JP5572490B2 - Flat reflector - Google Patents

Description

  The present invention relates to a planar reflector that reflects an electromagnetic wave incident on a closed space and converges it to a desired position in the closed space, for example, in a broadcast wave receiving system or a wireless communication system.

  When directly receiving TV broadcasts, for example, terrestrial digital broadcasts with indoor antennas, in buildings or indoors of ordinary households, a reception electric field strength of a predetermined level or more is necessary, but if sufficient reception electric field strength cannot be obtained, Then, an indoor re-transmission device is installed indoors to increase the received electric field strength (see, for example, Patent Document 1). The indoor retransmission apparatus receives a television broadcast wave by a receiving antenna, amplifies the signal to a predetermined signal level, and retransmits the signal from the retransmission antenna so that a desired received electric field strength can be obtained indoors. .

  By installing the indoor retransmission apparatus as described above, the indoor received electric field strength can be increased, but the indoor retransmission apparatus is very expensive and requires an installation location.

  For this reason, it is desired to increase the received electric field strength in the room by a simpler method than in the indoor retransmission apparatus. As a simple method, for example, a reflector is installed using an indoor wall surface, etc., and a television broadcast wave incident on the room is reflected by the reflector and converged to a desired position to improve the electric field strength at the convergence point. It is possible to do.

  In order to converge a reflected wave at a predetermined distance from a reflecting surface using a reflecting plate and form an electric field concentration point (focal point), it is necessary to curve the reflecting surface in a parabolic shape like a parabolic antenna, which is conventionally used. With the planar reflecting plate, the reflected wave cannot be converged at a predetermined distance from the reflecting surface.

  FIG. 6 shows a state of the reflected wave 13 when a plane wave (electromagnetic wave) 12 is incident perpendicularly to the front surface of the planar conductor plate 11. When the plane wave 12 is incident perpendicularly to the front surface of the planar conductor plate 11, the planar conductor plate 11, which may be regarded as having a reflection coefficient of approximately 1, has a planar shape if the principle of Huygens Fresnel in geometric optics is taken into consideration. A combined wave of the reflected waves 13 generated at all points on the conductor plate 11 becomes a plane wave having the same phase, that is, a plane wave. Therefore, electric field concentration does not occur at a specific point.

  On the other hand, as shown in FIG. 7, when a plane wave 12 is incident on the front surface of a parabolic conductor plate 11A having a curved reflecting surface, in particular, a parabolic surface, the parabolic conductor plate 11A. The reflected waves 13 generated at all the above points have the same phase (as is well known, the reflected wave is reflected with a phase difference of 180 degrees with respect to the incident wave). The equiphase surface 14 is also curved in a parabolic shape corresponding to the parabolic conductor plate 11A. As a result, the electric field concentrates on the focal point 15 at the focal position of the paraboloid. Utilizing the above-mentioned well-known geometrical optics principle, parallel incident radio waves are reflected by a reflector with a large area, and the reflected radio waves are concentrated on the focal point of the paraboloid so as to obtain a high antenna gain. Is a well-known parabolic antenna.

JP 2004-128720 A JP 2010-62689 A

D. Sievenpiper et al, “High-Impedance Electro-magnetic Surfaces with a Forbidden Frequency Band,” IEEE Trans, Microwave Theory Tech., Vol. 47, pp. 2059-2074, 1999 K. Chang et al, “High-Impedance Surface with Nonindentical Lattices,” iWAT2008, pp.422-425,2008 Ibuchi et al. “Examination of Reflection Direction Control by Aperiodic Array High-Impedance Surface” IEICE Technical Report A P2010-2 (2010-04)

  For example, when a terrestrial digital broadcast is directly received by an indoor antenna in a general home, the received signal needs to have a signal quality with a CN ratio equal to or higher than a predetermined value. For this purpose, it is necessary to obtain a sufficient received electric field strength for the received radio wave. A conceivable method for this purpose is to install a reflector formed in a parabolic shape so that an electric field converging region such as the focal point of the parabolic antenna is formed at a desired position in the room. It is conceivable to secure the quality of the predetermined received radio wave by arranging the indoor antenna.

  However, when installing a reflector using an indoor wall surface in a general home, etc., it is difficult to install a reflector formed in a parabolic shape because the wall surface is usually a flat surface. At the same time, it creates a useless installation space, which is not realistic.

  The present invention has been made to solve the above-described problems, and provides a planar reflector that can reflect an electromagnetic wave incident on a closed space and converge it at a desired position, thereby increasing the electric field strength at the convergence point. For the purpose.

The planar reflecting plate according to the present invention is arranged in a matrix at substantially equal intervals on a planar member having a dielectric constant of 1.5 or less and on the front surface of the planar member, and reflects the incident wave. of a plurality of phase delay elements for delaying the phase, comprising a flat conductor plate provided on the entire back surface of the planar member, the largest phase delay element of the phase retardation effect in the vicinity of the center of the planar member A phase delay element having a small phase delay effect is arranged in order toward the outside, and the reflected wave from the phase delay element is converged in a dotted or linear manner at a predetermined distance from the front surface of the planar member. that a flat planar reflector, the plurality of phase delay elements, formed by using a conductive flakes, the electromagnetic wave lengths of each side is λ / 2~λ / 8 (λ to try to converge Square patch element set to the same wavelength range) Ri, at least some of said plurality of phase delay elements has an opening hole in the middle portion of the patch element, the more phase delay elements of large phase delay effect, characterized by being set to a large opening holes.
Further, the planar member is made of polystyrene foam or wood, holds a predetermined distance between the plurality of phase delay elements and the planar conductor plate, and an interval between adjacent sides of the plurality of phase delay elements is It is more preferable that the opening hole is set to 0.05 to 0.1λ and the opening hole is formed in a square shape.

  According to the present invention, the electromagnetic wave incident on the planar conductor plate can be reflected and converged to a desired reception point, the electric field strength in the convergence area can be increased, and the reception quality of the received radio wave can be improved. Therefore, for example, an electromagnetic wave directly incident on the room is reflected by the planar reflector of the present invention and converged to a desired reception point, thereby improving the indoor wireless environment.

It is a sectional side view which shows the basic composition of the planar reflector which concerns on Example 1 of this invention. It is a perspective view of the patch element structure used as a phase delay element in the first embodiment. It is a figure which shows the reactance transition of the patch element structure in the Example 1. FIG. The specific structural example of the planar reflecting plate which concerns on the Example 1 is shown, (a) is a front view, (b) is a side view. It is a front view which shows the structural example of the planar reflecting plate which concerns on Example 2 of this invention. It is a figure which shows the state of the reflected wave when a plane wave (electromagnetic wave) injects into a planar conductor board. It is a figure which shows the state of the reflected wave at the time of entering a plane wave (electromagnetic wave) in a parabolic conductor plate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side sectional view showing a basic configuration of a planar reflector according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 21 denotes a planar member, which is formed into a flat plate shape using, for example, wood or foamed polystyrene having a dielectric constant of about 1.5 or less that is close to air. On the front surface of the planar member 21, a plurality of phase delay elements 22 are arranged at equal intervals (center interval). The phase delay element 22 reflects the incident wave 23 and delays the phase of the reflected wave 24. Note that Non-Patent Documents 1 to 3 of the above prior art documents describe the effect of the phase delay of the reflected wave due to the arrangement of the resonant element (corresponding to the phase delay element in the description of the present invention) on the reflector with respect to the incident wave, Since it is described in detail regarding the setting of the phase delay amount, for the basic understanding of the phase delay of the reflected wave 24, please refer to the description of the above document.

  When a plane wave (electromagnetic wave) is incident vertically on the front surface of the planar member 21, the incident wave 23 is reflected by the phase delay element 22 to become a reflected wave 24. At this time, the phase displacement amount of the reflected wave 24 is determined by the phase delay element 22.

  As the phase delay element 22, for example, an element Zc for delaying the reflected wave phase from the reflection at other positions is disposed near the center of the incident wave 23, and an element Zb having a phase delay effect lower than that of the element Zc is disposed around the element Zc. And an element Za having a lower phase delay effect is provided on the outer edge. That is, the element Zc having the largest phase delay effect is arranged as the phase delay element 22 at the center of the planar member 21, and the elements Zb and Za are sequentially fixed so that the phase delay effect becomes smaller toward the outside. It arrange | positions so that it may become a substantially concentric form at intervals.

  Specifically, an element having a high capacitive reactance is selected as Zc with respect to the frequency of the incident wave 23, and elements having a small capacitive reactance are sequentially selected as Zb and Za.

  By arranging the plurality of phase delay elements 22 on the front surface of the planar member 21 as described above, the incident wave 23 incident on the planar member 21 has a different phase delay effect when reflected, and thus the planar member 21. Even if the front surface is physically planar, that is, even if the phase delay element 22 is disposed in a planar shape, the equiphase surface 25 of the reflected wave 24 can be curved. In this case, as described above, the element Zc having the largest phase delay effect is arranged as the phase delay element 22 in the center of the planar member 21, and the elements Zb, By sequentially disposing Za in a concentric manner at regular intervals, it is possible to generate a convergence area 26 that is an area where the electromagnetic waves of the reflected wave converge at a finite distance from the reflection surface of the planar member 21. The distance between the planar member 21 and the convergence area 26 can be set by the value of the phase delay element 22.

  The planar reflection plate configured as described above is installed using the wall surface of the house, and the phase delay effect of the phase delay element 22 so that the convergence region 26 is generated at a position of, for example, 2 to 3 m from the planar reflection plate. By setting an indoor antenna at the position of the convergence area 26, for example, even in a room where direct reception of digital terrestrial broadcasting is difficult, the TV broadcast wave incident on the room is converged to reduce the signal level. It is possible to improve the signal quality of the required CN ratio and enable direct reception. The indoor antenna can receive the converged reflected wave 24 from the planar reflecting plate as long as it is in the vicinity of the convergence area 26 without being accurately placed at the position of the convergence area 26. For example, if the direction connects the planar member 21 and the convergence area 26, the range is approximately λ / 8 centered on the convergence area 26, and if the direction is parallel to the planar member 21, the distance is approximately λ / 4 centered on the convergence area 26. An indoor antenna can be installed in the range to receive the reflected wave 24 converged from the planar reflector. The planar reflector is installed using a wall surface facing the direction of arrival of TV broadcast waves, and the indoor antenna is connected to a television receiver installed indoors.

  For example, a patch element structure 30 shown in FIG. 2 is used as the phase delay element 22 disposed on the planar member 21 to reflect the incident wave 23 and delay the phase of the reflected wave. The patch element structure 30 has a configuration in which a planar conductor plate (ground plate) 31 and a patch element 32 using, for example, a rectangular conductor plate are arranged to face each other with a predetermined interval. The patch element 32 has, for example, a side length L of about λ / 2 to λ / 8, and a distance d from the planar conductor plate 31 of about 2 cm. The length of one side of the planar conductor plate 31 is set to a value sufficiently larger than that of the patch element 32. Note that λ represents the wavelength of the electromagnetic wave to be converged.

  The patch element structure 30 has parallel resonance characteristics, and FIG. 3 shows changes in reactance of the patch element structure. The horizontal axis represents frequency (f), and the vertical axis represents reactance X. I showed it. FIG. 3 shows that the patch element structure may function as an inductive reactance element or a capacitive reactance depending on the excitation frequency.

  As shown in FIG. 3, the patch element structure 30 functions as an inductive reactance element in the frequency region below the resonance point fo and as a capacitive reactance element in the frequency region above the resonance point fo. By setting the length L of one side in the range of about λ / 2 to λ / 8, the device can be operated as an inductive reactance element or a capacitive reactance element.

  In the planar reflector shown in FIG. 1, when the frequency of the incident wave 23 is fixed, the patch element 32 having a small size deviated from the resonance frequency of the patch element structure 30 can be obtained by using the characteristics of the patch element structure 30. Can be used to realize a capacitive reactance element, and the value of the capacitive reactance can be controlled by variably setting the size (area) of the patch element 32. In this case, even if the thickness of the patch element 32 is uniform, the value of the capacitive reactance changes only by controlling the value of the element size (area). Therefore, the size (area) is formed on the planar member 21 as shown in FIG. It is possible to converge the electric field in the form of dots or lines by using a planar reflecting plate in which a plurality of patch elements 32 having different () are arranged at a constant interval (center interval).

  4A and 4B show a specific configuration example of the planar reflector according to the first embodiment of the present invention. FIG. 4A is a front view, and FIG. 4B is a side view. FIG. 4 shows an example in which a plurality of patch elements 32 are arranged in a matrix on a single planar member 21.

  The planar member 21 is made of foamed polystyrene having a thickness T of about 2 cm in a square shape (horizontally long). For example, the lateral width W is set to about 180 to 190 cm and the height H is set to about 135 to 140 cm. A plurality of patch elements 32 are arranged on the front surface of the planar member 21 in, for example, 6 rows and 8 columns using conductor foil pieces, and a planar conductor plate 31A is provided on the entire rear surface of the planar member 21. . The planar conductor plate 31A is formed using, for example, a conductor foil piece, and functions as the planar conductor plate 31 of each patch element structure 30 shown in FIG. In other words, a plurality of patch element structures 30 are arranged on the planar member 21 in 6 rows and 8 columns.

  The patch element 32 is formed in a square shape having the same vertical and horizontal lengths La, and is arranged at a constant interval G. Each patch element 32 is provided with, for example, a rectangular opening hole 33 at the center. In this case, for the eight patch elements 32 arranged in each row, the opening hole 33 is set to a large value (hole dimension h3) so that the element area located at the center is the smallest, and as it goes in both directions. The opening holes 33 are sequentially set to small values (hole dimension h2) and (hole dimension h1) so as to increase the element area. The patch elements 32 located on both sides of each row are set so as to have the largest element area without providing the opening holes 33. The dimensions h1, h2, and h3 of the opening hole 33 indicate the lengths in the vertical and horizontal directions.

  That is, for each patch element 32 in each row, for example, the capacitive reactance value is set to be large so that the phase delay effect of the element at the center is maximized, and the capacitive element is set so that the phase delay effect becomes smaller toward both sides. Reactance values are set sequentially smaller. For example, the vertical and horizontal lengths La, the gap G, and the dimensions h1, h2, and h3 of the opening holes 33 are set as follows.

La: about 0.3λ to 0.5λ
G: about 0.05λ to 0.1λ
h1: about 0.05λ
h2: about 0.12λ
h3: about 0.15λ
By setting each patch element 32 and the opening hole 33 to the above dimensions, the patch element 32 can be operated as a capacitive reactance.

  By using the planar reflecting plate configured as described above, the reflected wave is converged linearly (longitudinal direction) about 2 m ahead from the planar member 21, and the electric field strength in the convergence region is improved by several dB. be able to.

  For example, a foamed polystyrene having a vertical and horizontal dimension of 2.7 m × 2.7 m and a thickness T of 2 cm is used as the planar member 21, and the vertical and horizontal lengths La of the patch elements 32 disposed on the front surface of the planar member 21. When the distance G and the dimensions h1, h2, and h3 of the opening hole 33 are set to the above values, the reflected wave reflected by the patch element 32 is converged linearly (longitudinal direction) in front of about 2 m, and The electric field strength in the convergence range can be improved by about 3 to 5 dB.

  Next, a planar reflecting plate according to Embodiment 2 of the present invention will be described.

  FIG. 5 is a front view showing a configuration example of the planar reflector according to the second embodiment of the present invention. The planar reflector according to the second embodiment shows an example in which a plurality of patch elements 32 are arranged in 8 rows and 8 columns on one planar member 21.

  A plurality of patch elements 32 are arranged in 8 rows and 8 columns on the front surface of the planar member 21, and a planar conductor plate 31 </ b> A is provided on the entire rear surface of the planar member 21. The patch element 32 is formed in a square shape having the same vertical and horizontal lengths La, and is arranged at a constant interval G.

  Each patch element 32 is provided with, for example, a rectangular opening hole 33 at the center. In this case, for one to a plurality of, for example, four patch elements 32 arranged in the center of the planar member 21, the opening hole 33 is set to a large value (hole dimension h3) so that the element area is minimized. The opening holes 33 are sequentially set to small values (hole dimension h2) and (hole dimension h1) so that the element area increases as going outward. That is, twelve patch elements 32 each having an opening hole 33 having a hole size h2 are disposed outside the four patch elements 32 positioned at the center, and further, an opening hole 33 having a hole dimension h1 is provided outside thereof. Twenty patch elements 32 are arranged. The patch element 32 positioned on the outermost side is set so that the element area is maximized without providing the opening hole 33.

  As described above, the patch element 32 having the largest phase delay effect is arranged at the center of the planar member 21, and the patch elements 32 having small opening hole sizes are substantially arranged so that the phase delay effect is gradually reduced in the outward direction. They are arranged concentrically. The numerical values of the vertical and horizontal lengths La, the gap G, and the dimensions h1, h2, and h3 of the opening holes 33 are set in the same manner as in the first embodiment.

  By using the planar reflector having the element arrangement shown in the second embodiment, the reflected wave can be converged in a dot shape in front of the planar member 21 by about 2 m.

  According to the first and second embodiments, the reflected wave can be converged in a dotted or linear manner at a finite distance from the reflecting surface, for example, at a position of about 2 to 3 m using the planar reflecting plate. Therefore, by installing the planar reflecting plate on the wall surface of the house and arranging the indoor antenna at the point-like or linear convergence region position, the received electric field strength of the indoor antenna can be improved by several dB. For this reason, even in a room where the reception field strength is not sufficient and direct terrestrial digital broadcasting is difficult to receive, the reception signal level of the indoor antenna is increased, and the signal quality of the required CN ratio is secured and direct reception is possible. It can be.

  In the first and second embodiments, an opening hole 33 is provided in the center of the patch element 32, and the reactance, that is, the phase delay effect of each patch element 32 is variably set by changing the element area according to the size of the opening hole 33. However, the opening area 33 may not be provided, and a predetermined phase delay effect may be obtained by changing the element area depending on the vertical and horizontal lengths of the patch elements 32.

  In the first and second embodiments, the case where the patch element 32 is formed in a square shape has been described. However, the patch element 32 can be formed in an arbitrary shape such as a polygon or a circle. In this case, the patch elements 32 are arranged so that the center distance is constant.

  In the first and second embodiments, the case where the patch element 32 is provided with the quadrangular opening hole 33 has been described. However, the shape of the opening hole 33 is not limited to the quadrangular shape and can be formed in an arbitrary shape. is there.

  In the first and second embodiments, the patch element 32 is used as the phase delay element. However, other elements may be used. For example, a plurality of reflective elements (reflective electrodes) are arranged on the front surface of the planar member 21 in the same manner as the patch element 32, and an inductance element and a capacitance element are connected to each reflective element so as to obtain a predetermined phase delay effect. Also good.

  Further, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage.

  DESCRIPTION OF SYMBOLS 21 ... Planar member, 22 ... Phase delay element, 23 ... Incident wave, 24 ... Reflected wave, 25 ... Equiphase surface, 26 ... Convergence zone, 30 ... Patch element structure, 31, 31A ... Planar conductor plate, 32 ... patch element, 33 ... opening hole of patch element.

Claims (2)

A planar member having a dielectric constant of 1.5 or less, and a plurality of phase delay elements arranged in a matrix at substantially equal intervals on the front surface of the planar member to reflect incident waves and delay the phase of the reflected waves And a planar conductor plate provided on the entire back surface of the planar member, a phase delay element having the largest phase delay effect is disposed near the center of the planar member, and sequentially phased toward the outside. arranged a small phase delay element of the delay effect, a flat planar reflector from the front Ru converges the reflected wave by the phase delay element in punctiform or linear at a position a predetermined distance of said planar member,
The plurality of phase delay elements are formed using conductor thin pieces, and the length of each side is set to be the same within a range of λ / 2 to λ / 8 (λ is the wavelength of the electromagnetic wave to be converged). It is a square patch element, and at least a part of the plurality of phase delay elements has an opening hole at the center of the patch element, and the opening hole is set to be larger for a phase delay element having a larger phase delay effect. A planar reflector characterized by the above.   The planar member is made of polystyrene foam or wood, and maintains a predetermined distance between the plurality of phase delay elements and the planar conductor plate,
  The planar reflector according to claim 1, wherein an interval between adjacent sides of the plurality of phase delay elements is 0.05 to 0.1λ, and the opening hole is a square.

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