Circularly polarized antenna and communication system

Abstract

A circularly polarized antenna comprises an antenna part and a feed part which are stacked up and down, the antenna part is arranged on a first substrate, and the antenna part comprises a first antenna unit which comprises a cross-shaped metal patch and a top layer arranged on the first substrate; the parasitic element forms a square with four disconnected edges by four metal strips and is arranged on the middle layer of the first substrate; the second antenna unit comprises a square metal patch which is arranged on the bottom layer of the first substrate; the feed part is arranged on the second substrate, and the feed part comprises a coupling slot arranged on the top layer of the second substrate; the matching microstrip line is arranged on the middle layer of the second substrate; the feed-in line is arranged on the bottom layer of the second substrate; the branch line coupler is arranged on the bottom layer of the second substrate, the matching microstrip line is electrically connected between the feed-in line and the branch line coupler through a via hole, the thickness of the substrate is increased through the layer changing technology, the achievable impedance range is increased, impedance matching is achieved, the gain bandwidth, the axial ratio bandwidth and the return loss bandwidth are increased, and the antenna performance is optimized.

Description

Technical Field

[0001] This invention relates to the field of virtual reality technology, and more particularly to a scanning method for virtual reality glasses, virtual reality glasses, and a storage medium. Background Technology

[0002] In recent years, phased array antenna technology has shifted from military to civilian applications, such as low-Earth orbit satellite communication systems and radar systems. Therefore, traditional phased array antenna technology has evolved from planar transceiver (T / R) modules to highly integrated vertically integrated T / R modules to reduce the size and weight of electronic devices. Thus, designing the structure and impedance matching between the integrated tile-type antenna and the T / R module will be a key development focus. Antenna polarization has also shifted from linear to circular polarization, primarily because circular polarized antennas do not require the same strict alignment of the radio wave polarization direction as linear polarization. Furthermore, circular polarized antennas can transmit and receive signals at different angles and in various environments, effectively reducing multipath distortion. This makes them highly suitable for use in low-Earth orbit satellite phased array antennas, radar phased array antennas, and 5G base station phased array antennas. With the increasing application of broadband wireless communication in recent years, miniaturization, wide bandwidth, high gain, and wide axial ratio of circular polarized antennas will be new challenges in the development of circular polarized antenna technology. Summary of the Invention

[0003] In view of this, the present invention provides a circularly polarized antenna that meets the requirements of wide bandwidth, high gain, and wide axial ratio of a circularly polarized antenna.

[0004] This invention provides a circularly polarized antenna, comprising an antenna section and a feed section stacked in layers. The antenna section is disposed on a first substrate, which includes a top layer, a middle layer, and a bottom layer. The antenna section includes: a first antenna element comprising a cross-shaped metal patch disposed on the top layer of the first substrate; a parasitic element consisting of four metal strips forming a square with four non-connected sides disposed on the middle layer of the first substrate; and a second antenna element comprising a square metal patch disposed on the bottom layer of the first substrate. The feed section is disposed on a second substrate, which includes a top layer, a middle layer, and a bottom layer. The feed section includes: a coupling slot disposed on the top layer of the second substrate; a matching microstrip line disposed on the middle layer of the second substrate; a feed line disposed on the bottom layer of the second substrate; and a branch line coupler disposed on the bottom layer of the second substrate. The matching microstrip line is electrically connected between the feed line and the branch line coupler through a via.

[0005] Preferably, the first substrate is soldered onto the second substrate.

[0006] Preferably, adjusting the chamfer of the cross-shaped metal patch of the first antenna element adjusts the high-frequency bandwidth of the operating frequency band.

[0007] Preferably, adjusting the width of the four metal strips of the parasitic element adjusts the low-frequency bandwidth of the operating frequency band.

[0008] Preferably, the coupling slot is used to couple the signal received by the antenna section and also to couple the signal transmitted by the feed section; the coupling slot includes a first slot and a second slot, and the first slot and the second slot are combined in a figure-eight shape.

[0009] Preferably, the branch line coupler includes: a first microstrip line in the form of a closed loop; a receiving end connected to one side of the first microstrip line; a transmitting end connected to one side of the first microstrip line; a first feed end connected to the other side of the first microstrip line; and a second feed end connected to the other side of the first microstrip line.

[0010] Preferably, the feed line includes a first feed line and a second feed line, which are combined in a figure-eight shape; the matching microstrip line includes a first matching microstrip line and a second matching microstrip line, which are combined in a figure-eight shape; the first matching microstrip line is electrically connected between the first feed line and the first feed end of the branch line coupler through a first via and a second via; the second matching microstrip line is electrically connected between the second feed line and the second feed end of the branch line coupler through a third via and a fourth via.

[0011] Preferably, the field pattern in the horizontal polarization direction is excited by the first feed line; and the field pattern in the vertical polarization direction is excited by the second feed line.

[0012] Preferably, when a signal enters the branch line coupler from the transmitting end, a left-hand circularly polarized field can be excited; when a signal enters the branch line coupler from the receiving end, a right-hand circularly polarized field can be excited.

[0013] The present invention also provides a communication system comprising the circularly polarized antenna described in any of the preceding claims.

[0014] Compared to existing technologies, the circularly polarized antenna provided by this invention includes an antenna section and a feed section stacked on top of each other. The antenna section and the feed section are disposed on different substrates, thereby giving the circularly polarized antenna the characteristics of a reconfigurable antenna, allowing for flexible replacement of the antenna module according to application requirements. The coupling slots, matching microstrip lines, feed lines, and branch line couplers of the feed section are disposed on different layers of the second substrate. By increasing the substrate thickness through layer-swapping technology, the achievable impedance range is increased to achieve impedance matching. Simultaneously, the gain bandwidth, axial ratio bandwidth, and return loss bandwidth are increased, optimizing antenna performance. Attached Figure Description

[0015] Figure 1This is a schematic diagram of a circularly polarized antenna according to an embodiment of the present invention.

[0016] Figure 2 This is a structural diagram of the combined structure of the antenna section and the feed section of a circularly polarized antenna according to an embodiment of the present invention.

[0017] Figure 3 This is a schematic diagram of the branch line coupler of a circularly polarized antenna according to an embodiment of the present invention.

[0018] Figure 4 The diagram shows the simulated field pattern and the actual measured field pattern of the transmitting port of a circularly polarized antenna in the YZ plane according to an embodiment of the present invention.

[0019] Figure 5 The present invention provides a schematic diagram of the simulated field pattern and an actual measured field pattern of the transmitting port of a circularly polarized antenna in the XZ plane according to an embodiment of the present invention.

[0020] Figure 6 The figures show the simulated axial ratio curve and the actual measured axial ratio curve of a circularly polarized antenna according to an embodiment of the present invention.

[0021] Figure 7 The images show the simulated gain curve and the actual measured gain curve of a circularly polarized antenna according to an embodiment of the present invention.

[0022] Figure 8 The figures show simulated return loss curves and actual measured return loss curves of the transmitting end of a circularly polarized antenna according to an embodiment of the present invention.

[0023] Figure 9 This is a schematic diagram of a structure in which the feed line and the branch line coupler are directly connected according to an embodiment of the present invention.

[0024] Figure 10 This is a schematic diagram of a structure in which the feed line and branch line coupler are connected by a matching microstrip line layer switching according to an embodiment of the present invention.

[0025] Figure 11 The diagram shows the gain curves of the feed line and the branch line coupler directly connected according to an embodiment of the present invention, and the gain curves of the feed line and the branch line coupler connected after being swapped through a matched microstrip line.

[0026] Figure 12 The diagram shows the axial ratio curves of the feed line and the branch line coupler directly connected according to an embodiment of the present invention, and the axial ratio curves of the feed line and the branch line coupler connected after layer switching via a matched microstrip line.

[0027] Figure 13The diagram shows the return loss curves when the feed line and the branch line coupler are directly connected according to an embodiment of the present invention, and the return loss curves when the feed line and the branch line coupler are connected after being swapped through a matched microstrip line.

[0028] Figure 14 This is a schematic diagram of the structure of the first antenna element of a circularly polarized antenna according to an embodiment of the present invention.

[0029] Figure 15 This is a frequency curve diagram of the first antenna element of a circularly polarized antenna according to an embodiment of the present invention at different chamfer sizes.

[0030] Figure 16 This is a schematic diagram of the parasitic element of a circularly polarized antenna according to an embodiment of the present invention.

[0031] Figure 17 This is a frequency curve diagram of the metal strip of the parasitic element of a circularly polarized antenna according to an embodiment of the present invention at different widths.

[0032] Explanation of main component symbols 10: Circularly polarized antenna 100: Antenna section 200: Power Supply Department J1: First substrate J2: Second substrate T1, T2: Top Floor M1, M2: Intermediate layer B1, B2: Bottom layer Ant1: First antenna element Ant2: Second antenna unit P1: Parasitic element Pa: solder pad S: Coupling slot hole S1: First slot S2: Second slot L: Matching microstrip line L1: First Matching Microstrip Line L2: Second matching microstrip line F: Feed line F1: First feed line F2: Second feed line C: Branch line coupler A1: First microstrip line RX: Receiver TX: Sender E1: First feed end E2: Second feed-in terminal H1-H4: Via 1 to Via 4 C1: Chamfer W1: Width The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0033] To facilitate understanding and implementation of this invention by those skilled in the art, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that this invention provides many applicable inventive concepts, which can be implemented in various specific forms. Those skilled in the art can utilize the details described in these or other embodiments, as well as other available structural, logical, and electrical variations, to implement the invention without departing from its spirit and scope.

[0034] This specification provides different embodiments to illustrate the technical features of different implementations of the invention. The configuration of elements in the embodiments is for illustrative purposes only and is not intended to limit the invention. Furthermore, the repetition of some reference numerals in the embodiments is for simplification and does not imply any correlation between different embodiments. The same element numbers used in the illustrations and specification represent the same or similar components. The illustrations in this specification are simplified and not drawn to scale.

[0035] Furthermore, in describing some embodiments of the present invention, the specification describes the method and / or procedure of the present invention in a specific order of steps. However, since the method and procedure are not necessarily performed according to the specific order of steps described, they are not limited to the specific order of steps. Those skilled in the art will understand that other orders are also possible implementations. Therefore, the specific order of steps described in the specification is not intended to limit the scope of the patent application. Moreover, the scope of the present invention for the method and / or procedure is not limited to the order of execution steps written therein, and those skilled in the art will understand that adjusting the order of execution steps does not depart from the spirit and scope of the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Some embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0037] Please see Figure 1 , Figure 1 This is a schematic diagram of a circularly polarized antenna according to an embodiment of the present invention. In this embodiment, the circularly polarized antenna 10 is mainly used in communication systems, such as low-Earth orbit satellite communication systems and radar systems. The circularly polarized antenna 10 operates in the Ku band.

[0038] like Figure 1 As shown, the circularly polarized antenna 10 includes an antenna section 100 and a feed section 200 stacked on top of each other. The antenna section 100 is disposed on a first substrate J1, which includes a top layer T1, a middle layer M1, and a bottom layer B1. The antenna section 100 includes a first antenna element Ant1, a parasitic element P1, and a second antenna element Ant2. The first antenna element Ant1 includes a cross-shaped metal patch and is disposed on the top layer T1 of the first substrate J1. The parasitic element P1 consists of four metal strips forming a square with four unconnected sides and is disposed on the middle layer M1 of the first substrate J1. The second antenna element Ant2 includes a square metal patch and is disposed on the bottom layer B1 of the first substrate J1.

[0039] A power supply unit 200 is disposed on a second substrate J2, which includes a top layer T2, an intermediate layer M2, and a bottom layer B2. In this embodiment, a first substrate J1 is soldered onto the second substrate J2. Figure 2 , Figure 2 This is a structural diagram of the combined antenna section and feed section of a circularly polarized antenna according to an embodiment of the present invention. As shown in the figure, the bottom layer B1 of the first substrate J1 and the top layer T2 of the second substrate J2 are soldered and fixed by BGA pads Pa, thereby giving the circularly polarized antenna 10 the characteristics of a resettable antenna, allowing the antenna section 100 to be flexibly replaced according to application requirements.

[0040] The power supply section 200 includes a coupling via S, a matching microstrip line L, a feed line F, and a branch line coupler C. The coupling via S is disposed on the top layer T2 of the second substrate J2, which is a ground metal layer. The matching microstrip line L is disposed on the middle layer M2 of the second substrate J2. The feed line F is disposed on the bottom layer B2 of the second substrate J2, and the branch line coupler C is disposed on the bottom layer B2 of the second substrate J2. The matching microstrip line L is electrically connected between the feed line F and the branch line coupler C via a via.

[0041] In this embodiment, the coupling slot S can be used to couple signals received by the antenna section 100, and also to couple signals transmitted by the feed section 200. The coupling slot S includes a first slot S1 and a second slot S2. The first slot S1 and the second slot S2 are combined in a figure-eight shape.

[0042] The branch-line coupler C includes a first microstrip line A1, a receiver RX, a transmitter TX, a first feed point E1, and a second feed point E2. Combined with... Figure 3 , Figure 3This is a schematic diagram of the branch line coupler C of a circularly polarized antenna according to an embodiment of the present invention. The first microstrip line A1 is a closed loop. The receiving end RX is connected to one side of the first microstrip line A1, the transmitting end TX is connected to one side of the first microstrip line A1, the first feed end E1 is connected to the other side of the first microstrip line A1, and the second feed end E2 is connected to the other side of the first microstrip line A1.

[0043] In this embodiment, the feed line F includes a first feed line F1 and a second feed line F2. The first feed line F1 and the second feed line F2 are combined in a figure-eight shape. Taking the transmitted signal of the antenna section 100 as an example, by using the first feed line F1 and the second feed line F2 to couple the transmitted signal to the first slot S1 and the second slot S2 respectively, the isolation between the two ends of the first feed line F1 and the second feed line F2 can be increased. Furthermore, by using the first slot S1 and the second slot S2 to share a grounding metal layer, the antenna pattern is shielded from interference radiated by the feed section 200.

[0044] The matching microstrip line L includes a first matching microstrip line L1 and a second matching microstrip line L2. The first matching microstrip line L1 and the second matching microstrip line L2 are combined in a figure-eight shape. The first matching microstrip line L1 is electrically connected between the first feed line F1 and the first feed terminal E1 of the branch line coupler C through a first via H1 and a second via H2. The second matching microstrip line L2 is electrically connected between the second feed line F2 and the second feed terminal E2 of the branch line coupler C through a third via H3 and a fourth via H4.

[0045] In this embodiment, the feed line F excites two polarization patterns through a dual-feed method. The first feed line F1 is electrically connected to the first feed terminal E1, exciting a horizontally polarized field pattern, and the second feed line F2 is electrically connected to the second feed terminal E2, exciting a vertically polarized field pattern. Taking the transmitting end TX as an example, when the signal enters both sides of the first microstrip line A1 from the transmitting end Tx, a signal with a 90-degree phase is generated at the output second feed terminal E2, and a signal with a 180-degree phase is generated at the first feed terminal E1. The phase difference between the two signals is 90 degrees, thus achieving the phase condition for circular polarization. After passing through the matched microstrip line L, the signal enters the feed line F, exciting two different polarization patterns. The first feed line F1 excites a horizontally polarized pattern, and the second feed line F2 excites a vertically polarized pattern. The signal excited by the feed line F is then coupled to the first slot S1 and the second slot S2, and then to the second antenna element Ant2 of the antenna section 100. From the second antenna element Ant2, the signal is coupled to the parasitic element P1 and the first antenna element Ant1, finally radiating out to form a circularly polarized radiation pattern. The working principle of the receiver RX receiving signal is similar to that of the transmitter TX transmitting signal. The antenna element 100 first receives the radiated circularly polarized signal, which is then coupled to the feed section 200, and finally received by the receiver RX of the coupler C. The transmitting end TX and receiving end RX of the branch line coupler C do not operate simultaneously; they can only transmit or receive at a time. Left-hand circularly polarized field patterns and right-hand circularly polarized field patterns are obtained through the transmitting end TX and receiving end RX of the branch line coupler C, respectively. That is, when a signal enters the branch line coupler C from the transmitting end Tx, a left-hand circularly polarized field pattern is excited; when a signal enters the branch line coupler C from the receiving end RX, a right-hand circularly polarized field pattern is excited. To change the direction of the excited left-hand and right-hand circularly polarized field patterns, the transmitting end TX and receiving end RX of the branch line coupler C are simply interchanged. Therefore, regardless of whether the satellite station's antenna array transceiver is left-hand or right-hand circularly polarized, the circularly polarized antenna of this invention can be matched to obtain the same polarization direction, increasing the antenna's flexibility.

[0046] Please see Figure 4 and Figure 5 , Figure 4 The diagram shows the simulated field pattern and the actual measured field pattern of the transmitting port of a circularly polarized antenna in the YZ plane according to an embodiment of the present invention. Figure 5 This diagram illustrates the simulated field pattern and the actual measured field pattern of the transmitting port of a circularly polarized antenna in the XZ plane according to an embodiment of the present invention. The field pattern is measured from both the transmitting port TX and the receiving port RX. Because the transmitting port TX and the receiving port RX are symmetrical, the measured performance at the transmitting port and the receiving port RX is consistent. In this embodiment, the transmitting port TX is used as an example for explanation. Figure 4 and Figure 5 As shown, the gain and field pattern obtained from the measured transmit port TX are consistent with the simulated gain and field pattern. The actual measured gain value is 7dB at the feed end E1 in the horizontal polarization direction on the XZ plane and 6.9dB at the feed end E2 in the vertical direction on the YZ plane. The actual implementation effect of the circularly polarized antenna of the present invention is good.

[0047] The radiation pattern of the circularly polarized antenna of this invention is very suitable for use with satellites. This is mainly because the positions of the antenna, ground receiving station, and orbiting satellite are constantly shifting. If electromagnetic waves encounter reflection and refraction during propagation, the polarization direction will be deflected, resulting in polarization mismatch and signal attenuation at the transmitting and receiving ends. Circularly polarized X signals have minimal attenuation in adverse weather conditions and can penetrate the ionosphere. They are not affected by the Faraday effect generated by the magnetic fields of the Earth's North and South Poles, which would otherwise affect the polarization mismatch and signal attenuation, thus ensuring communication quality.

[0048] Please refer to the following: Figure 6 , Figure 7 and Figure 8 , Figure 6 The figures show the simulated axial ratio curve and the actual measured axial ratio curve of a circularly polarized antenna according to an embodiment of the present invention. Figure 7 The images show the simulated gain curve and the actual measured gain curve of a circularly polarized antenna according to an embodiment of the present invention. Figure 8 The images show simulated and measured return loss curves of the transmitting end (TX) of a circularly polarized antenna according to an embodiment of the present invention. Figure 6 As shown, the actual measured axial ratio bandwidth matches the simulation. The frequencies with an axial ratio less than 3 dB are approximately 10.5 GHz to 14.6 GHz, and the axial ratio bandwidth is 4.1 GHz (32.8%). Figure 7 As shown, the simulated peak gain of the antenna is above 4 dB at frequencies from 10.5 GHz to 14.5 GHz, while the measured results show that the peak gain is above 4 dB at frequencies from 10.4 GHz to 14.3 GHz, with a gain bandwidth of 3.9 GHz (31.2%). The difference in bandwidth can be observed by examining the return loss curve, as shown below. Figure 8 As shown, the return loss in the actual measurement is slightly lower in frequency by about 200 MHz compared to the simulation, which corresponds to the peak gain measurement results.

[0049] In this embodiment, the matching microstrip line L is disposed on different layers of the second substrate J2 along with the first feed line F1, the second feed line F2, and the branch line coupler C. The substrate thickness is increased by layer replacement technology, thereby increasing the achievable impedance range to achieve impedance matching.

[0050] Please refer to the following: Figure 9-11 , Figure 9This is a schematic diagram of a structure where the feed line F is directly connected to the branch line coupler C. Figure 10 This is a schematic diagram of the structure in which the feed line F and the branch line coupler C are connected by a matching microstrip line L. Figure 11 The diagram shows the gain curves when the feed line F is directly connected to the branch line coupler C, and the gain curves when the feed line F and the branch line coupler C are connected through a matching microstrip line L. Figure 11 As shown, when the feed line F is directly connected to the branch line coupler C, the peak gain bandwidth of the antenna is greater than 4 dB (30.4%) in the 10.7 GHz to 14.5 GHz range. After the feed line F and the branch line coupler C are replaced by a matching microstrip line L, the peak gain bandwidth is greater than 4 dB in the 10.5 GHz to 14.5 GHz range (32%), and the gain bandwidth increases by 200 MHz.

[0051] Figure 12 The figures show the axial ratio curves for the feed line F and the branch line coupler C when directly connected, and for the feed line F and the branch line coupler C when connected via a matching microstrip line L. As shown, when the feed line F and the branch line coupler C are directly connected, the antenna's axial ratio bandwidth is less than 3 dB in the range of 10.8 GHz to 14.5 GHz (29.6%). After the feed line F and the branch line coupler C are connected via a matching microstrip line L, the axial ratio bandwidth is less than 3 dB in the range of 10.5 GHz to 14.6 GHz (32.8%), representing an increase of 400 MHz.

[0052] Figure 13 The figures show the return loss curves for the feed line F and the branch line coupler C when directly connected, and for the feed line F and branch line coupler C when connected via a matching microstrip line L. As shown, when the feed line F and branch line coupler C are directly connected, the antenna's return loss is less than 10 dB in the frequency range of 10.7 GHz to 14.4 GHz (29.6%). After the feed line F and branch line coupler C are connected via a matching microstrip line L, the frequency range of return loss less than 10 dB is 10.5 GHz to 14.5 GHz (32%), and the return loss bandwidth increases by 300 MHz.

[0053] By replacing the microstrip line L with a new layer, the antenna performance was improved by increasing the return loss bandwidth, gain bandwidth, and axial ratio bandwidth by 300 MHz, 200 MHz, and 400 MHz, respectively.

[0054] In this embodiment, adjusting the chamfer of the cross-shaped metal patch of the first antenna unit Ant1 adjusts the high-frequency operating bandwidth of the antenna unit 100 that is not yet connected to the branch line coupler C, in conjunction with... Figure 14 and Figure 15 , Figure 14 This is a schematic diagram of the structure of the first antenna element of a circularly polarized antenna according to an embodiment of the present invention. Figure 15 This is a frequency curve diagram of the first antenna element of a circularly polarized antenna according to an embodiment of the present invention at different chamfer sizes. As shown in the figure, when the chamfer C1 is 0 mm, i.e., there is no chamfer, no obvious high-frequency point can be obtained because the high-frequency impedance matching of the antenna is not good when there is no chamfer. When the chamfer C1 is 1.15 mm, the high-frequency point is about 13.8 GHz. When the chamfer C1 is 1.65 mm, the high-frequency point is about 14.3 GHz. That is, within a certain range, the larger the chamfer C1, the higher the high-frequency point and the wider the bandwidth.

[0055] In this embodiment, adjusting the width of the four metal strips of the parasitic element P1 adjusts the low-frequency bandwidth of the operating frequency band. Combined with... Figure 16 and Figure 17 , Figure 16 This is a schematic diagram of the parasitic element of a circularly polarized antenna according to an embodiment of the present invention. Figure 17 This figure shows the frequency curves of a metal strip, representing a parasitic element of a circularly polarized antenna according to an embodiment of the present invention, at different widths. As shown, when the width W1 of the metal strip is 0, i.e., there is no parasitic element P1, the low-frequency point is approximately 12.2 GHz. When the width W1 of the metal strip is 1 mm, the low-frequency point is approximately 11.8 GHz. When the width W1 of the metal strip is 1.5 mm, the low-frequency point is approximately 11.3 GHz. That is, within a certain range, the larger the width W1 of the metal strip, the lower the low-frequency point and the wider the bandwidth.

[0056] Compared to existing technologies, the circularly polarized antenna provided by this invention includes an antenna section and a feed section stacked on top of each other. The antenna section and the feed section are disposed on different substrates, thus possessing the characteristics of a reconfigurable antenna, allowing for flexible replacement of the antenna module according to application requirements. The coupling slots, matching microstrip lines, feed lines, and branch line couplers of the feed section are disposed on different layers of the second substrate. By increasing the substrate thickness through layer-swapping technology, the achievable impedance range is increased to achieve impedance matching. Simultaneously, the gain bandwidth, axial ratio bandwidth, and return loss bandwidth are increased, optimizing antenna performance.

[0057] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any appropriate changes and modifications made to the above embodiments within the essential spirit and scope of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A circularly polarized antenna, comprising an antenna section and a feed section stacked in upper and lower layers, characterized in that: The antenna portion is disposed on a first substrate, the first substrate including a top layer, a middle layer and a bottom layer, and the antenna portion includes: The first antenna element includes a cross-shaped metal patch disposed on the top layer of the first substrate; The parasitic element is a square composed of four metal strips with unconnected sides, and is disposed in the middle layer of the first substrate; The second antenna unit includes a square metal patch disposed on the bottom layer of the first substrate; The power feeding section is disposed on a second substrate, the second substrate including a top layer, a middle layer and a bottom layer, and the power feeding section includes: A coupling slot is disposed on the top layer of the second substrate; Matching microstrip lines are disposed in the middle layer of the second substrate; The feed line is disposed on the bottom layer of the second substrate; A branch line coupler is disposed on the bottom layer of the second substrate, and the matching microstrip line is electrically connected between the feed line and the branch line coupler through a via.

2. The circularly polarized antenna as described in claim 1, characterized in that, The first substrate is soldered onto the second substrate.

3. The circularly polarized antenna as described in claim 1, characterized in that, Adjusting the chamfer angle of the cross-shaped metal patch of the first antenna element adjusts the high-frequency bandwidth of the operating frequency band.

4. The circularly polarized antenna as described in claim 1, characterized in that, Adjusting the width of the four metal strips of the parasitic element adjusts the low-frequency bandwidth of the operating frequency band.

5. The circularly polarized antenna as described in claim 1, characterized in that: The coupling slot is used to couple the signal received by the antenna section and also to couple the signal transmitted by the feed section; The coupling slot includes a first slot and a second slot, which are combined in a figure-eight shape.

6. The circularly polarized antenna as described in claim 1, characterized in that: The branch line coupler includes: The first microstrip line is a closed loop; The receiving end is connected to one side of the first microstrip line; The transmitting end is connected to one side of the first microstrip line; The first feed terminal is connected to the other side of the first microstrip line; The second feed point is connected to the other side of the first microstrip line.

7. The circularly polarized antenna as described in claim 6, characterized in that: The feed line includes a first feed line and a second feed line, and the first feed line and the second feed line are combined in a figure-eight shape. The matching microstrip line includes a first matching microstrip line and a second matching microstrip line, and the first matching microstrip line and the second matching microstrip line are combined in a figure-eight shape. The first matching microstrip line is electrically connected between the first feed line and the first feed terminal of the branch line coupler through a first via and a second via. The second matching microstrip line is electrically connected between the second feed line and the second feed terminal of the branch line coupler through the third and fourth vias.

8. The circularly polarized antenna as described in claim 7, characterized in that: The horizontal polarization direction field pattern is excited by the first feed line; The field pattern in the vertical polarization direction is excited by the second feed line.

9. The circularly polarized antenna as described in claim 7, characterized in that: When a signal enters the branch line coupler from the transmitting end, a left-hand circularly polarized field is excited; When a signal enters the branch line coupler from the receiving end, it excites a right-hand circularly polarized field.

10. A communication system, characterized in that, Including the circularly polarized antenna as described in any one of claims 1-9.

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