KR101735782B1 - Array antenna - Google Patents

Abstract

At least one radiation part including a plurality of radiation elements, a radiation line connecting the plurality of radiation elements, and a power distribution part for distributing power supplied from the radiation part to the at least one radiation part at a first ratio
≪ / RTI >

Description

Array antenna {ARRAY ANTENNA}

The present invention relates to an array antenna in which radiating elements are arranged in series.

A patch array antenna in the form of a printed microstrip is often used in radar detectors for the 24GHz Industrial, Scientific and Medical (ISM) bands. At this time, for the special characteristics of the antenna, such as increasing the gain of the antenna or lowering the side lobe level (SLL), it is necessary to use a chebyshev, a binomial, a Taylor taylor) are required to be applied to the array antenna. In this case, a complicated power feeding circuit is required for feeding each radiating element. The design and performance optimization of an array antenna with a complex power supply circuit takes a long time.

In order to solve the above problems due to the complexity of the design, the patch array antenna for the 24 GHz band is designed such that the magnitude and phase of the current are uniformly input to each patch. However, the array antenna with the uniform magnitude and phase of the current input by the patch shows a high sidelobe level characteristic, and therefore, the detection region is very uneven. In addition, when the detection area of the radar detector is very narrow, it is difficult to generate a narrow and uniformly wide beam only by the radar algorithm because the level of the sub-lobe of the beam generated by the array antenna is high.

An array antenna with high gain and low sidelobe level characteristics is provided.

According to one embodiment, there is provided a power distribution system comprising: a plurality of radiating elements; at least one radiating element including a power feeding line connecting the plurality of radiating elements; and at least one radiating element, An array antenna is provided.

The first ratio in the array antenna may be determined based on an array function related to a side lobe level in a first direction perpendicular to the direction in which the plurality of radiating elements are arranged.

In the array antenna, the conductance of the first radiating element located at the center of the radiating element among the plurality of radiating elements may be larger than the conductance of the at least one second radiating element located at the edge of the radiating element among the plurality of radiating elements.

The conductance of the plurality of radiating elements in the array antenna may decrease at a second rate in a second direction from the first radiating element to the at least one second radiating element.

The second ratio in the array antenna may be a ratio determined based on an array function associated with the side lobe level in the second direction.

The array function in the array antenna may be a chebyshev array function.

The size of the plurality of radiating elements in the array antenna may decrease at a second rate in a second direction from the first radiating element to the at least one second radiating element.

The second ratio in the array antenna may be a ratio of the feed factor determined based on the array function of the array antennas and the array function related to the side lobe level in the second direction.

The feeding coefficient in the array antenna may be a coefficient determined through comparison of the coefficient of array function and array function.

The array antenna may further include a dielectric substrate on which at least one radiating part is printed in the form of a patch.

In the array antenna, the feeder line can control the phase of the current input to the plurality of radiating elements.

In the array antenna, the feed line may connect a plurality of radiating elements in series.

The power divider in the array antenna can match the impedance of at least one radiating part with respect to the feeding part.

The power distribution unit in the array antenna includes at least one first power distribution unit that provides power distributed at a first rate to at least one radiation unit and at least one first power distribution unit that distributes power supplied from the power feeding unit to the same power distribution unit And a second power distributing unit for providing the second power distributing unit.

In the array antenna, the impedance of the first power divider may be determined according to a first ratio and a predetermined impedance constant.

According to one embodiment, the beam is sharpened through a high gain and a narrow 3dB radiation characteristic (HPBW _3dB = 4.0 deg.) To perform centralized monitoring for a specific sensing area. In addition, based on the Chebyshev array function, performance equal to or less than the low side level (-20dB) in the horizontal direction and the vertical direction can be realized, thereby ensuring uniform detection performance in the horizontal and vertical directions. A beam having various slopes in boresight can be formed by adjusting the phase of a current input to each radiating element in the array antenna 100 according to one embodiment. By adjusting the number of radiating elements, Can be controlled. Also, it is possible to easily feed power to each radiating element based on various functions, and since it is a printing structure, it is also advantageous in mass production.

FIG. 1A is a plan view of an array antenna according to an embodiment, and FIG. 1B is a perspective view.
2 is a view illustrating a radiating part included in an array antenna according to an embodiment of the present invention.
3 is a diagram illustrating a power distribution unit according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

FIG. 1A is a plan view of an array antenna according to an embodiment, and FIG. 1B is a perspective view.

1A and 1B, an array antenna 100 according to an embodiment includes a radiation unit 110, a power distribution unit 120, and a power supply unit 130. [ The radiation unit 110 of the array antenna 100, the power distribution unit 120, and the feeding unit 130 may be arranged on the dielectric substrate 200 and the ground plane 300.

The radiating element 110 includes a plurality of radiating elements 111 and a feeder line 112 for connecting a plurality of radiating elements in series. The array antenna 100 according to an embodiment includes a plurality of radiating elements 110 Can be included. The radiation 110 may be printed in microstrip form and the radiation conductance G _R of each radiation element 111 may be adjusted to meet various requirements for antenna design, have. The feeder line 112 of the radiation unit 110 can control the slope of the emitted beam by adjusting the phase of the current input to each radiating element 111. [ The feed line 112 may be a line having an impedance of a predetermined magnitude, and the impedance of the line according to an embodiment may be 100 ohms.

The power dividing unit 120 includes a first power dividing unit 121, a second power dividing unit 122, and a third power dividing unit 123. The power distributor 120 may transmit the power provided from the power feeder 130 to the radiation unit 110. [ At this time, the first power divider 121 operates as a uniform power divider having a constant output power ratio (for example, -3 dB), and the second power divider 122 and the third power divider 123 operate And can operate as an unequal power distributor for distributing power of different sizes to the radiation unit 110. [ The second power splitter 122 and the third power splitter 123 can impedance match the impedance of the radiation unit 110 with respect to the feeder 130. According to one embodiment, an equal Wilkinson power divider may be used as the first power divider 121 and a non-equal Wilkinson power divider 122 as the second power divider 122 and the third power divider 123 Can be used.

The power feeder 130 may transmit the power to be provided to the radiation section to the power distributor 120. [ In one embodiment, the feeder 130 can be changed into various feeding forms such as a coaxial line or a coplanar waveguide (CPW) using a transition structure.

2 is a view illustrating a radiating part included in an array antenna according to an embodiment of the present invention.

The plurality of radiating elements 111 included in the radiating part 110 according to one embodiment are arranged in series in the y direction and the radiating elements located at the center among the plurality of radiating elements 111 are the largest, The size of the radiating element becomes smaller toward the both ends. At this time, the size of each radiating element 111 can be determined according to the radiation conductance. That is, a large-sized radiating element can have a larger radiation conductance than a small-sized radiating element. Since the array antenna according to one embodiment can be manufactured in a printed form on a dielectric substrate, each radiating element can be defined as a surface having a length in the x direction (width) and a length in the y direction (length). 2, the radiation unit 110 according to one embodiment includes nine radiating elements E1 to E9, and the number of radiating elements can be determined according to the purpose of use of the array antenna according to one embodiment have.

The radiation conductance of the plurality of radiation elements 111 included in the radiation section 110 according to one embodiment may be determined according to an array function having a low side-level characteristic. In one embodiment, a Chebyshev array function with a y-direction (vertical) side-lobe level of -20 dB was used to determine the radiation conductance. At this time, the angle of inclination of the beam for the forward (+ z direction) directivity characteristic of the array antenna 100 may be designed to be zero with respect to the z axis.

Equation 1 is an array factor (AF) of the array antenna 100 according to one embodiment, and the magnitude of the current applied to each radiating element 111 is calculated through Equation 1 and the Chebyshev array function .

[ Equation 1 ]

& Quot; (2 ) & quot ;

In Equation 1, i is the current applied to each radiating element 111, and AF is a function of?. Equation 2 represents?. When Equation (1) is developed, 15 terms can be calculated as shown in Equation (3) below.

& Quot; (3 ) & quot ;

In Equation 2, k is the wave number of the beam (k = 2? /?) And d is the interval between the radiating elements 111, which can be defined as 1/2 of the wavelength of the beam (d =? / 2). Therefore, the length of the feeder line (microstrip line) 112 connecting each radiating element can be designed to be a half wavelength (? / 2) of the beam. At this time, the phase of the current input to each radiating element is 0 °, but the phase of the current in each radiating element can be adjusted according to the radiation angle of the beam required according to the use environment. In addition, the number, gain, or beam width of the radiating elements can also be appropriately adjusted. Equation (4) is an expression summarizing expression (1), and expression (5) is an eighth-order Chebyshev array function.

& Quot; (4 ) & quot ;

& Quot; (5 ) & quot ;

Comparing the coefficients of the cosine terms in equations (4) and (5), Equation (6) can be obtained.

& Quot; (6 ) & quot ;

In this case, x ₀ in Equation (5) represents a coefficient R (R = 10 ^{- SLL / 20} , which can be determined according to the number M of radiating elements (M = 2N + 1, In the embodiment, since the side lobe level applied to the vertical direction is -20 dB, R = 10 ^{- (- 20) / 20} = 10).

& Quot; (7 ) & quot ;

Referring to Equation (6), in one embodiment, M = 9, R = 10, so that x ₀ is 1.0708. Finally, when x ₀ is substituted into Equation (5), the magnitude of the current applied to each radiating element (111) can be calculated as shown in Equation (8).

& Quot; (8 ) & quot ;

In Equation 8 i _{0n, 1n} i, i _{2n, 3n} i and i _4n is, indicates the amount of current normalized relative to the current size of the i _0. Here, in one embodiment, the normalized current magnitude for each radiating element 111 is a vertical feed factor.

Table 1 below shows the feed coefficient of each radiating element 111 and the conductance of each radiating element 111 calculated on the basis of the array factor function defined in Equation (1). In one embodiment the feed radiation coefficient of each element may be calculated by the coefficient comparison of the coefficients of the coefficient array and a Chebyshev function of the cos term of the array argument function of equation (1), the conductance coefficient is based on the power supply a- _n . ≪ / RTI > Equation (9) represents the sum of conductances of all the radiating elements included in the radiation unit 110.

& Quot; (9 ) & quot ;

In Equation 9, the total radiation conductance G _t can be calculated based on the constant of proportionality K of each radiating element 111 and the feed coefficient a _n , and in one embodiment, The sum of the proportional constant and the feed coefficient of the feeder 111 is 1. The proportional constant is calculated based on the respective feeding coefficients (a _n ) calculated through Equation (1).

& Quot; (10 ) & quot ;

Using the proportionality constant K (0.1784), the normalized radiation conductance of each radiating element 111 can be defined as: < EMI ID = 11.0 >

& Quot; (11 ) & quot ;

In one embodiment, the characteristic impedance of each feeder line 112 was determined to be 100 [Omega], so that the normalized impedance of the feeder line 112 was also set to 100 [Omega].

device Feed factor
(a _n ) Normalized
conductance Calculated value Optimum value Width (mm) Length (mm) Width (mm) Length (mm) E1 0.6014 0.0645 1.123 3.182 1.523 3.182 E2 0.6153 0.0675 1.173 3.173 1.573 3.173 E3 0.8121 0.1176 1.998 3.065 2.398 3.065 E4 0.9503 0.1611 2.703 3.011 3.503 3.011 E5 1.0000 0.1784 2.982 2.994 4.582 2.994 E6 0.9503 0.1611 2.703 3.011 2.903 3.011 E7 0.8121 0.1176 1.998 3.065 1.798 3.065 E8 0.6153 0.0675 1.173 3.173 0.973 3.173 E9 0.6014 0.0645 1.123 3.182 0.923 3.182

Referring to Table 1, the radiating element according to one embodiment has optimized width and length to increase the gain of the array antenna.

3 is a diagram illustrating a power distribution unit according to an embodiment.

The power divider 120 according to one embodiment can distribute power of different magnitudes to the respective radiation units 110. FIG. The magnitude of the power distributed to the radiation unit 110 from the second power distributor 122 and the third power distributor 123 of the power distributor 120 is the same as the size of the Chebyshev array having a side level of -30 dB in the horizontal direction It can be computed based on a function. At this time, the side lobe level in the horizontal direction can be determined to be a size capable of improving the detection performance in the horizontal direction.

3, the power divider 120 includes a first power divider 121, a second power divider 122 and a third power divider 123-1, 123-2, 123-3, 123-4). The power divider 120 may divide the power supplied from the power feeder 130 and apply the currents i _x1 to i _x8 to the radiation units 110 of the array antenna 100. [

And can operate as a uniform power divider that outputs a constant power by using the resistance (R ₀ ) of the first power splitter 121.

The second power distributor 122 may output different powers to the third power distributors 123-1, 123-2, 123-3, and 123-4.

The third power distributing units 123-1, 123-2, 123-3, and 123-4 may operate as unequal power distributors that distribute power of different sizes to the respective radiation units 110. [ At this time, the third power distributors 123-1, 123-2, 123-3 and 123-4 are connected to the resistors R ₁ to R ₄ and the symmetrically arranged impedances Z _1R , Z ' _1R and Z _1L and _{a, Z '1L, Z 2R,} Z' 2R, Z 2L, Z '2L, Z 3R, Z' 3R, Z 3L, Z '3L, Z 4R, Z' 4R, Z 4L, Z '4L) . That is, the n-th unit (123-n) is the power distribution parts 3, rooms connected to the n-th unit (123-n) by using a resistor R- _n and _nR impedance Z, Z _{'nR, nL} Z and Z' _nL And may provide power to the scalp 110.

The magnitude of the current applied to each of the radiation units 110 in the horizontal direction (that is, the horizontal direction feeding coefficient) is calculated by the mathematical method of calculating the magnitude of the current applied to each radiating element 111 arranged in the vertical direction, The feed factor in the horizontal direction can be obtained as shown in Equation (13).

& Quot; (12 ) & quot ;

& Quot; (13 ) & quot ;

The feeding coefficients for the radiating elements included in the array antenna 100 according to one embodiment, which are calculated using the vertical feeding coefficients of Equation 8 and the horizontal feeding coefficients of Equation 13, same.

E9 0.1750 0.1908 0.2741 0.3619 0.4465 0.5194 0.5730 0.6014 E8 0.1791 0.1952 0.2804 0.3703 0.4568 0.5314 0.5863 0.6153 E7 0.2363 0.2577 0.3701 0.4887 0.6029 0.7014 0.7738 0.8121 E6 0.2765 0.3015 0.4330 0.5718 0.7055 0.8207 0.9054 0.9503 E5 0.2910 0.3173 0.4557 0.6018 0.7424 0.8637 0.9528 1.0000 E4 0.2765 0.3015 0.4330 0.5718 0.7055 0.8207 0.9054 0.9503 E3 0.2363 0.2577 0.3701 0.4887 0.6029 0.7014 0.7738 0.8121 E2 0.1791 0.1952 0.2804 0.3703 0.4568 0.5314 0.5863 0.6153 E1 0.1750 0.1908 0.2741 0.3619 0.4465 0.5194 0.5730 0.6014 8 7 6 5 4 3 2 One

Referring to Table 2, the feed coefficient of each radiating element 111 is shown, and the normalized vertical feed coefficient of Equation 8 is applied to the vertical direction and the horizontal feed coefficient of Equation 13 is applied to the horizontal direction Respectively. For example, the feed coefficient 0.5194 of the radiating element corresponding to E1 in the third column is 0.6014 times of the feed coefficient 0.8637 of the radiating element corresponding to E5 in the third column, and the feed coefficient of the radiating elements in eight rows among the radiating elements corresponding to E5 in each row 0.2910 is 0.1750 / 0.6014 times the feed coefficient of one row of radiating elements.

The third power distributor 123 distributes power of different magnitudes in the horizontal direction according to Equation (13). The impedance of the elements included in the third power distributor 123 (Z _iR , Z _iL , Z ' _iR , Z' _iL and R) can be calculated based on the following equation (14).

& Quot; (14 ) & quot ;

Referring to Equation (14), Z ₀ is a predetermined impedance constant, and k is a ratio of unequal power. In one embodiment, Z ₀ was set to 50 ohms. The k and the impedances of the third power divider 123 according to one embodiment are shown in Table 3 (k and impedance of the first third power divider 123-1) (K and impedance of the fourth third power distributor 123-2), and Table 5 (k and impedance of the third third power distributor 123-3) And impedance).

k 1.0245 Z _{1 R} 69.03 [?] Z _1L 49.40 [Ω] Z ' _{1 R} 72.45 [?] Z ' _1L 50.61 [?] R ₁ 100.03 [?]

k 1.0786 Z _2R 65.65 [Ω] Z _2L 48.14 [Ω] Z ' _2R 76.37 [?] Z ' _2L 51.93 [?] R ₂ 100.29 [?]

k 1.1491 Z _3R 61.84 [Ω] Z _3L 46.64 [?] Z ' _3R 81.64 [Ω] Z ' _3L 53.60 [Ω] R ₃ 100.97 [?]

k 1.0442 Z _4R 67.75 [Ω] Z _4L 48.93 [?] Z ' _4R 73.87 [Ω] Z ' _4L 51.09 [Ω] R ₄ 100.09 [Ω]

The array antenna 100 according to an exemplary embodiment can perform focused monitoring for a specific sensing area by forming a sharp beam through a high gain and a narrow 3dB radiation angle characteristic (HPBW _3dB = 4.0). In addition, the array antenna according to an embodiment achieves uniform detection performance in the horizontal and vertical directions by achieving low side level (-30 dB and -20 dB respectively) in the horizontal direction and the vertical direction based on the Chebyshev array function can do. The phase of the current input to each radiating element in the array antenna 100 according to the embodiment can be adjusted so that a beam having various slopes in boresight can be formed and the width of the beam can be controlled by controlling the number of radiating elements can do. Also, it is possible to easily feed power to each radiating element based on various functions, and since it is a printing structure, it is also advantageous in mass production.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (15)

At least one radiation part including a plurality of radiation elements, and a feeder line connecting the plurality of radiation elements, and
The power provided from the power feeder is divided into different sizes determined based on a Chebyshev array function such that the side lobe level in the horizontal direction of the beam emitted by the radiator is -30 dB, Power distributing section
Lt; / RTI >
The horizontal direction being a direction perpendicular to the vertical direction in which the plurality of radiating elements are arranged and the conductance of the plurality of radiating elements being such that the vertical level of the side of the beam is -20 dB The array antenna decreases in proportion to the determined ratio . delete The method of claim 1,
Wherein a conductance of a first radiating element located at the center of the radiating element among the plurality of radiating elements is larger than a conductance of at least one second radiating element located at an edge of the radiating element among the plurality of radiating elements. delete delete delete 4. The method of claim 3,
Wherein a size of the plurality of radiating elements decreases at a second rate in a direction from the first radiating element to the at least one second radiating element. 8. The method of claim 7,
Wherein the second ratio is a ratio of a feed factor determined based on an array function of the array antennas and an array function associated with the vertical sidelobe levels. 9. The method of claim 8,
Wherein the feed coefficient is a coefficient determined by comparing the coefficient of the array function and the coefficient of the array function. The method of claim 1,
Wherein the at least one radiating part is printed in the form of a patch,
≪ / RTI > The method of claim 1,
Wherein the feed line controls the phase of a current input to the plurality of radiating elements. The method of claim 1,
Wherein the feeder wire connects the plurality of radiating elements in series. The method of claim 1,
Wherein the power distributing unit matches the impedance of the at least one radiating part with respect to the feeding part. The method of claim 1,
Wherein the power distributor comprises:
At least one first power distributor for providing the power of the different magnitude to the at least one radiation section, and
A second power distribution unit for providing the same power as the power provided from the power supply unit to the at least one first power distribution unit,
≪ / RTI > The method of claim 14,
Wherein an impedance of the first power divider is determined according to a ratio of power of the different magnitudes and a predetermined impedance constant.

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