Patent Application
20130106671
The present application claims priority of Korean Patent Application Nos. 10-2011-0110681 and 10-2012-0106353, filed on Oct. 27, 2011, and Sep. 25, 2012, respectively, which are incorporated herein by reference in their entirety.
1. Field of the Invention
Exemplary embodiments of the present invention relate to a communication system, and more particularly, to a multi-function feed network capable of controlling a radiation pattern diversity and an orthogonal polarization diversity of an antenna transmitting and receiving a signal in a communication system and an antenna including the multi-function feed network.
2. Description of Related Art
In a communication system, an antenna can wirelessly transmit and receive data through a predetermined frequency. In a communication system, an antenna, which is an important element for transmitting and receiving a signal, is located at an end of a transceiver to transmit and receive a signal. Many researches and developments into an antenna structure for effectively transmitting and receiving a signal have been conducted.
Various types of antennas are present, but an example of a generally used high frequency antenna may include a dipole antenna, a monopole antenna, a patch antenna, a horn antenna, a parabolic antenna, a helical antenna, a slot antenna, and the like. These antennas have been applied according to a communication distance and a service area.
Meanwhile, an example of essential resources used in a communication system may include frequency, polarization, space, and direction. Today, wireless communication services have been evolved to a type of transmitting high-speed and large-capacity data and various types of wireless communication services have been increased. Therefore, a frequency resource among resources of the communication system has been depleted.
A demand for a multiple input multiple output (hereinafter, referred to as ‘MIMO’) communication technology using a MIMO antenna due to a depletion of the frequency resource has been increased. The MIMO communication technology performs independent multiple channel transmission through the MIMO antenna to increase communication capacity. However, a terminal, a repeater, a base station, and the like, which use the currently used MIMO communication technology, use defined antenna beam patterns or fixed polarization. The MIMO antenna structure using the defined antenna beam patterns or the fixed polarization is not appropriate for the high-speed and large-capacity data transmission.
Therefore, a need exists for an MIMO antenna structure flexibly applying or using resources such as polarization, space, and direction (for example, antenna beam patterns), and the like, that are resources other than frequency resources of a communication system.
An embodiment of the present invention is directed to a multi-function feed network capable of providing antenna beam pattern diversity and orthogonal polarization diversity in a communication system and an antenna including the multi-function feed network.
The foregoing and other objects, features, aspects and advantages of the present invention will be understood and become more apparent from the following detailed description of the present invention. Also, it can be easily understood that the objects and advantages of the present invention can be realized by the units and combinations thereof recited in the claims.
An antenna including a multi-function feed network in a communication system, includes: array antenna elements configured to transmit and receive signals; and a feed network configured to divide and output a plurality of input signals to the array antenna elements, wherein the feed network includes: output nodes; boundary transmission lines connecting between the output nodes; cross transmission lines configured to be connected with a part of the boundary transmission lines and crossed in an area configured of the boundary transmission lines; input terminals configured to be connected with one of nodes formed by the boundary transmission lines and nodes formed by the cross transmission lines and input signals; and output terminals configured to be connected with each of the output nodes and output the input signals.
A multi-function feed network in a communication system, includes: a plurality of output nodes; boundary transmission lines connecting between the output nodes; cross transmission lines configured to be connected with a part of the boundary transmission lines and crossed in an area configured of the boundary transmission lines; input terminals configured to be connected with one of nodes formed by the boundary transmission lines and nodes formed by the crossing transmission lines and input signals; and output terminals configured to be connected with each of the output nodes and divide and output the input signals.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be noted that only components required to understand an operation in accordance with the present invention is described below and the description of other components will be omitted not to unnecessarily obscure the subject matters of the present invention.
An embodiment of the present invention relates to a multi-function feed network capable of reconfiguring antenna characteristics in a communication system and an antennal including the multi-function feed network. In this case, the antenna characteristics include, for example, polarization and radiation patterns. The multi-function feed network and an antenna including the multi-function feed network in accordance with the embodiment of the present invention may be used for various terrestrial or satellite communication systems for wirelessly transmitting and receiving data.
The antenna including the multi-function feed network in accordance with the embodiment of the present invention is described based on a multiple input multiple output (hereinafter, referred to as ‘MIMO’) antenna, but may be extendedly applied to an antenna structure that requires multiple input multiple output.
Referring to
A first input terminal 1 and a second input terminal 2 among the terminals 1, 2, 3, 5, 5, and 6 are terminals receiving a signal and the first output terminal 3, the second output terminal 4, the third output terminal 5, and the fourth output terminal 6 are terminals outputting a signal. For example, the output terminals 3, 4, 5, and 6 outputting the signal may have a quadrangular shape. In this configuration, a shape of the output terminals 3, 4, 5, and 6 is described by way of example, but may have other shapes other than the quadrangular shape.
Therefore, the first input transmission line IL1 is connected with the first input terminal 1 and the second input transmission line IL2 is connected with the second input terminal 2. The first output transmission line OL1 is connected with the first output terminal 3, the second output transmission line OL2 is connected with the second output terminal 2, the third output transmission line OL3 is connected with the third output terminal 5, and the fourth output transmission line OL4 is connected with the fourth output terminal 6.
In this configuration, describing electrical variables of the input transmission lines IL1 and IL2 and the output transmission lines OL1, OL2, OL3, and OL4, it may be assumed that input or output characteristic impedance is Z0 (for example, 50Ω) and an electrical length is θ0 (any value).
The first internal feed network 110 includes nodes N1, N2, N3, N4, N5, N6, N7, and N8 and transmission lines BL1, BL2, BL3, BL4, BL5, BL6, BL7, BL8, CL1, CL2, CL3, and CL4.
The first internal feed network 110 includes the first node N1 connected through the first output transmission line OL1, the second node N2 connected through the second output transmission line OL2, the third node N3 connected through the third output transmission line OL3, and the fourth node N4 connected through the fourth output transmission line OL4. The first internal feed network 110 includes the fifth node N5 connected through the first input transmission line IL1 and the sixth node N6 connected through the second input transmission line IL2. In addition, the first internal feed network 110 includes the seventh node N7 located between the second node N2 and the third node N3 and the eighth node N8 located between the third node N3 and the first node N1.
Next, the first boundary transmission line BL1 and the second boundary transmission line BL2 connect the fourth node N4 with the first node N1 and the fifth node N5 is located between the first boundary transmission line BL1 and the second boundary transmission line BL2. The third boundary transmission line BL3 and the fourth boundary transmission line BL4 connect the first node N1 with the second node N2 and the sixth node N6 is located between the third boundary transmission line BL3 and the fourth boundary transmission line BL4. The fifth boundary transmission line BL5 and the sixth boundary transmission line BL6 connect the second node N2 with the third node N3 and the seventh node N7 is located between the fifth boundary transmission line BL5 and the sixth boundary transmission line BL6. The seventh boundary transmission line BL7 and the eighth boundary transmission line BL8 connect the third node N3 with the fourth node N4 and the eighth node N8 is located between the seventh boundary transmission line BL7 and the eighth boundary transmission line BL8.
Finally, the first cross transmission line CL1 and the second cross transmission line CL2 connect the fifth node N5 with the seventh node N7. The third cross transmission line CL3 and the fourth cross transmission line CL4 connect the sixth node N6 with the eighth node N8. Here, the cross transmission lines CL1 and CL2 and the cross transmission lines CL3 and CL4 are connected with each other by RF crossover.
Here, describing the electrical variable of the boundary transmission lines BL1, BL2, BL3, BL4, BL5, BL6, BL7, and BL8 and the cross transmission lines CL1, CL2, CL3, and CL4, it may be assumed that the characteristic impedance is Z1 (Z1=2 Z0, for example, if Z0 is 50Ω, Z1 is 100Ω) and the electrical length is θ1=90°. Next, the signal output operation through the first feed network 100 will be described with reference to
Referring to
Here, each of the first signal SM1 and the second signal SM2 is output at the same power division ratio (0.25) through four output terminals 3, 4, 5, and 6.
In this case, a relative phase difference at the output terminals 3, 4, 5, and 6 may be determined according to the locations of each of the input terminals 1 and 2. For example, signals with a reference phase of 0° are output through the first output terminal 3 and the fourth output terminal 6 by the first signal SM1 input through the first input terminal 1 and signals with a phase delay of 180° are output through the second output terminal 4 and the third output terminal 5. Further, signals with a reference phase of 0° are output through the first output terminal 3 and the second output terminal 4 by the second signal SM2 input through the second input terminal 2 and signals with a phase delay of 180° are output through the third output terminal 5 and the fourth output terminal 6.
Here, input matching characteristics of each of the input terminals 1 and 2 and isolation characteristics between the input terminals 1 and 2 are very excellent in a wide band (about a bandwidth of about 10 to 20%). However, each output matching characteristic among the output terminals 3, 4, 5, and 6 is −6 dB and the isolation characteristic between the output terminals are partially shown. That is, the isolation characteristic of −6 dB is shown between the output terminals located in a diagonal direction that faces each other and the high isolation characteristic is shown among the remaining terminals.
In this way, in the exemplary embodiment of the present invention, the antenna with a planar six-port feeding structure like the first feed network 100 may be applied to an array antenna configured of four array elements. As described above, the first feed network 100 to which the array antenna is applied may be used to variously reconfigure the polarization and the radiation patterns.
Referring to
The second feed network 200 is different from the first feed network 100 in terms of the structure in which the second input terminal 2 is connected with the second internal feed network 210.
The second internal feed network 210 has a structure similar to the first internal feed network 110. However, the second internal feed network 210 additionally includes the ninth node N9 located between the third cross transmission line CL3 and the fourth cross transmission line CL4. Therefore, the ninth node N9 may be located in the vicinity of a center of an area configured of the transmission lines BL1 to BL10 that are formed through the output terminals 3, 4, 5, and 6.
In this case, the second input terminal 2 is connected with the ninth node N9 through the second input transmission line IL2. Therefore, the structure of the second feed network 200 is similar to the structure of the first feed network 100, except for the structure in which the second input terminal 2 is connected with the ninth node N9 located in the vicinity of the center of the second internal feed network 210. Therefore, a description of the detailed structure of the second feed network 200 refers to the description of the first feed network 100.
Referring to
Here, each of the first signal SM1 and the second signal SM2 is output at the same power division ratio (0.25) through four output terminals 3, 4, 5, and 6.
In this case, the relative phase difference at the output terminals 3, 4, 5, and 6 may be determined according to the locations of each of the input terminals 1 and 2. For example, the signals with a reference phase of 0° are output through the first output terminal 1 and the fourth output terminal 6 by the first signal SM1 input through the first input terminal 1 and the signals with a phase delay of 180° are output through the second output terminal 4 and the third output terminal 5. Further, the signals with the reference phase (the same phase) of 0° are output from all of the first output terminal 3, the second output terminal 4, the third output terminal 5, and the fourth output terminal 6 by the second signal SM2 input through the second input terminal 2.
Here, the input matching characteristics of each of the input terminals 1 and 2 and the isolation characteristics between the input terminals 1 and 2 are very excellent in a wide band (about a bandwidth of about 10 to 20%). However, each output matching characteristic among the output terminals 3, 4, 5, and 6 is very excellent and the isolation characteristic between the output terminals are partially shown. That is, the excellent isolation characteristic is shown among the output terminals with the output of the same phase difference (0° or 180°) and the isolation characteristic of −6 dB is shown between neighbor output terminals that have an output of a phase difference of 180° to the output terminals located in a diagonal direction.
Here, the locations of the first input terminal 1 and the second input terminal 2 may be opposite to each other. Therefore, the second input terminal 2 may be located (connected to the sixth node N6) at an edge or the outside of the second internal feed network 210 and the first input terminal 1 may also be connected to a node (not illustrated) that is located between the first cross transmission line 1 and the second cross transmission line located in the vicinity of the center of the second internal feed network 210.
In this case, the signals with the reference phase (the same phases) of 0° are output from all of the first output terminal 3, the second output terminal 4, the third output terminal 5, and the fourth output terminal 6 by the first signal SM1 input through the first input terminal 1. Further, the signals with a reference phase of 0° are output through the first output terminal 3 and the second output terminal 4 by the second signal Sm2 input through the second input terminal 2 and the signals with a phase delay of 180° are output through the third output terminal 5 and the fourth output terminal 6.
Referring to
The third feed network 300 is different from the first feed network 100 in terms of the structure in which the first input terminal 1 and the second input terminal 2 are connected with the third internal feed network 310.
The third internal feed network 300 has a structure similar to the first internal feed network 100 of the first feed network 100. However, the third internal feed network 300 additionally includes a tenth node N10 located between the first cross transmission line CL1 and the second cross transmission line CL2 and the ninth node N9 located between the third cross transmission line CL3 and the fourth cross transmission line CL4. Therefore, the ninth node N9 and the tenth node N10 may be located in the vicinity of the center of the area configured of the transmission lines BL1 to BL8 that are formed through the output terminals 3, 4, 5, and 6.
In this case, the first input terminal 1 is connected with the first switch 311 that is connected with the fifth node N5 and the tenth node N10. In this case, the first switch 311 may connect the first input terminal 1 with one of the fifth node N5 that is located at the edge of the area and the tenth node N10 that is located at the center of the area.
The second input terminal 2 is connected with the second switch 312 that is connected with the sixth node N6 and the ninth node N9. In this case, the second switch 312 may connect the second input terminal 2 with one of the sixth node N6 that is located at the edge of the area and the ninth node N9 that is located at the center of the area.
For example, the first switch 311 and the second switch 312 may be a single pole double throw (SPDT) switch.
Meanwhile, the first switch 311 and the second switch 312 cannot simultaneously select the ninth node N9 and the tenth node N10 that are located at a central point. The reason is that the input matching characteristic and the isolation characteristic between the input terminals are largely deteriorated.
The following Table 1 shows the output characteristics according to the switching operation of the switches 311 and 312 connected with the input terminals 1 and 2.
In Case 1, the first switch 311 connects the first input terminal 1 with the fifth node N5 and the second switch 312 connects the second input terminal 2 with the sixth node N6.
In this case, the signals with a reference phase of 0° are output through the first output terminal 3 and the fourth output terminal 6 by the first signal SM1 input through the first input terminal 1 and the signals with a phase delay of 180° are output through the second output terminal 4 and the third output terminal 5. Further, the signals with a reference phase of 0° are output through the first output terminal 3 and the second output terminal 4 by the second signal SM2 input through the second input terminal 2 and the signals with a phase delay of 180° are output through the third output terminal 5 and the fourth output terminal 6.
In Case 2, the first switch 311 connects the first input terminal 1 with the tenth node N10 and the second switch 312 connects the second input terminal 2 with the sixth node N6.
In this case, the signals with the reference phase (the same phases) of 0° are output from all of the first output terminal 3, the second output terminal 4, the third output terminal 5, and the fourth output terminal 6 by the first signal SM1 input through the first input terminal 1. Further, the signals with a reference phase of 0° are output through the first output terminal 3 and the second output terminal 4 by the second signal SM2 input through the second input terminal 2 and the signals with a phase delay of 180° are output through the third output terminal 5 and the fourth output terminal 6.
In Case 3, the first switch 311 connects the first input terminal 1 with the fifth node N5 and the second switch 312 connects the second input terminal 2 with the ninth node N9.
In this case, the signals with a reference phase of 0° are output through the first output terminal 1 and the fourth output terminal 6 by the first signal SM1 input through the first input terminal 1 and the signals with a phase delay of 180° are output through the second output terminal 4 and the third output terminal 5. Further, the signals with the reference phase (the same phase) of 0° are output from all of the first output terminal 3, the second output terminal 4, the third output terminal 5, and the fourth output terminal 6 by the second signal SM2 input through the second input terminal 2.
As described above, the structure of the third feed network 300 is similar to the structure of the first feed network 100 except that the structure in which the first input terminal 1 and the second input terminal 2 are connected with the third internal feed network 310 at the nodes N5, N6, N9, and N10 through the first switch 311 and the second switch 312. Therefore, the description of the detailed structure of the third feed network 300 refers to the description of the first feed network 100.
Meanwhile, for convenience of explanation, the configuration in which the first switch 311 and the second switch 312 are located outside the third internal feed network 310 is described, but may also be included in the third internal feed network 310.
Referring to
The fourth internal feed network 410 includes nodes N1, N2, N3, N4, N5, N6, N7, N8, N9, and N10. Here, the internal structure of the fourth internal feed network 410 is similar to the structure of the first internal feed network 110 of
The inductor lumped elements L0, the first capacitor lumped elements C1, and the second capacitor lumped elements C2 configuring the fourth internal feed network 410 may be represented by the following Equation 1.
The structure of the fourth feed network 400 is a right-handed, phase lag equivalent circuit.
Referring to
The fifth internal feed network 510 includes the nodes N1, N2, N3, N4, N5, N6, N7, N8, N9, and N10. Here, the internal structure of the fifth internal feed network 510 is similar to the structure of the first internal feed network 110 of
The capacitor lumped elements C0, the first inductor lumped elements L1, and the second inductor lumped elements L2 configuring the fifth internal feed network 410 may be represented by the following Equation 2.
The structure of the fifth feed network 500 is a left-handed, phase lag equivalent circuit.
In
Referring to
The array antenna elements 610, 620, 630, and 640 may be arranged in a ring type so as to form the polarization diversity. Here, the array antenna elements 610, 620, 630, and 640 include various types of planar antenna elements such as a microstrip antenna element, a stack microstrip antenna element, a print dipole antenna element, and the like. In this case, the array antenna elements 610, 620, 630, and 640 may form a right angle (90°) to have orthogonal linear component between the neighbor array antenna elements. In this case, each of the array antenna elements 610, 620, 630, and 640 of the antenna includes the antenna terminals A1, A2, A3, and A4 that receive signals.
Here, the antenna terminals A1, A2, A3, and A4 are located so as to face each other or so as not to face each other and the antenna terminals A1, A2, A3, and A4 that face each other need to be located in an opposite direction to each other.
For example, the first antenna terminal A1 and the fourth antenna terminal A4 are located so as to face each other. In addition, the second antenna terminal A2 and the third antenna terminal A3 are located so as to face each other. The first antenna terminal A1 and the third antenna terminal A3 are input with signals in an opposite direction to each other. Further, the second antenna terminal A2 and the fourth antenna terminal A4 are input with signals in an opposite direction to each other.
The array antenna elements 610, 620, 630, and 640 of the first antenna 600 are combined with the first feed network 100. Therefore, in order not to deteriorate the input matching characteristics of the array antenna elements 610, 620, 630, and 640, the mutual combiing characteristics of the array antenna elements 610, 620, 630, and 640 are not present. For example, when the array antenna elements are disposed, the array antenna elements may be disposed to have the combiing characteristics of about −20 dB or less.
The first output terminal 3 of the first feed network 3 is connected with the first antenna terminal A1, the second output terminal 4 thereof is connected with the second antenna terminal A2, the third output terminal 5 thereof is connected with the third antenna terminal A3, and the fourth terminal 6 thereof is connected with the fourth antenna terminal A4.
In this case, the first signal SM1 input through the first input terminal 1 of the first feed network 100 is transferred to each array antenna element 610, 620, 630, and 640 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 610, 620, 630, and 640 have the same amplitude. However, the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0° and the signals output through the second output terminal 4 and the third output terminal 5 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the first input terminal 1 forms linear polarization of −45° (or, linear polarization of +45°) due to the spatial in field power combining of the vector signals. A first main beam MB1 illustrated in the
The second signal SM2 input through the second input terminal 2 of the first feed network 100 is transferred to each array antenna element 610, 620, 630, and 640 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 610, 620, 630, and 640 have the same amplitude. However, the signals output through the first output terminal 3 and the second output terminal 4 are signals with a reference phase of 0° and the signals output through the third output terminal 5 and the fourth output terminal 5 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 2 forms the linear polarization of +45° (or linear polarization of −45° due to the spatial in field power combining of the vector signals. A second main beam MB2 illustrated in
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 are radiated to a free space in a form of the linear polarization signals that are orthogonal to each other. Therefore, the first antenna 600 may be used for polarization diversity.
Referring to
The array antenna elements 710, 720, 730, and 740 may be arranged in a cross type so as to form the polarization diversity. Here, the array antenna elements 710, 720, 730, and 740 include various types of planar antenna elements such as a microstrip antenna element, a stack microstrip antenna element, a print dipole antenna element, and the like. In this case, the array antenna elements 710, 720, 730, and 740 may form a right angle) (90° to have orthogonal linear component between the neighbor array antenna elements. In this case, each of the array antenna elements 710, 720, 730, and 740 includes the antenna terminals A1, A2, A3, and A4 that receive signals.
Here, the array antenna elements 710, 720, 730, and 740 need to be located in an opposite direction (for example, an opposite direction of the first feed network (a vertical direction in the
For example, the first antenna terminal A1 and the third antenna terminal A3 are located so as to face each other. In addition, the second antenna terminal A2 and the fourth antenna terminal A3 are located so as to face each other. The first antenna terminal A1 and the third antenna terminal A3 are input with signals in an opposite direction to each other. Further, the second antenna terminal A2 and the fourth antenna terminal A4 are input with signals in an opposite direction to each other.
The second antenna 700 is combined with the array antenna elements 710, 720, 730, and 740 in the first feed network 100. Therefore, in order not to deteriorate the input matching characteristics of the array antenna elements 710, 720, 730, and 740, the mutual combining characteristics between the array antenna elements 710, 720, 730, and 740 need not to be present. For example, when the array antenna elements 710, 720, 730, and 740 are disposed, the array antenna elements may be disposed to have the combining characteristics of about −20 dB or less.
The first output terminal 3 of the first feed network 100 is connected with the first antenna terminal A1, the second output terminal 4 thereof is connected with the second antenna terminal A2, the third output terminal 5 thereof is connected with the third antenna terminal A3, and the fourth terminal 6 thereof is connected with the fourth antenna terminal A4.
In this case, the first signal SM1 input through the first input terminal 1 of the first feed network 100 is transferred to each array antenna element 710, 720, 730, and 740 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 710, 720, 730, and 740 have the same amplitude. However, the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0° and the signals output through the second output terminal 4 and the third output terminal 5 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 1 forms the linear polarization of −45° (or linear polarization of +45°) due to the spatial in field power combining of the vector signals. The first main beam MB1 illustrated in
The second signal SM2 input through the second input terminal 2 of the first feed network 100 is transferred to each array antenna element 710, 720, 730, and 740 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 710, 720, 730, and 740 have the same amplitude. However, the signals output through the first output terminal 3 and the second output terminal 6 are signals with a reference phase of 0° and the signals output through the third output terminal 4 and the fourth output terminal 5 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 2 forms the linear polarization of +45° (or linear polarization of −45° due to the spatial in field power combining of the vector signals. A second main beam MB2 illustrated in the
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 are radiated to a free space in a form of the linear polarization signals that are orthogonal to each other. Therefore, the second antenna 700 may be used for polarization diversity.
Referring to
The array antenna elements 810, 820, 830, and 840 may be arranged in a ring type so as to form the polarization diversity. Here, the third antenna 800 is similar to the structure of the first antenna 600 of
In this case, each of the array antenna elements 810, 820, 830, and 840 includes the antenna terminals A1, A2, A3, and A4 that receive signals.
Here, the antenna terminals A1, A2, A3, and A4 are located so as to face each other or so as not to face each other and the antenna terminals A1, A2, A3, and A4 that face each other need to be located in an opposite direction to each other.
In this case, the first signal SM1 input through the first input terminal 1 of the second feed network 200 is transferred to each array antenna element 810, 820, 830, and 840 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 810, 820, 830, and 840 have the same amplitude. However, the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0° and the signals output through the second output terminal 4 and the third output terminal 5 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 1 forms the linear polarization of −45° (or linear polarization of +45°) due to the spatial in field power combining of the vector signals. The first main beam MB1 illustrated in
The second signal SM2 input through the second input terminal 2 of the second feed network 200 is transferred to each array antenna element 810, 820, 830, and 840 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 810, 820, 830, and 840 have the same amplitude. All the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 2 becomes null in a bore-sight direction due to the spatial in field power combining of the vector signals and forms a conical beam pattern with an omni-directional characteristic in an azimuth direction. That is, the polarization with patterns radiated by the signal input through the second input terminal 2 forms the horizontal polarization. A second conical beam 2 illustrated in
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 have the radiation patterns that are orthogonal to each other. Therefore, the third antenna 800 may be used for polarization diversity.
Referring to
Here, the changed second feed network 250 is a feed network with a structure in which the input terminals of the second feed network 200 are exchanged with each other. Therefore, the first input terminal 1 is connected with contacts of the cross transmission lines of the center of the feed network and the second input terminal 2 is connected with contacts of the boundary transmission lines outside the feed network.
The structure of the fourth antenna 900 is similar to the structure of the third antenna 800 except that the fourth antenna 900 includes the changed second feed network 250 as compared with the third antenna 800 of
In this case, the first signal SM1 input through the first input terminal 1 of the changed second feed network 250 is transferred to each array antenna element 910, 920, 930, and 940 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 910, 920, 930, and 940 have the same amplitude. All the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0°.
In this case, the polarization with patterns radiated by the signal input through the first input terminal 1 becomes null in a bore-sight direction due to the spatial in field power combining of the vector signals and forms a conical beam pattern with an omni-directional characteristic in an azimuth direction. That is, the polarization with patterns radiated by the signal input through the first input terminal 1 forms the horizontal polarization. The first conical beam 1 illustrated in
The second signal SM2 input through the second input terminal 2 of the changed second feed network 250 is transferred to each array antenna element 910, 920, 930, and 940 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 910, 920, 930, and 940 have the same amplitude. However, the signals output through the first output terminal 3 and the second output terminal 4 are signals with a reference phase of 0° and the signals output through the third output terminal 5 and the fourth output terminal 6 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 2 forms the linear polarization of −45° (or linear polarization of +45°) due to the spatial in field power combining of the vector signals. The second main beam MB2 illustrated in
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 have the radiation patterns that are orthogonal to each other. Therefore, the fourth antenna 900 may be used for polarization diversity.
Referring to
The array antenna elements 1010, 1020, 1030, and 1040 may be arranged in a cross type so as to form the polarization diversity. Here, the array antenna elements 1010, 1020, 1030, and 1040 include various types of planar antenna elements such as a microstrip antenna element, a stack microstrip antenna element, a print dipole antenna element, and the like. In this case, the array antenna elements 1010, 1020, 1030, and 1040 may form a right angle) (90° to have orthogonal linear component between the neighbor array antenna elements. In this case, each of the array antenna elements 1010, 1020, 1030, and 1040 includes the antenna terminals A1, A2, A3, and A4 that receive signals.
Here, the antenna terminals A1, A2, A3, and A4 need to be located in an opposite direction (for example, a vertical direction in
For example, the first antenna terminal A1 and the third antenna terminal A3 are located so as to face each other. In addition, the second antenna terminal A2 and the fourth antenna terminal A3 are located so as to face each other. The first antenna terminal A1 and the third antenna terminal A3 are input with signals in an opposite direction to each other. Further, the second antenna terminal A2 and the fourth antenna terminal A4 are input with signals in an opposite direction to each other.
The fifth antenna 1000 is combined with the array antenna elements 1010, 1020, 1030, and 1040 in the second feed network 200. Therefore, in order not to deteriorate the input matching characteristics of the array antenna elements 1010, 1020, 1030, and 1040, the mutual combining characteristics between the array antenna elements needs not to be present. For example, when the array antenna elements are disposed, the array antenna elements may be disposed to have the combining characteristics of about −20 dB or less.
The first output terminal 3 of the second feed network 200 is connected with the first antenna terminal A1, the second output terminal 4 thereof is connected with the second antenna terminal A2, the third output terminal 5 thereof is connected with the third antenna terminal A3, and the fourth terminal 6 thereof is connected with the fourth antenna terminal A4.
In this case, the first signal SM1 input through the first input terminal 1 of the second feed network 200 is transferred to each array antenna element 1010, 1020, 1030, and 1040 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 1010, 1020, 1030, and 1040 have the same amplitude. However, the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0° and the signals output through the second output terminal 4 and the third output terminal 5 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the first input terminal 1 forms the linear polarization of −45° (or linear polarization of +45°) due to the spatial in field power combining of the vector signals. The first main beam MB1 illustrated in
The second signal SM2 input through the second input terminal 2 of the second feed network 200 is transferred to each array antenna element 610, 620, 630, and 640 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 610, 620, 630, and 640 have the same amplitude. However, all the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 2 becomes null in a bore-sight direction due to the spatial in field power combining of the vector signals and forms a conical beam pattern with an omni-directional characteristic in an azimuth direction. That is, the polarization with patterns radiated by the signal input through the second input terminal 2 forms the vertical polarization. The second conical beam 2 illustrated in
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 are radiated to a free space in a form of the linear polarization signals that are orthogonal to each other. Therefore, the fifth antenna 1000 may be used for polarization diversity.
Referring to
Here, the changed second feed network 250 is a feed network with a structure in which the input terminals of the second feed network 200 are exchanged with each other. Therefore, the first input terminal 1 is connected with contacts of the cross transmission lines of the center of the feed network and the second input terminal 2 is connected with contacts of the boundary transmission lines outside the feed network.
The structure of the sixth antenna 1100 is similar to the structure of the third antenna 1000 except that the sixth antenna 110 includes the changed second feed network 250 as compared with the fifth antenna 1000 of
In this case, the first signal SM1 input through the first input terminal 1 of the changed second feed network 250 is transferred to each array antenna element 1110, 1120, 1130, and 1140 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 1110, 1120, 1130, and 1140 have the same amplitude. All the signals output through the first output terminal 3 and the fourth output terminal 6 are signals with a reference phase of 0°.
In this case, the polarization with patterns radiated by the signal input through the first input terminal 1 becomes null in a bore-sight direction due to the spatial in field power combining of the vector signals and forms a conical beam pattern with an omni-directional characteristic in an azimuth direction. That is, the polarization with patterns radiated by the signal input through the first input terminal 1 forms the vertical polarization. The first conical beam 1 illustrated in
The second signal SM2 input through the second input terminal 2 of the second feed network 200 is transferred to each array antenna element 1110, 1120, 1130, and 1140 through the output terminals 3, 4, 5, and 6. All the current distributions of signals output to the array antenna elements 1110, 1120, 1130, and 1140 have the same amplitude. However, the signals output through the first output terminal 3 and the second output terminal 4 are signals with a reference phase of 0° and the signals output through the third output terminal 5 and the fourth output terminal 6 are signals with a phase delay of 180°.
In this case, the polarization with patterns radiated by the signal input through the second input terminal 2 forms the linear polarization of −45° (or linear polarization of +45°) due to the spatial in field power combining of the vector signals. The second main beam MB2 illustrated in
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 are radiated to a free space in a form of the linear polarization signals that are orthogonal to each other. Therefore, the sixth antenna 1100 may be used for polarization diversity.
Referring to
The seventh antenna 1200 has a structure similar to the first antenna 600 of
Therefore, the description of the remaining structure except for the structure of the phase shifters 1211, 1221, 1231, and 1241 refers to the description of the first antenna 600.
The first phase shifter 1211 is located between the first output terminal 3 and the first antenna terminal A1. The second phase shifter 1221 is located between the second output terminal 4 and the second antenna terminal A2. The third phase shifter 1231 is located between the third output terminal 5 and the third antenna terminal A3. The fourth phase shifter 1241 is located between the fourth output terminal 6 and the fourth antenna terminal A4.
Here, the phase shifters 1211, 1221, 1231, and 1241 shift phases of signals input to the array antenna elements 1210, 1220, 1230, and 1240 as much as 90°. Therefore, the phase shifters 1210, 1220, 1230, and 1240 are the 90° phase shifters.
Here, when the phase shifters 1211, 1221, 1231, and 1241 are the phase shifters that shift a phase as much as 90°, the seventh antenna 1200 has the same structure as the first antenna 600.
Referring to
The eighth antenna 1300 has a structure similar to the first antenna 600 of
Therefore, the description of the remaining structure except for the structure of the phase shifters 1311, 1321, 1331, and 1341 refers to the description of the first antenna 600.
The first phase shifter 1311 is located between the first output terminal 3 and the first antenna terminal A1. The second phase shifter 1321 is located between the second output terminal 4 and the second antenna terminal A2. The third phase shifter 1331 is located between the third output terminal 5 and the third antenna terminal A3. The fourth phase shifter 1341 is located between the fourth output terminal 6 and the fourth antenna terminal A4.
Here, the second phase shifter 1321 and the fourth phase shifter 1341 are the 0° phase shifters and the first phase shifter 1311 and the third phase shifter 1331 are the 90° phase shifters. That is, the first phase shifters 1311 and the third phase shifters 1331 lead the phases of the signals output to the array antenna elements 1310 and 1330 as much as 90°
Here, the first signal SM1 input through the first input terminal 1 forms the first main beam MB1 pattern in a bore-sight direction with a left polarization (or right polarization) In addition, the second signal SM2 input through the second input terminal 2 forms the second main beam MB2 pattern in a bore-sight direction with a right polarization (or left polarization).
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 are radiated to a free space in a form of the linear polarization signals or the orthogonal circular polarization signals that are orthogonal to each other. Therefore, the eighth antenna 1300 may be used for polarization diversity.
Referring to
The ninth antenna 1400 has a structure similar to the first antenna 600 of
Therefore, the description of the remaining structure except for the structure of the phase shifters 1411, 1421, 1431, and 1441 refers to the description of the first antenna 600.
The first phase shifter 1411 is located between the first output terminal 3 and the first antenna terminal A1. The second phase shifter 1421 is located between the second output terminal 4 and the second antenna terminal A2. The third phase shifter 1431 is located between the third output terminal 5 and the third antenna terminal A3. The fourth phase shifter 1441 is located between the fourth output terminal 6 and the fourth antenna terminal A4.
Here, the phase shifters 1411, 1421, 1431, and 1441 are the 180° phase shifters.
Referring to
The tenth antenna 1500 has a structure similar to the first antenna 600 of
Therefore, the description of the remaining structure except for the structure of the phase shifters 1511, 1521, 1531, and 1541 refers to the description of the first antenna 600.
The first phase shifter 1511 is located between the first output terminal 3 and the first antenna terminal A1. The second phase shifter 1521 is located between the second output terminal 4 and the second antenna terminal A2. The third phase shifter 1531 is located between the third output terminal 5 and the third antenna terminal A3. The fourth phase shifter 1541 is located between the fourth output terminal 6 and the fourth antenna terminal A4.
Here, the second phase shifter 1521 and the fourth phase shifter 1541 are the 0° phase shifters and the first phase shifter 1511 and the third phase shifter 1531 are the 180° phase shifters. Here, the first phase shifter 1511 and the third phase shifter 1531 lead (lag) the phases of the signals output to the array antenna elements 1510 and 1530 as much as 180°.
Here, the first signal SM1 input through the first input terminal 1 forms the first main beam MB1 pattern in a bore-sight direction with a left polarization (or right polarization) In addition, the second signal SM2 input through the second input terminal 2 forms the second main beam MB2 pattern in a bore-sight direction with a right polarization (or left polarization).
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 are radiated to a free space in a form of the linear polarization signals that are orthogonal to each other. Therefore, the tenth antenna 1500 may be used for polarization diversity.
Referring to
The eleventh antenna 1600 has a structure similar to the first antenna 600 of
Therefore, the description of the remaining structure except for the structure of the phase shifters 1611, 1621, 1631, and 1641 refers to the description of the first antenna 600.
The first phase shifter 1611 is located between the first output terminal 3 and the first antenna terminal A1. The second phase shifter 1621 is located between the second output terminal 4 and the second antenna terminal A2. The third phase shifter 1631 is located between the third output terminal 5 and the third antenna terminal A3. The fourth phase shifter 1641 is located between the fourth output terminal 6 and the fourth antenna terminal A4.
Here, the first phase shifter 1611 and the second phase shifter 1621 are the 180° phase shifters and the third phase shifter 1631 and the fourth phase shifter 1641 are the 0° phase shifters. Here, the first phase shifter 1611 and the second phase shifter 1621 lead (lag) the phases of the signals output to the array antenna elements 1610 and 1630 as much as 180°.
Here, the first signal SM1 input through the first input terminal 1 forms the first conical beam CB1 pattern with the horizontal polarization. In addition, the second signal SM2 input through the second input terminal 2 forms the second conical beam CB2 pattern with the horizontal polarization.
Therefore, the independent signals applied through the first input terminal 1 and the second input terminal 2 are radiated to a free space in a form of the two linear polarization signals that are orthogonal to each other or one horizontal polarization signal. Therefore, the eleventh antenna 1600 may be used for polarization diversity.
Referring to
The twelfth antenna 1700 has a structure similar to the first antenna 600 of
Therefore, the description of the remaining structure except for the structure of the phase shifters 1711, 1721, 1731, and 1741 refers to the description of the first antenna 600.
The first phase shifter 1711 is located between the first output terminal 3 and the first antenna terminal A1. The second phase shifter 1721 is located between the second output terminal 4 and the second antenna terminal A2. The third phase shifter 1731 is located between the third output terminal 5 and the third antenna terminal A3. The fourth phase shifter 1741 is located between the fourth output terminal 6 and the fourth antenna terminal A4.
Here, the first phase shifter 1711 to the fourth phase shifter 1741 are the 90°/180° phase shifters. Two-bit phase shifter such as the first phase shifter 1711 to the fourth phase shifter 1741 may be set to be one of 90° or 180°. In this way, the second antenna 1700 may form the main beam pattern with two orthogonal linear polarizations or the circular polarization and the conical beam pattern with the horizontal polarization, thereby selectively the polarization diversity or the pattern diversity simultaneously.
The two polarization signals in which two independent input signals are orthogonal to each other or the two beam patterns (main beam pattern and conical beam pattern) signals with peak values in different directions are generated by the foregoing antennas 600 to 1700 and the generated signals are radiated to the free space. The antennas 600 to 1700 may be used as a 2×2 MIMO antenna structure that requires the high scattering wireless channel environment.
Referring to
The thirteenth antenna 1800 generates the linear polarization signal of −45° (first main beam −45°_MB1) and the horizontal polarization signal (second conical beam H_CB2) by the third antenna 800 structure. The thirteenth antenna 1800 generates the vertical polarization signal (first conical beam V_CB1) and the linear polarization signal of +45° (second conical beam +45°_MB2) by the sixth antenna 1100 structure.
Four signals input through the input terminals a, b, c, and d from the thirteen antenna 1800 have four independent radiation characteristics and are radiated to the free space. Therefore, the thirteenth antenna 1800 is a 4×4 MIMO antenna.
Referring to
In this case, the description of the structure of the thirteenth antenna 1800 refers to the description of the third antenna 800 and the sixth antenna 1100.
A first input terminal a of the thirteenth antenna 1800 corresponds to the first input terminal 1 of the third antenna 800 and a second input terminal b thereof corresponds to the second input terminal 2 of the third antenna 800. As described above, a third input terminal c of the thirteenth antenna 1800 corresponds to the first input terminal 1 of the sixth antenna 1100 and a fourth input terminal d corresponds to the second input terminal 2 of the sixth antenna 1100.
In this way, the linear polarization signal of −45° (first main beam −45°_MB1) and the horizontal polarization signal (second conical beam H_CB2) are generated by the third antenna 800 structure. Further, the vertical polarization signal (first conical beam V_CB1) and the linear polarization signal of 45° (second main beam +45°_MB2) are generated by the sixth antenna 1100 structure.
Referring to
The fourteenth antenna 1900 generates the horizontal polarization signal (first conical beam H_CB1) and the linear polarization signal of +45° (second main beam (+45°_MB2)) by the fourth antenna 900 structure. In addition, the fourteenth antenna 1900 generates the linear polarization signal of −45° (first main beam (−45°_MB1)) and the vertical polarization signal (second conical beam V_CB2) by the fifth antenna 1000 structure.
The four signals input through the input terminals a, b, c, and d from the fourteenth antenna 1900 have four independent radiation characteristics and are radiated to the free space. Therefore, the fourteenth antenna 1900 is the 4×4 MIMO antenna.
Referring to
In this case, the description of the detailed structure of the fourteenth antenna 1900 refers to the descriptions of the fourth antenna 900 and the fifth antenna 1000, respectively.
The first input terminal a of the fourteenth antenna 1900 corresponds to the first input terminal 1 of the fourth antenna 900 and the second input terminal b thereof corresponds to the second input terminal 2 of the fourth antenna 900. As described above, the third input terminal c of the fourteenth antenna 1900 corresponds to the first input terminal 1 of the fifth antenna 1000 and a fourth input terminal d thereof corresponds to the second input terminal 2 of the fifth antenna 1000.
In this way, the horizontal polarization signal (first conical beam H_CB1) and the linear polarization signal of +45° (second main beam +45°_MB2) are generated by the fourth antenna 900 structure. Further, the linear polarization signal of −45° (first main beam (−45°_MB1)) and the vertical polarization signal (second conical beam V_CB2) are generated by the fifth antenna 1000 structure.
Meanwhile, in
As described above, the 4×4 MIMO antennas in accordance with the embodiment of the present invention are described by way of example and may be implemented in various forms by the combination of 2×2 antennas.
Referring to
The fifteenth antenna 1500 shares the array antenna elements between two antenna structures included therein so as to reduce the size of the fifteenth antenna 1500. For example, the array antenna elements may have a regular square form so as to be shared between two antenna elements.
Meanwhile, the fifteenth antenna 2000 generates the horizontal polarization signal (second conical beam H_CB1) and the linear polarization signal of +45° (second main beam (+45°_MB2)) by the fifth antenna 1000 structure. In addition, the fifteenth antenna 2000 generates the linear polarization signal of −45° (second main beam −45°_MB2) and the vertical polarization signal (second conical beam V_CB2) by the fourth antenna 900B structure.
The four signals input through the input terminals a, b, c, and d from the fifteenth antenna 2000 have four independent radiation characteristics and are radiated to the free space. Therefore, the fifteenth antenna 2000 is the 4×4 MIMO antenna.
Referring to
In this case, the description of the detailed structure of the fourteenth antenna 2000 refers to the descriptions of the fourth antenna 900 and the fifth antenna 1000, respectively.
However, the fourth antenna 900B and the fifth antenna 1000F may share an antenna. Here, for convenience of explanation, the case in which the fourth antenna 900F may share the array antenna elements 1010, 1020, 1030, and 1040 of the fifth antenna 1000F with a regular square form is described by way of example, but may share the array antenna elements (herein, not illustrated) of the fourth antenna 900B with the fifth antenna 1000F.
Therefore, the first input terminal a of the fifteenth antenna 2000 corresponds to the first input terminal 1 of the fifth antenna 1000F and the second input terminal b thereof corresponds to the second input terminal 2 of the fifth antenna 1000. As described above, the third input terminal c of the fifteenth antenna 2000 corresponds to the first input terminal 1 of the fourth antenna 900B and the fourth input terminal d thereof corresponds to the second input terminal 2 of the fourth antenna 900B.
In this case, each of the output terminals 3′, 4′, 5′ and 6′ of the fourth antenna 900B is connected with antenna terminals A1′, A2′, A3′, and A4′ of the array antenna elements 1010, 1020, 1030, and 1040.
In this way, the horizontal polarization signal (second conical beam H_CB1) and the linear polarization signal of +45° (second main beam +45°_MB2) are generated by the fifth antenna 1000F structure. Further, the linear polarization signal of −45° (second main beam −45°_MB2) and the vertical polarization signal (second conical beam V_CB2) are generated by the fourth antenna 900B structure.
As described above, the fifteenth antenna 2000 in accordance with the embodiment of the present invention may radiate the two linear polarization signals of +45°/−45° in the main beam direction and may radiate the vertical/horizontal signals in the conical beam direction.
The fifteenth antenna 2000 disposes the antenna elements configured therein at the front/rear thereof while sharing the antenna and therefore, the area required for the antenna configuration may be reduced.
Referring to
The sixteenth antenna 2100 has a structure in which six antenna modules combined with the antennas 900B and 1000F are located at each surface of the regular hexahedron.
The fifteenth antennas 2000-1, 2000-2, 2000-3 (not illustrated, 2000-4 (not illustrated), 2000-5, and 2000-6 (not illustrated) configuring the sixteenth antenna 2100 are arranged on each surface of the regular hexahedron and therefore, the number of channels may be extended to 24 channels. Therefore, the sixteenth antenna 2100 is a 24×24 MIMO antenna apparatus.
As described above, the antennas (for example, MIMO antennas) including the multi-function feed network in accordance with the embodiment of the present invention have the high isolation characteristic between the array antenna elements and may variably control the polarization and the beam pattern of the antenna according to the wireless environment or the system requirement.
Further, the antennas including the multi-function feed network in the embodiment of the present invention may extend the number of channels of the signals input and output through the combining therebetween or the rearrangement in various forms.
For convenience of explanation, the embodiment of the present invention as described above proposes the antenna structures including various multi-function feed networks, but the antenna with various functions can be implemented by the combination of the multi-function feed networks and the antennas or the rearrangement of the elements in addition to the antenna structures including the foregoing multi-function feed network.
Meanwhile, the embodiments is described in detail in the detailed description of the present invention, but may be variously modified without departing from the scope of the present invention. Accordingly, the scope of the present invention is not construed as being limited to the described embodiments but is defined by the appended claims as well as equivalents thereto.
In accordance with the exemplary embodiments of the present invention, it is possible to provide various beam pattern diversities and orthogonal polarization diversities at the time of transmitting a signal using the antenna including the multi-function feed network, by providing various multi-function feed networks in which the antenna elements with the disposition and arrangement of the input and output terminals of the feed network configured of the plurality of transmission lines in the communication system are arrayed and the antennas including the multi-function feed networks.
Meanwhile, the embodiments is described in detail in the detailed description of the present invention, but may be variously modified without departing from the scope of the present invention. Accordingly, the scope of the present invention is not construed as being limited to the described embodiments but is defined by the appended claims as well as equivalents thereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2011-0110681 | Oct 2011 | KR | national |
| 10-2012-0106353 | Sep 2012 | KR | national |
