CN117999705A - Quadruple polarization diversity antenna system - Google Patents

Abstract

The present disclosure discloses a quad-polarized diversity (quadri-polarization diversity) antenna system. According to an embodiment of the invention, an antenna system includes an antenna array including a first column of dual-polarized (dual-polarized) antenna elements and a second column of dual-polarized antenna elements. The dual polarized antenna units have a first antenna element and a second antenna element, respectively, that cross each other perpendicularly. In each column, the first antenna elements are conductively connected and form a first sub-layer, and the second antenna elements are conductively connected and form a second sub-layer. The antenna system further includes an RF matrix that selectively adjusts the phase of the RF input signals and generates RF output signals for supply to the sublayers. The RF output signal, when radiated by the dual polarized antenna element, forms a first beam having +/-45 ° polarization (polarizations) and a second beam having 0 °/90 ° polarization, the first beam and the second beam being spatially formed facing different directions.

Description

Quadruple polarization diversity antenna system

Technical Field

The present invention relates to a quadriplegized diversity antenna system, which improves orthogonality of wireless channels by adjusting polarization between beams so that spatially adjacent beams have different dual-polarization (dual-polarization) characteristics, thereby enabling an increase in channel capacity of the system.

Background

The statements in this section merely serve to provide background information related to the present disclosure and may not constitute prior art.

The polarization of an antenna refers to the direction of the magnetic field (E-plane) of the radio wave relative to the earth's surface, which is determined at least in part based on the physical structure and orientation of the antenna element. For example, a simple straight antenna element has one polarization when mounted vertically and another polarization when mounted horizontally. The magnetic field of an electric wave is at right angles to the electric field, but the polarization of an antenna element is conventionally understood to refer to the direction of the electric field.

In mobile communication, MIMO (multiple-input multiple-output) antennas are generally designed as dual-polarized antennas (dual-polarized antenna) to reduce the effects of multipath-based attenuation (fading) and perform polarization diversity (diversity) functions. However, in a Massive MIMO system using multiple beams, correlation coefficients of radio channels become high due to interference between adjacent beams, and thus it is difficult to efficiently use space resources.

Disclosure of Invention

First, the technical problem to be solved

In order to improve the gain of an antenna, the present disclosure aims to provide an antenna array adapted to a separation space (or sector plate) by beams each having a different polarization, a configuration of an antenna panel in which the antenna array is arranged, and beam spatial multiplexing using the same.

(II) technical scheme

According to one embodiment of the invention, an antenna system includes an antenna array including a first column of dual-polarized (dual-polarized) antenna elements and a second column of dual-polarized antenna elements. The dual polarized antenna units have a first antenna element and a second antenna element, respectively, that cross each other perpendicularly. In each column, the first antenna elements are conductively connected and form a first sub-layer, and the second antenna elements are conductively connected and form a second sub-layer. The antenna system further includes an RF matrix that selectively adjusts the phase of the RF input signals and generates RF output signals for supply to the sublayers. The RF output signal, when radiated by the dual polarized antenna element, forms a first beam having +/-45 ° polarization (polarizations) and a second beam having 0 °/90 ° polarization, the first beam and the second beam being formed spatially in different directions.

The RF matrix may be implemented by a quadrature hybrid coupler (quadrature hybrid coupler: QHC) formed on the PCB. The RF matrix may be configured to selectively adjust the phases of the plurality of split signals based on a phase difference for forming the first beam and the second beam and a phase difference for determining the first beam polarization and the second beam polarization.

For a dual of the RF input signals propagated by the first beam, the phase adjusted based on the RF matrix circuitry is defined to achieve the desired spatial direction for forming the first beam. For a dual RF input signal of the RF input signals propagated by the second beam, the phase adjusted based on the RF matrix circuit is defined to achieve the desired spatial direction and polarization synthesis for forming the second beam.

The dual polarized antenna element has +/-45 ° polarization characteristics, and the 0 °/90 ° polarization of the second beam is obtained by polarization synthesis (Polarization Synthesis).

Drawings

Fig. 1 shows a prior art 4T4R polarized diversity antenna system utilizing a +45°/-45 ° dual polarized antenna array.

Fig. 2 shows a spatially multiplexed beam pattern that may be formed based on the antenna system of fig. 1.

Fig. 3 shows a 4T4R polarized diversity antenna system using +/-45 ° dual polarized antenna arrays according to an embodiment of the invention.

Fig. 4a is a conceptual diagram of the RF domain of the antenna system of fig. 3, which is simply shown for ease of illustration.

Fig. 4b shows a dual beam that can be formed by the antenna system of fig. 3 and the input signals associated with forming the beam.

Fig. 4c shows a table of phase shifts that occur during arrival of input signals T1, T2, T3, T4 via the RF matrix at the antenna array sub-layers in order to form a dual beam as shown in fig. 4 b.

Fig. 5a is an example of implementing an RF matrix with quadrature hybrid couplers (quadrature hybrid coupler, QHC) in accordance with an aspect of the disclosure.

Fig. 5b illustrates the beam pattern and dual polarization characteristics of the beams that can be formed using the RF matrix 500 shown in fig. 5 a.

Fig. 6a shows a 4T4R polarization diversity antenna system using an antenna array comprising heterogeneous dual polarization antenna elements according to another embodiment of the invention.

Fig. 6b is a top view of an exemplary antenna panel that may be employed in the antenna system of fig. 6 a.

Fig. 6c and 6d are front views (front views) illustrating the antenna panel structure of fig. 6 b.

Fig. 6e shows the structure where the same polarization sub-layers in different columns are connected to the RF links with different lengths of RF path.

Fig. 7a shows an antenna panel with dual polarized antenna elements arranged with heterogeneity according to another embodiment of the invention.

Fig. 7b shows the main coverage and auxiliary coverage that can be covered with the antenna panel shown in fig. 7 a.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Where reference is made to reference numerals, the same reference numerals are used wherever possible to designate the same technical features as the corresponding reference numerals in different drawings. Meanwhile, it should be noted that, in the entire specification, if it is considered that a specific description of related known technical features and functions may cause the subject matter of the present invention to be unclear, a detailed description thereof will be omitted.

The present disclosure relates to a polarization diversity antenna system adapted for spatial (sector) separation by beams each having a different polarization in order to improve the gain of an antenna.

First, a description of a technical solution for forming beams having different polarization characteristics in an antenna system using a dual polarized antenna array may be helpful in more clearly understanding the technical usability of the proposed technology.

Fig. 1 shows a prior art 4T4R polarized diversity antenna system utilizing a +45°/-45 ° dual polarized antenna array. The antenna system of fig. 1 may achieve quad-polarization diversity by polarization synthesis in the digital domain. Fig. 2 shows a spatially multiplexed beam pattern that may be formed based on the antenna system of fig. 1.

Referring to fig. 1, an antenna array employed in an antenna system is composed of two columns of dual polarized antenna elements. Each dual polarized antenna element comprises a first antenna element 101a polarized at +45° and a second antenna element 101b polarized at-45 °. That is, the antenna array is constituted by two columns of dual polarized antenna elements including +45° linear radiating elements and-45 ° linear radiating elements. In each column, the antenna elements 101a, 101b are connected to feed lines (FEEDER LINE) 111a, 111b according to polarization categories. That is, in each column, a +45° polarized first antenna element 101a is conductively connected to a first feed line 111a and forms a first sub-layer, and a-45 ° polarized second antenna element 101b is conductively connected to a second feed line 111b and forms a second sub-layer. Thus, in the dual polarized antenna array illustrated in fig. 1, the antenna elements 101a, 101b are divided into four sub-layers.

The four sub-layers are connected to the four antenna ports by feed lines 111a, 111b, respectively. Each antenna port is connected to an RF link 130. The RF link 130 includes RF elements such as a low noise amplifier (low noise amplifier, LNA) and a Power Amplifier (PA) and a filter, respectively, and provides an RF transmission path and an RF reception path. Thus, the antenna system of fig. 1 is 4T4R.

Typically, the distance between antenna elements having the same polarization characteristics is typically 0.5λ, where λ is the wavelength at the center frequency of the frequency band of the antenna array. To ensure a weak correlation, the larger the distance, the better. That is, in the illustrated drawing, the distance between adjacent columns may be 0.5λ to 1λ.

The antenna system of fig. 1 forms two beams with different dual polarization characteristics (i.e., a first beam with +/-45 ° orthogonal polarization (orthogonal polarizations) and a second beam with V/H orthogonal polarization) from a dual polarized antenna array to different spatial directions by adjusting the phase in the digital domain (e.g., digital unit 120) for polarization synthesis of signals T1-T4 and the beam direction required for signals T1-T4.

As illustrated in fig. 2, beams having a beam width of about 40 ° with respect to the horizontal plane can be formed in different spatial directions (spatial direction; 10-point direction and 2-point direction in fig. 2). The 10-point directional beam and the 2-point directional beam have different dual polarization characteristics. In particular, these beams may have a number of side lobes (sidelobe).

The + -45 deg. marked in fig. 2 for showing the dual polarization characteristics of each beam means that the beam has two orthogonal polarizations consisting of +45 deg. linear polarization and-45 deg. linear polarization, and V/H means that the beam has two orthogonal polarizations consisting of 90 deg. (V) linear polarization and 0 deg. (H) linear polarization. For example, a beam formed toward 10 points has a +45° polarized wave (radio wave) and a-45 ° polarized wave (radio wave), and a beam formed toward 2 points has a 90 ° polarized wave and a 0 ° polarized wave. This is also the same in the other figures. Strictly speaking, a "beam forming +/-45 ° orthogonal polarization in a 10-point direction" refers to a beam forming +45° linear polarization and a beam forming-45 ° linear polarization, and a "beam forming V/H orthogonal polarization in a 2-point direction" refers to a beam forming 90 ° (V) linear polarization and a beam forming 0 ° (H) linear polarization in a 2-point direction.

In fig. 2, a 10-point directional beam of +/-45 ° orthogonal polarization is formed by providing T1 signals having different phases to the first antenna port and the third antenna port and T2 signals having different phases to the second antenna port and the fourth antenna port.

In fig. 2, a V/H orthogonally polarized 2-point directional beam is formed by providing T3 signals having different phases and T4 signals having different phases to the first to fourth antenna ports. If T3 signals having different phases are radiated from four sub-layers of the antenna array, 90 ° (V) polarization is formed as a result of polarization synthesis. Similarly, if T4 signals having different phases are radiated from four sub-layers of the antenna array, 0 ° (H) polarization is formed as a result of polarization synthesis.

In contrast to the illustration in fig. 2, it is noted that the phase adjustment can also be performed in the digital unit so that the 10-point direction beam has a V/H orthogonal polarization and the 2-point direction beam has a +/-45 ° orthogonal polarization.

The antenna system illustrated in fig. 1 can be implemented by adding digital processing functions for polarization separation/synthesis and beamforming in the digital domain in the system as an integrated RRH (Remote Radio Head) antenna system, i.e., AAS (Active Antenna System) or RRA (Remote Radio Antenna) system. The antenna system illustrated in fig. 1 requires hardware to implement beamforming and polarization synthesis/separation performed in the digital domain, and thus the amount of heat generated will increase. For example, a specific method of forming beams having +/-45 ° orthogonal polarization and V/H orthogonal polarization from a dual polarized antenna array by phase adjustment in a digital domain (e.g., a digital unit) is disclosed in korean patent application No. 10-2020-0046256, filed 16 of the applicant of the present invention in 2020, month 04.

Fig. 3 shows a 4T4R polarized diversity antenna system using +/-45 ° dual polarized antenna arrays according to an embodiment of the invention. The antenna system shown in fig. 3 can form two independent beams (i.e., a beam with +/-45 deg. orthogonal polarization and a beam with V/H orthogonal polarization) in different spatial directions by performing RF signal processing including phase adjustment on signals in the RF domain.

The antenna system of fig. 3 employs an antenna array substantially identical to the antenna system of fig. 1. That is, the antenna array of fig. 3 is composed of two columns of dual polarized antenna elements. Each dual polarized antenna element comprises a +45° polarized first antenna element 301a and a-45 ° polarized second antenna element 301b. In each column, the antenna elements 301a, 301b are connected to feed lines (FEEDER LINE) 311a,311b according to the polarization category. Thus, in the dual polarized antenna array shown in fig. 3, the antenna elements 301a, 301b are divided into four sub-layers.

The transmission signals T1, T2, T3 are supplied from the digital unit 320 to the four RF links 330, and the RF signals output from the RF links 330 are subjected to signal processing by an RF matrix 340 and supplied to the four sub-layers of the antenna array. Thus, the antenna system of fig. 3 is 4T4R.

Rf matrix 340 is configured to perform signal processing including signal splitting and phase adjustment of Rf signals input from Rf link 330. The RF matrix 340 may be implemented by passive elements such as hybrid couplers, directional couplers, phase shifters, and the like. The signal-processed RF signals output from the RF matrix 340 are radiated into space through four sub-layers of the antenna array, as a result of which, as shown in fig. 2, two independent beams (i.e., a beam having +/-45 ° orthogonal polarization and a beam having V/H orthogonal polarization) can be formed into different spatial directions. In contrast to the illustration of fig. 2, it is noted that the phase adjustment may also be performed in the RF matrix 340 such that the 10-point directional beam has V/H orthogonal polarization and the 2-point directional beam has +/-45 ° orthogonal polarization.

The antenna system of fig. 3 may be implemented by an AAS/RRA system having an RF circuit formed with an RF matrix 340, and may also be implemented in a form in which an RF circuit substrate is disposed between LEGACY ANTENNA systems and RRHs, the RF circuit substrate being formed with the RF matrix 340. Thus, existing LEGACY ANTENNA systems can also be easily changed to support quad-polarization diversity. However, the RF matrix 340 will cause RF loss, which may make it difficult to maintain accurate inter-beam spacing.

In addition, the antenna array shown in fig. 3 has two columns (columns) of dual polarized antenna elements, but in other implementations the antenna array may have more columns in order to form more beams, or in order to form a narrower beam width.

In the 4T4R polarization diversity antenna system of fig. 3, as will be described below with reference to fig. 4a, 4b and 4c, only the RF matrix 340 is provided for RF signals to perform signal processing including phase shifting to achieve polarization combining and a desired beam direction.

Fig. 4a is a conceptual diagram of the RF domain of the antenna system of fig. 3, which is simply shown for ease of illustration. Fig. 4b shows a dual beam that can be formed by the antenna system of fig. 3 and the input signals associated with forming the beam. The table (table) of fig. 4c shows the phase shifts that occur during arrival of the input signals T1, T2, T3, T4 at the antenna array sub-layers via the RF matrix 340 in order to form a dual beam as shown in fig. 4 b.

Referring to fig. 4a and 4b, the input signals T1, T2 form a first beam with +/-45 ° orthogonal polarization through the RF matrix 340, and the input signals T3, T4 form a second beam with V/H polarization through the RF matrix 340. The two beams have different spatial directions. In fig. 4b, the first beam with +/-45 ° orthogonal polarization is directed toward 10 points and the beam with V/H orthogonal polarization is directed toward 2 points.

In order to form the beam pattern as shown in fig. 4b, the RF matrix 340 performs signal processing on the input signals T1, T2, T3, T4, in other words, the phase shift (PHASE SHIFT) that occurs during the arrival of the input signals T1, T2, T3, T4 at the sub-layers of the antenna array through the RF matrix 340 is as follows.

The target polarization of the input signal T1 is +45° polarization, provided via the RF matrix 340 to the sub-layers of +45° polarized antenna elements of the first column (C1; left column) labeled "c1+45" in the table of fig. 4 b) and the sub-layers of +45° polarized antenna elements of the second column (C2; right column) labeled "c2+45" in the table of fig. 4 b.

The target polarization of the input signal T2 is-45 deg. polarized and is provided via the RF matrix 340 to the sub-layers of-45 deg. polarized antenna elements of the first column (C1) (labeled "C1-45" in the table of fig. 4 b) and the sub-layers of-45 deg. polarized antenna elements of the second column (C2-45).

The target polarization of the input signal T3 is H polarization and the target polarization of the input signal T4 is V polarization. The input signal T3 and the input signal T4 are provided to the four sublayers (C1+45, C1-45, C2+45, C2-45) of the dual polarization array via the RF matrix 340, respectively.

The input signal T1 is split by the RF matrix 340 into two split signals, one of which reaches the first column of sub-layers (c1+45) with +45° polarization without phase shifting; the other split signal reaches the second column of sub-layers (c2+45) with +45° polarization after a phase shift of-90 °. The target polarization of the input signal T1 is +45° polarization, -90 ° phase shift is used only for beamforming (beamforming). The two split signals corresponding to the input signal T1 are radiated by the sub-layers (c1+45, c2+45) in a state having a phase difference of-90 ° from each other, and thus a beam having +45° polarization is formed in a spatial direction inclined to the left side by about 30 ° with respect to the normal line of the antenna array.

The input signal T2 is split by the RF matrix 340 into two split signals, one of which reaches the first column of sub-layers (C1-45) with-45 ° polarization without phase shifting; the other split signal reaches the second column of sub-layers (C2-45) with-45 polarization after a phase shift of-90. The target polarization of the input signal T2 is-45 deg. polarization, -90 deg. phase shift is used only for beamforming (beamforming).

The two split signals corresponding to the input signal T2 are radiated by the sub-layers (C1-45, C2-45) in a state having a phase difference of-90 ° from each other, and thus a beam having a polarization of-45 ° is formed in a spatial direction inclined to the left by about 30 ° with respect to the normal line of the antenna array.

The input signal T3 is split by the RF matrix 340 into four split signals, the first split signal reaching the first column of sub-layers (c1+45) without phase shifting, the second, third and fourth split signals reaching the first column of sub-layers (C1-45), the second column of sub-layers (c2+45) and the second column of sub-layers (C2-45) after 180 °,90 ° and 270 ° phase shifting, respectively. The phase shift (180) of the second split signal is used only for polarization synthesis, the phase shift (90) of the third split signal is used only for beamforming, and the phase shift (270) of the fourth split signal is the sum of the phase shift (90) for beamforming and the phase shift (180) for polarization synthesis.

The first and second split signals corresponding to the input signal T3 are radiated by the sub-layers (c1+45, C1-45) of the first column (C1) in a state having a phase difference of 180 ° with each other, thus forming a beam having 0 ° (H) polarization (i.e., generating polarization synthesis). The third and fourth split signals are radiated by the sub-layers (c1+45, C1-45) of the first column (C1) in a state having a phase difference of 180 ° from each other, thus forming a beam having 0 ° (H) polarization (i.e., generating polarization synthesis). Further, the first split signal radiated from the sub-layer (c1+45) of the first column and the third split signal radiated from the sub-layer (c2+45) of the second column have a phase difference of +90° from each other, and the second split signal radiated from the sub-layer (C1-45) of the first column and the fourth split signal radiated from the sub-layer (C2-45) of the second column have a phase difference of +90° from each other, so that a beam having 0 ° (H) polarization is formed obliquely to the right side by about 30 ° with respect to the normal line of the antenna array.

The input signal T4 is split by the RF matrix 340 into four split signals, the first split signal reaching the first column of sub-layers (c1+45) without phase shifting, the second, third and fourth split signals reaching the first column of sub-layers (C1-45), the second column of sub-layers (c2+45) and the third column of sub-layers (C2-45) after 180 °,90 ° and 270 ° phase shifting, respectively.

The first and second split signals corresponding to the input signal T4 are radiated by the sub-layers (c1+45, C1-45) of the first column (C1) in a state having a phase difference of 0 ° from each other, thus forming a beam having a polarization of 90 ° (V) (i.e., generating polarization synthesis). The third and fourth split signals are radiated by the sub-layers (c1+45, C1-45) of the first column (C1) in a state having a phase difference of 0 ° from each other, thus forming a beam having a polarization of 90 ° (V) (i.e., generating polarization synthesis). Furthermore, the first split signal radiated from the sub-layer (c1+45) of the first column and the third split signal radiated from the sub-layer (c2+45) of the second column have a phase difference of +90° from each other, and the second split signal radiated from the sub-layer (C1-45) of the first column and the fourth split signal radiated from the sub-layer (C2-45) of the second column have a phase difference of +90° from each other, so that a beam having a polarization of 90 ° is formed to be inclined to the right side by about 30 ° with respect to the normal line of the antenna array.

Fig. 5a is an example of an implementation of an RF matrix 500 using quadrature hybrid couplers (quadrature hybrid coupler, QHC) in accordance with an aspect of the disclosure. QHC may also be referred to as a "branch-line coupler" or a "90 ° Hybrid coupler". Fig. 5b illustrates a beam pattern and dual polarization characteristics of beams that may be formed using the RF matrix 500 shown in fig. 5 a. It is noted that the polarization characteristics of the beam shown in fig. 5b are opposite to those shown in fig. 4 b. That is, the 10-point directional beam in fig. 4b has +45°/-45 ° orthogonal polarization, and the 2-point directional beam in fig. 5b has +45°/-45 ° orthogonal polarization. As illustrated in fig. 2, strictly, "forming a beam of +/-45 ° orthogonal polarization toward the 2-point direction" means forming a beam of +45° linear polarization and a beam of-45 ° linear polarization toward the 2-point direction, "forming a beam of V/H orthogonal polarization toward the 10-point direction" means forming a beam of 90 ° (V) linear polarization and a beam of 0 ° (H) linear polarization toward the 10-point direction.

The RF matrix 500 shown in fig. 5a has four input ports (marked with white circles) on the PCB, three QHCs 510a, 510b, 510c formed by conductive sheets, and four output ports (marked with black circles).

As shown in the enlarged view of fig. 5a, each QHC510a, 510b, 510c has four arms (arms) (i.e., a first arm to a fourth arm), there is an output in the second arm and the third arm if a signal is input in the first arm, and no output in the fourth arm. Further, there is a phase difference of 90 ° (i.e., λ/4) between the output signals of the second arm portion and the third arm portion. The QHC510a, 510b, 510c has a vertically/laterally symmetrical shape, and if a signal is input in the second arm, there is an output in the first arm and the fourth arm, and no output in the third arm. I.e. in a completely symmetrical configuration.

The input signal T1 reaches the sub-layer (c1+45) of the first column via "first input port-first arm of the first QHC510 a-second arm of the first QHC510 a-first output port". Also, the input signal T1 reaches the sub-layer (c2+45) of the second column via "first input port-first arm of the first QHC510 a- (phase delay of 90 °) -third arm of the first QHC510 a-third output port". Therefore, from the viewpoint of the input signal T1, the radio signal radiated from the sub-layer (c2+45) of the second column has a phase delay of 90 ° compared with the radio signal radiated from the sub-layer (c1+45) of the first column, and a beam having +45° polarization is formed in a spatial direction inclined to the right by about 30 ° with respect to the normal of the antenna array as shown in fig. 5 b.

The input signal T2 reaches the sub-layer (C1-45) of the first column via "second input port-first arm of the second QHC510 b-second output port". Also, the input signal T2 reaches the sub-layer (C1-45) of the second column via "second input port-first arm of the second QHC510 b- (phase delay of 90 °) -third arm of the second QHC510 b-fourth output port". Thus, from the point of view of the input signal T2, the radio signal radiated from the sub-layer (C2-45) of the second column has a phase delay of 90 ° compared to the radio signal radiated from the sub-layer (C1-45) of the first column, and a beam having +45° polarization is formed in a spatial direction inclined to the right by about 30 ° with respect to the normal of the antenna array as shown in fig. 5 b.

The input signal T3 passes through "third input port-fourth arm of the third QHC 510C- (phase delay of 90 °) -second arm of the third QHC 510C-fourth arm of the first QHC510 a- (phase delay of 90 °) -second arm of the first QHC510 a-first output port" and reaches the sub-layer (c1+45) of the first column. Also, the input signal T3 passes through "third input port-fourth arm of the third QHC 510C- (phase delay of 90 °) -second arm of the third QHC 510C-fourth arm of the first QHC510 a-third output port" and reaches the sub-layer (c2+45) of the second column. Also, the input signal T3 passes through "third input port-fourth arm of the third QHC 510C-third arm of the third QHC 510C- (phase delay of 90 °) -fourth arm of the second QHC510 b- (phase delay of 90 °) -second arm of the second QHC510 b-second output port" and reaches the sub-layer (C1-45) of the second column. Also, the input signal T3 is supplied to the sub-layer (C2-45) of the second column via "third input port-fourth arm of the third QHC 510C-third arm of the third QHC 510C- (phase delay of 90 °) -fourth arm of the second QHC510 b-third arm of the second QHC510 b-fourth output port".

Thus, from the point of view of the input signal T3, the radio signal radiated from the sub-layer (C1-45) of the first column has a phase delay of 0 ° compared to the radio signal radiated from the sub-layer (C1-45) of the first column, and the radio signal radiated from the sub-layer (C2-45) of the first column has a phase delay of 0 ° compared to the radio signal radiated from the sub-layer (C2-45) of the second column. As a result, a beam having a polarization of 90 ° (V) is formed (i.e., polarization synthesis is generated). Also, the radio signal radiated from the sub-layer (c1+45) of the first column has a phase delay of 90 ° compared to the radio signal radiated from the sub-layer (c2+45) of the second column, and the radio signal radiated from the sub-layer (C1-45) of the first column has a phase delay of 90 ° compared to the radio signal radiated from the sub-layer (C2-45) of the second column, so that a beam having a polarization of 90 ° (V) is formed with a tilt of about 30 ° to the left side with reference to the normal of the antenna array as shown in fig. 5 b.

The input signal T4 passes through "fourth input port-first arm of the third QHC 510C-second arm of the third QHC 510C-fourth arm of the first QHC510 a- (phase delay of 90 °) -second arm of the first QHC510 a-first output port" and reaches the sub-layer (c1+45) of the first column. The input signal T4 reaches the sub-layer (c2+45) of the second column via "the fourth input port-the first arm of the third QHC 510C-the second arm of the third QHC 510C-the fourth arm of the first QHC510 a-the third output port". Moreover, the input signal T4 reaches the sub-layer (C1-45) of the second column via "fourth input port-first arm of the third QHC 510C- (phase delay of 90 °) -third arm of the third QHC 510C- (phase delay of 90 °) -fourth arm of the second QHC510 b- (phase delay of 90 °) -second arm of the second QHC510 b-second output port". Also, the input signal T4 is supplied to the sub-layer (C2-45) of the second column via "fourth input port-first arm of the third QHC 510C- (phase delay of 90 °) -third arm of the third QHC 510C- (phase delay of 90 °) -fourth arm of the second QHC510 b-third arm of the second QHC510 b-fourth output port".

Thus, from the point of view of the input signal T4, the radio signal radiated from the sub-layer (C1-45) of the first column has a phase delay of 180 ° compared to the radio signal radiated from the sub-layer (C1-45) of the first column, and the radio signal radiated from the sub-layer (C2-45) of the first column has a phase delay of 180 ° compared to the radio signal radiated from the sub-layer (C2-45) of the second column. Eventually, a beam with 0 ° (H) polarization is formed (i.e., polarization synthesis is generated). Also, the radio signal radiated from the sub-layer (c1+45) of the first column has a phase delay of 90 ° compared to the radio signal radiated from the sub-layer (c2+45) of the second column, and the radio signal radiated from the sub-layer (C1-45) of the first column has a phase delay of 90 ° compared to the radio signal radiated from the sub-layer (C2-45) of the second column, so that a beam having 0 ° (H) polarization is formed obliquely to the left side by about 30 ° with reference to the normal of the antenna array as shown in fig. 5 b.

Fig. 6a illustrates a 4T4R polarization diversity antenna system using an antenna array including heterogeneous dual polarization antenna elements according to another embodiment of the present invention.

The antenna system shown in fig. 6a does not require signal processing in the digital or RF domain, and uses dual polarized antenna elements of a different type to form a spatially multiplexed orthogonal polarized beam similar to that of fig. 1 or 3. Thus, the Tx signals T1, T2, T3, T4 marked in fig. 6a are signals in the digital domain which have not been polarization synthesized. Similarly, the Rx signal does not perform polarization synthesis in the digital domain.

Referring to fig. 6a, an antenna array is illustrated in which four columns of heterogeneous dual polarized antenna elements are arranged. The two columns on the left side are composed of +45°/-45° dual polarized antenna elements, and the two columns on the right side are composed of V/H dual polarized antenna elements.

In each column, antenna elements 601a, 601b, 602a, 602b are connected to feed lines 611a, 611b, 612a, 612b according to polarization categories. For example, in each of the first and second columns, a +45° polarized first antenna element 601a is connected to a first feed 611a and forms a first sub-layer, and a-45 ° polarized element second antenna 601b is connected to a second feed 611b and forms a second sub-layer. In each of the third and fourth columns, a first antenna element 602a polarized at 90 ° (V) is connected to a first feed line 612a and forms a first sub-layer, and a second antenna element 602b polarized at 0 ° (H) is connected to a second feed line 612b and forms a second sub-layer. Thus, in the dual polarized antenna array illustrated in fig. 6a, the antenna elements 601a, 601b, 602a, 602b are divided into eight sub-layers.

To form beams by each polarization class using the antenna array shown in fig. 6a, sub-layers with the same polarization are interconnected in the RF domain. That is, to have a dual sub-layer for each polarization connected to one RF link 630, the interconnections are in the RF domain. Thus, the antenna system is 4T4R. The combination between the sub-layers can be achieved by constructing a simple RF synthesizer (combiner) over the RF domain.

As will be described later, the antenna panel is formed with a first region (or first face) and a second region (or second face) that are at a predetermined obtuse angle (90 ° < θ <180 °) to each other, the first region of the antenna panel (ANTENNA PANEL) is arranged with antenna elements having +45 °/-45 ° polarization, and the second region of the antenna panel is arranged with antenna elements having V/H polarization. The first region and the second region may be, for example, 120 °. Therefore, since the antenna panel is folded along the length direction, the +45°/-45 ° dual polarization antenna array and the H/L dual polarization antenna array are arranged to be directed in different directions in space. In this configuration, the beam having +45°/-45 ° polarization and the beam having V/H polarization are mechanically steered (scheduling) in the spatial direction in which the two regions of the antenna panel face, with appropriate adjustment of the angle (θ) formed by the two regions of the antenna panel, so that the antenna system of fig. 6a can generate a spatially multiplexed orthogonal polarized beam similar to that of fig. 1 or 3.

The antenna system of fig. 6a requires only a simple RF combiner, such as RF combiner (combiner), to form a spatially multiplexed beam pattern, without the hardware (required in the antenna system of fig. 1) for signal processing in the digital domain, thus improving the heating problem. Furthermore, the antenna system of fig. 6a can accurately maintain the interval between beams, and in particular, can minimize the overlapping area between beams having different dual polarizations, which affects SINR performance, as compared to the antenna system shown in fig. 3.

Fig. 6b to 6d are diagrams for explaining the structure of an antenna panel in which dual polarized antenna elements of isomerization (diversity) are arranged and the usefulness of the structure thereof employed in the antenna system of fig. 6 a.

Fig. 6b is a top view of an exemplary antenna panel 600 that may be employed by the antenna system of fig. 6 a. Referring to fig. 6b, the left half 610 of the antenna panel 600 is arranged with +45 °/-45 ° dual polarized antenna elements 601, and the right half 620 of the antenna panel 600 is arranged with H/V dual polarized antenna elements 602.

If the left half face 610 and the right half face 620 form one plane (refer to the front view of fig. 6c (a)), and a phase difference is maintained between RF signals introduced in dual polarized antenna elements having the same polarization characteristics, a spatially multiplexed dual beam pattern as shown in fig. 6c (b) can be obtained. In contrast, if the left side 610 of the antenna panel 600 forms a predetermined obtuse angle (θ) with the right side 620 of the antenna panel (refer to the front view of (a) of fig. 6 d), a dual beam pattern as shown in (b) of fig. 6d can be obtained even if the RF signals introduced in the dual polarized antenna elements having the same polarization characteristics are not phase-adjusted. The beam pattern of fig. 6c (b) has many side lobes (sidelobe) around the main lobe, and the size of the side lobes in the beam pattern of fig. 6d (b) is negligible. That is, it can be seen that the arrangement of dual polarized antenna elements of the structure and isomerism (diversity) of the antenna panel as shown in fig. 6d (a) is more advantageous for spatial polarization multiplexing.

Further, by combining the structure of the antenna panel 600 as in fig. 6d (a) with RF beam forming, it is also possible to make the spatial direction in which the beam is directed larger than that provided based on the angle (θ) formed by the two regions of the antenna panel. For example, in the left half 610 of the antenna panel 600 shown in fig. 6d (a), by making the RF path from the sub-layer of the first column to the RF link 630 larger than the RF path from the sub-layer of the second column to the RF link 630, a beam having +45°/-45° orthogonal polarization can be formed more to the left than the spatial direction in which the left half 610 of the antenna panel 600 faces. Thus, by combining the structure of the antenna panel 600 and RF beamforming as shown in fig. 6d (a), the angle (θ) formed by the left and right halves 610 and 620 of the antenna panel 600 can also be made larger (i.e., closer to 180 °). In view of this, fig. 6e illustrates a structure in which the same polarized sub-layers located in different columns are connected to the RF link 630 using RF paths of different lengths.

Fig. 7a illustrates an antenna panel 700 of dual polarized antenna elements according to another embodiment of the present invention, which are folded in the length direction and folded in the width direction as well, and arranged with heterogeneity (diversity).

Referring to fig. 7a, the bending in the length direction (x) divides the antenna panel into a left side region and a right side region, and the bending in the width direction (y) further divides the antenna panel into an upper side region and a lower side region. In other words, the antenna panel for arranging the antenna elements is divided into four areas (faces) facing different directions.

It is to be noted that, in order to prevent antenna elements having the same dual polarization from being arranged on two sides adjacent in the horizontal direction or the vertical direction of the antenna panel, the +/-45 ° antenna element 701 and the V/H antenna element 702 are alternately arranged in four regions (sides). For example, the upper left side of the antenna panel has V/H dual polarized antenna elements 702 arranged thereon, the upper right side has +/-45 ° dual polarized antenna elements 701 arranged thereon, the lower left side has +/-45 ° dual polarized antenna elements 701 arranged thereon, and the lower right side has V/H dual polarized antenna elements 702 arranged thereon.

Similar to the antenna panel 600 shown in fig. 6a, in each region (face) of the antenna panel 700 shown in fig. 7a, the antenna elements of each column may be connected to the feed lines (FEEDER LINE) in terms of polarization categories and form sub-layers. Moreover, sub-layers having the same polarization and located in different columns may be interconnected in the RF domain. That is, in the area (face) designated by the antenna panel 700, a pair of sub-layers located in different columns may be interconnected in the RF domain for each polarization to connect to the same RF link. Thus, an antenna system using the antenna panel 700 shown in fig. 7a can support 8T8R.

Alternatively, it is also possible that +/-45 ° dual polarized antenna units 701 arranged at the upper right and lower left of the antenna panel 700 are connected to one dual RF link, and V/H dual polarized antenna units 702 arranged at the upper left and lower right of the antenna panel are connected to the other dual RF link. So that the antenna system using the antenna panel 700 shown in fig. 7a can support 4T4R.

The +/-45 deg. dual polarized antenna element 701 arranged at the upper right forms a first beam having +45 deg./-45 deg. orthogonal polarization, the V/H dual polarized antenna element 702 arranged at the upper left forms a second beam having V/H orthogonal polarization, the +/-45 deg. dual polarized antenna element 701 arranged at the lower left forms a third beam having +45 deg./-45 deg. orthogonal polarization, and the V/H dual polarized antenna element arranged at the lower right forms a fourth beam having V/H orthogonal polarization. The spatial directions facing the first to fourth beams are respectively consistent with the spatial directions facing the corresponding surfaces of the antenna panels. Thus, the first to fourth beams face different spatial directions.

In addition, as shown in fig. 7b, the third beam and the fourth beam formed by the dual polarized antenna elements arranged in the lower left and lower right regions can cover the shadow region that cannot be covered by the first beam and the second beam formed by the antenna elements arranged in the upper right and upper left regions. Thus, the lower left and lower right regions (providing the main coverage of the antenna system) may be arranged with a smaller number of dual polarized antenna elements than the upper right and upper left regions.

The above description is merely for illustrating the technical idea of the embodiment of the present invention, and it is obvious to those skilled in the art to which the present invention pertains that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the present embodiment is not intended to limit the technical idea of the embodiment of the present invention, but is intended to be illustrative, and the scope of the technical idea of the present invention is not limited by the embodiment. The scope of the present invention should be construed based on the appended claims, and all technical ideas within the scope equivalent thereto should be construed to be all falling within the scope of the claims of the present invention.

Cross-reference to related applications

The present application claims priority from korean application No. 10-2021-0127232 at 9/27/2021 and korean application No. 10-2022-0110133 at 9/2022, the contents of which are incorporated herein by reference in their entirety.

Claims (10)

1. A polarization diversity antenna system, comprising:

An antenna array comprising a first column of dual polarized antenna elements and a second column of dual polarized antenna elements, wherein the dual polarized antenna elements have first antenna elements and second antenna elements that intersect perpendicularly with each other, respectively, in each column the first antenna elements are electrically connected to each other and form a first sub-layer, and the second antenna elements are electrically connected to each other and form a second sub-layer; and

An RF matrix for splitting an RF input signal into a plurality of split signals, selectively adjusting phases of the plurality of split signals, and providing the split signals to the first sub-layer of the first column, the second sub-layer of the first column, the first sub-layer of the second column, and the second sub-layer of the second column,

The RF output signal, when radiated by the dual polarized antenna element, forms a first beam having +/-45 ° polarization and a second beam having 0 °/90 ° polarization, and the first beam and the second beam are spatially formed facing different directions.

2. The polarization diversity antenna system of claim 1, wherein the RF matrix is implemented by quadrature hybrid couplers QHC formed in a PCB.

3. The polarization diversity antenna system of claim 2, wherein the RF matrix comprises:

A first QHC, a second QHC, and a third QHC;

a first input port connected to a first arm of the first QHC, a second input port connected to a first arm of the second QHC, a third input port connected to a fourth arm of the third QHC, and a fourth input port connected to a second arm of the third QHC; and

A first output port connected to a second arm of the first QHC, a second output port connected to a third arm of the first QHC, a third output port connected to a second arm of the second QHC, and a fourth output port connected to a third arm of the second QHC,

The second arm of the third QHC is connected to the fourth arm of the first QHC, and the third arm of the third QHC is connected to the fourth arm of the second QHC.

4. The polarization diversity antenna system of claim 3, wherein the first input port, the second input port, the third input port, and the fourth input port are connected to the first sub-layer of the first column, the first sub-layer of the second column, the second sub-layer of the first column, and the second sub-layer of the second column, respectively.

5. The polarization diversity antenna system of claim 3, wherein the first input port, the second input port, the third input port, and the fourth input port are each connected to an RF link for providing the RF input signal.

6. The polarization diversity antenna system of claim 1, wherein the RF matrix selectively adjusts the phase of the plurality of split signals based on a phase difference used to form the first beam and the second beam and a phase difference used to determine the first beam polarization and the second beam polarization.

7. The polarization diversity antenna system of claim 6, wherein for a pair of the RF input signals propagated by the first beam, a phase adjusted based on the RF matrix circuitry is defined to achieve a desired spatial direction for forming the first beam.

8. The polarization diversity antenna system of claim 6, wherein for a pair of the RF input signals propagated by the second beam, the phase adjusted based on the RF matrix circuitry is defined to achieve a desired spatial direction and polarization synthesis for forming the second beam.

9. The polarization diversity antenna system of claim 1, wherein the dual polarized antenna element has +/-45 ° polarization characteristics.

10. The polarization diversity antenna system of claim 9, wherein the 0 °/90 ° polarization of the second beam is obtained by polarization synthesis.