WO2018093176A2

WO2018093176A2 - Mimo antenna assembly of laminated structure

Info

Publication number: WO2018093176A2
Application number: PCT/KR2017/013034
Authority: WO
Inventors: 김덕용; 정배묵; 유창우; 문영찬; 박남신; 박범식; 윤민선; 박민식; 장성호
Original assignee: 주식회사 케이엠더블유
Priority date: 2016-11-16
Filing date: 2017-11-16
Publication date: 2018-05-24
Also published as: WO2018093176A3

Abstract

A MIMO antenna assembly of a lightweight laminated structure is disclosed. One aspect of the present invention provides a MIMO antenna assembly of a lightweight laminated structure, wherein a calibration network, which has been placed between an existing antenna element and a filter, is formed on one board together with a power amplifier and a digital circuit, and the filter is closely attached to the lower portion of a PCB on which a feeding network is formed. The present invention adopts a strategy to reduce the antenna assembly to a compact size while managing a phase deviation caused by the filter at an allowable level. Another aspect of the present invention provides a calibration method in a MIMO antenna operating in a Time Division Duplex (TDD) scheme and a MIMO antenna using the same, wherein the calibration method can perform a TX/RX calibration in a single calibration hardware configuration and perform the calibration in real time during operation.

Description

Stacked MIMO Antenna Assembly

The present invention relates to a multiple input multiple output (MIMO) antenna. More specifically, the present invention relates to a lightweight MIMO antenna assembly having a laminated structure and a calibration in a MIMO antenna operating in a time division duplex (TDD) scheme.

The contents described in this section merely provide background information on the present embodiment and do not constitute a prior art.

Multiple Input Multiple Output (MIMO) technology is a technology that dramatically increases the data transmission capacity by using multiple antennas. The transmitter transmits different data through each transmit antenna, and the receiver transmits different data through appropriate signal processing. Spatial multiplexing technique to distinguish. Therefore, as the number of transmit / receive antennas is increased, channel capacity increases to allow more data to be transmitted and received. For example, if you increase the number of antennas to 10, you get about 10 times the channel capacity using the same frequency band compared to the current single antenna system.

4G LTE-advanced uses up to 8 antennas. Currently, products with 64 or 128 antennas are being developed in the pre-5G phase, and base station equipment with a much larger number of antennas is expected to be used in 5G. This is called Massive MIMO technology. While the current cell operation is 2-Dimension, 3D-Beamforming is possible when Massive MIMO technology is introduced. Massive MIMO technology is also called Full Dimension MIMO (FD-MIMO).

In Massive MIMO technology, as the number of antenna elements increases, so does the number of transceivers and filters. Nevertheless, due to lease costs and space constraints, making RF components (antenna elements / filters / power amplifiers / transceivers) small, light and inexpensive will determine the success or failure of antennas employing Massive MIMO technology. Massive MIMO antennas require high power to increase coverage, and the power consumption and heat generated by these high powers are a negative factor in reducing weight and size.

Therefore, it is a challenge for the industry to develop a structure of an antenna system that can reduce / reduce such an antenna system and facilitate electrical connection and assembly between a plurality of RF elements.

SUMMARY OF THE INVENTION The present invention has a main object to provide a MIMO antenna having a compact and lightweight laminated structure.

In addition, the present invention proposes an assembly method capable of minimizing the accumulation amount of assembly tolerances generated when assembling a plurality of filters and a structure capable of uniformly transmitting the clamping force necessary to secure the electrical characteristics of the filter.

In addition, the present invention provides a calibration technique that performs TX / RX calibration with one calibration hardware configuration in a MIMO antenna operating in a time division duplex (TDD) scheme and can perform calibration in real time while operating. There is another purpose.

According to an aspect of the present embodiment, a MIMO antenna system including an antenna assembly having a stacked structure is provided. In the MIMO antenna system, a laminated antenna assembly is embedded between the radome and a housing having a heatsink formed on the rear surface thereof. An antenna assembly having a stacked structure includes a first printed circuit board (PCB) on which a feeding network is formed; A plurality of antenna elements installed on an upper surface of the first printed circuit board facing the radome and connected to the power supply network; And a filter assembly disposed on a lower surface of the first printed circuit board and including a plurality of band pass filters connected to the feed network. The antenna assembly of the stacked structure further includes a second printed circuit board disposed to face the housing, and further comprising a second printed circuit board having a plurality of transmit / receive circuits connected to the plurality of band pass filters.

According to another aspect of the present embodiment, a MIMO antenna assembly having a stacked structure is provided. The multilayer MIMO antenna assembly includes a first printed circuit board (PCB) on which a feeding network is formed; A plurality of antenna elements installed on an upper surface of the first printed circuit board and connected to the feeding network; And a filter assembly disposed on a lower surface of the first printed circuit board and including a plurality of band pass filters connected to the feed network. In addition, the multilayer MIMO antenna assembly includes a second printed circuit board disposed under the first printed circuit board. The second printed circuit board includes a plurality of transmission / reception circuits connected to the plurality of band pass filters, a digital circuit connected to the plurality of transmission / reception circuits to perform digital processing of baseband signals, and a calibration circuit in which a plurality of switches are connected in a tree structure. Formed.

According to another aspect of the present embodiment, a first printed circuit board (PCB) having a feeding network and a plurality of through holes electrically connected to the feeding network; A plurality of antenna elements installed on an upper surface of the first printed circuit board and connected to the feeding network; And a plurality of band pass filters adhered to the lower surface of the first printed circuit board. Each bandpass filter has a first port having a conductive first pin extending from an interior cavity and protruding from an upper surface thereof, each bandpass filter having a protruding portion of the first pin printed on the first print. It is tightly coupled to the first printed circuit board while being inserted into the through hole formed in the circuit board. Embodiments of the MIMO antenna assembly may further include one or more of the following features.

In some embodiments, the first port includes an opening formed in the upper surface; An insulating bush inserted into the opening to close the opening; And the conductive pins penetrating through the insulating bush and protruding from the bush.

In some embodiments, the plurality of band pass filters may include a plurality of fastening grooves fastened by the printed circuit board and bolts on the upper surface.

In some embodiments, the plurality of band pass filters form a filter assembly assembled in a row on a push bar having insertion protrusions inserted into insertion holes formed in the first printed circuit board.

In some embodiments, the plurality of band pass filters include a step portion for receiving the push bar, wherein the step portions are provided with insertion protrusions and fastening holes, and the push bars are inserted with insertion protrusions of respective band pass filters. Insertion grooves are formed, and a plurality of fastening grooves are fastened by fastening holes and bolts of each band pass filter.

In some embodiments, the MIMO antenna assembly further includes a second printed circuit board having a plurality of transmit and receive circuits connected to the plurality of band pass filters.

In some embodiments, a plurality of RF sockets connected to the plurality of transceiver circuits are mounted on an upper surface of the second printed circuit board, and each bandpass filter protrudes from a lower surface of the second printed circuit board. And a second port including a groove having a groove into which the groove is inserted and a conductive pin extending from the hollow inside and penetrating the groove formed in the protrusion, wherein each band pass filter has a conductive pin at the second port. It is coupled to the second printed circuit board while being inserted into a hole formed in the socket.

In some embodiments, the second port of each bandpass filter includes an opening formed in the groove; An insulating bush inserted into the opening to close the opening; And the conductive pins penetrating through the insulating bush and protruding from the bush.

In some embodiments, a plurality of structures are formed on an upper surface of the second printed circuit board, the contact pads being electrically connected to the transmission and reception circuits, and each bandpass filter is disposed in a cavity therein. A second port having a conductive plunger electrically connected and protruding from the bottom surface, each bandpass filter coupled to the second printed circuit board with the plunger in contact with the contact pad; do.

In some embodiments, the second port of each bandpass filter includes an opening formed in the lower surface; An insulating bush inserted into the opening to close the opening; A barrel barrel penetrating the insulating bush and protruding from the bush; The plunger having at least a portion inserted into the barrel of the cylinder; And a spring disposed in the barrel to support the plunger.

In some embodiments, the plurality of bandpass filters may be assembled in a line to a push bar coupled with the second printed circuit board to form a filter assembly, and the push bar coupled with the second printed circuit board. Provides uniform pressure to each bandpass filter such that each bandpass filter is coupled to the second printed circuit board with a uniform force.

In some embodiments, a lower surface of the plurality of band pass filters may include a fastening groove fastened by a bolt and a second printed circuit board having a plurality of transceiving circuits.

According to another aspect of the present embodiment, a first printed circuit board (PCB) having a feeding network and a plurality of contact pads electrically connected to the feeding network; A plurality of antenna elements installed on an upper surface of the first printed circuit board and connected to the feeding network; And a plurality of band pass filters adhered to the lower surface of the first printed circuit board. Each bandpass filter has a first port having a conductive first plunger extending from an interior cavity and protruding from an upper surface thereof, wherein each bandpass filter includes the first plunger in the first printed circuit. The first printed circuit board is in close contact with the contact pad formed on the substrate. Embodiments of the MIMO antenna assembly may further include one or more of the following features.

In some embodiments, the first port includes an opening formed in the upper surface; An insulating bush inserted into the opening to close the opening; A barrel barrel penetrating the insulating bush and protruding from the bush; At least a portion of the conductive plunger inserted into the barrel of the cylinder; And a spring disposed in the barrel to support the conductive plunger.

In some embodiments, a plurality of structures are formed on an upper surface of the second printed circuit board, the contact pads being electrically connected to the transmission and reception circuits, and each bandpass filter is disposed in a cavity therein. A second port having a conductive plunger electrically connected and protruding from the bottom surface, each bandpass filter having the second port with the conductive plunger of the second port in contact with the contact pad; It is coupled to a printed circuit board.

In some embodiments, the second port of each bandpass filter includes an opening formed in a lower surface thereof; A bush inserted into the opening to close the opening; A barrel barrel penetrating the bush and protruding from the bush; At least a portion of the conductive plunger inserted into the barrel of the cylinder; And a spring disposed in the barrel of the cylinder to support the conductive plunger.

In some embodiments, a plurality of structures are formed on an upper surface of the second printed circuit board, the contact pads being electrically connected to the transceiver circuits, and each bandpass filter is formed from an internal cavity. A second port having a conductive rod extending from and protruding from the bottom surface, each bandpass filter coupled to the second printed circuit board with the conductive rod in contact with the contact pad.

In some embodiments, the second port of each bandpass filter includes an opening formed in the lower surface; An insulating bush inserted into the opening to close the opening; And the conductive rod passing through the insulating bush and protruding from the bush.

According to yet another aspect of this embodiment, each bandpass filter has a first port electrically connected to an interior cavity and having a conductive rod protruding from the top surface, wherein each bandpass filter The conductive rod is in close contact with the first printed circuit board while being in contact with the contact pad formed on the first printed circuit board. In some embodiments, the first port includes an opening formed in the upper surface; An insulating bush inserted into the opening to close the opening; A conductive pin penetrating the insulating bush and protruding from the bush; And the conductive rod fixed to the end of the conductive pin in a vertical direction.

According to another aspect of the present embodiment, a MIMO antenna system operating with a time division duplex (TDD) communication protocol includes a plurality of antenna elements, a plurality of band pass filters connected to the plurality of antenna elements, and a plurality of band pass filters. It includes a plurality of transmission and reception circuits connected. Each transmit / receive circuit includes an RF interface connected to the band pass filter, and a transmission path and a reception path connected to the RF interface by time division. The MIMO antenna system is a calibration network in which a plurality of switches are connected in a tree structure, and a switch located at the top of the tree structure is selectively connected to a specific transmission path among the plurality of transmission paths and a specific reception path among the plurality of reception paths. The plurality of switches located at the lowest position in the tree structure further includes a calibration network, each connected to a plurality of directional couplers coupled to RF interfaces of the plurality of transceiver circuits. According to the MIMO antenna system, the specific transmission path is used for application of a pilot signal for calibration for the plurality of reception paths in a downlink time interval, and the specific reception path in the uplink time interval is used for the plurality of transmissions. It is used as a feedback path for calibration of the paths. Embodiments of the MIMO antenna system may further include one or more of the following features.

In some embodiments, the MIMO antenna system further includes processing circuitry coupled to the plurality of transmit / receive circuits and perform transmit calibration for the plurality of transmit paths and receive calibration for the plurality of receive paths. .

In some embodiments, the processing circuit includes, as an offset value, an RF deviation of the plurality of previously measured bandpass filters and antenna feeder lines in the deviation between each transmission path and each reception path. The transmission calibration and the reception calibration are performed.

In some embodiments, the processing circuit performs calibration in real time while the MIMO antenna is operating.

In some embodiments, the plurality of transmission and reception circuits, the calibration network and the processing circuit are formed on one printed circuit board.

In some embodiments, the processing circuitry forms a first calibration path comprised of the plurality of directional couplers, the calibration network and the specific receive path, and transmits via each transmit path via the first calibration path. A signal is obtained and a transmission calibration is performed based on a comparison between the transmission signal applied to each transmission path and the transmission signal acquired through the first calibration path.

In some embodiments, the processing circuit generates a pilot signal for calibration of each receive path, forms a second calibration path comprised of the particular transmission path, the calibration network and the directional coupler, and the second calibration. The pilot signal is inserted into each reception path through a path, and reception calibration is performed based on a comparison between the generated pilot signal and a pilot signal extracted from an output signal of each reception path.

In some embodiments, each transmitting circuit comprises an up converter, a D / A converter and a power amplifier (PA), wherein the specific transmission path further comprises a switch located between the power amplifier and the D / A converter, The switch further includes a switch for bypassing a pilot signal applied to the specific transmission path to the calibration network in an uplink time interval.

In some embodiments, each receiving circuit comprises a low noise amplifier (LNA), an A / D converter and a down converter, wherein the specific receiving path further comprises a switch located between the low noise amplifier and the A / D converter, The switch further includes a switch receiving a transmission signal via each transmission path that is fed back from the calibration network in a downlink time interval.

In some embodiments, the pilot signal has a frequency in-band of the received signal.

In some embodiments, the pilot signal has an out-band frequency of the received signal.

In some embodiments, each transmit / receive circuit further comprises a circulator coupled to the transmit path, the receive path and the RF interface, wherein a received signal input from the RF interface to the circulator is transferred to the receive path. The transmission signal input to the circulator from the transmission path is transmitted to the RF interface.

In some embodiments, the receiving path is connected to the circulator via a TDD switch, the TDD switch being a first input connected to the circulator, a first output connected to the receiving path, and a terminating resistor connected thereto. And a two output terminal, wherein the TDD switch is connected to the first input terminal in the downlink time interval.

According to another aspect of the present invention, a plurality of antennas, a plurality of band pass filters connected to the plurality of antennas, a plurality of transmission / reception circuits connected to the plurality of band pass filters, and a time division duplex (TDD) through the plurality of antennas The present invention provides a method for calibrating a MIMO antenna system including a plurality of transmission and reception circuits for transmitting and receiving in a communication protocol, and a calibration network in which a plurality of switches are connected in a tree structure. The method includes a first calibration comprising a directional coupler coupled to a branch between the plurality of transmission and reception circuits and the band pass filter, and a reception path included in a specific transmission and reception circuit among the calibration network and the plurality of transmission and reception circuits. Forming a path. The method includes obtaining a transmission signal transmitted to the plurality of bandpass filters through the first calibration path; And performing transmission calibration based on a comparison between the transmission signal applied to each transmission path and the transmission signal acquired through the first calibration path. Embodiments of the calibration method may further include one or more of the following features.

In some embodiments, the process of forming the first calibration path and the process of acquiring the transmission signal are performed in a downlink time interval.

In some embodiments, the performing of the calibration may further include including, as an offset value, RF deviations of the plurality of bandpass filters previously measured in deviations between transmission paths included in each transmission and reception circuit. .

In some embodiments, the calibration method comprises: generating a pilot signal for calibration of each receive path; Forming a second calibration path including a directional coupler coupled to a branch between the plurality of transmission / reception circuits and the band pass filter, a transmission path included in a specific transmission / reception circuit among the calibration network and the plurality of transmission / reception circuits. Process of doing; Inserting the pilot signal into a transmission path included in the specific transmission / reception circuit to insert the pilot signal into a reception path included in the plurality of transmission / reception circuits through the second calibration path; And performing reception calibration based on a comparison between the generated pilot signal and the pilot signal extracted from the output signal of each reception path.

In some embodiments, the forming of the second calibration path and the inserting of the pilot signal are performed in an uplink time interval.

In some embodiments, the performing of the reception calibration may include offsetting RF deviations of the plurality of previously measured bandpass filters and antenna feeder lines to deviations between respective reception paths included in each transceiver circuit. It further includes the process of including it as a value.

1 is a perspective view illustrating an exemplary appearance of an antenna device having an antenna assembly according to the present invention.

2 is a diagram illustrating a stack structure of an exemplary massive MIMO antenna.

3 is an exploded view of an exemplary subassembly implementing first to second layers in the stack structure of FIG. 2.

4 is a diagram illustrating a laminated structure of a massive MIMO antenna system according to an embodiment of the present invention.

FIG. 5 is an exploded view of a massive MIMO antenna according to an embodiment of the present invention taking the stacked structure of FIG.

6 is an exploded view of a subassembly in which filters are coupled to a first PCB to which an antenna element is coupled according to an embodiment of the present invention.

7 is a diagram illustrating an exemplary structure in which a bandpass filter is connected to a PCB through an RF connector.

8 is a perspective view showing the structure of a cavity filter according to an embodiment of the present invention.

9 is a cross-sectional view illustrating a structure in which a cavity filter is connected to a first PCB and a second PCB according to an embodiment of the present invention.

10 is a cross-sectional view illustrating a structure in which a cavity filter is connected to a first PCB and a second PCB according to another embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a structure in which a cavity filter is connected to a first PCB and a second PCB according to another embodiment of the present invention.

12 illustrates filter assemblies according to an embodiment of the present invention.

FIG. 13 is a view illustrating a state in which filter assemblies are assembled in a first PCB according to an embodiment of the present invention.

14 is a circuit diagram illustrating the function of a massive MIMO antenna assembly according to the present invention.

FIG. 15A illustrates a transmission / reception module in which no SPDT switch exists between the RF IC and the RF devices, and FIG. 15B illustrates a transmission / reception module in which an SPDT switch exists between the RF IC and the RF devices.

16 is a diagram for explaining signal flow in TX calibration.

17 is a diagram for explaining signal flow in RX calibration.

FIG. 18 is a diagram for explaining a fixed phase deviation of filters and antenna feeder lines.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

Throughout the specification, when a part is said to include, 'include' a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated. . As used herein, the term "calibration network" refers to a path for feeding back a transmission signal for each transmission path obtained through a bidirectional coupler coupled to an output terminal of each transmission path to a calibration processor, and each reception path from a calibration processor. Refers to an RF circuit that provides a path through which a pilot signal is transmitted to an input terminal of a.

1 is a perspective view illustrating an exemplary appearance of an antenna device having an antenna assembly according to the present invention. The antenna device 10 includes a housing 12 in which a heat sink is largely formed, and a radome 11 coupled to the housing. An antenna assembly to be described later is embedded between the housing 12 and the radome 11. A power supply unit 13 is coupled to the bottom of the housing 11, for example, via a docking structure, and the power supply unit 13 operates electronic components provided in the antenna assembly. Provide operating power for

1. 적층구조의 Massive MIMO 안테나 어셈블리Massive MIMO Antenna Assembly

The massive MIMO antenna 20 illustrated in FIG. 2 includes a radome, a housing in which a heat sink is formed outside, and an antenna assembly arranged therebetween. The antenna assembly is configured in such a way that the RF elements and the modules in which the digital elements are implemented are combined in a stacked structure. The main modules of the illustrated antenna assembly can be divided into six layers.

The first layer includes a printed circuit board (PCB) 210 on which a calibration network is implemented, and a plurality of antenna elements 210 installed on the top thereof. The second layer consists of a plurality of filters 230, each filter 230 being electrically connected to signal lines of the RF feeding network on the first layer via an RF interface such as an RF connector.

The third layer includes a PCB 240 in which analog processing circuitry such as a power amplifier (PA) is implemented. Each power amplifier included in the analog processing circuit is electrically connected to the corresponding filters 230 on the second layer through an RF interface. In addition, the analog processing circuitry is connected via a calibration network and an RF interface.

The fourth layer includes a digital board 250 and a power supply unit (PSU) 250 in which digital processing circuits are implemented. The digital board 250 converts a digital signal received from a base station base band unit (BBU) into an analog RF signal, converts an analog RF signal received from an antenna into a digital signal, and transmits the digital signal to the base station BBU. The digital board 250 is connected to the PCB 240 in which the analog processing circuit on the third layer is implemented through the RF interface.

As shown, a plurality of sublayers corresponding to the first layer and a filter bank corresponding to the second layer are combined to form a subassembly of the antenna assembly. The first sub-layer includes a PCB in which an RF feeding network is implemented and a plurality of antenna elements installed on the top thereof. The second sub layer includes a reflector, and the third sub layer includes a PCB on which a calibration network is implemented. The first sub layer to the third sub layer constituting the first layer may be implemented as a multi-layer PCB. In particular, in FIG. 2, a filter bank incorporating a plurality of filters is fastened to sublayers. The filter bank is a structure for securing a mating connection and a fastening force of the plurality of filters, which inevitably increases the size of the subassembly.

In the stack structure illustrated in FIGS. 2 and 3, a calibration network is located between the antenna and the filter. The calibration network typically consists of a plurality of switches and is connected to RF couplers coupled to the back of each filter. Thus, the feed network and the filters are bound to connect via an RF connector (eg, a standardized RF interface such as a coaxial connector). In addition, since the analog board and the digital board on which the power amplifier is formed are composed of separate layers, the RF connector is also used for the RF interface between them. As described above, the MIMO antenna system illustrated in FIGS. 2 and 3 is composed of a plurality of layers, and each layer is connected to each other through an RF connector, and thus it is difficult to reduce weight and size.

The present invention proposes a Massive MIMO antenna system having a slimmer and more compact laminated structure.

4 is a diagram illustrating a laminated structure of a massive MIMO antenna system according to an embodiment of the present invention. FIG. 5 is an exploded view of a massive MIMO antenna according to an embodiment of the present invention taking the stacked structure of FIG. 6 is an exploded view of a subassembly in which filters are coupled to a first PCB to which an antenna element is coupled according to an embodiment of the present invention.

As described later, the present invention operates the calibration function at the front end of the filter 430 (that is, at the output end of the power amplifier), not at the front end of the antenna element 410. Note that the phase deviation caused by the filter and antenna feeder lines can be managed at an acceptable level by producing / using filters with a fixed phase deviation. By operating the calibration function at the output of the power amplifier, the calibration network located between the existing antenna element and the filter can be formed together with the power amplifier and the digital circuit on a single board, and a PCB with a feeding network is formed. The filter can be tightly attached to the lower part. In other words, the present invention manages the phase deviation caused by the filter and the antenna feeder line at an acceptable level, but takes a strategy of reducing the antenna assembly to a compact size.

As shown in FIG. 4, in a stacked structure according to an embodiment of the present invention, a calibration network is formed on one board 440 together with a power amplifier and a digital circuit. Thus, there is no need for an RF cable connection between the power amplifier, the calibration network, and the digital circuit. In addition, compared to FIG. 2, the stacking structure of FIG.

The MIMO antenna assembly according to the present embodiment includes a first PCB 420 and a second PCB 440. An RF power supply network is formed in the first PCB 420. A plurality of antenna elements 410 are fastened to an upper surface of the first PCB 420 to be electrically connected to the RF power supply network, and a plurality of band pass filters 430 are tightly fastened to the lower surface to be electrically connected to the RF power supply network. do. At least one ground plane is formed in the first PCB 420, and the ground plane may function as a reflector for the plurality of antenna elements. That is, by using the ground plane formed on the first PCB 420 as a reflector, the separate reflector illustrated in FIG. 3 may be omitted. The second PCB 440 is formed with a digital processing circuit that performs baseband processing, an analog processing circuit that provides a plurality of transmit / receive (TX / RX) circuits, and a calibration network. The band pass filter 430 is electrically connected to the signal line of the first PCB 410 and is electrically connected to the signal line of the second PCB 440.

Hereinafter, the fastening structure between the band pass filter and the PCB will be described. The present invention proposes a new fastening structure between the filter and the PCB with improved size and assembly. In addition, the present invention proposes a fastening structure that can uniformly provide the fastening force necessary to secure the electrical characteristics of the plurality of filters, thereby minimizing the cumulative amount of assembly tolerances generated when the plurality of filters are assembled.

First, a conventional fastening structure will be described with reference to FIG. 7. 7 is a diagram illustrating an exemplary structure in which a bandpass filter is connected to a PCB through an RF connector. When the bandpass filter is fastened to the PCB, an RF connector of a blind mating connector type is typically used. FIG. 7 illustrates a cavity filter with

RF connectors

711 and 712 on the top and bottom surfaces, respectively. On the PCB, an RF connector (female) inserted into an RF connector (male) located under the cavity filter is surface mounted. Each cavity filter is individually fastened to the PCB via a fastening structure 713.

In the structure illustrated in FIG. 7, since each cavity filter is individually fastened to the PCB, assembly tolerances occur in RF characteristics due to the difference in the fastening force between the cavity filters. In addition, each cavity filter must be spaced apart from the PCB by the length (A) of the fastening structure 713 in consideration of the length of the assembly of the RF connectors, inevitably increases in size. In particular, in order to apply blind mating connection to both the upper and lower surfaces of the filter, a very complicated hardware structure (eg, a structure in which a filter is embedded in a separate assembly case such as the filter bank illustrated in FIG. 3) is required.

필터의 PCB 간의 RF 인터페이스RF interface between PCB of filter

8 is a perspective view showing the structure of a cavity filter according to an embodiment of the present invention. 9 is a cross-sectional view illustrating a structure in which a cavity filter is connected to a first PCB and a second PCB according to an embodiment of the present invention. In Fig. 9, to avoid confusion, the internal structure of the cavity filter is omitted.

As shown in FIG. 8, the cavity filter includes a first input / output port 810 and a second input / output port 860. The first input and output port 810 is disposed on the upper surface (eg, cover) of the cavity filter, and the second input and output port 860 is disposed on the lower surface of the cavity filter. It should be noted that these input /

output ports

810 and 860 are configured with a pin structure and are different from standardized RF interfaces such as coaxial connectors.

Referring to FIG. 8, the first input / output port 810 is configured as a fin structure inserted into an opening section formed on an upper surface of the cavity filter. The fin structure includes a conductive fin 811 and an insulating bush 812. The conductive pin 811 penetrates through the insulating bush 812 and protrudes from the insulating bush 812. The fin structure is inserted into the opening to seal the opening. A portion of the conductive pin 811 protrudes from the top surface of the cavity filter. In addition, a plurality of fastening grooves 820a to 820c fastened by the first PCB and the bolt are formed on the upper surface of the cavity filter.

As shown in FIG. 9, the cavity filter is tightly coupled to the bottom surface of the first PCB 420 in which a feeding network is formed. The first PCB 420 has a plurality of plated through holes 920 connected to the power feeding network. The cavity filter is fastened in close contact with the bottom surface of the first PCB 420 with a portion of the conductive pin 811 inserted into the through hole 820 formed in the first PCB 420. A soldering process may be performed on the contact portion between the conductive pin 811 and the through hole 920.

Meanwhile, since a plurality of RF ICs or digital ICs are mounted in the second PCB 440, in order to prevent damage to the mounted devices, the cavity filter needs to be coupled to the upper surface of the second PCB 440 at a predetermined distance. There is. Referring to FIG. 8 again, an opening is formed in the protrusion 850 protruding in the height direction on the lower surface of the filter. The fin structure 860 coupled with the conductive pin 861 and the bush 862 is inserted into an opening formed in the protrusion 850 to seal the opening. In addition, the protrusion 850 having the opening is formed with an insertion portion 851 for accommodating a socket mounted on a second PCB to be described later. In addition, the lower surface of the filter is formed with a fastening groove 840 is fastened by the structure and the bolt formed in the second PCB 440.

9, the cavity filter is coupled to the upper surface of the second PCB 440 on which the RF circuit is formed. A socket 950 is surface mounted on the top surface of the second PCB 440. The socket 950 includes a hole into which the second coaxial pin 861 of the cavity filter is inserted and at least one contact pin 951 electrically contacting the conductive pin 861 inserted into the hole. When the socket 950 is accommodated in the insertion portion 851 of the cavity filter, the conductive pin 861 is inserted into the hole of the socket 950. The upper surface of the cavity filter and the second PCB 440 is spaced apart by the height of the protrusion 850 formed on the lower surface of the cavity filter. The height of the protrusion 850 is designed in consideration of the size of the elements mounted on the upper surface of the second PCB 440, and the separation distance between the cavity filter and the second PCB 440 is lower than that of the connection structure using the RF connector of FIG. Decrease significantly.

10 is a cross-sectional view illustrating a structure in which a cavity filter is connected to a first PCB and a second PCB according to another embodiment of the present invention. Note that in FIG. 10, the internal structure of the cavity filter is omitted to avoid confusion.

Referring to FIG. 10, the first input / output port is configured with a fin structure inserted into an opening section formed in an upper surface of the cavity filter. The pin structure includes a spring pin connector and an insulating bush 1014. The spring pin connector has a cylindrical conductive barrel 1012 which penetrates the insulating bush 1014 and protrudes from the insulating bush 1014, a conductive plunger 1011 at least partially inserted into the barrel 1012, And a spring 1013 disposed in the barrel 1012 to support the plunger 1011. The fin structure is inserted into the opening to seal the opening. A portion of the plunger 1011 protrudes from the top surface of the cavity filter and is configured to be pushed into the barrel barrel 1212 by pressing pressure (eg, as it adheres to the first PCB 420).

The cavity filter is tightly coupled to the bottom surface of the first PCB 420 in which a feeding network is formed. The first PCB 420 has a plurality of contact pads (not shown) connected to the power feeding network. The cavity filter is in close contact with the bottom surface of the first PCB 420 while the head of the plunger 1011 is in contact with the contact pad formed in the first PCB 420. A portion of the plunger 1011 is pushed into the barrel 1012 of the cylinder as the upper surface of the cavity filter is in close contact with the first PCB 420. A spring 1013 inside barrel 1012 provides a suitable contact pressure between the head of the plunger 1011 and the contact pad.

Like the first I / O port, the second I / O port consists of a fin structure inserted into an opening section formed in the upper surface of the cavity filter. The pin structure includes a spring pin connector and an insulating bush 1054. The spring pin connector has a cylindrical barrel 1052 protruding from the insulating bush 1054 through the insulating bush 1054, a plunger 1051 at least partially inserted into the barrel 1052, and a barrel 1052. ) And a spring 1053 disposed within and supporting the plunger 1051.

A socket 1060 is surface mounted on the top surface of the second PCB 440. A contact pad 1061 is formed on the upper surface of the socket 1060 to be electrically connected to the transceiver circuit. The cavity filter is coupled with the second PCB 440 with the head of the plunger 1051 of the second input / output port being in contact with the contact pad 1061 formed in the second PCB 440. In the example of FIG. 10, the cavity filter and the top surface of the second PCB 440 are spaced apart by the height of the socket 1060 mounted in the second PCB 440. In some other examples, similar to the embodiment of FIGS. 8 and 9, a protrusion protruding in the height direction may be formed on the lower surface of the filter, and a spring pin connector may be located in the opening formed in the protrusion. At least a portion of the socket mounted on the second PCB 440 may be inserted into an opening formed in the protrusion.

FIG. 11 is a cross-sectional view illustrating a structure in which a cavity filter is connected to a first PCB and a second PCB according to another embodiment of the present invention. 11 also, the internal structure of the cavity filter is omitted in order to avoid confusion.

Referring to FIG. 11, the first input / output port includes a fin structure inserted into an opening section formed on an upper surface of the cavity filter. The fin structure includes an insulating bush 1113, a conductive pin 1111 penetrating through the insulating bush 1113, and protruding from the insulating bush 1113, and a conductive pin fixed perpendicularly to the distal end of the conductive pin 1111. A conductive rod 1112. The conductive rod 1112 is bent so that its ends protrude from the top surface of the filter. The cavity filter is tightly coupled to the bottom surface of the first PCB 420 in which a feeding network is formed. Similar to the embodiment of FIG. 10, the first PCB 420 is formed with a plurality of contact pads (not shown) connected to the power feeding network. The cavity filter is fastened in close contact with the bottom surface of the first PCB 420 with the end of the conductive rod 1052 being in contact with the contact pad formed in the first PCB 420. The conductive rod 1112 is bent to the lower side of the filter as the upper surface of the cavity filter is in close contact with the first PCB 420. The conductive rod 1112 preferably has an elastic force to provide an appropriate contact pressure with the contact pad.

Like the first I / O port, the second I / O port consists of a fin structure inserted into an opening section formed in the upper surface of the cavity filter. The fin structure includes an insulating bush 1153 inserted into the opening, a conductive pin 1151 penetrating through the insulating bush 1153, and protruding from the insulating bush 1153, and perpendicular to the ends of the conductive pin 1151. And a conductive rod 1152 fixed with a. The conductive rod 1152 is bent in the middle to protrude from the bottom surface of the filter.

Similar to the embodiment of FIG. 10, a socket 1160 is surface mounted on the top surface of the second PCB 440. A contact pad 1161 is formed on the upper surface of the socket 1160 to be electrically connected to the transceiver circuit. The cavity filter is coupled with the second PCB 440 with the end of the conductive rod 1152 of the second input / output port being in contact with the contact pad 1161 formed in the second PCB 440. In the example of FIG. 10, the cavity filter and the top surface of the second PCB 440 are spaced apart by the height of the socket 1160 mounted in the second PCB 440. In some other examples, similar to the embodiment of FIGS. 8 and 9, protrusions protruding in the height direction may be formed on the lower surface of the filter, and pin structures may be located in the openings formed in the protrusions. At least a portion of the socket mounted on the second PCB 440 may be inserted into an opening formed in the protrusion.

It should be noted that the structures of the first input / output port and the second input / output port of the cavity filter illustrated in FIGS. 9 to 11 may be used in combination as necessary. For example, the cavity filter may have a structure of a first input / output port illustrated in FIG. 9 and a structure of a second input / output port illustrated in FIG. 10 or 11.

푸시바(push bar)를Push bar 이용한 필터 결합 Filter combination

The cavity filters may be separately assembled to the lower surface of the first PCB 420 and the upper surface of the second PCB 440, but a large variation in RF characteristics may occur due to the fastening force difference between the cavity filters. The present invention proposes an assembly method capable of minimizing the accumulation amount of assembly tolerances generated when assembling a plurality of filters and a structure capable of uniformly transmitting the clamping force necessary to secure the electrical characteristics of the filter.

12 is an enlarged view illustrating an enlarged view of filter assemblies and a portion at which a filter is coupled to a push bar, according to an exemplary embodiment. FIG. 13 is a view illustrating a state in which filter assemblies are assembled in a first PCB according to an embodiment of the present invention.

As shown in FIG. 12, the filter assembly includes a push bar 1210 and a set of filters assembled in line to the push bar 1210. The filter is formed with a step 1250 to receive the push bar 1210. The stepped part 1250 has a shape in which one side of the filter is cut at right angles. The stepped part 1250 is provided with fastening holes 1253 into which the

insertion protrusions

1251a and 1251b and the bolt are inserted. Correspondingly, the push bars 1210 are formed with insertion grooves (not shown) into which the

insertion protrusions

1251a and 1251b of each filter are inserted, and are inserted between the insertion grooves (not shown) by respective cavity filters and bolts. A plurality of fastening grooves (not shown) to be fastened are formed.

In addition, the push bar 1210 has two or

more insertion protrusions

1211a and 1211b inserted into insertion holes (not shown) formed in the first PCB. When the

insertion protrusions

1211a and 1211b of the push bar 1210 are inserted into the insertion holes (not shown) of the first PCB, the conductive pins of the group of filters assembled to the push bar 1210 as illustrated in FIG. 10. It is inserted into the through holes formed in the first PCB. 13 shows an exemplary shape in which four filter assemblies are assembled to a first PCB.

At both ends of the push bar 1210, a plurality of

fastening holes

1212a and 1212b are formed to be fastened by the structure of the second PCB and the bolts. In a state where the socket mounted on the second PCB is accommodated in the insertion hole formed in the protrusion of the filters of the one end assembled in the push bar 1210, and the second coaxial pin is inserted into the hole of the socket, the push bar 1210 is connected to the second PCB. It is bolted to the structure and can provide a uniform clamping force to a group of filters assembled to the push bar 1210. If the push bar 1210 is bent, it is difficult to transfer a uniform load or clamping force to each filter, so the push bar 1210 should have a certain level or more of rigidity.

The method of fastening the filter to the PCB by using the push bar 1210 minimizes the accumulation of tolerances when the filters are coupled to the PCB, adjusts the tolerances consistently, and provides stable blind mating with the antenna and the RF transceiver circuit. Makes it possible. In addition, in order to obtain a fastening force necessary for acquiring the RF characteristics when the filter is fastened, an apparatus and an assembly structure required for the filter are not required separately. In addition, if the " filter assembly " pre-assembled is used in the assembly process of the antenna assembly, the antenna assembly can also be contributed to simplifying the assembly process.

Furthermore, the structure for the unique electrical connection between the filter and the PCB proposed by the present invention does not require a coaxial connector or RF cabling, and the unique fastening structure between the PCB and the filter assembly proposed by the present invention is a filter for each filter. Instead of fastening to the PCBs individually, the push bars can be used to fasten the filters to the PCB, allowing easy disassembly of the antenna assembly or filter assembly. It is easy to replace the faulty antenna.

2. 빔포밍 캘리브레이션(beamforming calibration)2. Beamforming Calibration

In order to provide beamforming in the antenna, the amplitude and phase of each TX path and each RX path in the Radio module must be kept constant. However, in the actual Radio module, each TX / RX path has a deviation. Have. Compensating for this deviation is called beamforming calibration in the radio module.

The present invention proposes a method of temporally split-sharing the same RF path in TX and RX calibration using characteristics of a MIMO antenna system operating in a time division duplex (TDD) scheme. do.

In TX calibration, the variation of RF characteristics (phase / amplitude / delay, etc.) between each transmission path is calculated based on a correlation calculation between the feedback signal captured at the rear end of the transmission path and the transmitted signal using the magnetic transmission signal. Measure and perform TX calibration to compensate for the measured deviation. In addition, for the reception path, a pilot signal is inserted into each reception path, and RF characteristics (phase / amplitude / delay) between the reception paths are based on a correlation operation between the pilot signal and the signal output at the rear end of the reception path. Etc.) Measure the deviation and perform an RX calibration that compensates for the measured deviation. This calibration algorithm itself is substantially the same as that disclosed in Korean Patent Application No. 10-2015-0063177 (Publication No. 10-2016-0132166) filed by the applicant. The disclosures of the above Korean patent applications are all incorporated herein by reference.

Hereinafter, an exemplary circuit configuration and signal connection of a massive MIMO antenna assembly will be described with reference to FIGS. 14, 15A, and 15B.

14 is a circuit diagram illustrating the function of a massive MIMO antenna assembly according to the present invention. As shown in FIG. 14, a digital processing circuit for performing baseband processing, an analog processing circuit divided into a plurality of transmission / reception modules, and a calibration network are formed in the second PCB. Each transmit / receive module is connected via an RF interface to a bandpass filter connected to an antenna element. As described above, TX / RX calibration according to one embodiment of the present invention is performed on the filter front end. In this manner, compared to the configuration performed at the front end of the antenna (that is, the rear end of the filter), a calibration H / W (eg, a calibration network) can be realized by utilizing a free space on the second PCB on which the RF transceiver circuit and the like are formed. The complexity and connection at 2PCB is reduced, resulting in spatial gain and material cost savings.

Referring to FIG. 15A, each transmit / receive module includes a plurality of RF elements and an RF IC for providing a transmission path and a reception path for a corresponding antenna element.

The RF IC includes an up converter for up-converting a baseband digital transmission signal received from a digital processing circuit to a transmission frequency and a D / conversion for converting the up-converted digital transmission signal into an analog RF transmission signal. A converter may be included. The up converter and the D / A converter form part of the transmission path. In addition, the RF IC may include an A / D converter that converts an analog RF received signal into a digital received signal, and a down converter that converts the digital received signal into a baseband digital received signal. The A / D converter and the down converter form part of the reception path. The RF down converter down converts the received received signal to baseband, and the A / D converter converts the baseband signal into a digital signal. The baseband digital signal is sent to a digital processing circuit.

Each transmission path further includes a power amplifier (PA), a circulator and a directional coupler. Each receive path further includes a low noise amplifier (LNA). A circulator is installed at the connection portion between the transmission path and the reception path. The received signal (that is, the uplink RF signal) input from the filter side to the circulator is transmitted to the LNA via the circulator. In addition, a transmission signal (downlink RF signal) input from the power amplifier to the circulator is transmitted to the filter side. Between the LNAs of the circulators are included SPDT switches that function as TDD switches. One terminal of the SPDT switch is connected with a terminating resistor to minimize changes in Voltage Standing Wave Ratio (VSWR) characteristics. When the transmit / receive module operates in transmit mode (ie, in the downlink time interval), the SPDT switch connects the circulator to the terminating resistor. When the transmit / receive module operates in the receive mode (ie, in the uplink time interval), the SPDT switch connects the circulator to the LNA.

As shown in FIG. 15B, unlike the transmission paths of the other transmission / reception modules, the SPDT switch 1510 is further included in the transmission path TX0 of the specific transmission / reception module. Similarly, unlike the reception paths of the other transmission / reception modules, the reception path RX1 of the specific transmission / reception module further includes an SPDT switch 1560 after the low noise amplifier (LNA).

The calibration network (which may be referred to as a 'matrix switch') consists of a plurality of switches that take a tree structure. The highest switch SPDT is connected to the SPDT switch 1510 included in the specific transmission path among the plurality of transmission paths, and is also connected to the SPDT switch 1560 included in the specific reception path among the plurality of reception paths. The lowest switches SP4T are connected to an SPDT switch connected to a directional RF coupler located at the rear of the power amplifier on the plurality of transmission paths. By selective switching of the switches included in the calibration network, each transmission path and each reception path is selected.

Hereinafter, the signal flow in the TX / RX calibration application in the TDD scheme proposed by the present invention will be described in detail.

TX 캘리브레이션TX calibration

16 is a diagram for explaining signal flow in TX calibration.

In FIG. 16, when the TX calibration is performed for the transmission paths TX0 and TX1, the signal flow is indicated by a thick line. In Figure 16, "CAL # 0, CAL # 1, CAL # 2 ..." refers to the transmission signal captured by the directional coupler coupled to the rear end of the power amplifier of each transmission path. In addition, "TX CAL" also refers to the captured transmission signal, for convenience, to describe the signal flow and connection relationship between the transmission and reception circuit and the calibration network, for convenience, the "captured transmission signal" output from the top switch of the calibration network It is indicated as "TX CAL".

The analog RF signal (i.e., transmit signal) transmitted from the RFIC to each transmission path is captured by a directional coupler behind the power amplifier. For example, the analog RF signal transmitted to the transmission path TX0 is captured by the directional coupler, and the captured signal CAL # 0 is input to the lowest switch of the calibration network. At this time, the LNA of the reception path RX1 is OFF. Similarly, the downlink RF signal transmitted to the transmission path TX1 is captured by the directional coupler behind the power amplifier, and the captured signal CAL # 1 is input to the lowest switch of the calibration network. The captured signal CAL # 1 is transmitted to the RF IC through the SPDT switch 1560 located on the specific receive path RX1 through the top switch of the calibration network.

The captured signal passes through an A / D converter and a down converter for the specific reception path RX1, which is included in the RF IC, and then a correlation operation with a corresponding original transmission signal is applied and used for calibration. The specific TX calibration algorithm is substantially the same as that disclosed in Korean Patent Application No. 10-2015-0063177 (Publication No. 10-2016-0132166).

RX 캘리브레이션RX calibration

In the case of the TDD scheme, when the transmission path is ON (i.e., in the downlink time interval), the reception path must be kept in the OFF state. do.

Since the RU (Calibration Unit) performing the calibration has no information on the received signal, a RU (Pilot) signal is inserted to determine RF characteristics such as delay, phase, and gain of the reception paths. The pilot signal may be inserted in-band or out-of-band in the RX band. However, it is more appropriate to insert a pilot signal into a band in order to accurately detect amplitude and phase in real time even while the main signal of each reception path is received. Herein, 'inserted in-band' means that the frequency band allowed for receiving the uplink RF signal is inserted outside the band actually used for transmitting and receiving the uplink RF signal.

The inserted pilot signal is removed by the digital filter in the digital domain, so it does not affect the reception modem performance. In the case of the Massive MIMO antenna system according to the present invention, the pilot signal is inserted into the RX filter output terminal. If the RX filter removes the pilot signal, the pilot element does not emit radiation by the antenna element. Therefore, on-service calibration, that is, calibration can be performed in real time while the antenna system is operating.

17 is a diagram for explaining signal flow in RX calibration.

In FIG. 17, when RF calibration is performed for the reception paths RX0 and RX1, the signal flow is indicated by a thick line. In FIG. 17, RX CAL, CAL # 0, CAL # 1, CAL # 2 ... all refer to pilot signals used for RX calibration. However, in order to explain the signal flow and the connection relationship between the transceiver circuit and the calibration network, for convenience, the pilot signal transmitted from the RFIC to the transceiver circuit is denoted as "RX CAL", and the pilot signal output from the lowest switch of the calibration network is " CAL # 0, CAL # 1, CAL # 2 ... ".

Referring to FIG. 17, a pilot signal "RX CAL" used to calibrate each reception path is input to a specific transmission path TX0 from an RFIC. The pilot signal " RX CAL " input to the specific transmission path TX0 is transmitted to the top switch of the calibration network through the SPDT switch 1360 located in front of the power amplifier. The reception paths to which the pilot signal is inserted are selected by the switches included in the calibration network. The pilot signal is inserted into the reception path through which the received signal is transmitted by the directional coupler located on the selected reception path, and finally delivered to the RFIC corresponding to the selected reception path. For example, in the case of the reception path RX0, the pilot signal "CAL # 0" is transmitted to the RF IC through the circulator, the SPDT switch and the LNA along with the reception signal. In addition, in the case of the reception path RX1, the pilot signal ("CAL # 1") is transmitted to the RF IC through the circulator, the SPDT switch and the LNA along with the received signal.

The pilot signal together with the received signal passes through an A / D converter and a down converter for the corresponding receive path provided in each RF IC, and is then separated from the received signal through a digital filter. The separated pilot signal is used for calibration by applying a correlation operation to the pilot signal "RX CAL" input to a specific transmission path TX0. The specific RX calibration algorithm is substantially the same as that disclosed in Korean Patent Application No. 10-2015-0063177 (Publication No. 10-2016-0132166).

As described above, the calibration method proposed by the present invention can perform calibration in real time while operating in a time division duplex (TDD) antenna. In addition, it performs TX / RX calibration with one calibration H / W configuration and can perform calibration in real time while the antenna system is operating. Further, in addition to the up converter or the down converter for the transmission signal and the reception signal, there is no need for a separate up converter or down converter for performing TX calibration and RX calibration. That is, a down converter for a reception signal of a specific reception path is used for down conversion of a captured transmission signal, and an up converter for a transmission signal of a specific transmission path is used for up conversion of a pilot signal to be inserted into each reception path.

FIG. 18 is a diagram for explaining a fixed phase deviation of filters and antenna feeder lines. As described above, in the above embodiments, the calibration function was applied to the front end of the filter (ie, the output stage of the power amplifier), not to the front end of the antenna element. That is, a magnetic transmission signal was captured at the front of the filter, and a pilot signal was inserted at the front of the filter. Thus, as shown in FIG. 18, the fixed RF deviation (especially phase deviation) of each filter and antenna feeder lines is inevitably excluded from the real time deviation measurement. Thus, in some embodiments, in order to compensate for fixed RF deviations of the respective filters and antenna feeder lines, these previously measured fixed RF deviations are offset in each transmission path and each receiving path deviation measured in real time. Calibration is performed by including (offset) value. That is, after the RF deviations of the plurality of previously measured band pass filters and the antenna feeder lines are included as offset values in the deviations between the transmission paths, calibration of each transmission path may be performed. In addition, after the RF deviations of the plurality of previously measured band pass filters and the antenna feeder lines are included as offset values in the deviations between the reception paths, calibration of each reception path may be performed. Note that the phase deviation caused by the filter and antenna feeder lines can be managed at an acceptable level by producing / using filters with a fixed phase deviation.

In addition, although the above embodiments have been described assuming that the calibration is applied to the front end of the filter, the calibration method proposed by the present invention also applies to the structure applied to the front end of the antenna, that is, the structure in which the lowest switches of the calibration network are coupled to the front end of the antenna. Applicable.

The above description is merely illustrative of the technical idea of the present embodiment, and those skilled in the art to which the present embodiment belongs may make various modifications and changes without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of the present embodiment but to describe the present invention, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present embodiment.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is incorporated herein by reference in its entirety, the patent application number No. 10-2016-0152609 filed in Korea on November 16, 2016, and the patent application number filed in Korea on March 06, 2017. 10-2017-0028430, Patent Application No. 10-2017-0028434, filed in Korea on March 06, 2017, and Patent Application No. 10-2017-0028442, filed in Korea on March 06, 2017 Insist on priority.

Claims

Radome;

A housing having a heat sink formed on a rear surface thereof; And

A MIMO antenna system comprising an antenna assembly of a laminated structure embedded between the radome and the housing, wherein the antenna assembly,

A first printed circuit board (PCB) on which a feeding network is formed;

A plurality of antenna elements installed on an upper surface of the first printed circuit board facing the radome and electrically connected to the feed network;

A filter assembly disposed on a lower surface of the first printed circuit board and including a plurality of band pass filters electrically connected to the feed network; And

A second printed circuit board disposed to face the housing, the second printed circuit board having a plurality of transmission / reception circuits electrically connected to the plurality of band pass filters;

Including, MIMO antenna system.
The method of claim 1,

In the second printed circuit board,

And a digital circuit electrically connected to the plurality of transmission / reception circuits to perform digital processing of a baseband signal.
The method of claim 1,

The plurality of band pass filters are in close contact with the first printed circuit board, characterized in that the MIMO antenna system.
The method of claim 1,

Each bandpass filter has a first port directly connected to said feed network without RF cabling.
The method of claim 4, wherein

The first printed circuit board has a plurality of through holes electrically connected to the feed network,

The first port of each bandpass filter has conductive pins extending from an interior cavity and protruding from an upper surface thereof, and each bandpass filter has a portion of the conductive pins of the first printed circuit. And being in close contact with the first printed circuit board while being inserted into the through hole formed in the substrate.
The method of claim 4, wherein

The first printed circuit board includes a plurality of contact pads connected to the power supply network.

The first port of each bandpass filter includes a conductive plunger electrically connected to an interior cavity and protruding from an upper surface, wherein each bandpass filter has a portion of the conductive plunger being the first port. And being in close contact with the first printed circuit board while being in contact with the contact pad formed on the printed circuit board.
The method of claim 4, wherein

The first printed circuit board includes a plurality of contact pads connected to the power supply network.

The first port of each band pass filter has a conductive pin extending from an interior cavity and protruding from an upper surface thereof, and a conductive rod fixed perpendicularly to an end of the conductive pin. And each band pass filter is in close contact with the first printed circuit board while a portion of the conductive rod is in contact with the contact pad formed on the first printed circuit board.
The method of claim 1,

The filter assembly,

And a plurality of band pass filters are assembled in a line in a push bar fastened to the second printed circuit board.
The method of claim 8,

The push bar coupled to the second printed circuit board,

And providing uniform pressure to each bandpass filter such that each bandpass filter is coupled to the second printed circuit board with a uniform force.
The method of claim 1,

Each bandpass filter,

And a second port connected directly to the transmission / reception circuit without RF cabling.
The method of claim 10,

A plurality of RF sockets connected to the plurality of transceiver circuits are mounted on an upper surface of the second printed circuit board.

The second port of each band pass filter has a protrusion formed from the bottom surface and a groove in which the RF socket is inserted at the center and a conductive pin extending from the hollow inside and penetrating the groove formed in the protrusion,

Each bandpass filter is coupled to the second printed circuit board with a portion of the conductive pin inserted into a hole formed in the RF socket.
The method of claim 10,

The upper surface of the second printed circuit board is mounted with a plurality of structures formed with a contact pad electrically connected to the transceiver circuit,

The second port of each bandpass filter has a conductive plunger extending from the interior cavity and protruding from the bottom surface,

Each bandpass filter is coupled to the second printed circuit board with a portion of the conductive plunger in contact with the contact pad.
The method of claim 10,

The upper surface of the second printed circuit board is mounted with a plurality of structures formed with a contact pad electrically connected to the transceiver circuit,

The second port of each band pass filter has a conductive pin which extends from the cavity inside and protrudes from the lower surface, and a conductive rod fixed perpendicularly to the end of the conductive pin. ,

Each bandpass filter is coupled to the second printed circuit board with a portion of the conductive rod in contact with the contact pad.
The method of claim 1,

In the second printed circuit board,

And a calibration circuit in which a plurality of switches are connected in a tree structure.
The method of claim 1,

At least one ground plane is formed on the first printed circuit board, and the ground plane functions as a substitute for a reflector for a plurality of antenna elements.
A multilayer MIMO antenna assembly,

A first printed circuit board (PCB) on which a feeding network is formed;

A plurality of antenna elements installed on an upper surface of the first printed circuit board and connected to the feeding network;

A filter assembly disposed on a lower surface of the first printed circuit board and including a plurality of band pass filters connected to the feed network; And

A plurality of transmit / receive circuits disposed under the first printed circuit board, connected to the plurality of bandpass filters, connected to the plurality of transmit / receive circuits, and perform digital processing of baseband signals; Second printed circuit board with calibration circuit connected in structure

MIMO antenna assembly comprising a.
The method of claim 16,

In the second printed circuit board,

And a digital circuit further connected to the plurality of transmission / reception circuits to perform digital processing of a baseband signal.
The method of claim 16,

In the second printed circuit board,

And a calibration circuit, in which a plurality of switches are connected in a tree structure, further comprising a MIMO antenna assembly.
The method of claim 16,

The plurality of band pass filters,

And a first port directly connected to the power supply network without RF cabling, and fastened to the first printed circuit board in close contact with the first printed circuit board.
The method of claim 16,

Each bandpass filter has a second port connected directly to the transceiver circuit without RF cabling.