JP2010136296A - Circular polarized wave patch antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve miniaturization, thickness reduction and high performance without any cost increase in a circular polarized wave patch antenna adopting a feeding system by capacitive coupling. <P>SOLUTION: The circular polarized wave patch antenna 1a, includes: a vertically flat box-shaped base substrate 2 consisting of a dielectric material or a magnetic material; a radiation electrode 10a which has a plane shape of almost square and is formed on a top face 3 of the base substrate; a GND electrode 6 which is formed on a bottom 5 of the base substrate; a feeding electrode 21a which is formed on the top face of the base substrate and is arranged opposite to one side 13 of the almost square in the radiation electrode through a gap 30; and a feeding line 20 for supplying an electric power to the feeding electrode. The feeding line is a thin line, and a feeding terminal 22 used as a feeding point is connected to a base end of the feeding line, and the feeding electrode is connected to a tip of the feeding line. In the radiation electrode, a recess 40 enclosing the feeding electrode is formed at the one side opposed to the feeding electrode through the gap. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circularly polarized patch antenna used for mobile communications, local area networks, ITS, ETC, GPS, and the like.

  As an application example of the present invention, a GPS signal receiving antenna built in a small electronic device is cited. As is well known, a GPS signal receiving antenna receives a circularly polarized electromagnetic wave signal transmitted from a GPS satellite, and the GPS signal is used by a navigation device in a ship or an automobile to acquire its position information. To be served. Many of the GPS signal receiving antennas are for right-handed circular polarization.

  By the way, in recent years, the GPS is used not only for a built-in car navigation device integrated with a navigation device for ship navigation or an in-vehicle audio device, but also for various devices, particularly portable electronic devices. There is a strong demand for miniaturization of GPS receiving antennas mounted on electronic devices.

  One method for reducing the size of a GPS receiving antenna is, for example, a network service provided by a mobile communication carrier such as a mobile phone equipped with a GPS receiving function (for example, triangulation using a base station). ), A 1/4 wavelength type linearly polarized chip antenna that is easy to miniaturize instead of having a low right-handed circularly polarized wave receiving performance is used as a GPS receiving antenna.

  However, GPS is called PND, which is different from conventional built-in car navigation devices, and is a detachable and portable car navigation device, a portable information terminal without a telephone function such as a PDA, and an ultra-small size called an ultra mobile PC. The use is expanding to a wide variety of electronic devices such as portable computers and digital cameras capable of recording location information of shooting locations. Usually, these devices do not cooperate with a network service via an information communication network such as a mobile communication network, and adopt a method of positioning by a single device. Therefore, it is desirable to mount a right-handed circularly polarized antenna with high reception performance on these devices. The present invention relates to a circularly polarized antenna including a right-handed circularly polarized antenna suitable for thinning.

  There are two types of circularly polarized patch antennas depending on the feeding method. FIG. 13 shows a schematic structure of a circularly polarized patch antenna 1j corresponding to the first feeding method. (A) is a plan view, and (B) is a side sectional view of this circularly polarized patch antenna 1j mounted on a circuit board. This circularly polarized patch antenna 1j is a pin-fed circularly polarized patch antenna and is often used for car navigation and the like, and is a flat box with a thickness of about 4 to 5 mm made of a dielectric or magnetic material. A radiation electrode 10j made of a substantially square conductor having a side of about 15 mm to 25 mm is formed on the upper surface 3 of the substrate 2, and a GND electrode 6 is formed on the lower surface 5 in a planar shape. A metal power supply pin 20j for supplying power to the radiation electrode 10j is inserted into the lower surface 5 side on which the GND electrode 6 is formed while being connected to the radiation electrode 10j on the upper surface 3, and the tip thereof is connected to the GND electrode 6. It protrudes from the lower surface 5 of the base 2 so as to be non-contact. The feed pin 20j is normally inserted into a through hole 51 formed in the circuit board 50 on which the circularly polarized patch antenna 1j is mounted, and the circuit board 50 is opposite to the surface 52 on which the antenna 1j is mounted. The surface 53 is connected to a receiving circuit formed on the circuit board 50 by solder 54. As a result, the received GPS signal is sent to the receiving circuit on the circuit board 50.

  In this method, the substrate 2 and the radiation electrode 10j are reduced in size by one size for PND. The impedance is adjusted according to the position of the pin 20j. Further, this circularly polarized patch antenna 1j chamfers one opposing corner 11 in order to make it circularly polarized, and this chamfered portion serves as a degenerate separation element 12 so as to cause two resonances whose phases are shifted by 90 degrees. It has become.

  Since the input impedance of the circularly polarized patch antenna 1j fed by the pin 20j is controlled mainly by the relative position between the radiation electrode 10j and the feed pin 20j, the impedance matching has a wide adaptation range. On the other hand, since the power supply pins 20j are inserted into the circuit board 50 and soldered at the back surface 53, it is difficult to automate the mounting and the assembly cost is increased. In addition, since the power feed pin 20j protrudes from the lower surface 5 of the base 2, it is not suitable for high-density mounting required for smaller equipment.

  FIG. 14 shows a structure of a general circularly polarized patch antenna 1k corresponding to the second power feeding method. In this circularly polarized patch antenna 1k, a radiation electrode 10k having a substantially square planar shape is formed on an upper surface 3 of a base 2 made of a dielectric material or a magnetic material in a flat box shape. Then, power is supplied to the radiation electrode 10k from the tip (feed electrode) 21k of the thin line (microstrip) signal line (feed line) 20. Specifically, one side 13 of the radiation electrode 10k and the feeding electrode 21k are spaced apart from each other and a gap 30 is provided between these electrodes (10k, 21k), and between these electrodes (10k, 21k). This is a type that supplies power by capacitive coupling.

  The shape of the radiation electrode 10k is similar to the circularly polarized patch antenna 1j adopting the feeding method using the pins 20j, and the degenerate separation elements 12 are provided at two corners 11 facing each other in a substantially square shape, and the phase is 90 degrees. Two resonances which are shifted are caused. The power supply line 20 whose tip is the power supply electrode 21k extends orthogonally from the substantially center of one side 13 of the substantially square radiation electrode 10 to the outside of the square, and passes through the side surface 4 of the base body 20 to the lower surface 5. Has reached.

  The GND electrode 6 may be provided on the upper surface 3 and the side surface 4 of the flat box-shaped base 2, but in the illustrated example, the GND electrode 6 is provided on almost the entire lower surface 5 of the base 10. A base end 22 of the power supply line 20 is a power supply terminal 22 that is connected to a wiring on a circuit board at the time of mounting and serves as a power supply point. The power supply terminal 22 is disposed on the lower surface 5 of the base 2. . Note that a gap 31 is provided between the GND electrode 6 and the power supply terminal 22 on the lower surface 5 of the base 2 so that the GND electrode 6 does not short-circuit between the power supply line 20 and the power supply terminal 22. The radiation electrode 10k, the feeder line 20, and the GND electrode 6 are made of a conductor such as gold, silver, copper, palladium, platinum, silver platinum, or silver palladium, and these conductors are printed, plated, etched, vapor deposited, and applied. Etc. can be formed.

  Of course, there is a circularly polarized patch antenna in which the radiation electrode 10k and the feeding electrode 21k are directly connected. However, on the equivalent circuit, since only the R component and the L component are in series, the applicable range of impedance matching is narrow. On the other hand, in the circularly polarized patch antenna 1k employing the second feeding method, the input impedance can be varied by adjusting the width t of the feeding electrode 21k and the gap G of the gap 30, and impedance matching can be achieved. The application range can be widened. However, the circularly polarized patch antenna 1k of the second feeding method has a problem that the bandwidth is narrower by the amount of the added capacitance component compared to the circularly polarized patch antenna 1j adopting the feeding method by the pin 20j. There is. Note that the circularly polarized patch antenna 1k corresponding to the second power feeding method is described in Patent Document 1 below.

Further, Patent Document 2 below describes a circularly polarized patch antenna that can widen the bandwidth while adopting the above-described second feeding method. The structure of the circularly polarized patch antenna (conventional example) described in Patent Document 2 is shown in FIG. A circularly polarized patch antenna 1L according to this conventional example is an improved form of a general circularly polarized patch antenna 1k that employs the above-described second feeding method, and is arranged via one side 13 of the radiation electrode 10L and a gap 30. A linear conductor 21L is arranged, and the linear conductor (feeding electrode) 21L and the thin line-shaped feeding line 20 are connected to form a T-shaped horizontal bar and a vertical bar, respectively. Accordingly, the circularly polarized patch antenna 1k according to this conventional example has a large coupling capacity and a wide bandwidth as compared with the general circularly polarized patch antenna 1j while ensuring ease of mounting.
JP-A-11-74721 JP 2001-177314 A

  In the above-mentioned conventional example, the bandwidth has been successfully expanded while adopting a charging method based on capacitive coupling that can cope with automation of mounting. However, electronic devices are required to be further reduced in size and thickness, and circularly polarized patch antennas used in these devices are required to be particularly thinner. In order to reduce the thickness of the patch antenna, it is the most effective method to make the substrate thinner.

  However, when the substrate is made thinner, the capacitive component due to the radiation electrode and the GND electrode on the front and back surfaces (upper and lower surfaces) of the substrate becomes larger, the capacitive coupling tends to be under-coupled, and the inductive tendency in the input impedance becomes remarkable. It becomes difficult to maintain not only impedance matching but also various characteristics such as phase, gain, and axial ratio.

  In order to cancel the inductivity of the input impedance, the gap should be narrowed by reducing the distance between the feed electrode and the radiation electrode. However, if the gap is extremely narrow, the accuracy of the gap formation in mass production Is difficult to maintain, and there are individual differences in characteristics. There is also a possibility that the radiation electrode and the feeding electrode are short-circuited, resulting in a defective product. In particular, when forming each electrode by a process using a screen printing method or a wet etching method that is inexpensive and suitable for mass production, the yield is extremely poor if the design value of the gap is extremely narrow. Of course, it is more difficult to stably form an extremely narrow gap by the electrode forming method by sheet metal molding. If it is intended to manufacture with higher accuracy, the cost for manufacturing equipment and quality control increases.

  Certainly, in the above conventional example, the length of the linear conductor can be increased to increase the coupling capacitance, and the inductive tendency of the input impedance can be canceled without narrowing the gap. However, as the antenna becomes thinner, both ends of the linear conductor must be extended to the corners of the substantially square radiation electrode, that is, near the strong electric field portion. Then, this time, the input impedance tends to be overcoupled, the characteristics are dramatically reversed, and it becomes extremely difficult to match the impedance. Of course, characteristics such as gain and axial ratio also deteriorate.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the size, thickness, and performance of a circularly polarized patch antenna that employs a capacitively coupled feeding method without increasing the cost. It is to make it achieve.

  In order to achieve the above object, the present invention includes a box-shaped base body made of a dielectric material or a magnetic material and flattened vertically, and a radiation electrode having a substantially square planar shape and formed on the top surface of the base body. A GND electrode formed on the lower surface of the base, a power supply electrode formed on the upper surface of the base and disposed opposite to the substantially square side of the radiation electrode via a gap, and the power supply electrode A circularly polarized patch antenna provided with a power supply line for supplying power to the power supply line, wherein the power supply line has a thin line shape, a power supply terminal serving as a power supply point is connected to a base end, and the power supply electrode is connected to a front end. The radiating electrode is a circularly polarized patch antenna in which a concave portion surrounding the feeding electrode is formed on the one side facing the feeding electrode via the gap.

  The concave portion may be formed so as to have a shape in which a tip of a convex portion formed on the one side facing the power supply electrode through the gap is cut out in a substantially U-shape.

  The feed electrode and the feed line are formed in a shape corresponding to a T-shaped horizontal bar and a vertical bar, respectively, and the T-shaped horizontal bar is arranged inside the recess with the gap interposed therebetween. It can also be a wave patch antenna.

  A circle in which the power supply electrode is formed by branching into a plurality of teeth such that the front end of the power supply line has a comb shape, and each front end of the comb tooth is disposed inside the recess through the gap It can also be a polarized patch antenna. A plurality of the concave portions may be formed corresponding to the respective tips of the comb teeth.

  In any one of the above circularly polarized patch antennas, the GND electrode formed on the lower surface of the base extends to the side of the base in the form of two parallel thin wires, and the extended portion extends to the side of the base. It is good also as arrange | positioning in parallel with the both sides of the extension direction of the said feed line so that at least one part of the said feed line may be clamped.

  In any one of the above circularly polarized patch antennas, if the length of all the line segments forming the bottom of the concave portion is equal to or less than 1/8 of the total length of the substantially square four sides of the radiation electrode, the characteristics are further improved. It can be a circularly polarized patch antenna.

  According to the present invention, it is possible to provide a high-performance, small and thin circularly polarized patch antenna at low cost.

  In the circularly polarized patch antenna of the present invention, the radiating electrode is closely coupled to the feeding electrode in the weak electric field concentration region by devising the opposing shape of the feeding terminal and the radiating electrode facing each other through the gap. Yes. This makes it possible to easily match the input impedance and maintain good radiation characteristics such as gain and axial ratio, even if the substrate becomes thin and tends to be inductive or under-coupled. Yes. Hereinafter, as embodiments of the present invention, mainly circularly polarized patch antennas in which the opposing shape of the feeding electrode and the radiating electrode are different will be described.

=== First Embodiment ===
FIG. 1 shows an electrode structure of a circularly polarized patch antenna 1a according to the first embodiment of the present invention. (A) is a top view of the upper surface 3 of the base | substrate 2 in which the radiation electrode 10a is formed, (B) is an enlarged view of the principal part 100a in (A). In the present embodiment, similar to the general circularly polarized patch antenna 1k shown in FIG. 14, two diagonal corners 11 are chamfered on the upper surface 3 of a box-like base 2 flattened up and down, and degenerate. A substantially square-shaped radiation electrode 10a on which the separation element 12 is formed and a power supply line 20 having a thin wire tip at the power supply electrode 21a are disposed, and the power supply electrode 21a is substantially on one side 13 of the radiation electrode 10a. The one side 13 is disposed opposite the gap 30 at the center. Further, on the back surface (not shown) of the base 2, the GND electrode 6 is formed on almost the entire surface except the region where the power supply terminal 22 is formed, similarly to the structure shown in FIG. 14B. The above structure in the first embodiment is substantially the same as that of the general circularly polarized patch antenna 1k.

  However, in the first embodiment, as shown in an enlarged view in FIG. 1B, the tip of the thin line-shaped power supply line 20 is used as a power supply electrode 21a, and the radiation electrode 10a includes a gap ( A recess 40 is formed surrounding the feeding electrode 21 a via a halftone dot portion 30. The input impedance includes the width t of the power supply electrode 21a and the depth d of the concave portion, the distance y1 between the tip 23 of the power supply electrode 21a and the bottom 41 of the concave portion 40, and both side lines 24 of the power supply electrode 21a and the inner line of the concave portion 40. What is necessary is just to match by adjusting the distance (y2, y3) of 42, etc.

  In this way, due to the structure in which the feeding electrode 21a is surrounded by the recess 40 formed in the radiation electrode 10a, the tip 23 of the feeding electrode 21a and the line segments 24 on both sides are respectively connected to the bottom 41 of the recess 40 and the inner side lines. Opposite the minute 42 via the gap 30. Therefore, in the general circularly polarized patch antenna 1k, only the tip 21k of the feeder line 20 contributes to capacitive coupling, whereas in the circularly polarized patch antenna 1a in the first embodiment, the feeder electrode 21a. The line segments of both side lines 24 also contribute to capacitive coupling. Therefore, when the substrate 2 is thinned, the coupling capacity increases without reducing the distance (y1 to y3) between the feeding electrode 21a and the radiation electrode 10a to narrow the gap 30, and tends to be under-coupled and inductive. Can be eliminated.

=== Second Embodiment ===
FIG. 2 shows the electrode structure of the circularly polarized patch antenna 1b in the second embodiment of the present invention. (A) is a top view of the upper surface 3 of the base | substrate 2 in which the radiation electrode 10b is formed, (B) is an enlarged view of the principal part 100b in (A). In this embodiment, the recess 40 is formed outside the area where the substantially square radiation electrode 10b is formed. Specifically, two protrusions 43 are formed on one side 13 facing the power supply electrode 21b, and the protrusions 43 sandwich the power supply electrode 21b from both sides with a gap 30 interposed therebetween. In other words, the radiation electrode 10b has a shape in which a convex portion is provided on one side 13 facing the feeding electrode 21b, and the convex portion is cut out in a U-shape. A recess 40 is formed inside the U-shape, and the bottom 41 of the U-shape, that is, the bottom 41 of the recess 40 is a part of one side 13 of the radiation electrode 10b. The feeding electrode 21b is surrounded by three sides (41, 42) inside the U-shape.

  In the second embodiment, the concave portion 40 is provided outside the substantially square area of the radiation electrode 10b, and is configured to be capacitively coupled with the feeding electrode 21b efficiently without reducing the area of the radiation electrode 10b. Therefore, as compared with the first embodiment, a more optimal matching state can be easily obtained, and deterioration of characteristics can be reduced.

=== Third embodiment ===
FIG. 3 shows the electrode structure of the circularly polarized patch antenna 1c in the third embodiment of the present invention. (A) is a top view of the upper surface 3 of the base | substrate 2 in which the radiation electrode 10c is formed, (B) is an enlarged view of the principal part 100c in (A). In the third embodiment, the feeding electrode 21c is not a mere tip of a thin line, the feeding line 20 is a T-shaped vertical bar, and the tip of the feeding line 20 is branched left and right so as to be T-shaped. A T-shaped horizontal bar portion is used as a feeding electrode 21c. With this shape, since the capacitive coupling is performed between the side 13 of the radiation electrode (10c, 10d) and the feeding electrode 21c formed of a T-shaped horizontal bar, the coupling capacitance is increased as compared with the first embodiment, and the gap The circularly polarized patch antenna 1c can be made thin without narrowing 30. In addition to the line segment 25c corresponding to the T-shaped horizontal bar, the feeding electrode 21c is capacitively coupled to the inner line segments (41, 42) of the recess in addition to the line segment 25c corresponding to the T-shaped horizontal bar. Thus, a sufficient coupling capacity can be obtained without extending the length of the T-shaped horizontal bar 25c, and the impedance can be easily matched.

  In the third embodiment, as shown in FIG. 4, the feeding electrode 21d having the same shape as that of the circularly polarized patch antenna 10c is employed, and the recess 40 of the radiation electrode 10d is formed as in the second embodiment. You may form outside the substantially square external shape.

=== Fourth embodiment ===
FIG. 5 shows an electrode structure of a circularly polarized patch antenna 1e according to the fourth embodiment of the present invention. (A) is a top view of the upper surface 3 of the base | substrate 2 in which the radiation electrode 10e is formed, (B) is an enlarged view of the principal part 100e in (A). Similarly to the third embodiment, the fourth embodiment also branches the tip of the thin wire-shaped power supply line 20 to increase the coupling capacitance, and uses the branch portion as a power supply electrode 21e. In the fourth embodiment, the tip of the power supply line 20 is branched in a comb shape. In the fourth embodiment, like the circularly polarized patch antenna 1f shown in FIG. 6, the shape of the feeding electrode 21f is not changed, and the recess 40 is formed outside the substantially square outer shape of the radiation electrode 10f. May be.

=== Fifth embodiment ===
FIG. 7 shows an electrode structure of a circularly polarized patch antenna 1g according to the fifth embodiment of the present invention. (A) is a top view of the upper surface 3 of the base | substrate 2 in which the radiation electrode 10g is formed, (B) is an enlarged view of the principal part 100g in (A). In the fifth embodiment, the shape of the feeding electrode 21g is a comb-like shape as in the fourth embodiment. However, in this embodiment, each of the tips 25g of the feeding electrode 21g branched into a plurality of comb teeth is surrounded by the individual recesses 40. Thereby, in addition to the outer side line 26g of the feeding electrode 21g and the tip 25g of each comb tooth, the bottom 27 of the comb tooth and the inner side line part 28 are narrower than the inner side (41, 42) of each recess 40 and the tip part 43 of the side wall. Opposing via the gap 30 (dot portion in the figure), the coupling capacity can be further increased. In this fifth embodiment as well, as in the circularly polarized patch antenna 1h shown in FIG. 8, the same comb-shaped feeding electrode 21h is adopted, and the recess 40 is outlined to form the outer shape of the radiation electrode 10h. There is a modification formed outside the square.

=== Sixth embodiment ===
FIG. 9 shows an electrode structure of a circularly polarized patch antenna 1i according to the sixth embodiment of the present invention. (A) is the perspective view seen from the upper surface 3 side of the base | substrate 2 in which the radiation electrode 10i is formed, (B) is the perspective view seen from the lower surface 4 side in which the GND electrode 6 is formed. In the sixth embodiment, two thin wires (GND terminals) 7 are connected to the GND electrode 5 formed on the lower surface 4 of the base 2, and the GND terminal 7 extends to the side surface 4 of the base 2. . At least a part of the power supply line 20 is sandwiched between the two GND terminals 7. In this figure, a portion of the power supply line 20 formed on the side surface 4 of the base 2 is sandwiched. Of course, the GND terminal 7 may be extended to the upper surface 3 and the power supply line 20 may be clamped to the connection portion with the power supply electrode 21i. In addition, the shape of the radiation electrodes (10a to 10h) and the power supply electrodes (21a to 21h) in the first to fifth embodiments can be adopted for the radiation electrode 10i and the power supply electrode 21i on the upper surface 3. Here, the same shape as the circularly polarized patch antenna 1d shown as the modification of the third embodiment is shown.

  In the circularly polarized patch antenna 1i according to the sixth embodiment, since the capacitive reactance component can be provided in a portion other than the feeding electrode 21i in the feeding line 20, the input impedance of the antenna 1i can be set in a very wide band. Can be matched.

=== About the optimum dimensions of the recess ===
In the circularly polarized patch antennas (1a to 1i) in the first to sixth embodiments, the radiation electrodes (10a to 10i) and the feeding electrode are maintained while maintaining the characteristics as compared with the conventional example shown in FIG. (21a to 21i) can be formed in a very narrow region. In other words, by optimizing the size of the recess 40 in the facing region between the one side 13 of the radiation electrode (10a to 10i) and the feeding electrode (21a to 21i), a circle with excellent characteristics can be achieved while achieving a reduction in thickness. Polarized patch antennas (1a to 1i) can be obtained. Therefore, the circularly polarized patch antennas (1a to 1i) according to the embodiment of the present invention are characterized by using the length of the bottom 41 of the recess 40 with respect to the entire circumference of the substantially square forming the outer shape of the radiation electrodes (10a to 10i) as a parameter. Evaluated. In the evaluation, the circularly polarized patch antenna (the product of the present invention) 1i having the structure shown in FIG. 9 and the conventional circularly polarized patch antenna (the conventional product) 1L shown in FIG. The characteristics of right-handed antenna gain and axial ratio were compared.

  FIG. 10A shows the size of each part of the inventive product 1i employed for the characteristic evaluation. Moreover, the size of each part in the conventional product 1L is shown in FIG. Inventive product 1i and conventional product 1L have L = 2a + 2b, where L is the entire circumference of a substantially square forming the outer shape of the radiation electrode (10i, 10L), and in this evaluation, a = b = 7 mm. Further, the distance G between the radiation electrode (10i, 10L) and the feeding electrode (21i, 21L) is 0.5 mm.

  The base 2 is flat in the vertical direction, and the upper surface 3 and the lower surface 5 have a substantially square box shape. The horizontal length X and the vertical length Y of the upper surface 3 and the lower surface 4 are both 12 mm. The length W of the T-shaped feeding electrode 21L of the conventional product 1L is equal to the length of one side 13 of the radiation electrode 10L. That is, the length is obtained by removing the degenerate separation element 12 formed at the corner 11 from the length a (= b = 7 mm) of each side of the substantially square side of the radiation electrode 10L. Then, the ratio of the outer circumference L of the radiation electrode 10i and the width C of the bottom 41 of the recess 40 in the product 1i is used as a parameter, and the thickness of the substrate 2 (in the depth direction in the drawing) is 1.5 mm to 2.0 mm. The characteristics were evaluated. Even when the degenerate separation element 12 is not formed by the chamfered portion provided at the corner 11 of the radiation electrode (10i, 10L) but is formed by a protrusion provided in a substantially square diagonal extension direction, the substantially square outer shape L is similarly 2a + 2b.

  The right-handed antenna gain characteristics and axial ratio characteristics of the invention product 1i and the conventional product 1L shown in FIG. 15 are shown in FIGS. 11 and 12, respectively. From these figures, it can be seen that the inventive product 1i is generally superior in characteristics to the conventional product 1L, regardless of the value of the width C of the bottom 41 of the recess 40. And the remarkable characteristic improvement was recognized by C / L <= 1/8. In other words, the circularly polarized patch antenna according to the present invention has excellent characteristics when the width of the bottom of the recess is set to 1/8 or less of the total length L of the four sides of the substantially square forming the outer shape of the radiation electrode. I understood that. In the circularly polarized patch antenna 10g of the fifth embodiment, a plurality of recesses 40 are formed. In this case, the length of the entire line segment of the bottom 41 of the recess 40, that is, each recess 40 is The total value of the lengths of the bottom 40 is C.

1 is a structural diagram of a circularly polarized patch antenna according to a first embodiment of the present invention. FIG. 6 is a structural diagram of a circularly polarized patch antenna according to a second embodiment of the present invention. FIG. 6 is a structural diagram of a circularly polarized patch antenna according to a third embodiment of the present invention. It is a structural diagram of a modified example of the circularly polarized patch antenna of the third embodiment. FIG. 10 is a structural diagram of a circularly polarized patch antenna according to a fourth embodiment of the present invention. It is a block diagram of the modification of the circularly polarized patch antenna of the said 4th Example. FIG. 10 is a structural diagram of a circularly polarized patch antenna according to a fifth embodiment of the present invention. It is a structural diagram of a modified example of the circularly polarized patch antenna of the fifth embodiment. FIG. 10 is a structural diagram of a circularly polarized patch antenna according to a sixth embodiment of the present invention. It is a figure which shows the size of each site | part of the circular polarization patch antenna of this invention, and the conventional circular polarization patch antenna. It is a figure which shows the right-handed antenna gain characteristic of the circular polarization patch antenna of this invention, and the conventional circular polarization patch antenna. It is a figure which shows the axial ratio characteristic of the circular polarization patch antenna of this invention, and the conventional circular polarization patch antenna. FIG. 3 is a structural diagram of a general circularly polarized patch antenna that employs a pin feed method. FIG. 2 is a structural diagram of a general circularly polarized patch antenna that employs a power feeding method based on capacitive coupling. FIG. 6 is a structural diagram of a conventional circularly polarized patch antenna that employs a power feeding method using capacitive coupling.

Explanation of symbols

1a to 1k, 1L circularly polarized patch antenna 2 substrate 3 substrate upper surface 4 substrate side surface 5 substrate lower surface 6 GND electrode 7 GND terminal 10a to 10k, 10L radiation electrode 12 degenerate separation element part 13 one side of radiation electrode 20 feeder line 21a to 21i, 21k, 21L Feed electrode 22 Feed terminal 30 Gap 40 Recess 41 Recess bottom

Claims (7)

A vertically flat box-shaped substrate made of a dielectric material or a magnetic material, a radiation electrode having a substantially square planar shape and formed on the upper surface of the substrate, and formed on the lower surface of the substrate A GND electrode; a power supply electrode formed on an upper surface of the base body and disposed opposite to the substantially square side of the radiation electrode via a gap; and a power supply line for supplying power to the power supply electrode A circularly polarized patch antenna,
The power supply line is a thin line, a power supply terminal serving as a power supply point is connected to the proximal end, and the power supply electrode is connected to the distal end,
The circularly polarized patch antenna, wherein the radiation electrode is formed with a recess surrounding the power supply electrode on the one side facing the power supply electrode through the gap.   The concave portion is formed so as to have a shape in which a tip of a convex portion formed on the one side facing the power supply electrode through the gap is cut into a substantially U-shape. The circularly polarized patch antenna according to claim 1.   The power supply electrode and the power supply line are formed in a shape corresponding to a T-shaped horizontal bar and a vertical bar, respectively, and the T-shaped horizontal bar is disposed inside the recess through the gap. The circularly polarized patch antenna according to claim 1 or 2, characterized by the above.   The power supply electrode is formed in a plurality of branches so that the front end of the power supply line has a comb shape, and each front end of the comb tooth is disposed inside the recess through the gap. The circularly polarized patch antenna according to claim 1 or 2.   The circularly polarized patch antenna according to claim 4, wherein a plurality of the concave portions are formed corresponding to the respective tips of the comb teeth.   The GND electrode formed on the lower surface of the base extends to the side of the base in the form of two parallel thin wires, and the extended portion sandwiches at least a part of the power supply line on the side of the base. As described above, the circularly polarized patch antenna according to any one of claims 1 to 5, wherein the circularly polarized patch antenna is disposed in parallel to both sides in the extending direction of the feeder line.   The length of all the line segments which form the bottom side of the said recessed part is 1/8 or less of the sum total of the length of four sides of the substantially square of the said radiation electrode, It is any one of Claims 1-6 characterized by the above-mentioned. Circularly polarized patch antenna.

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