external connection portion 162 that is a connection portion with an external (a connector in the present embodiment) provided at an outer peripheral end, and an external connection. A matching unit 164 that impedance-matches (matches) a high-frequency signal fed from the outside via the unit 162; a supply unit 166 that supplies the matched high-frequency signal to the slot 144 (146, 148) by electromagnetic coupling; A termination resistor 168 provided at the end of the supply unit 166, and a through hole 170 provided adjacent to the termination resistor 168 and electrically connecting the termination resistor 168 and the outer peripheral side portion 142 a of the conductive member 142. Consists of.

  The supply unit 166 is provided so as to overlap with the extending portions 146b and 148b of the slot 144 (146 and 148) in the planar direction of the dielectric substrate 120 (conductive layer 140). In the present embodiment, the supply unit 166 reversely rotates with the spiral portions 146a and 148a when viewed from the conductive layer 140 side (the power supply pattern 160) so that all the extended portions 146b and 148b overlap the power supply pattern 160 twice. It is provided in a spiral shape counterclockwise when viewed from the side. As shown in FIG. 1, except for one of the extended portions 148b, the remaining extended portions 146b, 148b are configured to overlap the supply portion 166 twice, but all the extended portions 146b, 148b may overlap with the supply unit 166 twice. Further, the overlap between the feeding pattern 160 and the extending portions 146b and 148b of the slots 144 (146 and 148) is not limited to two places. It is good also as three or more places, and good also as one place. When there are a plurality of overlapping portions in the same extending portion 146b, 148b, the interval between the overlapping portions may be set so that the high-frequency signals do not cancel each other in consideration of the phase difference of the high-frequency signals.

  The connection pattern 172 electrically connects the inner peripheral side portion 142b and the outer peripheral side portion 142a of the conductive member 142, and corresponds to a connection portion of the connection lines recited in the claims. In the present embodiment, the connecting pattern 172 is formed on one surface of the dielectric substrate 120 by the same manufacturing process as the power feeding pattern 160. That is, the connecting pattern 172 is configured by etching the conductor foil attached to the back surface of the dielectric substrate 120 on which the conductive layer 140 is formed to form a predetermined pattern. As shown in FIGS. 1 and 3, one end of the connection pattern 172 is connected to the conductive member 142 through a through hole 174 (inner peripheral side through portion described in claims) provided in the dielectric substrate 120. It is electrically connected to the inner peripheral portion 142b. Further, the other end of the connection pattern 172 is electrically connected to the outer peripheral side portion 142a of the conductive member 142 via the above-described through hole 170 (also serving as the outer peripheral side through portion described in the claims). Has been. In the present embodiment, as shown in FIG. 1, the through hole 174 is provided at a position overlapping the antenna shaft 102. However, the formation position of the through hole 174 is not particularly limited as long as one end thereof is in contact with the inner peripheral portion 142b.

  Further, the through hole 170 (a connection portion between the connection pattern 172 and the outer peripheral portion 142a) is provided in the vicinity of the external connection portion 162 that is a connection portion between the power feeding pattern 160 and the outside. That is, in the planar direction of the dielectric substrate 120 (conductive layer 140), the connection pattern 172 is configured to be drawn from the inner peripheral side portion 142b to the external connection portion 162 of the outer peripheral side portion 142a.

  In addition to the power supply pattern 160 and the connection pattern 172 described above, a GND connection portion 176 that is electrically connected to an external (connector) GND terminal is provided on the surface of the dielectric substrate 120 where the power supply pattern 160 is formed. Yes. The GND connection portion 176 is electrically connected to the outer peripheral side portion 142 a of the conductive member 142 through a through hole 176 a provided in the dielectric substrate 120. Thus, since the GND connection portion 176 is provided on the same surface as the external connection portion 162, connection to the outside is easy.

  Next, in the antenna device 100 configured as described above, the operation of the antenna will be described with reference to FIGS. 1 and 3. When a high frequency signal is supplied through the connector in a state where the connector is electrically connected to the external connection unit 162 and the GND connection unit 176, the high frequency signal injected into the external connection unit 162 is matched by the matching unit 164. Then, it proceeds spirally along the supply unit 166. Then, the high-frequency signal is transmitted to the outer peripheral side portion 142 a of the conductive member 142 that is GND through the terminal resistor 168 and the through hole 170 provided at the terminal of the supply unit 166. In the process of traveling the power feeding pattern 160, the high frequency signal is electromagnetically coupled to the extended portions 146b and 148b of the slot 144 (146, 148). Thereby, the high frequency current is transmitted to the spiral portions 146a and 148a via the extending portions 146b and 148b, and the high frequency current flows along the spiral shape of the spiral portions 146a and 148a. Therefore, an electromagnetic field due to the high-frequency current is generated around the slot 144 (mainly the spiral portions 146a and 148a), and therefore, along the antenna axis 102, in front of the conductive layer 140 (on the opposite side to the dielectric substrate 120) and rear ( Circularly polarized waves can be emitted or received in both directions of the dielectric substrate 120 side. In the present embodiment, when the high frequency current reaches the inner peripheral side ends of the spiral portions 146a and 148a, the high frequency current passes through the through hole 174 provided in the inner peripheral side portion 142b of the conductive member 142 that is GND. Via the connection pattern 172. And it is transmitted to the outer peripheral side part 142a of the conductive member 142 which is GND through the connection pattern 172 and the through hole 170.

  As described above, according to the antenna device 100 according to the present embodiment, since the spiral slot 144 is provided in the conductive member 142 as the antenna element, circularly polarized waves can be emitted or received. Further, since the antenna shaft 102 is the same and a plurality of such slots 144 are provided, the antenna characteristics can be improved (the directivity of circular polarization can be improved). In addition, since the plurality of slots 144 includes a plurality of at least two types of slots 146 and 148 having different electrical lengths, a single antenna device 100 can emit or receive a plurality of circularly polarized waves having different wavelengths. In addition, the antenna characteristics can be improved in each case. Furthermore, in the planar direction of the dielectric substrate 120 (conductive layer 140), the slot 146 and the slot 148 are provided rotationally symmetrically about the antenna axis 102, so that the antenna characteristics can be further improved.

  Further, in the present embodiment, the power supply pattern 160 is provided so that power is supplied from the vicinity of the end on the outer peripheral side to each slot 144 (146, 148). Therefore, the influence of the size of the power feeding pattern 160 on the size of the antenna device 100 in the planar direction can be reduced as compared with the configuration in which power is fed to the slot 144 from the inner peripheral side. That is, the physique of the antenna device 100 can be made smaller than before.

  Further, in the present embodiment, extended portions 146b and 148b extending radially from the outer peripheral side end portions of the spiral portions 146a and 148a radially in the outer peripheral direction are provided as the plurality of slots 144 (146, 148). The high-frequency current is supplied from the power feeding pattern 160 to the extending portions 146b and 148b. Therefore, power can be supplied to the slot 144 without making the power supply pattern 160 complicated so as to partially overlap the slot 144. Note that the shapes of the extending portions 146b and 148b are not limited to radial shapes. Moreover, it is not limited to the structure connected with the outer peripheral side edge part of spiral part 146a, 148a. Any shape can be adopted as long as it changes its direction from the vicinity of the outer periphery of the spiral portions 146a and 148a and extends in the outer peripheral direction.

  Moreover, in this embodiment, the inner peripheral side part 142b and the outer peripheral side part 142a of the electrically-conductive member 142 are electrically connected by the connection pattern 172 (and the through holes 170 and 174). Therefore, even if power is supplied to the slot 144 (146, 148) from the outer peripheral side, the high-frequency current escapes from the inner peripheral part 142b to the outer peripheral part 142a, so that the potential at the inner peripheral part 142b is unstable in terms of high frequency. Thus, the antenna characteristics can be stabilized.

  In the present embodiment, the connection part (through hole 170) between the connection pattern 172 and the outer peripheral part 142 a of the conductive member 142 is in the vicinity of the external connection part 162 of the power supply pattern 160. When the connection part is away from the external connection part 162, the high-frequency current released from the inner peripheral part 142b to the outer peripheral part 142a by the connection pattern 172 is directed to the external connection part 162 (GND connection part 176) in the outer peripheral part 142a. Direction), the antenna characteristics may be degraded accordingly. On the other hand, as shown in the present embodiment, when the connection part is in the vicinity of the external connection part 162, transmission of the escaped high-frequency current in the outer peripheral part 142a can be suppressed, and the antenna characteristics can be further improved.

(Second Embodiment)
Next, 2nd Embodiment of this invention is described based on FIG.4 and FIG.5. FIG. 4 is an exploded perspective view showing a schematic configuration of the antenna device 100 according to the present embodiment. FIG. 5 is a perspective view showing the assembled state. In FIG. 4, the power feeding pattern 160 and the connecting pattern 172 are illustrated separately from the dielectric substrate 120, but in actuality, as illustrated in the first embodiment, they are arranged on the dielectric substrate 120. .

  Since the antenna device 100 according to the second embodiment is often in common with that according to the first embodiment, the detailed description of the common parts will be omitted below, and different parts will be described mainly. In addition, about the component same as 1st Embodiment, the code | symbol same as 1st Embodiment is provided.

  As shown in FIGS. 4 and 5, the antenna device 100 according to the present embodiment further includes a high-dielectric member 180 and a reflecting member 200 as main parts with respect to the antenna device 100 shown in the first embodiment. It is characterized by.

  The high dielectric member 180 is made of a material having a relative dielectric constant higher than that of the dielectric substrate 120 and is on the conductive layer 140 and covers the conductive layer 140 so as to cover at least a part of the slot 144 (146, 148). Are placed in contact with each other. As described above, when the high dielectric member 180 is disposed in contact with the conductive layer 140 (in other words, the slot 144), the wavelength shortening effect of shortening the wavelength in the dielectric is large, and this effect causes resonance at a desired frequency. Thus, the electrical length of the slot 144 (146, 148) can be shortened effectively. That is, the size of the antenna device 100 can be further reduced as compared with the configuration shown in the first embodiment. If the electrical length is the same, circularly polarized waves having a frequency lower than that of the configuration without the high dielectric member 180 can be emitted or received. The electrical length of the slot 144 (146, 148) can also be shortened by the wavelength shortening effect of the dielectric substrate 120. However, in the case of the dielectric substrate 120, the thickness and size are designed in consideration of only the wavelength shortening effect in order to perform the function of holding the conductive layer 140, the power feeding pattern 160, and the connecting pattern 172 in a desired positional relationship. I can't. On the other hand, by providing the high dielectric member 180 separately from the dielectric substrate 120, the electrical length of the slot 144 (146, 148) can be effectively shortened.

  In the present embodiment, as the high dielectric member 180, a material including ceramic or the like and having a relative dielectric constant of about 15 to 20 is employed. Then, as shown in FIGS. 4 and 5, the conductive layer 140 is disposed in contact with the slot 144 (146, 148) so as to be entirely covered. More specifically, the planar shape and size of the high dielectric member 180 are the same as the planar shape and size of the dielectric substrate 120. As described above, in the slot 144 (146, 148), the influence of the wavelength shortening effect increases as the coverage of the high dielectric member 180 increases. As a result, the size of the antenna device 100 can be further reduced. In the first embodiment, the lengths of the spiral portions 146a and 148a are set to about one wavelength. However, in the present embodiment, by adding the effect of the high dielectric member 180 to the same configuration, The length of the spiral portion 146a is 70 mm, and the length of the spiral portion 148a of the slot 148 is 90 mm. However, when the volume of the high dielectric member 180 that covers the slot 144 is increased, the dielectric loss is also increased. Therefore, it is preferable to balance the dielectric loss and the wavelength shortening effect.

  The reflecting member 200 corresponds to the radio wave reflecting member described in the claims, and is a circularly polarized wave reverse to the spiral direction of the slot 144 radiated behind the conductive layer 140 (dielectric substrate 120 side), or In order to reduce reception of the conductive layer 140 from the dielectric substrate 120 side, the conductive layer 140 is disposed at a predetermined distance from the conductive layer 140 so as to sandwich the power feeding pattern 160 therebetween (that is, with respect to the conductive layer 140). Parallel arrangement).

  As such a reflecting member 200, a known member can be adopted. In this embodiment, EBG (Electromagnetic Band Gap) is adopted as an example. In the EBG, polygonal (for example, hexagonal) metal electrodes are periodically arranged on the surface of a dielectric substrate, and a dielectric substrate is formed between each metal electrode and a metal film formed on the back surface of the dielectric substrate. Each of which is electrically connected by a connecting material in a via hole penetrating through. The EBG has characteristics of a circuit in which the inductor (L) and the capacitor (C) are continuously connected to each other, so that an LC resonance occurs at a specific frequency and an impedance when a high-frequency signal is transmitted through the surface. Occurs. The frequency region where the impedance increases is called a band gap. In the present embodiment, an EBG is disposed behind the conductive layer 140 so that the resonance frequencies of the slots 144 (146, 148) and the EBG are matched. Therefore, the high frequency signal radiated behind the conductive layer 140 can be attenuated by the effect of the LC resonance of the EBG. That is, due to the effect of the reflecting member 200, circularly polarized waves can be efficiently radiated in front of the conductive layer 140 (on the side opposite to the dielectric substrate 120).

  In addition, the code | symbol 220 shown in FIG.4 and FIG.5 is a support member. In the present embodiment, the support member 220 is configured as a metallic cylindrical member having the same inner peripheral shape as the planar shape of the dielectric substrate 120. On the other opening end of the supporting member 220, the feeding pattern 160 is arranged in the cylinder in a state where the supporting member 220 is arranged on one surface of the reflecting member 200 so that the one opening end contacts. Further, the surface of the dielectric substrate 120 where the power supply pattern 160 is formed is disposed in contact with the dielectric substrate 120. The antenna device 100 is configured by placing a high dielectric member 180 in contact with the surface of the dielectric substrate 120 where the conductive layer 140 is formed.

  Next, the effect of the antenna device 100 according to the present embodiment will be described with reference to FIGS. 6 and 7. 6A and 6B are diagrams showing the directivity of the antenna. FIG. 6A shows 1.575 GHz (slot 146), and FIG. 6B shows 1.227 GHz (slot 148). FIG. 7 is a diagram showing the relationship between frequency and voltage standing wave ratio (VSWR). 6A and 6B, the position of the front side (opposite to the dielectric substrate 120) of the conductive layer 140 along the antenna axis 102 is set to 0 with the intersection of the conductive layer 140 and the antenna axis 102 as the center. The directions along the plane of the conductive layer 140 are 90 ° and 270 °, and the rear (dielectric substrate 120 side) position of the conductive layer 140 along the antenna axis 102 is 180 °. 6 (a) and 6 (b), the right-handed circularly polarized wave is shown by a solid line with respect to the counterclockwise spiral (left-handed) spiral portions 146a and 148a. The left-handed circularly polarized wave radiated with the wave is also shown by a broken line for reference.

  As shown in FIGS. 6A and 6B, at each frequency (1.575 GHz, 1.227 GHz), circularly polarized waves are efficiently emitted in front of the conductive layer 140 (on the side opposite to the dielectric substrate 120). Obviously you can. It is also clear that the antenna characteristics (circular polarization directivity) are improved at each frequency. Further, as shown in FIG. 7, it is clear that there is no particular problem in practical use because VSWR (Voltage Standing Wave Ratio) is 2 or less at each frequency.

  As described above, according to the antenna device 100 according to the present embodiment, the electrical length of the slot 144 (146, 148) can be shortened by the effect of the high dielectric member 180. That is, the size of the antenna device 100 can be reduced.

  Further, the high-frequency signal radiated to the back of the conductive layer 140 can be reduced by the effect of the reflecting member 200, and circularly polarized waves can be efficiently radiated to the front of the conductive layer 140 (on the side opposite to the dielectric substrate 120). .

  In the present embodiment, the cylindrical member as the support member 220 is made of metal. Therefore, since the support member 220 functions as GND together with the conductive member 142, the antenna characteristics can be further stabilized. Further, when a cylindrical member is employed as the reflecting member 200, in order to attenuate the high-frequency signal, the opposing distance between the conductive layer 140 and the reflecting member 200 is set to a predetermined distance (for example, about 1/4 wavelength). The facing distance can be defined by the length of the member.

  In the present embodiment, an example in which the high dielectric member 180 and the reflecting member 200 are both provided as the antenna device 100 has been described. However, the configuration may include only one of the high dielectric member 180 and the reflecting member 200.

  Moreover, in this embodiment, in order to reduce the high frequency signal radiated | emitted behind the conductive layer 140, the example which arrange | positions EBG as the reflection member 200 was shown. However, a known radio wave absorbing member that absorbs a high-frequency signal may be arranged to reduce the high-frequency signal radiated behind the conductive layer 140.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the present embodiment, an example in which the conductive layer 140, the power feeding pattern 160, and the connection pattern 172 are configured by patterning the conductive foils disposed on both surfaces of the dielectric substrate 120 has been described. However, the conductive layer 140, the power feeding pattern 160, and the connection pattern 172 that are respectively formed on both surfaces of the dielectric substrate 120 are not limited to the above example. For example, you may comprise by screen-printing an electrically conductive paste.

  In the present embodiment, an example in which the outer peripheral shape in the planar direction of the dielectric substrate 120 and the conductive layer 140 is circular has been shown. However, the shape is not particularly limited to a circle, and a rectangular shape or the like can also be adopted. In addition, the dielectric substrate 120 and the conductive layer 140 may have different shapes.

  In the present embodiment, the shape of the spiral portions 146a and 148a of the slot 144 (146 and 148) is an example of the Archimedes spiral. However, the shape of the spiral portions 146a and 148a is not particularly limited to the above example, and may be any spiral shape.

  In the present embodiment, an example in which a plurality of slots 146 and 148 having different electrical lengths is included as the plurality of slots 144 is shown. However, the slots 144 may all have the same electrical length, or may include a plurality of three or more types of slots 144 having different electrical lengths.

  In the present embodiment, the slot 144 (146, 148) has spiral portions 146a, 148a and extended portions 146b, 148b, respectively, and the power feeding pattern 160 is disposed so as to overlap the extended portions 146b, 148b. Indicated. However, the power feeding pattern 160 has at least the spiral portions 146a and 148a, and may be disposed so as to overlap the vicinity of the outer peripheral end portion as a part of the slot 144.

  In the present embodiment, the example in which the spiral portions 146a and 148a spiral counterclockwise around the antenna shaft 102 is shown. However, it may be a clockwise rotation that spirals clockwise around the antenna shaft 102. That is, when viewed from the conductive layer 140 side, the spiral directions of the spiral portions 146a and 148a and the supply portion 166 of the power feeding pattern 160 may be the same. Also in this case, as viewed from the conductive layer 140 side, the spiral direction of the spiral portions 146a and 148a and the supply portion 166 of the power feeding pattern 160 can be expected to be equivalent to or equivalent to the reverse direction.

It is the top view which looked at the antenna device concerning a 1st embodiment from the conductive layer side. It is sectional drawing which follows the II-II line | wire of FIG. It is the top view which looked at the antenna apparatus from the electric power feeding pattern side. It is a disassembled perspective view which shows schematic structure of the antenna device which concerns on 2nd Embodiment. It is a perspective view which shows the assembled state. It is a figure which shows the directivity of an antenna, (a) is 1.575 GHz, (b) is 1.227 GHz. It is a figure which shows the relationship between a frequency and a voltage standing wave ratio (VSWR).

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Antenna apparatus 102 ... Antenna shaft 120 ... Dielectric substrate (dielectric)
140 ... conductive layer 142 ... conductive member 142a ... outer peripheral part 142b ... inner peripheral part 144,146,148 ... slots 146a, 148a ... spirals 146b, 148b ... Extension part 160 ... feeding pattern (feeding line)
172... Connection pattern (connection portion of connection lines)

Claims (9)

For a flat conductive member, a conductive layer provided with a plurality of spiral slots penetrating in the thickness direction of the conductive member as antenna elements with the same antenna axis;
An antenna device including a feeding line that is disposed at a predetermined distance from the conductive layer via a dielectric and feeds power to the slot;
In the planar direction of the conductive layer, the feeder line is provided so as to overlap with the vicinity of the outer peripheral end of each of the plurality of slots via the dielectric,
An antenna device, wherein an inner peripheral side portion with respect to the slot and an outer peripheral side portion with respect to the slot among the conductive members are electrically connected by a connecting wire different from the conductive member.   2. The connection part between the connecting wire and the outer peripheral side part of the conductive member in the planar direction of the conductive layer is set in the vicinity of a connection part between the power supply line and the outside. Antenna device. The dielectric is a flat dielectric substrate,
The conductive layer is provided on one surface side of the dielectric substrate, the power supply line is provided on the back side of the surface on which the conductive layer is provided,
The connecting line penetrates through the dielectric substrate and is electrically connected to an inner peripheral side through portion electrically connected to an inner peripheral side portion of the conductive member and an outer peripheral side electrically connected to an outer peripheral side portion of the conductive member. 3. The method according to claim 1, further comprising: a penetrating portion; and a connecting portion that electrically connects the inner peripheral side penetrating portion and the outer peripheral side penetrating portion on the back surface side of the dielectric substrate. Antenna device.   The antenna device according to claim 1, wherein the plurality of slots include a plurality of at least two types of slots having different electrical lengths.   5. The antenna device according to claim 4, wherein in the planar direction of the conductive layer, among the plurality of slots, slots having the same electrical length are provided rotationally symmetrically about the antenna axis. . The plurality of slots have a spiral portion and an extending portion extending in the outer peripheral direction by changing the direction from the vicinity of the end portion on the outer peripheral side of the spiral portion,
The antenna device according to claim 1, wherein the feeder line is provided so as to overlap with an extended portion of the slot.   A high dielectric member having a relative dielectric constant higher than that of the dielectric is disposed in contact with the conductive layer so as to cover at least a part of the slot on the conductive layer. The antenna device according to claim 1.   The antenna device according to claim 7, wherein the slot is entirely covered with the high dielectric member.   The antenna according to any one of claims 1 to 8, further comprising a radio wave reflection member or a radio wave absorption member arranged at a predetermined distance so as to sandwich the feeder line therebetween with respect to the conductive layer. apparatus.

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