KR20080025105A - 2port cross phase compensation patch antenna - Google Patents

Abstract

A two port cross phase compensation patch antenna is provided to obtain an isolation effect by generating cross polarization at two adjacent antennas. A two port cross phase compensation patch antenna includes at least one radiator(11), a plurality of + and - compensation feeding contacts(12a,12b,13a,13b), a T distributor(26), a pair of lines(25-1,25-3) and a pair of 180 degree phase shift lines(25-2,25-4). The radiators are formed on a radiator dielectric substrate(10) by printing or etching. The plurality of + or - compensation feeding contacts are formed at an L or W shaft of the radiator. The T distributor is installed on a lower surface(22) of a line dielectric substrate(20) to distribute signals fed from ports(27,28). The lines connect the signals distributed at the T distributor with a pair of positive feeding contacts(23a,24a). The 180 degree phase shift lines connect the signals distributed at the T distributor with a pair of negative feeding contacts(23b,24b).

Description

2-Port Cross Phase Compensation Patch Antenna

The present invention relates to an antenna which is installed inside a small repeater and the like, and is used for an antenna built-in interference cancellation repeater for processing interference signals or echo cancellation by increasing the isolation between adjacent antennas.

As the base station and repeater for mobile phones, which are recently used, are becoming smaller in size, antennas for base stations and repeaters are also required to be miniaturized. In recent years, the miniaturization of the antenna becomes more urgent given that the method of implementing a small repeater by embedding the antenna in the repeater is widely used. When the size of the antenna is reduced, problems such as a large number of back lobes of the antenna radiation pattern are generated and the gain is lowered.

Recently, there is a demand for an interference canceling repeater that amplifies by removing interference signals while embedding an antenna in a repeater. In an antenna used for an interference canceling repeater, isolation between two antennas, a donor antenna and a service antenna, is an important issue. Various efforts have been made to increase the isolation between two adjacent antennas in a small repeater. Efforts have been made to increase the antenna gain to narrow the radiated beam width and to reduce the backlobe of the radiated antenna. However, these efforts are very difficult to solve when the antenna size is small. Due to technical limitations, the industry is also making efforts to attach a device or a device to block the radio wave outside the antenna.

As a method of increasing the isolation in the conventional antenna, there are those related to a patch antenna that increases the directivity of the radiation pattern and reduces the back lobe through the arrangement of a plurality of radiators such as four or sixteen. In this method, the number of radiators increases, the size of the antenna increases, and the number of radiators increases, which makes the distribution circuit complex and the loss in the distribution circuit and the feed line, which makes the antenna difficult and the miniaturization difficult. Another technique is to build a thin metal wall of conductors around the patch antenna to prevent radio waves radiated from the radiator from radiating to the back of the radiator.However, the wall of the conductors must be enlarged to increase the blocking effect to some extent. Due to the size of the size is limited and there is a difficulty to make a separate attachment, the effect is minimal. In another method, the radio absorber is attached to the rear of the antenna to absorb the radio waves radiated to the rear of the antenna to maximize the isolation effect. However, the radio absorber does not increase the area of the radio absorber. The disadvantage is that the price rises.

In the present invention, the two ports are input horizontally and vertically to the radiator without attaching a separate attachment to the periphery or the back of the antenna, and make two “+” feed points and “-” feed points for each port, and the signals that are introduced from the ports. It is aimed at maximizing the isolation effect between the antennas by generating and feeding the compensation signal by reversing the phase.

In order to increase the isolation between the antennas, it is necessary to increase the blocking effect of radio waves generated from the antennas, and to do so, it is necessary to secure enough space between the two antennas or to block the spatial passage existing between the two antennas. However, since the actual environment using a repeater is a narrow space, it is difficult to secure enough space between the two antennas, and in recent years, it is necessary to increase the isolation by putting the antenna inside the repeater for the purpose of miniaturization. In such an environment, a metal plate is placed around the antenna to block radio waves from going to the rear of the antenna, or a radio wave absorber or a barrier of a metal material is inserted between the two antennas, but the effect remains within several dB. As an alternative, recently, digital signal processing techniques have been used to convert analog signals to digital, FFT processing to remove echo signals as digital filters, reverse FFT processing, and convert to analog signals. However, even this is a difficult task, it is difficult to improve more than 10dB.

In the present invention, in order to obtain an effect of significantly blocking the isolation between two adjacent antennas by more than 70 dB without attaching a separate device to the outside between two adjacent antennas in a narrow space, cross polarization is performed by performing cross compensation compensation on one patch. Since the propagation method is designed to generate separate radio waves from one antenna, the radio waves generated from two antennas near each other increase heterogeneity, thereby minimizing interference effect and obtaining high isolation effect.

Efforts are being made to increase isolation by generating cross-polarization horizontally and vertically in general patch antennas. However, the effect is not so great at adjacent distances. The present invention devises a method of generating cross polarization by performing cross-compensation feeding on one patch, and the interference generated by two antennas near each other is increased due to the generation of separate radio waves from one antenna. In addition to minimizing this, the effect is to increase the isolation effect.

In order to generate cross polarization in one patch radiator as shown in FIG. 1, a feed point is made horizontally on the patch (L axis), and a signal input from the horizontal port is input, and the feed point is also vertically on the patch (W axis). Make a connection to the vertical port. Thus, the electric wave generated at the feed point fed to the horizontal axis (L axis) is made into horizontal polarization, and the electric wave generated at the feed point fed to the vertical axis (W axis) is generated as vertical polarization. These two polarizations are 90 degrees each other, causing an isolation effect.

To achieve a higher isolation effect, both the horizontal and vertical ports are phase compensated. The incoming signal from the horizontal port 27 is divided into two signals at the T divider 26, one of which is directly connected via the line 25-1 to the “+” feed point 23a and another divided signal. Is connected to the “-” feed point 23b through the 180 degree phase inversion line 25-2. The electric field of the horizontally polarized wave in which the phase compensation power supply is applied is radiated correctly horizontally and is evenly distributed on four sides of the radiator. In addition, the signal coming from the vertical port 28 is divided into two signals in the T divider 26, one of which is directly connected via the line 25-3 to the “+” feed point 24a and another distributed. The signal is connected to the “-” feed point 24b through a 180 degree phase inversion line 25-4. The electric field of the vertically polarized wave in which the phase compensation feeding is performed is vertically radiated correctly and evenly distributed on four sides of the radiator.

Thus, two ports 27 and 28 which are different from each other horizontally and vertically are formed in one radiator 11, and two feed points are formed at each of the horizontal and vertical ports with “+” and “-”. In addition, the input signal is divided into the positive signal and the 180-phase phase shifted “-” signal by distributing the signal from each port. The signals of the two ports subjected to the compensation feeding have different cross polarization characteristics, and each polarization has a unique polarization characteristic very strongly, and when these characteristics are connected to each port, a strong isolation effect is obtained.

Using this phenomenon, if a vertical port signal is input to two antennas in a donor direction and a horizontal port signal is input to another service antenna in a narrow space, an isolation effect of 70 dB or more can be obtained due to the strong cross polarization characteristic. Will be.

In order to obtain a more powerful isolation effect in the above structure, the abnormal impedance compensation feeding by changing the 50 ohm impedance at the incoming port 27 to an impedance other than the 50 ohm input from the vertical port 28 through the T divider 26. You can do When the 50 ohm impedance position of the horizontal axis (L axis) of FIG. 2 is moved outward and the compensating feed points 12a and 12b are caught at the high impedance position and connected to the incoming line, the 50 ohm generated from the vertical port 28 The effect of the magnetic field and the heterogeneity is greater, resulting in more than 75dB of isolation effect.

Cross-polarization isolation values obtained by crossing horizontal and vertical polarizations in conventional patch antennas are about 40 to 45 dB when the two antennas are 50 mm apart. Isolation is obtained, so it has more than 35dB of blocking effect compared to the existing antenna, and does not need to use the digital signal processing technique, and it can be used for the interference canceling repeater such as WCDMA or wireless LAN by using the small repeater with built-in antenna. .

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

1 is a view showing an embodiment according to the present invention. As shown in the front of FIG. 1, the radiator 11 of copper foil is implemented on the dielectric substrate 10 by an etching method, and the compensation feed points 12a and 12b for the horizontal port and the compensation feed points 13a and 13b for the vertical port are made. As shown in FIG. 2, a “+” side feed point 12a and a symmetrical point of the “+” side feed point 12b are formed on the horizontal L axis around the origin (0,0). Then, in the vertical W direction, the feed point 13a on the “+” side and another feed point “-” on the symmetry point 13b are made, and two horizontal feed points and a vertical feed point on one radiator are made. Two in total form four feed points and two horizontal and vertical ports.

In Fig. 2, on the radiator patch 11 on the dielectric substrate 10, a “+” side feed point 12a is formed along the length L axis of the patch from the origin (0,0) to the + L / 2 direction and again the origin. Another feed point 12b at the symmetry point of the feed point 12a is formed in the -L / 2 direction from (0,0). The feed point 12a is a positive 50 ohm feed point having the same impedance as the line impedance, and the feed point 12b is a negative 50 ohm feed point that is 180 degrees out of phase with the feed point 12a.

The incoming signal from the horizontal port 27 is a line having an impedance of 50 ohms. The signal is divided into two signals through the T divider 26 to be divided into two signals to be taken to the positive and negative feed points. The signal coming directly into the feeder through the line 25-1 from the signal becomes a positive signal and is connected to the positive feed point 23a, and another signal is phased through the phase inversion line 25-2. It is reversed 180 degrees and connected to the negative feed point 23b. The phase inverting line 25-2 uses a ground coplanar line to pass a negative signal distributed by the T divider 26 through a line having a line length λ / 2 to invert the signal 180 degrees to reverse the negative feed point 23b. ) To form feed points and ports for compensation feed, and connecting lines.

The signal coming from the vertical port 28 is also a line having an impedance of 50 ohms. The signal is divided into two signals through the T divider 26 to be divided into two signals to be taken to the positive and negative feed points. The signal coming directly to the feeder through the line 25-3 in the signal becomes a positive signal and is connected to the positive feed point 24a, and another signal is phased through the phase inversion line 25-4. It is reversed 180 degrees and connected to the negative feed point 24b. The phase inversion line 25-4 uses a ground coplanar line to pass the negative signal distributed by the T divider 26 through a line having a line length λ / 2 to invert the signal 180 degrees to negatively feed the point 24b. ) To form feed points and ports for compensation feed, and connecting lines.

In the above method, a process and results of designing a small interference canceling antenna used for a WCDMA repeater in a 2 GHz band using an FR-4 substrate will be described. As the radiator layer dielectric substrate 10, a FR-4 substrate having a dielectric constant of 4.4 mm and a thickness of 0.8 mm was used. The line layer dielectric substrate was also made of one radiator 11 having a length of 100x100 mm and a size of 54 mm using a material of the same specification. A connecting pin for supporting a diameter of 1 mm between the radiator layer substrate 10 and the line layer substrate 20 with an air gap between the radiator layer substrate 10 and the line layer substrate 20 at 4 mm. 32), and the "+" and "-" two feed points 23a and 23b of the compensation feed through the ground coplanar line 25 and the T divider 26 through the signal coming from the horizontal polarization port 27. ) And the feed point (12a, 12b) of the radiator through the feed pin 31 by soldering to produce an antenna. Again, the signal from the vertical polarization port 28 is connected to the two “+” and “-” feed points 24a and 24b of the compensation feed through the ground coplanar line 25 and the T divider 26 and feed. The pins 31 connect the antennas to the feed points 13a and 13b of the radiator by soldering. The through hole 29 is connected to the edge of the line layer substrate 20 in order to connect with the ground plate copper foil 21 on the line layer and the copper foil 22 under the lower layer of the line layer substrate 20. Holes are processed in the line layer substrate 20, and holes 14 are processed at the same position in the radiator layer 10, and soldered therebetween with support pins 32 to connect the two substrates 10 and 20. do.

By designing the antenna and arranging the antennas facing each other with the back side facing each other at 50mm, the donor signal is input to the horizontal compensation feed port and the service signal is input to the vertical port. The characteristics of the model set up were obtained through computer simulations as shown in Table 1 and Table 2. As shown in Table 1, in the 2.0 GHz band, the S11 was -10 dB, and the frequency band was 50 ~ 53MHz or more. As shown in Table 2, gain is obtained more than 9.6 dBi and radiation efficiency is more than 98%, so it can be seen that it operates as an antenna no matter which signal is input, and the FB Ratio is also excellent -21 dB. .

As a result of measuring the isolation between the two antennas and securing 50 mm, it can be seen that the average of about -70 dB is secured in the WCDMA band from -69 dB to -73 dB as shown in FIG. 3. To further increase the isolation characteristics, change the line and the compensation feed point distributed from the compensation feed port to 70 ohms or 100 ohms instead of the normal 50 ohms, and then increase the isolation characteristics if the difference is made at 50 ohms of the vertical polarization feed point. It becomes the number.

To increase the gain and increase the isolation characteristics, increasing the number of antenna radiators and arranging them can increase the effect. For example, if you make a 1x2 array of patch antennas with two radiators, you can increase the gain by about 12dB and increase the isolation effect. In order to further increase the gain, if the number of radiators is arranged in 2x2 (4) or 4x4 (16), the antenna with higher gain can be realized.

Antenna S11 Characteristics -10 dB min (GHz) -10 dB max (GHz) -10 dB bandwidth (MHz) Donor side antenna 2.04 2.095 53 Service side antenna 2.04 2.09 52

Antenna Gain and Efficiency, F-B Ratio, 3dB Beam Width Gain (dB) Tot. effic. F-B Ratio (dB) 3 dB Beam Width (degree) Phi = 0 Phi = 90 Phi = 0 Phi = 90 Donor side antenna 9.6 98% -21.7 -23.4 57.1 69.1 Service side antenna 9.6 98% -23.3 -22.3 70.5 57.4

When the antenna to which the present invention is applied is used for repeaters such as WCDMA, WiFi, WiBro, etc., it is possible to realize a repeater with a small antenna and to suppress an interference signal and an echo signal between adjacent antennas. As a result, an efficient interference elimination repeater can be realized at a low cost.

1: Top, bottom and side views of a 2-port cross-phase compensated patch antenna

Figure 2: Detailed view of the top of a two-port cross-phase compensation patch antenna

Figure 3: Two-Port Cross-Phase Feed Patch Antenna S11 and S21 Isolation Characteristics

<Detailed Description of Details>

10: dielectric substrate for radiator, 11: radiator

12a, 23a: horizontal positive feed point, 12b, 23b: horizontal negative feed point

13a, 24a: vertical positive feed point, 13b, 24b: vertical negative feed point

14: hole for supporting connecting pin

20: track dielectric board, 21: radiator ground board, 22: track ground board

25-1, 25-3: line, 25-2, 25-4: 180 degree phase inversion line

26: T-distributor, 27: port for horizontal compensation class, 28: port for vertical compensation class, 29: through hole

31: connecting pin for power supply, 32: connecting pin for support

Claims (8)

In the 2-port cross-phase compensation feeding antenna, Forming one or more radiators 11 on the radiator dielectric substrate 10 by printing or etching; Forming two “+” and “−” compensation feed points 12a and 12b on either axis of the L or W axis in the radiator 11; Forming two "+" and "-" compensation feed points (13a, 13b) on the other axis of the radiator (11); The lower surface 22 of the line dielectric substrate 20 is composed of a T divider 26 for distributing the signals coming from the ports 27 and 28; 180-degree phase inversion line directly connected to lines 25-1 and 25-3 and negative feed points 23b and 24b that directly connect the signal distributed by the T divider 26 to the positive feed points 23a and 24a. (25-2, 25-4); Both horizontal compensation feed points 23a and 23b and vertical compensation feed points 24a and 24b of the line layer 20 are connected to the horizontal compensation feed points 12a and 12b and the vertical compensation feed point 13a of the radiator layer 10. , 13b) between the two-port cross-phase compensation feeding patch antenna, characterized in that for connecting the power supply connecting pin (31). The method of claim 1, The position of the compensation feed points 12a and 12b symmetrically formed at the origin (0,0) with the L axis of the radiator on the radiator 11 formed by the etching technique or the like on the dielectric substrate 10 along the L axis in the -L / 2 direction. And a feed point (12a, 12b) to move in the + L / 2 direction to form a cross-feed compensation patch antenna. The method of claim 1, On the radiator 11 formed by the etching technique or the like on the dielectric substrate 10, the positions of the compensation feed points 13a and 13b symmetrically formed at the origin (0,0) with the W axis of the radiator along the W axis are -W / 2. And a feed point (13a, 13b) to move in the + W / 2 direction to form a cross-feed compensation patch antenna. The method of claim 1, A two-port crossover, characterized in that it is implemented as a ground coplaner line 25 or a microstrip line to connect from the input port 26 to both feed points 23a and 23b of the radiator on the line dielectric substrate 20. Phase Compensation Patch Antenna. The method of claim 1, A two-port cross-phase compensation feeding patch antenna, characterized in that forming a plurality of radiators 11, one or more, two, four, etc. by a printing or etching method on the radiator dielectric substrate (10). The method of claim 1, The bottom plate 22 of the line dielectric substrate 20 and the ground plate 22 around the ground coplanar line 25 and the ground plate 21 of the top surface of the line dielectric substrate 20 are spaced at regular intervals. 29) 2-port cross-phase compensation feeding patch antenna, characterized in that the processing by connecting. The method of claim 1, The two-port cross-phase compensation feeding patch antenna, characterized in that the support between the radiator dielectric substrate 10 and the line dielectric substrate 20 is fixed with a support connecting pin 32 while maintaining a predetermined distance d. The method of claim 1, A two-port cross-phase, characterized in that to form a T divider 26 or Wilkins divide in order to halve or quarter divide the signal coming from the ports (27, 28) of the line dielectric substrate 20 Compensation patch antenna.

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