KR20200121153A - Planar array antenna using shorted patch antenna element - Google Patents

Abstract

Disclosed is an array antenna using a shorted patch antenna. The disclosed array antenna determines a distance between grounds corresponding to a shorted patch antenna in consideration of characteristics of the array antenna, so that the characteristics of the array antenna can be excellently maintained, and further, the direction detection performance using the array antenna is excellent.

Description

Planar array antenna device using short-circuit patch antenna {PLANAR ARRAY ANTENNA USING SHORTED PATCH ANTENNA ELEMENT}

The following embodiments relate to an array antenna device disposed on a plane, and more specifically, to a planar array antenna device using a short patch antenna as an antenna element.

Recently, in the 2.4 GHz band, as the usage of wireless applications such as Bluetooth, Wi-Fi, and mobile communication increases rapidly, there is a problem that the performance of the system is deteriorated due to signal interference by other systems in close proximity. Therefore, a technology for estimating and removing the direction of an interference signal that causes performance degradation of the system is important, and recently, research on an array antenna capable of beam steering as a technology for effectively detecting and identifying an interference signal has been actively conducted. However, when the individual element antennas are arranged in a limited space, gain characteristics and pattern distortion occur due to the mutual coupling characteristics between the elements, thereby deteriorating the performance of the array antenna.

The following embodiments aim to determine the distance between the grounds of individual antenna elements constituting the array antenna.

The following embodiments aim to determine the distance between the grounds of individual antenna elements in consideration of interference and mutual coupling between antenna elements.

According to an exemplary embodiment, a planar antenna device includes a planar dielectric base, a plurality of rectangular grounds arranged in a grid shape at predetermined intervals on the dielectric base, and a short patch antenna disposed on each of the grounds, , The predetermined spacing is determined in consideration of a beam width of the planar antenna device and interference between the short-circuited patch antennas.

Here, the short-circuit patch antenna may include a vertical antenna extending in a direction perpendicular to the square ground and a horizontal antenna perpendicular to the vertical antenna and extending in a direction parallel to the ground.

In addition, a vertical feed part perpendicular to the rectangular ground and extending in a direction parallel to the vertical antenna, and a vertical feed part perpendicular to the vertical feed part from the vertical feed part, extending toward the vertical antenna in a direction parallel to the ground. It includes a horizontal power feeding part, and the length of the vertical power feeding part may be shorter than the length of the vertical antenna part.

In addition, an incidence angle estimating unit for estimating an incidence angle of a signal received using the short-circuit patch antennas may be further included.

Here, the incident angle estimating unit may estimate the incident angle of the signal using a MUSIC or ESPRIT technique.

In addition, the predetermined interval may be determined such that a beam width of the planar antenna device is equal to or greater than a first reference value, and interference between the short-circuited patch antennas is equal to or less than a second reference value.

According to example embodiments, a distance between grounds of individual antenna elements constituting the array antenna may be determined.

According to example embodiments, the distance between the grounds of individual antenna elements may be determined in consideration of interference between antenna elements and mutual coupling.

1 is a diagram illustrating a concept of detecting an unauthorized wireless device that hacks or jams another communication device.
Fig. 2 is a diagram showing an array antenna according to an exemplary embodiment.
Fig. 3 is a diagram showing the performance of an array antenna according to an exemplary embodiment.
Fig. 4 is a diagram showing a concept of determining a spacing between grounds corresponding to antenna elements in an array antenna according to an exemplary embodiment.
Fig. 5 is a diagram showing a concept of forming a beam in a specific direction using an array antenna according to an exemplary embodiment.
Fig. 6 is a diagram showing a concept of estimating a direction of an incident signal using an array antenna according to an exemplary embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a concept of detecting an unauthorized wireless device that hacks or jams another communication device.

The first communication device 120 transmits and receives radio waves to exchange data with the second communication device 130. The third communication device 140 may leak data between the first communication device 120 and the second communication device 130 by intercepting radio waves transmitted and received by the first communication device 120.

In addition, the third communication device 140 may interfere with data exchange between the first communication device 120 and the second communication device 130 by transmitting a jammer to the first communication device 120. The third communication device 140 transmits a radio wave at a strength that is much stronger than that of the second communication device 130 to prevent the first communication device 120 from receiving the radio wave from the second communication device 130. do.

Even if the third communication device 140 does not intentionally interfere with the communication of the first communication device 120, the third communication device 140 is not less than a predetermined strength by standards or laws, or outside a predetermined frequency band. If radio waves are transmitted in the frequency band of, it may interfere with communication of the first communication device 120. Therefore, each communication device (120, 130, 140) must transmit a radio wave in a predetermined strength and a predetermined frequency band according to standards or laws.

According to one side, the radio wave detection device 110 detects radio waves transmitted by other communication devices 120, 130, and 140, so that any communication device 120, 130, or 140 has a strength that is greater than or equal to a predetermined strength by standards or laws, or It can be determined whether radio waves are transmitted in a frequency band other than a predetermined frequency band. In this case, the radio wave detection apparatus 110 must be able to estimate the incident angle of the radio wave, and for this purpose, a directional antenna, in particular, an array antenna composed of a plurality of antenna elements 111, 112, 113, and 114 may be used.

The radio wave detection device 110 has a wide frequency band of signals that can be detected, and in order to be used in various environments, the antenna elements 111, 112, 113, and 114 constituting the array antenna are used as a shorted patch antenna. Configurable. Since the short-circuit patch antenna has a flat shape, if an array antenna is configured using a short-circuit patch antenna, the radio wave detection device 110 can be miniaturized. However, if short-circuited patch antennas are disposed adjacent to each other for miniaturization, there is a problem in that the performance of the array antenna is deteriorated due to interference or mutual coupling between the antennas.

Fig. 2 is a diagram showing an array antenna according to an exemplary embodiment.

FIG. 2A is a diagram showing an individual antenna element constituting an array antenna, and FIG. 2B is a view showing an array antenna constructed using the antenna element shown in FIG. 2A. .

In (a) of FIG. 2, the short-circuit patch antenna used as an antenna element of the array antenna is positioned on a ground 231 made of a metal plate. According to one side, the ground 231 may be located on a planar dielectric base.

The antenna unit 210 is located on the ground 231, a vertical antenna 214 extending in a direction perpendicular to the ground, and a horizontal antenna extending in a direction parallel to the ground 230 at a right angle to the vertical antenna 214 It consists of 215.

The short-circuit patch antenna is powered using the power feeding unit 223. The feeding part 223 includes a vertical feeding part 224 extending from the ground in a direction perpendicular to the ground, and a horizontal feeding part 225 extending from the vertical feeding part 224 toward the vertical antenna 214 in a direction parallel to the ground. ). The vertical feed part 224 may be parallel to the vertical antenna 214, and the horizontal feed part 225 may be perpendicular to the vertical feed part 224.

According to one side, the length of the horizontal feeding unit 225 may be adjusted so as not to contact the vertical antenna 214. In addition, the height of the vertical power feeding unit 224 may be lower than that of the vertical antenna 214. In this case, the vertical feeding part 214 and the horizontal feeding part 225 do not contact the vertical antenna 214 and the horizontal antenna 215.

The power supply unit 223 supplies power to the antenna unit 210 by using an indirect power supply method in a state in which there is no direct electrical contact with the antenna unit 210. According to one side, the power supply unit 223 may include a power supply terminal passing through the ground and receive power through the power supply terminal.

Table 1 below shows the main system parameters of the shorted patch antenna.

[Table 1]

Referring to Table 1, the width (w, 211) of the vertical antenna 214 is 52.1 mm, and the length (l, 212) of the horizontal antenna 215 is 21.9 mm. The height (h, 213) of the vertical antenna 214 is 13 mm, and the height (hf, 223) of the vertical power supply unit 224 is 8.7 mm. The length (lf, 222) of the horizontal power supply unit 225 is 21 mm, and the width (wf, 221) of the horizontal power supply unit 225 is 3.3 mm. The operating frequency of the short-circuited patch antenna having the parameters shown in Table 1 is 1.7GHz ~ 2.8GHz.

In FIG. 2B, the short patch antennas 241, 242, 243 and 244 are arranged in a lattice shape at a predetermined first interval 251 on the dielectric base. Grounds 261, 262, 263, and 264 corresponding to each of the short-circuit patch antennas 241, 242, 243, and 244 are also arranged at a predetermined second interval 252. In this case, the grounds 261, 262, 263, and 264 may have a rectangular shape.

Fig. 3 is a diagram showing the performance of an array antenna according to an exemplary embodiment.

FIG. 3A is a diagram showing a reflection coefficient according to a frequency of the array antenna shown in FIG. 2B. The horizontal axis represents the frequency, and the vertical axis represents the reflection coefficient in dB scale.

Referring to FIG. 3A, the reflection coefficient 312 of the antenna actually configured as shown in FIG. 2B is not significantly different from the result 311 calculated using simulation.

FIG. 3(b) is a diagram showing the frontal gain (Bore-sight Gain) according to the frequency of the array antenna shown in FIG. 2(b), where the horizontal axis represents the frequency, and the vertical axis represents the gain in dB scale. Represented by

Referring to FIG. 3B, the gain 322 of the antenna actually configured as shown in FIG. 2B is not significantly different from the result 321 calculated using simulation.

Referring to FIGS. 3A and 3B, it can be seen that the array antenna actually implemented as shown in FIG. 2B has little effect of interference or mutual coupling between each antenna element.

In general, antenna elements 241, 242, 243, and 244 constituting an array antenna are located spaced apart by a half-wavelength distance. However, even in this case, the distance 252 between the grounds 261, 262, 263, and 264 corresponding to the antenna elements 241, 242, 243, and 244 can be changed within a certain range.

If the distance 252 between the grounds decreases, interference between the antenna elements 241, 242, 243, and 244 increases, thereby deteriorating the characteristics of the array antenna. In addition, when the distance 252 between grounds increases, the area of the ground decreases, thereby deteriorating the characteristics of the antenna elements 241, 242, 243, and 244, and the characteristics of the array antenna.

Therefore, the distance 252 between grounds must be determined in consideration of the performance of the array antenna.

The array antenna according to the exemplary embodiment may be used to detect a communication device that transmits a strong radio wave in the direction of another communication device, or transmits a radio wave without complying with a standard or statute. In this case, the distance 252 between grounds may be determined such that the array antenna has a wider beam width.

Fig. 4 is a diagram showing a concept of determining a spacing between grounds corresponding to antenna elements in an array antenna according to an exemplary embodiment.

FIG. 4A is a diagram showing isolation of each antenna element according to a distance between grounds. In FIG. 4A, the horizontal axis represents the distance between grounds, and the vertical axis represents the degree of isolation in dB scale. The four graphs 421, 422, 423, and 424 shown in FIG. 4A represent the isolation degrees of the four antenna elements 411, 412, 413, and 414 constituting the array antenna.

Looking at each graph briefly, the degree of isolation of the antenna elements 411, 412, 413, and 414 has a relatively small value when the distance between grounds is '0', and is relatively small when the distance is not '0'. It has a large value. However, if the distance between the grounds is not '0', the degree of isolation does not increase significantly even if the distance between the grounds increases.

4B is a diagram showing characteristics of an array antenna according to a distance between grounds. The horizontal axis represents the distance between grounds, and the right vertical axis represents the half power beam width in dB scale. Referring to the graph 432, the half power beam width increases in proportion as the distance between grounds increases. In addition, the left vertical axis of FIG. 4B represents the pattern deviation of the array antenna in dB scale. The pattern deviation of the array antenna means the difference between the maximum value and the minimum value of the gain of the array antenna, and the smaller the deviation of the pattern within a predetermined band or beam width, the better. Referring to the graph 431, the pattern deviation maintains a relatively constant value even when the distance between grounds increases.

According to one side, the distance 152 between grounds may be determined in consideration of at least one or more of various characteristics of the array antenna shown in FIG. 4 (isolation between devices, half power beam width, and pattern deviation).

For example, when the array antenna is used to detect another communication device, since it is advantageous to have a wide beam width, the distance 152 between grounds may be determined such that the beam width of the array antenna is equal to or greater than a first threshold.

Further, since the performance of the array antenna is better as the pattern deviation is small, the distance 252 between grounds may be determined such that the pattern deviation of the array antenna is equal to or greater than the second threshold.

In addition, if the degree of isolation between antenna elements is low, since interference or mutual coupling between antenna elements increases and the performance of the array antenna deteriorates, the distance 252 between the grounds may be determined so that the degree of isolation between antenna elements is equal to or greater than the third threshold. have.

Here, the first threshold, the second threshold, and the third threshold may be determined according to performance or characteristics required for the array antenna.

According to one side, a range is determined using a first threshold, a second threshold, a third threshold, and the like, and the distance 252 between grounds may be selected within the range.

Fig. 5 is a diagram showing a concept of forming a beam in a specific direction using an array antenna according to an exemplary embodiment.

When antenna elements are disposed on a plane as shown in FIG. 2B, signals incident from a specific direction are received at different phases from each antenna element. If the phase of the signals received from each antenna element is appropriately modified, a large gain can be given to signals incident from a specific direction, and a small gain can be given to signals incident from another direction.

The gain according to the direction of the array antenna is called a beam pattern, and FIG. 5 shows the maximum for 0 degrees 510, 15 degrees 520, and 30 degrees 530 using the array antenna shown in FIG. 2(b). It shows the formation of a beam pattern having a gain. The horizontal axis of FIG. 5 represents the direction, and the vertical axis represents the gain of the array antenna in dB scale.

Referring to FIG. 5, it can be seen that beam patterns having excellent characteristics can be formed in each direction by using the array antenna shown in FIG. 2. Accordingly, as shown in FIG. 4, when the distance 252 between grounds is determined in consideration of the characteristics of the array antenna, it can be confirmed that the performance of the array antenna is excellent.

Fig. 6 is a diagram showing a concept of estimating a direction of an incident signal using an array antenna according to an exemplary embodiment.

As described above. The phase of the signal received from each antenna element is determined according to the incident angle of the signal. Therefore, by analyzing the phase of the received signal, it is possible to estimate the incident angle of the signal. Representative examples of algorithms for estimating the angle of incidence of a signal include Multiple Signal Classification (MUSIC) and Estimation of Signal Parameters via Rotation Invariance Techniques (ESPRIT).

The array antenna shown in FIG. 2B may further include an incidence angle estimating unit for estimating an incident angle of a signal incident to the array antenna using a MUSIC or ESPRIT technique.

6, when a signal is incident at a specific azimuth angle (622) and a specific elevation angle (632), the performance of the incidence angle estimator is the estimated azimuth angle 621 and the estimated altitude. It can be evaluated as errors 641 and 642 between the angle 631 and the direction angle 622 at which the actual signal is incident and the elevation angle 632 at which the actual signal is incident.

According to one side, the errors 641 and 642 between the estimated direction angle 621 and the estimated elevation angle 631 and the actual signal incident direction 622 and the actual signal incident elevation angle 632 are It may be defined as a root mean square error as shown in Equation 1 below.

[Equation 1]

는 평균 제곱근 오차이고,

는 실제 신호가 입사한 방향각이고,

는 추정된 방향각이다. 또한,

는 실제 신호가 입사한 고도각이고,

는 추정된 고도각이다.here,

Is the root mean square error,

Is the direction angle at which the actual signal is incident,

Is the estimated direction angle. In addition,

Is the elevation angle at which the actual signal is incident,

Is the estimated elevation angle.

For the two cases where the direction angle is 90 degrees, the elevation angle is 0 degrees, and the direction angle is 70 degrees and the elevation angle is 50 degrees, the incidence angle estimation results using the array antenna shown in Fig. 2(b) are shown below. It is shown in Table 2.

[Table 2]

In this case, the root mean square error is only 1.1 and 1.4, respectively, and the side lobe level (SLL) also shows 9.6dB and 3.1dB, respectively, so that the array antenna shown in Fig. 2(b) has quite excellent performance. Can be seen. As a result, when the distance 252 between grounds is determined in consideration of the characteristics of the array antenna as shown in FIG. 4, it can be confirmed that the performance of the array antenna is excellent.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -A hardware device specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of the program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operation of the embodiment, and vice versa.

Although the embodiments have been described by the limited embodiments and drawings as described above, various modifications and variations can be made from the above description to those of ordinary skill in the art. For example, the described techniques are performed in a different order from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and claims and equivalents fall within the scope of the claims to be described later.

110: radio wave detection device
111, 112, 113, 114: array antenna
120: first communication device
130: second communication device
140: third communication device

Claims (6)

In the planar antenna device,
A planar dielectric base;
A plurality of rectangular grounds arranged in a grid shape at predetermined intervals on the dielectric base;
Short-circuited patch antennas placed above each ground
Including,
The predetermined spacing is determined in consideration of a beam width of the planar antenna device and interference between the short-circuited patch antennas. The method of claim 1, wherein the shorted patch antenna
A vertical antenna extending in a direction perpendicular to the square ground; And
A horizontal antenna perpendicular to the vertical antenna and extending in a direction parallel to the ground
Planar antenna device comprising a. The method of claim 2,
A vertical feeding part perpendicular to the square ground and extending in a direction parallel to the vertical antenna; And
A horizontal feeding part extending from the vertical feeding part toward the vertical antenna in a direction perpendicular to the vertical feeding part and parallel to the ground.
Including,
The length of the vertical feeding part is shorter than the length of the vertical antenna part. The method of claim 1,
Incident angle estimating unit for estimating the incident angle of the received signal using each of the short-circuit patch antennas
Planar antenna device further comprising a. The method of claim 4, wherein the incident angle estimation unit
A planar antenna device that estimates the angle of incidence of the signal using a MUSIC or ESPRIT technique. The method of claim 1, wherein the predetermined interval is
The planar antenna device is determined such that the beam width of the planar antenna device is equal to or greater than a first reference value, and interference between the short-circuited patch antennas is equal to or less than a second reference value.

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