JP5794688B2 - Aperture shared array antenna and adaptive directional receiver - Google Patents

Description

  The present invention relates to a proposal of a novel array antenna structure, and more particularly, to a novel array antenna that can be used for an adaptive array antenna or the like that can obtain a high signal-to-interference rejection ratio (SIR) in mobile communication in a high frequency band higher than the VHF band. The present invention relates to an array antenna structure and an adaptive directional receiver using the novel array antenna.

  In land mobile communication, communication quality of received signals deteriorates due to fading and multipath. An adaptive array antenna is an effective means for solving this problem. A general adaptive array antenna is composed of a plurality of antennas and receivers provided for each antenna, and forms adaptive directivity in the baseband. Therefore, a large number of receivers are required, which is disadvantageous in terms of economy and power consumption. It is. For this reason, an electronic scanning waveguide (ESPAR antenna) has been proposed as an adaptive array antenna including only one receiver (see Patent Document 1).

  Mobile multimedia broadcasting (ISDB-Tmm), which is a broadcasting system for mobile terminals derived from the terrestrial integrated digital broadcasting service (ISDB-T) system, has a 14.5 MHz width (207.5 M to 222 MHz) in the VHF band, and is an ISDB- Broadcast service is realized using the same 429 kHz-wide segment as T. An ISDB-Tmm broadcast wave uses orthogonal frequency division multiplexing (OFDM) modulation, and a diversity antenna or an adaptive array antenna is effective in order to receive the mobile wave with high quality.

In addition, ISDB-TSB (Integrated Services Digital Broadcasting-Terrestrial) is a digital radio standard based on ISDB-T.
For Sound Broadcasting, as in ISDB-T, OFDM modulation is used as a multiplexing method in order to prevent multipath interference. ISDB-Tmm is a method adapted to the frequency band (V-HIGH) of 207.5 to 222 MHz, whereas ISDB-TSB is a method adapted to the frequency band (V-LOW) of 90 to 108 MHz, The frequency of ISDB-TSB is a low band close to 1/2 of ISDB-Tmm. Unlike terrestrial broadcasting, terrestrial broadcasting causes multipath (delayed wave) interference caused by reflection from buildings. This multipath disturbance is a ghost disturbance in analog broadcasting. Since OFDM can be demodulated without signal degradation, it has a feature of being resistant to multipath interference. Therefore, a single frequency network (SFN) system capable of retransmission relaying at the same frequency can be used in places where areas are adjacent by handling other than the main wave as a multipath, and the frequency can be used effectively.

However, in the diversity antenna and adaptive array antenna in the VHF band, since the physical length of each antenna element is large, it is difficult to mount a plurality of antenna elements on an automobile or an information terminal. For example, when an ESPAR antenna having a circular array with a radius of 0.2λ is constructed in the FM band, the array radius is 0.72 m, the monopole length is 0.9 m, and the volume is 1.5 m ^3. It is difficult to mount an adaptive array antenna in the VHF band on the information terminal in view of the physical length of the antenna element. In addition, the ESPAR antenna has a problem that it is difficult to apply to the mobile communication such as the blind algorithm is used for forming the adaptive directivity and the calculation amount is large and it is not suitable for use in the mobile communication environment. .

  In view of such circumstances, the group of the present inventors has already made the concept of the ESPAR antenna by operating the rear defogger of the vehicle (automobile) as an antenna opening and by providing a plurality of ports on the antenna opening. It has been proposed by computer simulation that a VHF band adaptive antenna for a vehicle (automobile) that forms adaptive directivity in a one-channel receiving system by applying this has wideband characteristics (see Non-Patent Document 1).

JP 2003-142926 A

Nullsaliza Abdullah et al., “Application to shared aperture FM adaptive antenna ESPER antenna using rear defogger”, IEICE technical report, 2009-189, 2010, p. 29-34

  However, the technique described in Non-Patent Document 1 merely verifies an adaptive antenna of a single-band reception system by computer simulation and experiment, and whether or not the technique can be applied to an aperture shared array antenna for multiband. Has not been considered.

  An object of the present invention is to provide an array antenna that can be applied to multiband with a small and simple structure, and an adaptive directional receiver using the array antenna.

  To achieve the above object, according to a first aspect of the present invention, there is provided: (a) first and second end stripes spaced apart from each other in parallel; The first to m-th m main grid lines connected in parallel to each other to the first and second end stripes, respectively, and (c) ) A rectangular grid-shaped shared antenna aperture having four auxiliary grid lines provided in parallel so as to intersect all of the main grid lines, with the direction perpendicular to the longitudinal direction of the main grid lines as the longitudinal direction. The gist of the invention is that it is an array antenna with an aperture plane. In the aperture-plane shared array antenna according to the first aspect, the four auxiliary grid lines are set as the first, second, third, and fourth auxiliary grid lines in order from the first end stripe side, and the mth The intersection of the first main grid line and the first auxiliary grid line is the first feeding point, the intersection of the mth main grid line and the third auxiliary grid line is the second feeding point, the first feeding point The intersection point of the main grid line and the fourth auxiliary grid line is selected as the third feeding point, and the intersection point of the first main grid line and the second auxiliary grid line is selected as the fourth feeding point. According to the fourth feeding point, four electromagnetically independent virtual antennas are arranged on the shared antenna opening surface.

  The gist of a second aspect of the present invention is an adaptive directivity receiving apparatus using the array antenna with an aperture plane according to the first aspect. That is, the adaptive directivity receiving apparatus according to the second aspect of the present invention includes: (a) first and second end stripes, m, which are spaced apart from each other and arranged in parallel; The first and m-th m main grid lines connected in parallel to each other and perpendicular to the longitudinal direction of the main grid lines are connected to the respective end stripes of the second end stripe and the second end stripes. An aperture plane shared array antenna having a rectangular grid-shaped shared antenna aperture plane having four auxiliary grid lines provided in parallel so as to cross all of the main grid lines, with the direction as a longitudinal direction; ) Four auxiliary grid lines are set as the first, second, third and fourth auxiliary grid lines in order from the first end stripe side, and the m-th main grid line and the first auxiliary grid line are Select the active element feed point to capture the wireless signal from the air at the intersection. And a baseband signal generator connected to the feed point of the active element, (c) the intersection of the mth main grid line and the third auxiliary grid line, the first main grid line and the fourth The intersection of the first auxiliary grid line and the intersection of the first main grid line and the second auxiliary grid line are selected as the feeding points of the first, second and third parasitic elements, respectively. Using the first, second and third variable reactance circuits respectively connected to the feed points of the second and third parasitic elements, and (d) the objective function output from the baseband signal generator, the first, A reactance adaptive control circuit for adjusting a ground reactance value of the second and third variable reactance circuits. In the adaptive directional receiver according to the second aspect of the present invention, the active element and the first, second, and third elements are controlled by controlling the ground reactances of the first, second, and third parasitic elements, respectively. The radio signal is demodulated while controlling the directivity of the array antenna composed of the above parasite elements.

  According to the present invention, it is possible to provide an array antenna that can be applied to a multiband with a small and simple structure, and an adaptive directional receiver using the array antenna.

It is a typical top view explaining the outline of the structure of the aperture-plane shared array antenna which concerns on the prior examination example examined until it reached this invention. FIG. 2 is a schematic plan view illustrating an enlarged detail of a part of the structure of an aperture plane shared array antenna according to a prior study example illustrated in FIG. 1. FIG. 2 is a schematic bird's-eye view for explaining the structure of a rear defogger provided in a vehicle (automobile) body, in particular, a rear metal body and a rear metal body, to which the array antenna with an aperture plane according to the example of prior study shown in FIG. 1 is applied. . It is a typical top view explaining the outline of the structure of the aperture-plane shared array antenna which concerns on the comparative example (comparative example 1) for comparing with a prior examination example. It is a typical top view explaining the outline of the structure of the aperture-plane shared array antenna which concerns on the other comparative example (comparative example 2) for comparing with a prior examination example. The frequency dependence (solid line) of the average value of the VSWR seen from each port (feeding point) of the aperture-area shared array antenna according to the prior study example shown in FIG. The frequency dependence (broken line) of the average value of VSWR as seen from each port (feeding point) of the array antenna and the VSWR as seen from each port (feeding point) of the aperture shared antenna according to Comparative Example 2 shown in FIG. It is a figure shown in comparison with the frequency dependence (a dashed-dotted line) of an average value. The frequency dependence (solid line) of the average value of the inter-port coupling (CBP) between the ports of the aperture plane shared array antenna according to the prior study example shown in FIG. 1 is shown in FIG. Frequency dependence (dashed line) of the average value of inter-port coupling between each port of the array antenna and frequency dependence of the average value of inter-port coupling between each port of the aperture-shared array antenna according to Comparative Example 2 shown in FIG. It is a figure shown in comparison with (one-dot chain line). The frequency dependence (solid line) of the average value of the spatial correlation (SCC) as seen from each port (feeding point) of the aperture shared array antenna according to the prior study example shown in FIG. 1 is shown in Comparative Example 1 shown in FIG. Frequency dependence (dashed line) of the average value of the spatial correlation seen from each port (feeding point) of the aperture shared antenna array and each port (feeding point) of the aperture shared antenna according to Comparative Example 2 shown in FIG. It is a figure shown in comparison with the frequency dependence (one-dot chain line) of the average value of the spatial correlation seen from. The first port of the aperture-shared array antenna shown in FIG. 1 is used as the active element feed point, and the remaining three ports are used as the parasite element feed points. It is a figure which shows the cumulative distribution (CCDF) of signal-to-interference noise ratio SINR in 760 MHz (one-dot chain line), 830 MHz (dashed line), and 900 MHz (solid line) when an adaptive beam is formed by changing. The first port of the aperture shared antenna according to Comparative Example 1 shown in FIG. 4 is used as a feed point for active elements, and the remaining three ports are used as feed points for parasite elements. It is a figure which shows the cumulative distribution (CCDF) of signal-to-interference noise ratio SINR in 760 MHz (one-dot chain line), 830 MHz (dashed line), and 900 MHz (solid line) when an adaptive beam is formed by changing. The first port of the aperture shared antenna according to Comparative Example 2 shown in FIG. 5 is used as a feed point for active elements, and the remaining three ports are used as feed points for parasite elements. It is a figure which shows the cumulative distribution (CCDF) of signal-to-interference noise ratio SINR in 760 MHz (one-dot chain line), 830 MHz (dashed line), and 900 MHz (solid line) when an adaptive beam is formed by changing. It is a typical block diagram explaining the outline of the structure of the adaptive directivity receiver using the aperture-plane shared array antenna which concerns on the prior examination example examined until it reaches this invention. It is a schematic diagram explaining the structure of the OFDM signal used for the adaptive directivity receiver which concerns on the prior examination example shown in FIG. It is a typical top view explaining the outline of the structure of the array antenna with an opening surface which concerns on embodiment of this invention. It is a typical top view explaining the outline of the structure of the aperture-plane shared array antenna which concerns on the comparative example (comparative example 3) for comparing with embodiment of this invention. It is a typical top view explaining the outline of the structure of the aperture-plane shared array antenna which concerns on the other comparative example (comparative example 4) for comparing with embodiment of this invention. The frequency dependence (solid line) of the average value of the VSWRs as seen from each port (feeding point) of the aperture shared antenna according to the embodiment of the present invention shown in FIG. 14 is related to Comparative Example 3 shown in FIG. Frequency dependence (broken line) of the average value of VSWR viewed from each port (feeding point) of the aperture-plane shared array antenna and each port (feeding point) of the aperture-shared array antenna according to Comparative Example 4 shown in FIG. It is a figure shown in comparison with the frequency dependence (two-dot chain line) of the average value of VSWR. The frequency dependence (solid line) of the average value of the inter-port coupling (CBP) between the ports of the aperture-plane shared array antenna according to the embodiment of the present invention shown in FIG. 14 is related to Comparative Example 3 shown in FIG. Frequency dependence (broken line) of the average value of inter-port coupling between the ports of the aperture shared antenna array and the average value of the inter-port coupling between the ports of the aperture shared antenna according to Comparative Example 4 shown in FIG. It is a figure shown in comparison with frequency dependence (two-dot chain line). The frequency dependence (solid line) of the average value of the spatial correlation (SCC) as seen from each port (feeding point) of the array antenna with an aperture plane according to the embodiment of the present invention shown in FIG. 14 is compared with that shown in FIG. The frequency dependence (dashed line) of the average value of the spatial correlation as viewed from each port (feeding point) of the aperture shared antenna according to Example 3 and each port of the aperture shared antenna according to Comparative Example 4 shown in FIG. It is a figure shown in comparison with the frequency dependence (two-dot chain line) of the average value of the spatial correlation seen from (feeding point). The first port of the aperture shared antenna array according to the embodiment of the present invention shown in FIG. 14 is used as a feed point for active elements, and the remaining three ports are used as feed points for parasite elements. 900 MHz (solid line), 1000 MHz (dashed line), 1080 MHz (one-dot chain line), 2075 MHz (two-dot chain line), 2100 MHz (dotted line), 2200 MHz (thick solid line; double line) when an incident beam is changed to form an adaptive beam It is a figure which shows the cumulative distribution (CCDF) of signal-to-interference noise ratio SINR. The first port of the aperture shared antenna according to Comparative Example 4 shown in FIG. 16 is used as the feed point of the active element, and the remaining three ports are used as feed points of the parasite element. Signal-to-interference at 900 MHz (solid line), 1000 MHz (dashed line), 1080 MHz (one-dot chain line), 2075 MHz (two-dot chain line), 2100 MHz (dotted line), 2200 MHz (thick solid line; double line) when an adaptive beam is formed by changing It is a figure which shows the cumulative distribution (CCDF) of noise ratio SINR. The first port of the aperture shared antenna according to Comparative Example 3 shown in FIG. 15 is used as the feeding point of the active element, and the remaining three ports are used as the feeding points of the parasite element. Signal-to-interference at 900 MHz (solid line), 1000 MHz (dashed line), 1080 MHz (one-dot chain line), 2075 MHz (two-dot chain line), 2100 MHz (dotted line), 2200 MHz (thick solid line; double line) when an adaptive beam is formed by changing It is a figure which shows the cumulative distribution (CCDF) of noise ratio SINR. It is a typical block diagram explaining the outline of the structure of the adaptive directivity receiving apparatus using the aperture-plane shared array antenna which concerns on embodiment of this invention.

  With reference to FIGS. 1 to 13, an aperture plane shared array antenna that has already been partially studied in Non-Patent Document 1 for a single band will be described as a prior study example up to the present invention. With reference to FIGS. 14 to 23, a dual-band aperture shared antenna according to an embodiment of the present invention and an adaptive directional receiver using the double-band aperture shared antenna will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and ratios between plane dimensions and the like are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Prior study example)
In the array antenna having an aperture plane according to the prior study example up to the present invention, 21 _s substantially corresponds to the structure already disclosed in FIG. 2 of Non-Patent Document 1, but as shown in FIG. _{Each of} the first end stripe G _pp1 and the second end stripe G _pp2 and the first end stripe G _pp1 and the second end stripe G _pp2 arranged in _parallel with each other The first main grid line G _h1 , the second main grid line G _h2 , the third main grid line G _h3 ,..., The mth main grid line G _h1 , the second main grid line G _h2 , the third main grid line G _h3,. The grid line G _hm (m = 17) and the direction perpendicular to the longitudinal direction of the 1st to m-th main grid lines G _h1 , G _h2 , G _{h3 ,.} Two pieces arranged in parallel so as to cross all of G _h1 , G _h2 , G _h3 ,..., G _hm A rectangular grid-like shared antenna aperture surface having auxiliary grid lines G _v11 and G _v12 is provided.

The two auxiliary grid line G _v11, G _v12, in order from the first end stripe G _pp1 side, is defined as the first auxiliary grid line G _v11, second auxiliary grid line G _v12, shown in FIG. 1 As described above, the end of the m-th main grid line G _hm on the first end stripe G _pp1 side is used as the first feeding point P ₁ , the m-th main grid line G _hm and the second auxiliary grid line. The intersection with G _v12 is the second feeding point P ₂ , the end of the first main grid line on the second end stripe G _pp2 side is the third feeding point P ₃ , and the first main grid line And the first auxiliary grid line G _v11 are selected as the _fourth feeding point P _4, and the first to fourth feeding points P ₁ , P ₂ , P ₃ , P _{4 are used as} the common antenna opening surface. A four-element antenna array for a single band is configured by arranging four electromagnetically independent virtual antennas.

In the prior study example, since the experiment is performed with a 1/10 scale model, the computer simulation by the electromagnetic analysis simulator IE3D is also scaled to 1/10. Therefore, in FIG. 1, the horizontal width a = 110 mm, the height b = 48 mm, the width d ₁₁ = 5 mm measured in the horizontal direction of the first end stripe G _pp1 and the second end stripe G _pp2 , the first The distance d ₁₂ = 18 mm measured in the horizontal direction between the auxiliary grid line G _v11 and the second auxiliary grid line G _v12 , between the second auxiliary grid line G _v12 and the second end stripe G _pp2 The distance d ₁₃ measured in the horizontal direction is 40.5 mm. The frequency band of FM radio in Japan is 76-90 MHz, and the band in the 1/10 scale model shown in FIG. 1 is 760-900 MHz. Since the performance of the antenna of the vehicle (car) is strongly influenced by the body, the opening according to the preceding study example is also shown in the state of mounting the antenna on the bodies 33 and 32 of the vehicle (car) as shown in FIG. The plane shared array antenna 21 _s is evaluated.

Taking into account the structure of the rear defogger of a vehicle (automobile) as shown in FIG. 3, the preceding study example opening face array antenna is 21 _s in accordance with, in the 1/10 scale model shown in FIG. 2, the width 0.5mm The main grid lines G _h1 , G _h2 , G _h3 ,..., G _hm having a thickness of 40 μm (m = 17 in the prior study example) are spaced at 2.5 mm intervals (both ends are 1.25 mm intervals). Along the first direction (for example, the horizontal direction), it is affixed to a glass having a relative dielectric constant of 7 and a thickness of 0.5 mm. This opening surface shared array antenna 21 _s is mounted on the window portion of the rear metal body 32 as shown in FIG.

The key parameter for realizing the aperture plane shared array antenna 21 _{s according} to the prior study example as four electromagnetically independent virtual antennas and realizing it as a four-element array antenna is a spatial correlation (SCC) between the virtual antennas. ). Spatial correlation (SCC) is a performance index that represents the similarity of the three-dimensional complex directivity of a plurality of antennas. The lower the value, the greater the diversity gain. The spatial correlation ρ _e is expressed by the following equation (1).

...... (1)

Here, A ₁ (θ, φ) and A ₂ (θ, φ) are the complex directivities of the two antennas, and A ₁ ^* (θ, φ) represents the complex conjugate of A ₁ (θ, φ). , A ₂ ^* (θ, φ) represents the complex conjugate of A ₂ (θ, φ). In order to evaluate the performance of the array antenna 21 _{s according to} the prior study example, VSWR, inter-port coupling (CBP), and spatial correlation (SCC) are analyzed by the electromagnetic analysis simulator IE3D, and the comparison example 1 shown in FIG. according compared to two comparative examples of open surface array antenna 21 _b according to the comparative example 2 shown in open surface array antenna 21 _a and FIG. 5 shows the comparison result, respectively 6, 7 and 8.

Actually, more than 100 cases of the combinations of the positions of the ports P ₁ , P ₂ , P ₃ , and P ₄ were examined. For convenience, only the structure of the comparative example shown in FIGS. 4 and 5 will be described. Then, the performance is compared with the performance of the aperture plane shared array antenna 21 _{s according to} the previous study example. For example, although not shown, there are cases where there are two auxiliary grid lines (vertical grid lines) G _v11 and G _{v12 at} the approximate center of the shared antenna aperture surface as shown in FIG. As a result of comparison, the result of calculating inter-port coupling (CBP) and spatial correlation (SCC) at f = 830 MHz provides two auxiliary grid lines (vertical grid lines) G _v11 and G _v12 , It has been confirmed that the inter-linkage (CBP) increases and the spatial correlation (SCC) decreases.

Also opening face array antenna 21 _a according to Comparative Example 1 shown in FIG. 4, 1/10 is a structure of the scale model, the width a = 110 mm, height b = 48 mm, the first end stripes G _pp1 and the The second end stripe G _pp2 has the same width d ₂₁ = 5 mm as measured in the horizontal direction, which is the same as the aperture-plane shared array antenna 21 _{s according} to the prior study example shown in FIG. However, the opening surface array antenna 21 _a according to Comparative Example 1 shown in FIG. 4, the distance measured in the horizontal direction between the first auxiliary grid line G _v21 and the second auxiliary grid line G _v22 d ₂₂ = 43 mm, and the distance d measured in the horizontal direction between the first auxiliary grid line G _v11 and the second auxiliary grid line G _v12 of the aperture-area shared array antenna 21 _{s according} to the prior study example shown in FIG. _Wider than _twelve . Therefore, conversely, the distance d ₂₃ = 28mm next measured in the horizontal direction between the second auxiliary grid line G _v22 and the second end stripes G _pp2, openings according to the prior study example shown in FIG. 1 narrower than the distance d _13, measured in the horizontal direction between the second auxiliary grid line G _v12 surface array antenna 21 _s and the second end stripes G _pp2.

Also in the aperture plane array antenna 21 _a according to Comparative Example 1 shown in FIG. 4, similar to the opening surface array antenna 21 _s according to the prior study example shown in FIG. 1, the first end stripe G _pp1 side seventeenth feeding point P ₁ the end portion first major grid lines G _hm, seventeenth main grid line intersection of the G _hm and second auxiliary grid line G _v22 second feeding point P ₂ , The end of the first main grid line on the second end stripe G _pp2 side is the third feeding point P ₃ , and the intersection of the first main grid line and the first auxiliary grid line Gv 21 is the first Four feed points P ₄ are selected, and four virtual antennas are arranged on the shared antenna opening surface by the first to fourth feed points P ₁ , P ₂ , P ₃ , P ₄ , and four elements for a single band. It is intended to constitute an antenna array.

Also opening face array antenna 21 _a according to Comparative Example 2 shown in FIG. 5, 1/10 is a structure of the scale model, the width a = 110 mm, height b = 48 mm, the first end stripes G _pp1 and the The second end stripe G _pp2 has the same width d ₂₁ = 5 mm as measured in the horizontal direction, which is the same as the aperture-plane shared array antenna 21 _{s according} to the prior study example shown in FIG. However, the opening surface array antenna 21 _a according to Comparative Example 2 shown in FIG. 5, the point is only one auxiliary grid line G _v31 in the center, the opening surface array antenna according to the prior study example shown in FIG. 1 Different from 21 _s . In FIG. 5, the distance d32 = 49.75 mm between the first end stripe G _pp1 and the auxiliary grid line G _v31 and the distance between the auxiliary grid line G _v31 and the second end stripe G _pp2. d33 = d32 = 49.75 mm.

Therefore, in the aperture plane array antenna 21 _a according to Comparative Example 2 shown in FIG. 5, the auxiliary grid line G _v31 central one has not been in any of the reference points of the four feeding points. That is, the open surface array antenna 21 _a, the end first feed point of the first end stripe G _pp1 side of the 17 th major grid lines G _hm P ₁ according to Comparative Example 2 shown in FIG. 5 The point that the end of the first main grid line on the second end stripe G _pp2 side is the third feeding point P ₃ is that the array antenna 21 for the aperture plane according to the prior study example shown in FIG. _s , but the intermediate point between the auxiliary grid line G _v31 on the 17th main grid line G _hm and the second end stripe G _pp2 is the second feeding point P ₂ , the first one The intermediate point between the first end stripe G _pp1 on the main grid line G _h1 and the auxiliary grid line G _v31 is selected as the _fourth feed point P ₄ . The first to fourth feed points P ₁ , P ₂ , P ₃ , and P ₄ are intended to form a single-band four-element antenna array by arranging four virtual antennas on the shared antenna opening surface. doing.

In the VSWR shown in FIG. 6, the inter-port coupling (CBP) shown in FIG. 7, and the spatial correlation (SCC) shown in FIG. 8, the characteristics of the aperture-area shared array antenna 21 _{s according} to the prior study example up to the present invention are shown. a solid line, the characteristics of the aperture plane array antenna 21 _a according to Comparative example 1 shown in FIG. 4 by the broken line shows the characteristic of the opening surface array antenna 21 _b according to the comparative example 2 shown in FIG. 5 by the dashed line . FIG. 6 shows the average value of VSWR as seen from _four ports (feed points) P ₁ , P ₂ , P ₃ , and P ₄ . As shown in FIG. 6, in the band of 760-900MHz, VSWR is the indicated prior study showing the opening surface array antenna 21 _s and 4 of Example according to Comparative Example 1 of the opening surface array antenna 21 _a 1 Although characteristics are good, it can be seen that the characteristics of the opening surface array antenna 21 _b according to the comparative example 2 shown in FIG. 5 is poor.

In FIG. 7, the coupling coefficient CBP ₁₂ between the _first port P ₁ and the second port P ₂ , the coupling coefficient CBP ₂₃ between the _second port P ₂ and the third port P _3, and the third port P _3. coupling between the coupling coefficient CBP ₃₄ and the fourth port P _4, fourth port P ₄ to the first port P ₁ coupling coefficient between CBP _41, the first port P ₁ and the third port P ₃ The coefficient CBP ₁₃ and the average value of the coupling coefficient CBP ₂₄ between the _second port P ₂ and the fourth port P ₄ are shown. As shown in FIG. 7, in the band of 760 to 900 MHz, the inter-port coupling (CBP) is also related to the aperture shared array antenna 21 _s (solid line) according to the prior study example shown in FIG. 1 and the comparative example 1 shown in FIG. Although the characteristics of the aperture plane shared array antenna 21 _a (broken line) are excellent, it can be seen that the characteristics of the aperture plane shared array antenna 21 _b (one-dot chain line) according to Comparative Example 2 shown in FIG. 5 are inferior.

8, the first virtual antenna A ₁ to the first port P ₁ and the feeding point (theta, phi) and second virtual antennas A ₂ (theta to the second port P ₂ to a feeding point, phi ) and spatial correlation SCC _12, the second virtual antenna a ₂ (theta, phi) and third third of the port P ₃ to the feeding point of the virtual antennas a ₃ (theta, spatial correlation between phi) SCC ₂₃ , third virtual antenna a ₃ (theta, phi) and fourth virtual antennas a ₄ (theta, phi) spatial correlation between the SCC ₃₄ to the fourth port P ₄ to the feeding point, the fourth virtual antennas a ₄ (θ, φ) and the first virtual antenna A ₁ (θ, φ) spatial correlation SCC ₄₁ , the first virtual antenna A ₁ (θ, φ) and the third virtual antenna A ₃ (θ, φ) ) and spatial correlation SCC _13, and second virtual antenna a ₂ of (theta, phi) and fourth virtual antennas a ₄ (theta, shows the average of spatial correlation SCC ₂₄ with phi) . As shown in FIG. 8, in the band of 760 to 900 MHz, the spatial correlation (SCC) is related to the aperture plane shared array antenna 21 _s (solid line) according to the prior study example shown in FIG. 1 and the comparative example 2 shown in FIG. Although the characteristics of the aperture plane shared array antenna 21 _b (one-dot chain line) are excellent, it can be seen that the characteristics of the aperture plane shared array antenna 21 _a (broken line) according to Comparative Example 1 shown in FIG. 4 are inferior.

As described above, from the examination results of more than 100 cases including the structures shown in FIGS. 4 and 5, two auxiliary grid lines (vertical grid lines) are provided at the approximate center of the shared antenna opening as shown in FIG. ) G _v11 and G _v12 are provided, and the end of the m-th main grid line G _hm on the first end stripe G _pp1 side is set to the first feeding point P ₁ and the m-th main grid line G _hm. And the second auxiliary grid line G _v12 is the second feeding point P ₂ , the end of the first main grid line on the second end stripe G _pp2 side is the third feeding point P ₃ , When the intersection of the first main grid line and the first auxiliary grid line _Gv11 is selected as the _fourth feeding point P4, all of VSWR, inter-port coupling (CBP), and spatial correlation (SCC) However, in the 760-900 MHz band, a single-band four-element antenna array is used. We are finding that the best was obtained.

The rear defogger of a vehicle (automobile) is a resistor, and there is a concern about the influence of high resistivity. Generally, the power consumption of a defogger of a vehicle (automobile) is 200 W. When m = 17 main grid lines G _h1 , G _h2 , G _h3 ,..., G _hm , the power consumption per line is 12 W, and the voltage of the vehicle (automobile) is 12 V, so the resistance of the metal grid lines Is 12 ohm · m. The cross section of the metal grid line of the vehicle (automobile) is 1 mm wide, 40 μm thick, and the cross sectional area is 4 × 10 ⁻⁸ (m ² ). Accordingly, the resistivity is 12 (ohm) × 4 × 10 ⁻⁸ (m ² ) = 4.8 × 10 ⁻⁷ ohm · m.

In the previous study example, a 1/10 scale model was used, but the resistivity was 4.8 × 10 ⁻⁷ (ohm · m) × 10 × 0.5 = 2.4 × 10 ⁻⁶ ohm · m. Set and calculate the VSWR, inter-port coupling, and spatial correlation of each port (feeding point) P ₁ , P ₂ , P ₃ , P ₄ of the aperture plane shared array antenna 21 _{s according} to the prior study example by the electromagnetic analysis simulator IE3D As a result of evaluation by simulation, it was found that there was little variation due to resistance.

As shown in FIG. 12, adaptive directional receiving apparatus according to the prior study example, four ports provided around the opening surface array antenna 21 _s according to the prior study example (feeding point) P _1, P _2, A four-element adaptive array antenna in which the first port P ₁ , which is one of P ₃ and P ₄ , is used as a feeding point for active elements and the remaining three ports P ₂ , P ₃ and P ₄ are parasite elements. Prepare. Here, the “active element” is an excitation element (feeding element) that outputs a radio signal captured from the air to the receiving device side, and an antenna output is obtained from the first port P ₁ .

A baseband signal generation unit 24 including a digital signal processor (DSP) is connected to the active element having the first port P ₁ as a feeding point. From the active element to the RF front end unit of the baseband signal generation unit 24, A radio signal captured from the air is output. An arithmetic processing circuit (DSP) provided in the baseband signal generation unit 24 processes the baseband signal generated by the baseband signal generation unit 24. The DSP does not necessarily have to be built in the baseband signal generation unit 24 and may be connected to the outside of the baseband signal generation unit 24 as a physical configuration.

The “parasite element” means a non-excitation element that does not directly contribute to a radio signal from the air. For example, the first parasite element having the second port P ₂ as a feeding point may be a variable with a first inductor. A series circuit of capacitive diodes is connected, and the variable capacitive diode and the second inductor are connected in parallel so that one terminal is connected to the connection point of the first inductor and the variable capacitive diode, and the first variable reactance circuit 22a is connected. It is composed. The first variable reactance circuit 22 a is connected to the DSP of the baseband signal generation unit 24 via the reactance adaptive control circuit 23.

Similarly, a series circuit of a first inductor and a variable capacitance diode is connected to the second parasitic element having the third port P ₃ as a feeding point, and one terminal is connected to the connection point of the first inductor and the variable capacitance diode. As shown, the variable capacitance diode and the second inductor are connected in parallel to form a second variable reactance circuit 22b. The second variable reactance circuit 22 b is connected to the DSP of the baseband signal generation unit 24 via the reactance adaptive control circuit 23. Similarly, a series circuit of a first inductor and a variable capacitance diode is connected to the third parasitic element having the fourth port P ₄ as a feeding point, and one terminal is connected to the connection point of the first inductor and the variable capacitance diode. As shown, the variable capacitance diode and the second inductor are connected in parallel to form a second variable reactance circuit 22b. The second variable reactance circuit 22 b is connected to the DSP of the baseband signal generation unit 24 via the reactance adaptive control circuit 23.

An active element having the first port P ₁ as a feeding point, a _first parasitic element having the second port P ₂ as a feeding point, a second parasitic element having a third port P ₃ as a feeding point, and a fourth The third parasitic element having the port P ₄ as the feeding point has four ports P ₁ , P ₂ , P ₃ , and P ₄ provided around the opening surface that is the same lattice-like surface as the feeding point. Therefore, although it is electrically short-circuited and not spatially separated as a physical hardware configuration, it can function as four independent antennas in terms of high-frequency electromagnetic waves as shown in FIG. It is.

  In the adaptive directivity receiving apparatus according to the prior study example, as shown in FIG. 13A, an OFDM signal is used as an incident signal. A guard section HGI is provided at the head of each symbol section of the OFDM signal. The guard interval HGI is a cyclic copy of the waveform of the copy source interval TGI at the tail of each symbol interval as a dummy signal. Each symbol section includes a guard section HGI, a data section following the guard section HGI, and a copy source section TGI following the data section. When a delayed wave delayed by the guard interval HGI as shown in FIG. 13B is received with respect to the main wave shown in FIG. 13A, the error rate of the OFDM signal rapidly deteriorates. When the delayed wave is received in a superimposed manner, the correlation coefficient between the guard interval HGI and the copy source interval TGI becomes small.

The DSP of the baseband signal generator 24 shown in FIG. 12 uses a guard interval HGI for each symbol interval of the OFDM signal shown in FIG. 13 using the antenna output of the active element having the first port P ₁ as a feeding point. The complex correlation coefficient between the copy source section TGI and the reactance adaptive control circuit 23 is calculated so that the variable reactance circuits 22a, 22b, 22c is controlled. For the control of the reactance adaptive control circuit 23, for example, a simplex method using an objective function as a correlation coefficient may be used.

  In the computer simulation, two OFDM signals having the same amplitude (delayed wave and main wave) are incident from two random directions on a horizontal plane. The cumulative distribution (CCDF) of signal-to-interference and noise ratio SINR was calculated for 100 patterns of arrival angle combinations. As the incident angle of the vertical plane of the incoming wave, an average value of 0.48 ° obtained in the field test conducted by the present inventors was used. As shown in FIG. 13B, the delayed wave is delayed by the guard interval HGI with respect to the main wave shown in FIG.

In the configuration shown in FIG. 12, among the ports P ₁ , P ₂ , P ₃ , and P ₄ , which port is selected as the active element to be fed, the antenna output is used as the output, and which port is the parasitic element. As to whether the variable reactance circuit should be connected to the parasitic element, the cumulative distribution of the signal-to-interference noise ratio SINR (CCDF) at a frequency of 830 MHz is measured using the metal grid wire as copper, and the first port P It has been confirmed that the best performance is obtained when the variable reactance circuits 22a, 22b, and 22c are connected by using ₁ as an active element feeding point and the other ports P ₂ , P ₃ , and P ₄ as parasite elements.

Although the data is not shown, the cumulative distribution of the signal-to-interference noise ratio SINR at 830 MHz when the first port P ₁ is the feeding point of the active element and the resistivity of the metal grid line is taken into consideration ( From the CCDF), it is known that the performance is slightly degraded by the high resistance of the metal grid lines.

Opening face array antenna 21 _s according to the prior study example shown in FIG. 1, open face shared array according to Comparative Example 2 shown in open surface array antenna 21 _a and 5 according to Comparative Example 1 shown in FIG. 4 the antenna 21 _b, the first port P ₁ and the feeding point of the active element, as a feeding point of the remaining three ports P _2, P _3, P ₄ the parasitic elements, changing the incident direction of the advance wave and the delayed wave FIG. 9, FIG. 10 and FIG. 11 show the cumulative distribution (CCDF) of the signal-to-interference noise ratio SINR at 760, 830, and 900 MHz when the adaptive beam is formed. 9, FIG. 10 and FIG. 11, the cumulative distribution of SINR at 760 MHz is indicated by a one-dot chain line, the cumulative distribution of SINR at 830 MHz is indicated by a broken line, and the cumulative distribution of SINR at 900 MHz is indicated by a solid line. As is clear from a comparison of FIGS. 9, 10, and 11, the cumulative distribution of SINR over the range of 760 to 900 MHz in the case of the aperture shared antenna 21 _s according to the prior study example is the comparative example shown in FIG. than the opening surface array antenna 21 _b according to the comparative example 2 shown in open surface array antenna 21 _a and 5 according to 1, can be understood to be excellent dramatically.

In addition, a rectangular grid-shaped shared antenna aperture is formed using metal grid lines, and a plurality of ports are provided around the antenna aperture, thereby arranging four electromagnetically independent virtual antennas. A VHF band adaptive array antenna for vehicles (automobiles) that forms adaptive directivity in a single-band receiving system by applying the ESPAR antenna concept. It was also verified by experiments that the influence of the resistivity of the metal grid line is small.

  The following embodiment of the present invention provides a technical idea for further development to multi-band based on the evaluation in the above-mentioned prior study example for single band. Further, the technical idea of the present invention does not specify the material, shape, structure, arrangement, etc. of the component parts as described below, and the technical idea of the present invention is the technical idea described in the claims. Various changes can be made within the scope.

(Embodiment of the present invention)
As shown in FIG. 14, the shared aperture array antenna 21 _{w according} to the embodiment of the present invention is separated from each other and arranged in parallel with the first end stripe G _pp1 and the second end stripe G. and _pp2, each of the first end stripes G _pp1 and second ends stripe G _pp2, and connect the ends of the respective sides, the first major grid lines No. G _h1 that are disposed in parallel to each other, The second main grid line G _h2 , the third main grid line G _h3 ,..., The m th main grid line G _hm (m is a positive integer greater than or _{equal to} 5), and the first to m th Crossing all of the main grid lines G _h1 , G _h2 , G _h3 ,..., G _{hm with} the direction perpendicular to the longitudinal direction of the first main grid lines G _h1 , G _h2 , G _{h3 ,.} four auxiliary grid lines provided in parallel as G _v41, G _v42, rectangle and a _G v43, G _v44 It comprises a grid shared antenna aperture plane.

The first end stripe G _pp1 and the second end stripe G _{pp2 define} two opposing sides of the rectangle that constitutes the shared antenna opening surface of the opening surface sharing array antenna 21 _w according to the embodiment of the present invention. None, the first main grid line G _h1 and the m-th main grid line G _hm form the other two opposite sides of the rectangle forming the shared antenna aperture. When the wavelength of the carrier wave of the radio signal received by the shared antenna aperture plane is λ, in FIG. 14, the two opposite sides formed by the first end stripe G _pp1 and the second end stripe G _pp2 are shown. It is preferable to select a value in the range of the length b = 0.1λ to 0.4λ, and the other two 2 formed by the first main grid line G _h1 and the mth main grid line G _hm are opposed to each other. It is preferable to select a value in the range of side length a = 0.2λ to λ. For example, a shared antenna aperture in a double band band of a frequency band of 90 to 108 MHz (V-LOW) adapted to ISDB-TSB and a frequency band of 207.5 to 222 MHz (V-HIGH) adapted to ISDB-Tmm In order to achieve this, it is possible to select values of about b = 48 cm and a = 1.1 m. This dimension can be adapted to the dimension of the rear defogger of the vehicle (automobile). When applied to a rear defogger of a vehicle (automobile), the first end stripe G _pp1 and the second end stripe G _pp2 can be used as power supply lines. If the values of b = 48 mm and a = 110 cm are selected according to the antenna size scaling rule, it is possible to obtain a shared antenna aperture in the double band bands of 900 to 1080 MHz and 2075 to 2220 MHz.

Four auxiliary grid lines G _v41 , G _v42 , G _v43 , G _v44 are arranged in order from the first end stripe G _pp1 side, the first auxiliary grid line G _v41 , the second auxiliary grid line G _v42 , _Are defined as a third auxiliary grid line G _v43 and a fourth auxiliary grid line G _v44, and as shown in FIG. 14, the intersection of the _mth main grid line G _hm and the first auxiliary grid line G _v41 is The first feeding point P ₁ , the intersection of the m-th main grid line G _hm and the third auxiliary grid line G _v43 is the second feeding point P ₂ , the first main grid line and the fourth auxiliary grid The intersection point with the line G _v44 is selected as the third feeding point P ₃ , and the intersection point between the first main grid line and the second auxiliary grid line G _v42 is selected as the _fourth feeding point P ₄ . With four feeding points P ₁ , P ₂ , P ₃ , P ₄ , four electromagnetically independent virtual antennas are arranged on the shared antenna opening surface, and four elements are arranged. The antenna array is configured.

As shown in FIG. 14, the first, second, third, and fourth feeding points P ₁ , P ₂ , P ₃ , and P ₄ constitute the vertices of the parallelogram, but they are not necessarily complete. It is not limited to a (strict) parallelogram. However, the lengths l ₁₂ , l ₂₃ , l ₃₄ , and l ₄₁ of each side of the parallelogram are preferably equal to each other within an error of ± 10% (if the lengths of the sides of the parallelogram are equal) It becomes a diamond.) Further, the distances from the second feeding point P ₂ to the other three feeding points P ₁ , P ₃ , P4 are equal to each other within a range of error ± 10%, and the other three feeding points from the fourth feeding point P ₄ The distances to the feeding points P ₁ , P ₂ , P ₃ are preferably equal to each other within an error of ± 10%.

Further, the lengths l ₁₂ , l ₂₃ , l ₃₄ , and l ₄₁ of each side of the parallelogram are preferably values in the range of 0.1λ to 0.5λ. For example, in FIG. 14, it is possible to select values such as l ₁₂ = l ₃₄ = 0.17λ to 0.43λ and l ₂₃ = l ₄₁ = 0.20λ to 0.49λ. As described above, the shapes at which the first, second, third and fourth feeding points P ₁ , P ₂ , P ₃ , P ₄ form vertices are the lengths of each side l ₁₂ , l ₂₃ , l ₃₄ , If l ₄₁ is equal to each other within an error range of ± 10%, it is not necessarily limited to a perfect parallelogram, but a topology having a certain symmetry is preferable. For example, instead of l ₁₂ = l ₃₄ and l ₂₃ = l ₄₁ , an unequal side quadrangle or trapezoid (trapegion) such that l ₁₂ = l ₄₁ and l ₂₃ = l ₃₄ may be used.

More specifically, for example, l ₁₂ = l ₃₄ = 57.5 cm, l ₂₃ = l ₄₁ for use as a shared antenna aperture in the double band bands of 90-108 MHz and 207.5-222 MHz. = A value of about 66.1 cm can be selected. If the values of l ₁₂ = l ₃₄ = 57.5 mm and l ₂₃ = l ₄₁ = 66.1 mm are selected according to the size scaling rule of the antenna, the shared antenna in the double band bands of 900 to 1080 MHz and 2075 to 2220 MHz It can be used as an opening surface.

In order to evaluate the performance of the aperture plane shared array antenna 21 _{w according} to the embodiment of the present invention, VSWR, inter-port coupling (CBP), and spatial correlation (SCC) are analyzed by the electromagnetic analysis simulator IE3D, and the comparison shown in FIG. compared to the two comparative examples of open surface array antenna 21 _d of the comparative example 4 shown in open surface array antenna 21 _c and 16 according to example 3, the comparison result, respectively 17, 18 and 19 Indicated.

In the structure shown in FIG. 14, the distance d ₄₃ = 0.04λ to 0.15λ measured in the horizontal direction between the second auxiliary grid line G _v42 and the third auxiliary grid line G _v43 is selected. The distance d ₄₂ measured in the horizontal direction between the first auxiliary grid line G _v41 and the second auxiliary grid line G _v42 can be selected to a value of about 0.10λ to 0.30λ. The distance d ₄₄ measured in the horizontal direction between the fourth auxiliary grid line G _v44 and the second end stripe G _pp2 can be selected to a value of about 0.002λ to 0.008λ. .

In the comparison shown in FIGS. 17, 18 and 19, the dimensions of the structure shown in FIG. 14 are set to a width a = 110 mm and a height b = 48 mm in accordance with the double band bands of 900 to 1080 MHz and 2075 to 2220 MHz. In this case, for example, the width d ₄₁ = 5 mm measured in the horizontal direction of the first end stripe G _pp1 and the second end stripe G _pp2 , and the aperture plane shared array antenna 21 _{s according} to the prior study example of FIG. The same value can be adopted. Further, the distance d ₄₃ = 18 mm measured in the horizontal direction between the second auxiliary grid line G _v42 and the third auxiliary grid line G _v43 is also the same as that of the aperture plane shared array antenna 21 _{s according} to the previous study example. Although the value can be adopted, the distance d ₄₂ measured in the horizontal direction between the first auxiliary grid line G _v41 and the second auxiliary grid line G _v42 is selected to be about 39 mm, and the fourth auxiliary grid is selected. The distance d ₄₄ measured in the horizontal direction between the line G _v44 and the second end stripe G _pp2 can be selected to be about 1 mm.

In FIG. 14, the values of b = 48 mm and a = 110 cm are selected, and the common antenna opening surface in the double band band of 900 to 1080 MHz and 2075 to 2220 MHz is shown in FIG. Similarly to the above, the common antenna array antenna according to the embodiment of the present invention has a 21 _w main grid line G _h1 , G _h2 , G _h3 ,..., G _{hm having} a width of about 0.5 mm. The distance between the grid lines G _h1 , G _h2 , G _h3 ,..., G _hm can be selected to be about 2.5 mm, and the distance between both ends can be selected to be about 1.25 mm.

An aperture-plane shared array antenna 21 _{c according} to Comparative Example 3 shown in FIG. 15 is the same as the structure of the prior study example for single band shown in FIG. 1, and includes the first auxiliary grid line G _v51 and the second auxiliary grid. a structure having two only of the auxiliary grid line _{G v51,} G v52 grid line G _V52. That is, in the shared aperture array antenna 21 _{c according} to Comparative Example 3 shown in FIG. 15, the horizontal width a = 110 mm, the height b = 48 mm, and the first end stripe G _pp1 and the second end stripe G _pp2 are horizontal. Width measured in the direction d ₅₁ = 5 mm, distance d ₅₂ = 18 mm measured in the horizontal direction between the first auxiliary grid line G _v51 and the second auxiliary grid line G _v52, and the second auxiliary grid line G _v52 And the distance d ₅₃ = 40.5 mm measured in the horizontal direction between the second end stripe G _pp2 and the second end stripe G _pp2 .

In opening face array antenna 21 _c according to the Comparative Example 3 shown in FIG. 15, the end first feeding point P ₁ of the first end stripe G _pp1 side of the m-th primary grid line G _hm, The intersection of the m-th main grid line G _hm and the second auxiliary grid line G _v52 is the second feeding point P ₂ , the end of the first main grid line on the second end stripe G _pp2 side. Is selected as the third feeding point P ₃ , and the intersection of the first main grid line and the first auxiliary grid line Gv 51 is selected as the _fourth feeding point P _4, and the first to fourth feeding points P ₁ , P ₁ , By P ₂ , P ₃ , and P ₄ , it is intended to form a single-band four-element antenna array by arranging four virtual antennas on the shared antenna opening surface.

Also opening face array antenna 21 _c according to Comparative Example 4 shown in FIG. 16, in order from the first end stripe G _pp1 side, the first auxiliary grid line G _V61, the second auxiliary grid line G _v62, third _{14 in that} the four auxiliary grid lines G _v61 , G _v62 , G _v63 , G _v64 of the auxiliary grid line G _v63 and the fourth auxiliary grid line G _v64 are provided. Although the same as the aperture plane shared array antenna 21 _w , the interval between the four auxiliary grid lines G _v61 , G _v62 , G _v63 , G _v64 is related to the embodiment of the present invention shown in FIG. It is different from the aperture plane shared array antenna 21 _w .

That is, also in the aperture plane shared array antenna 21 _{c according} to the comparative example 4 shown in FIG. 16, the lateral width a = 110 mm, similarly to the aperture plane shared array antenna 21 _{w according} to the embodiment of the present invention shown in FIG. Height b = 48 mm, width d ₆₁ = 5 mm measured in the horizontal direction of the first end stripe G _pp1 and the second end stripe G _pp2 , the second auxiliary grid line G _v62 and the third auxiliary The distance d ₆₄ = 18 mm measured in the horizontal direction from the grid line G _v63 . However, the first auxiliary grid line G _v61 and the second auxiliary grid line are at a distance d ₆₂ = 18 mm measured in the horizontal direction between the first end stripe G _pp1 and the first auxiliary grid line G _v61. at a distance d ₆₃ = 22 mm as measured in the horizontal direction between the G _v62, the distance d ₆₅ = d ₆₃ measured in the horizontal direction between the third auxiliary grid line G _V63 and the fourth auxiliary grid line G _V64 14 is different from the structure shown in FIG. 14 in that the distance d ₆₆ = d ₆₁ = 18 mm measured in the horizontal direction between the fourth auxiliary grid line G _v64 and the second end stripe G _pp2 at 22 mm. .

An aperture plane shared array antenna 21 _{c according} to Comparative Example 4 shown in FIG. 16 is similar to the aperture plane shared array antenna 21 _{w according} to the embodiment of the present invention shown in FIG. The intersection between _hm and the first auxiliary grid line G _v61 is the first feeding point P ₁ , and the intersection between the m-th main grid line G _hm and the third auxiliary grid line G _v63 is the second feeding point P 1. ₂ , the intersection of the first main grid line and the fourth auxiliary grid line G _v64 is the third feeding point P ₃ , the intersection of the first main grid line and the second auxiliary grid line G _v62 is The fourth feeding point P ₄ is selected, and four electromagnetically independent virtual antennas are arranged on the shared antenna opening surface by the first to fourth feeding points P ₁ , P ₂ , P ₃ , P _4. It is intended to constitute a four-element antenna array.

In the VSWR shown in FIG. 17, the inter-port coupling (CBP) shown in FIG. 18, and the spatial correlation (SCC) shown in FIG. 19, the characteristics of the array antenna 21 _{w according} to the embodiment of the present invention are indicated by a solid line. the characteristics of the opening surface array antenna 21 _c in broken lines according to Comparative example 3 shown in FIG. 15 shows the characteristic of the opening surface array antenna 21 _d according to Comparative example 4 shown in FIG. 16 by a two-dot chain line. FIG. 17 shows the average value of VSWR as seen from _four ports (feed points) P ₁ , P ₂ , P ₃ , and P ₄ . As shown in FIG. 17, in the double-band bands of 900 to 1080 MHz and 2075 to 2220 MHz, the VSWR has excellent characteristics of the aperture shared antenna 21 _{w according} to the embodiment of the present invention shown in FIG. It can be seen that the characteristics of the aperture plane shared array antenna 21 _{d according} to Comparative Example 4 shown in FIG.

In FIG. 18, as in FIG. 7, the coupling coefficient CBP ₁₂ between the _first port P ₁ and the second port P ₂ , the coupling coefficient CBP ₂₃ between the _second port P ₂ and the third port P ₃ , The coupling coefficient CBP ₃₄ between the third port P ₃ and the fourth port P ₄ , the coupling coefficient CBP ₄₁ between the _fourth port P ₄ and the first port P ₁ , the first port P ₁ and the third port coupling coefficient CBP ₁₃ and the second port P ₂ of the port P ₃ and indicates the average value of the coupling coefficient CBP ₂₄ and the fourth port P _4. As shown in FIG. 18, in the double-band bands of 900 to 1080 MHz and 2075 to 2220 MHz, the inter-port coupling (CBP) is also the aperture plane shared array antenna 21 _w (solid line) according to the embodiment of the present invention shown in FIG. It can be seen that the characteristic of the aperture plane shared array antenna 21 _d (two-dot chain line) according to Comparative Example 4 shown in FIG. 16 is the most inferior.

In FIG. 19, similarly to FIG. 8, the spatial correlation SCC ₁₂ between the first virtual antenna A ₁ (θ, φ) and the second virtual antenna A ₂ (θ, φ), the second virtual antenna A ₂ ( θ, φ) and the third virtual antenna A ₃ (θ, φ), the spatial correlation SCC ₂₃ , the third virtual antenna A ₃ (θ, φ) and the fourth virtual antenna A ₄ (θ, φ) Spatial correlation SCC ₃₄ , fourth virtual antenna A ₄ (θ, φ) and first virtual antenna A ₁ (θ, φ) spatial correlation SCC ₄₁ , first virtual antenna A ₁ (θ, φ) spatial correlation between the third virtual antenna a ₃ (θ, φ) spatial correlation SCC _13, and second virtual antennas a ₂ and (theta, phi) and fourth virtual antennas a ₄ (θ, φ) The average value of SCC ₂₄ is shown. As shown in FIG. 19, with respect to the spatial correlation (SCC) in the double-band bands of 900 to 1080 MHz and 2075 to 2220 MHz, the aperture shared array antenna 21 _w (solid line) according to the embodiment of the present invention shown in FIG. 15, there is a large difference in the characteristics of the aperture-plane shared array antenna 21 _c (broken line) according to Comparative Example 3 shown in FIG. 15 and the aperture-plane shared array antenna 21 _d (two-dot chain line) according to Comparative Example 4 shown in FIG. I couldn't.

Although the illustration of other structures is omitted, from the examination results of 100 or more cases including the structures shown in FIG. 15 and FIG. Lines G _v41 , G _v42 , G _v43 , G _v44 are provided, and the intersection of the m-th main grid line G _hm and the first auxiliary grid line G _v41 is the first feeding point P ₁ , and the m-th main line. grid lines G _hm and third auxiliary grid line G _V43 the intersection of the second feeding point P ₂ of the first main grid lines intersection of the fourth auxiliary grid line G _v44 third feeding point P ₃ , the intersection of the first main grid line and the second auxiliary grid line G _v42 is selected as the _fourth feeding point P _4, and the first to fourth feeding points P ₁ , P ₂ , P _{3 are selected.} by P _4, and forming an antenna array of the four electromagnetic independent four elements by arranging virtual antenna to the shared antenna aperture plane As for the VSWR, the inter-port coupling (CBP), and the spatial correlation (SCC), it was found that the four-element antenna array is the best in the double band bands of 900 to 1080 MHz and 2075 to 2220 MHz. .

As shown in FIG. 23, the adaptive directivity receiving apparatus according to the embodiment of the present invention includes four ports provided around the aperture plane shared array antenna 21 _{w according} to the embodiment of the present invention described above. (Feeding point) The first port P ₁ , which is one of P ₁ , P ₂ , P ₃ and P ₄ , is used as the feeding point of the active element, and the remaining three ports P ₂ , P ₃ and P ₄ are parasites. A four-element adaptive array antenna as an element is provided. Here, the “active element” is an excitation element (feeding element) that outputs a radio signal captured from the air to the receiving apparatus side, as already described in the adaptive directivity receiving apparatus according to the preceding study example. antenna output can be obtained from the port P _1.

A baseband signal generation unit 24 including a digital signal processor (DSP) is connected to the active element having the first port P ₁ as a feeding point. From the active element to the RF front end unit of the baseband signal generation unit 24, A radio signal captured from the air is output. An arithmetic processing circuit (DSP) provided in the baseband signal generation unit 24 processes the baseband signal generated by the baseband signal generation unit 24. The DSP does not necessarily have to be built in the baseband signal generation unit 24 and may be connected to the outside of the baseband signal generation unit 24 as a physical configuration.

The “parasite element” means a non-excited element that does not directly contribute to a radio signal from the air as already described in the adaptive directional receiver according to the preceding study example, and the second port P ₂ is used as a feeding point. For example, a series circuit of a first inductor and a variable capacitance diode is connected to the first parasitic element, and one terminal is connected to a connection point of the first inductor and the variable capacitance diode. Two inductors are connected in parallel to form a first variable reactance circuit 22a. The first variable reactance circuit 22 a is connected to the DSP of the baseband signal generation unit 24 via the reactance adaptive control circuit 23.

Similarly, a series circuit of a first inductor and a variable capacitance diode is connected to the second parasitic element having the third port P ₃ as a feeding point, and one terminal is connected to the connection point of the first inductor and the variable capacitance diode. As shown, the variable capacitance diode and the second inductor are connected in parallel to form a second variable reactance circuit 22b. The second variable reactance circuit 22 b is connected to the DSP of the baseband signal generation unit 24 via the reactance adaptive control circuit 23. Similarly, a series circuit of a first inductor and a variable capacitance diode is connected to the third parasitic element having the fourth port P ₄ as a feeding point, and one terminal is connected to the connection point of the first inductor and the variable capacitance diode. As shown, the variable capacitance diode and the second inductor are connected in parallel to form a second variable reactance circuit 22b. The second variable reactance circuit 22 b is connected to the DSP of the baseband signal generation unit 24 via the reactance adaptive control circuit 23.

An active element having the first port P ₁ as a feeding point, a _first parasitic element having the second port P ₂ as a feeding point, a second parasitic element having a third port P ₃ as a feeding point, and a fourth The third parasitic element having the port P ₄ as the feeding point has four ports P ₁ , P ₂ , P ₃ , and P ₄ provided around the opening surface that is the same lattice-like surface as the feeding point. Therefore, although the physical hardware configuration is electrically short-circuited and is not spatially separated, as shown in FIG. 19, in the double-band bands of 900 to 1080 MHz and 2075 to 2220 MHz, high-frequency electromagnetic waves Specifically, it can be regarded as functioning as four independent antennas.

  In the adaptive directivity receiving apparatus according to the embodiment of the present invention, as shown in FIG. 13A, an OFDM signal having an inverse discrete Fourier transform signal as a data section is used as an incident signal. A guard section HGI is provided at the head of each symbol section of the OFDM signal. The guard interval HGI is a cyclic copy of the waveform of the copy source interval TGI at the tail of each symbol interval as a dummy signal. Each symbol section includes a guard section HGI, a data section following the guard section HGI, and a copy source section TGI following the data section. When a delayed wave delayed by the guard interval HGI is received with respect to the main wave shown in FIG. 13A, similarly to the case shown in FIG. 13B, the error rate of the OFDM signal rapidly deteriorates. When the delayed wave is received in a superimposed manner, the correlation coefficient between the guard interval HGI and the copy source interval TGI becomes small.

DSP baseband signal generation unit 24 shown in FIG. 23, the first port P ₁ using the antenna output of the active element to the feeding point, and a guard interval HGI for each symbol period of the OFDM signal shown in FIG. 13 The complex correlation coefficient between the copy source section TGI and the reactance adaptive control circuit 23 is calculated so that the variable reactance circuits 22a, 22b, The ground reactance value of 22c is controlled. For the control of the reactance adaptive control circuit 23, for example, a simplex method using an objective function as a correlation coefficient may be used.

  In the computer simulation, two OFDM signals having the same amplitude (delayed wave and main wave) are incident from two random directions on a horizontal plane. The cumulative distribution (CCDF) of signal-to-interference and noise ratio SINR was calculated for 100 patterns of arrival angle combinations. As the incident angle of the vertical plane of the incoming wave, an average value of 0.48 ° obtained in the field test conducted by the present inventors was used. Similarly to the case shown in FIG. 13B, the delayed wave is delayed by the guard interval HGI with respect to the main wave shown in FIG.

An aperture plane shared array antenna 21 _{w according} to the embodiment of the present invention shown in FIG. 14, an aperture plane shared array antenna 21 _{d according} to Comparative Example 4 shown in FIG. 16, and an aperture according to Comparative Example 3 shown in FIG. for surface array antenna 21 _c and the first port P ₁ and the feeding point of the active element, as a feeding point of the remaining three ports P _2, P _3, P ₄ the parasitic elements, the preceding wave and the delayed wave The cumulative distribution (CCDF) of the signal-to-interference noise ratio SINR at 900, 1000, 1080, 2075, 2100, and 2222 MHz when the incident direction is changed and the adaptive beam is formed is shown in FIGS. . 20, FIG. 21 and FIG. 22, the cumulative distribution of SINR at 900 MHz is indicated by a solid line, the cumulative distribution of SINR at 1000 MHz is indicated by a broken line, the cumulative distribution of SINR at 1080 MHz is indicated by a one-dot chain line, and the cumulative distribution of SINR at 2075 MHz is indicated by two points. In the chain line, the cumulative distribution of SINR at 2100 MHz is indicated by a dotted line, and the cumulative distribution of SINR at 2200 MHz is indicated by a thick solid line (double line).

As is clear from a comparison of FIGS. 20 and 21, the shared aperture antenna 21 _{w according} to the embodiment of the present invention has a rectangular grid shape with a width a = 110 mm and a height b = 48 mm. With respect to the dimensions of the antenna aperture plane, the cumulative distribution of SINR is dramatic over the double-band bands of 900 to 1080 MHz and 2075 to 2220 MHz, as compared with the aperture plane shared array antenna 21 _{d according} to Comparative Example 4 shown in FIG. It can be understood that it is excellent. In addition, in the case of the aperture plane shared array antenna 21 _{c according} to the comparative example 3 shown in FIG. 15, as can be seen from FIG. 22, only in the single band band of 900 to 1080 MHz, the cumulative distribution of SINR is excellent, and the double band It turns out that it is not suitable for.

If the size of the aperture plane shared array antenna 21 _{w according} to the embodiment of the present invention shown in FIGS. 17 to 20 is increased by 10 times, a double size of 90 to 108 MHz and 207.5 to 222 MHz is determined according to the size scaling law of the antenna. It can be easily understood that the cumulative distribution of SINR is excellent in the band of the band. That is, the structure of the array antenna 21 _{w with} the opening surface according to the embodiment of the present invention is mounted on the vehicle (automobile) so that the dimensions correspond to the dimensions of the rear defogger of the vehicle (automobile), and is mounted on the ISDB-TSB. It can be used in a double-band band in which the frequency is approximately twice as high as the frequency band of 90 to 108 MHz (V-LOW) and the frequency band of 207.5 to 222 MHz (V-HIGH) that conforms to ISDB-Tmm. It is suitable for constituting an antenna array of elements.

Furthermore, by selecting the size of the rectangular grid-shaped shared antenna aperture according to the embodiment of the present invention according to the antenna size scaling rule, a double-band four-element antenna array in an arbitrary frequency band can be opened. It can be easily understood that the antenna can be constituted by the plane-sharing array antenna 21 _w .

(Other embodiments)
Although the present invention has been described according to the embodiment of the present invention as described above, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. In particular, by selecting a desired dimension according to the size scaling rule, a double-band four-element antenna array in an arbitrary frequency band can be realized. Therefore, the aperture plane shared array antenna 21 _w of the present invention is a vehicle (automobile). In addition to the rear defogger, it can be applied to a vehicle retrofit planar antenna, a planar sheet antenna, and the like. Further, it may be used an opening plane array antenna 21 _w of the present invention in a residential windows and walls, as the array antenna for a portable terminal, it is also possible to use an open surface array antenna 21 _w of the present invention. As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

21 _s , 21 _w , 21 a, 21 b, 21 _c , 21 _d ... Open-area shared-array antennas 22 a, 22 b, 22 c... Variable reactance circuit 23 ... Reactance adaptive control circuit 24 ... Baseband signal generation unit 33, 32 ... Body P ₁ , P ₂ , P ₃ , P ₄ ... Port (feeding point)

Claims (15)

First and second end stripes spaced apart and arranged in parallel;
m is a positive integer, and the first and m-th m main grid lines provided in parallel to each other are connected to the first and second end stripes, respectively. When,
A rectangular grid-shaped shared antenna aperture having four auxiliary grid lines provided in parallel so as to intersect all of the main grid lines, with the direction orthogonal to the longitudinal direction of the main grid lines as the longitudinal direction The four auxiliary grid lines are first, second, third and fourth auxiliary grid lines in order from the first end stripe side, and the m-th main grid line and the first The intersection of the auxiliary grid line is a first feeding point, the intersection of the m-th main grid line and the third auxiliary grid line is a second feeding point, the first main grid line and the The intersection point with the fourth auxiliary grid line is selected as the third feeding point, the intersection point between the first main grid line and the second auxiliary grid line is selected as the fourth feeding point, and the first to first points are selected. 4 electromagnetic waves are formed on the opening surface of the shared antenna by 4 feeding points. An array antenna with a shared aperture, characterized in that virtually independent virtual antennas are arranged.    The distances from the second feeding point to the first, third, and fourth feeding points are equal to each other within an error of ± 10%, and the first, second, and third from the fourth feeding point. The distance-to-feeding point array antennas according to claim 2, wherein the distances to the feed points are equal within a range of an error of ± 10%.   The wavelength of the carrier wave of the radio signal received by the shared antenna aperture is λ, the distance from the second feeding point to the first, third, and fourth feeding points, and the fourth feeding point to the 3. The aperture-plane shared array antenna according to claim 2, wherein the distances to the first, second, and third feeding points are each in a range of 0.1λ to 0.5λ.   3. The aperture-plane shared array antenna according to claim 1, wherein the first, second, third, and fourth feed points constitute respective vertices of a parallelogram.   5. The aperture plane shared array antenna according to claim 4, wherein the lengths of the sides of the parallelogram are equal to each other within an error of ± 10%.   The length of each side of the parallelogram is a value in a range of 0.1λ to 0.5λ, where λ is a wavelength of a carrier wave of a radio signal received by the shared antenna aperture. The aperture-plane shared array antenna according to 4 or 5.   The shared antenna opening surface is configured by using a rear defogger of an automobile, and is mounted on the automobile. First and second end stripes that are spaced apart from each other and arranged in parallel, and m is a positive integer, each end of each side is connected to each of the first and second end stripes. The first to m-th m main grid lines provided in parallel to each other, the direction perpendicular to the longitudinal direction of the main grid lines is defined as the longitudinal direction, and provided in parallel so as to intersect all of the main grid lines An aperture plane shared array antenna comprising a rectangular grid-shaped shared antenna aperture plane having four auxiliary grid lines formed;
The four auxiliary grid lines are set as the first, second, third and fourth auxiliary grid lines in order from the first end stripe side, and the mth main grid line and the first auxiliary grid are used. Selecting a power supply point of an active element that captures a radio signal from the air at an intersection with a line, and a baseband signal generator connected to the power supply point of the active element;
The intersection of the mth main grid line and the third auxiliary grid line, the intersection of the first main grid line and the fourth auxiliary grid line, and the first main grid line and the above The intersection point with the second auxiliary grid line is selected as the feeding point of the first, second, and third parasitic elements, respectively, and is connected to the feeding point of the first, second, and third parasitic elements, respectively. First, second and third variable reactance circuits;
A reactance adaptive control circuit that adjusts ground reactance values of the first, second, and third variable reactance circuits using an objective function output from the baseband signal generation unit, and the first, second, and The radio signal is demodulated while controlling the directivity of the array antenna composed of the active element and the first, second and third parasitic elements by controlling the ground reactance of the third parasitic element, respectively. An adaptive directional receiver characterized by the above.   The intersection of the mth main grid line and the first auxiliary grid line is a first feeding point, and the intersection of the mth main grid line and the third auxiliary grid line is a second feeding point. Point, the intersection of the first main grid line and the fourth auxiliary grid line is the third feeding point, and the intersection of the first main grid line and the second auxiliary grid line is the fourth The distance from the second feed point to the first, third, and fourth feed points is equal to each other within an error of ± 10%, and the fourth feed point to the first feed point. 9. The adaptive directional receiver according to claim 8, wherein the distances to the first, second and third feeding points are equal to each other within a range of error ± 10%.   The wavelength of the carrier wave of the radio signal is λ, the distance from the second feeding point to the first, third, and fourth feeding points, and the first, second, and second from the fourth feeding point. The adaptive directivity receiving apparatus according to claim 9, wherein the distances to the three feeding points are each in a range of 0.1λ to 0.5λ.   The intersection of the mth main grid line and the first auxiliary grid line is a first feeding point, and the intersection of the mth main grid line and the third auxiliary grid line is a second feeding point. Point, the intersection of the first main grid line and the fourth auxiliary grid line is the third feeding point, and the intersection of the first main grid line and the second auxiliary grid line is the fourth 9. The adaptive directional receiver according to claim 8, wherein the first, second, third, and fourth feed points constitute respective vertices of a parallelogram.   The adaptive directional receiver according to claim 11, wherein the lengths of the sides of the parallelogram are equal to each other within an error of ± 10%.   The adaptation according to claim 11 or 12, wherein a length of each side of the parallelogram is a value in a range of 0.1λ to 0.5λ, where λ is a wavelength of a carrier wave of the radio signal. Directional receiver.   14. The reactance adaptive control circuit searches for a condition for the objective function to be an optimum value by a simplex method using the objective function as a correlation coefficient. Adaptive directional receiver.   The adaptive directional receiver according to claim 8, wherein the shared antenna opening surface is configured by using a rear defogger of an automobile and is mounted on the automobile.