This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0010209 filed in the Korean Intellectual Property Office on Jan. 25, 2021, the entire contents of which are incorporated herein by reference.
The present disclosure relates to an antenna apparatus and a feed network thereof.
Antenna apparatuses generating dual-orthogonal circular polarization may be implemented in various forms. A phase difference of a dual-orthogonal component is generated in a single radiation element through an artificial transformation (e.g., a slot is placed at the center) to generate dual circular polarization. However, the antenna apparatus having such a structure has a low antenna gain, and a narrow band property in which an input matching and axial ratio property is within approximately 3%. In addition, there is an antenna apparatus structure constituted by the single radiation element and a 90° hybrid combiner. The structure performs dual-orthogonal feed by using a circuit operation property of the 90° hybrid combiner to generate the dual circular polarization. Such a structure also has the low antenna gain and operates in a band in which the input matching and axial ratio property is approximately 10%.
Meanwhile, there is an antenna apparatus generating single circular polarization by using four radiation elements. The antenna apparatus generating the circular polarization by using four radiation elements may increase the antenna gain through adjustment of an arrangement interval among four radiation elements, and improve the axial ratio property in a wide observation angle area. However, different feed networks are required for generating the dual-orthogonal circular polarization through the antenna apparatus generating the single circular polarization.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
At least one exemplary embodiment among exemplary embodiments may provide an antenna apparatus capable of generating dual-orthogonal polarization by a single feed network
An exemplary embodiment of the present invention may provide an antenna apparatus. The antenna apparatus may include: a feed network including a plurality of first internal transmission lines arranged in a cross form and a plurality of second internal transmission lines arranged in a ring form around the plurality of first internal transmission lines; and a plurality of radiation elements positioned around the feed network and radiating signals fed by the feed network.
The number of plurality of first internal transmission lines may be at least 4 and the number of plurality of second internal transmission lines may be at least 8, and the number of input ports of the feed network may be at least 2 and the number of output ports of the feed network may be at least 4.
Each internal transmission line included in the plurality of first internal transmission lines and the plurality of second internal transmission lines may have a first property impedance and a predetermined electrical length.
The feed network may further include an input transmission line connected to the input port and an output transmission line connected to the output port.
The input transmission line and the output transmission line may have a second property impedance, and the first property impedance may be twice larger than the second property impedance, and the predetermined electrical length may be 90°.
A first input signal corresponding to a right-handed circular polarization may be input into a first input port of the at least two input ports, and a second input signal corresponding to a left-handed circular polarization may be input into a second input port of the at least two input ports.
At least one output port of the at least four output ports may be positioned between the first input port and the second input port.
The number of plurality of radiation elements may be at least 4, and the antenna apparatus may further include at least four transmission lines connected to each of the at least four output ports and each of the at least four radiation elements.
Two transmission lines of the at least four transmission lines may be transmission lines having a phase delay of 0° and two remaining transmission lines may be transmission lines having a phase delay of 90°.
The feed network may be formed on a first printed circuit board, the plurality of radiation elements may be formed on a second printed circuit board, and the second printed circuit board may be formed to be erected perpendicular to the first printed circuit board.
Another exemplary embodiment of the present invention may provide a feed network providing feed signals to a plurality of radiation elements. The feed network may include: a first input port into which a first signal is input; a second input port into which a second signal is input; a plurality of first internal transmission lines arranged in a cross form; a plurality of second internal transmission lines arranged around the plurality of first internal transmission lines; and a plurality of output ports providing feed signals to the plurality of radiation elements, respectively.
In the plurality of first internal transmission lines, an internal transmission line corresponding to one line and an internal transmission line corresponding to the remaining line constituting the cross form may not be connected to each other, but may cross.
The number of plurality of first internal transmission line may be at least 4 and the number of plurality of second internal transmission lines may be at least 8, the number of plurality of output ports may be at least 4, and the number of plurality of radiation elements may be at least 4.
The feed network may further include: a first input transmission line connected to the first input port; a second input transmission line connected to the second input port; and a plurality of output transmission lines connected to the plurality of output ports, respectively.
Each internal transmission line included in the plurality of first internal transmission lines and the plurality of second internal transmission lines may have a first property impedance and a predetermined electrical length, and the first input transmission line, the second input transmission line, and each of the plurality of output transmission lines may have a second property impedance larger than the first property impedance.
The first property impedance may be twice larger than the second property impedance, and the predetermined electrical length may be 90°.
The first signal may be a signal corresponding to a right-handed circular polarization, and the second signal may be a signal corresponding to a left-handed circular polarization.
At least one output port of the plurality of output ports may be positioned between the first input port and the second input port.
According to at least an exemplary embodiment of the exemplary embodiments, a dual-orthogonal circular polarization can be generated through a single feed network.
According to at least an exemplary embodiment of the exemplary embodiments, a dual-orthogonal circular polarization having a high antenna gain and an axial ratio property can be generated.
Hereinafter, exemplary embodiments of the present invention will be described in detail so as to be easily implemented by those skilled in the art, with reference to the accompanying drawings. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. Further, it is to be understood that the accompanying drawings are just used for easily understanding the exemplary embodiments disclosed in this specification and a technical spirit disclosed in this specification is not limited by the accompanying drawings and all changes, equivalents, or substitutes included in the spirit and the technical scope of the present invention are included.
Terms including an ordinary number, such as first and second, are used for describing various elements, but the elements are not limited by the terms. The terms are used only to discriminate one element from another element.
It should be understood that, when it is described that a component is “connected to” or “accesses” another component, the component may be directly connected to or access the other component or a third component may be present therebetween. In contrast, when it is described that a component is “directly connected to” or “directly accesses” another component, it is understood that no element is present between the element and another element.
Through the specification, it should be understood that the term “include” or “have” indicates that a feature, a number, a step, an operation, a component, a part or the combination thereof described in the specification is present, but does not exclude a possibility of presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof, in advance. Accordingly, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.
As illustrated in
The feed network 200 may include two input ports IN1 and IN2, and four output ports OUT1, OUT2, OUT3, and OUT4. A first input signal corresponding to right-handed circular polarization may be input into a first input port IN1, and a second input signal corresponding to left-handed circular polarization may be input into a second input port IN2. Here, a first input signal SM1 input into the first input port IN1 and a second input signal SM2 input into the second input port IN2 are orthogonal and isolated from each other. As illustrated in
The first to fourth radiation elements 100a to 100d may be radiation elements generating linear polarization. The first to fourth radiation elements 100a to 100d may be positioned around (outside) the feed network 200. The first radiation element 100a may be positioned on a first lateral surface of the feed network 200 and the second radiation element 100b may be positioned on a second lateral surface of the feed network 200. In addition, the third radiation element 100c may be positioned on a third lateral surface of the feed network 200 and the fourth radiation element 100d may be positioned on a fourth lateral surface of the feed network 200. That is, the first to fourth radiation elements 100a to 100d may be positioned in order clockwise based on the first input port IN1. Each of the first to fourth radiation elements 100a to 100d may be implemented as a dipole radiation element.
The first transmission line 110a may be connected between the first output port OUT1 and the first radiation element 100a of the feed network 200, and the second transmission line 110b may be connected between the second output port OUT2 and the second radiation element 100b of the feed network 200. In addition, the third transmission line 110c may be connected between the third output port OUT3 and the third radiation element 100c of the feed network 200, and the fourth transmission line 110d may be connected between the fourth output port OUT4 and the fourth radiation element 100d of the feed network 200. Each of the first transmission line 110a and the third transmission line 110c may be a transmission line having a phase delay of 0°. In addition, each of the second transmission line 110b and the fourth transmission line 110d may be a transmission line having a phase delay of 90°.
Signals radiated from the first to fourth radiation elements 100a to 100d to a free space are spatially combined with each other, and therefore, right-handed circular polarization (RHCP) and left-handed circular polarization (LHCP) may be generated. That is, the first to fourth radiation elements 100a to 100d may generate the right-handed circular polarization (RHCP) in response to the first input signal SM1 input into the first input port IN1 of the feed network 200. In addition, the first to fourth radiation elements 100a to 100d may generate the left-handed circular polarization (LHCP) in response to the second input signal SM2 input into the second input port IN2 of the feed network 200.
As illustrated in
The feed network 200 according to an exemplary embodiment may include first and second input transmission lines 210_1 and 210_2, first to fourth output transmission lines 211a to 211d, and a plurality of internal transmission lines 220.
One end of the first input transmission line 210_1 may correspond to the first input port IN1 and one end of the second input transmission line 210_2 may correspond to the second input port IN2. Ends of the respective first to fourth output transmission lines 211a to 211d may correspond to the first to fourth output ports OUT1 to OUT4, respectively. Each of the first and second input transmission lines 210_1 and 210_2 may have a characteristic impedance Z0 and an electrical length θ0. In addition, each of the first to fourth output transmission lines 211a to 211d may also have the characteristic impedance Z0 and the electrical length θ0.
A plurality of internal transmission lines 220 may include first to twelfth internal transmission lines 220_1 to 220_12. Each of the first to twelfth internal transmission lines 220_1 to 220_12 may also have a property impedance Z1 and an electrical length 90°. Here, the characteristic impedances Z1 and Z0 may satisfy a relationship of Equation 1 below.
Z
1=2*Z0 (Equation 1)
That is, characteristic impedances of the internal transmission lines 220_1 to 220_12 may have values which are twice larger than the characteristic impedances of the input and output transmission lines 210_1 and 210_2, and 211a to 211d. When the impedances of the input and output transmission lines are 50 ohms (Ω), the impedances of the internal transmission lines are 10 ohms (Ω).
The ninth to twelfth internal transmission lines 220_9 to 220_12 may be arranged in a cross form based on the center of the feed network 200. In addition, the first to eighth internal transmission lines 220_1 to 220_8 may be arranged in a ring form around the ninth to twelfth internal transmission lines 220_9 to 220_12.
In
In the feed network 200 having such a configuration and such a connection relationship, signals output from the first to fourth output ports OUT1 to OUT4 may have the same amplitude property and a phase difference of 180° from each other. A relationship of the signals in the case of the first input signal SM1 and the second input signal SM2 is as follows.
First, a case where the first input signal SM1 is input into the first input port IN1 will be described. As illustrated in
Next, a case where the second input signal SM2 is input into the second input port IN2 will be described. As illustrated in
Relationships of the signals output from the first to fourth output ports OUT1 to OUT4 are organized in response to the first input signal SM1 and the second input signal SM2 are shown in Table 1 below.
Meanwhile, as described in
Referring to
Referring to
Since the arrangement interval of the first to fourth radiation elements 100a to 100d generating the linear polarization is related to a gain property of an entire antenna apparatus 1000, mutual combination properties among elements, and a size (or volume) of the entire antenna apparatus 1000, the arrangement interval may be optimally determined according to a required specification of the antenna apparatus 1000.
Referring to
Referring to
Referring to
The substrate 300 and the substrates 400a to 400d may be implemented by using a TRF-45 substrate (a dielectric constant Er=4.5, a dielectric thickness H=0.61 mm, an operating thickness T=0.018, and a loss tangent tan δ=0.003@1.9 GHz) of Taconic. Operating bands of the first to fourth radiation elements 100a to 100d may be set as a GPS band. The feed network 200 and the first to fourth transmission lines 110a to 110d may be implemented as a non-combination meander line in order to reduce a circuit size. In an area A where the ninth and tenth internal transmission lines 220_9 and 220_10 and the eleventh and twelfth internal transmission lines 220_11 and 220_12 are not connected to each other, but cross, an operating frequency is low and a wavelength becomes thus larger, and as a result, the area A may be implemented as a short wire line of 1 mm (0.005λ0). Meanwhile, referring to
Referring to
Referring to
In Table 2 below, the main radiation property parameter of the antenna in the simulation is organized. Here, the radiation property parameter may include the antenna gain, a beam width of 3 dB, and the axial ratio property.
As such, the antenna apparatus according to an exemplary embodiment may generate independent dual-orthogonal circular polarization, and provide a high antenna gain and a high axial ratio property.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Number | Date | Country | Kind |
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10-2021-0010209 | Jan 2021 | KR | national |