TWI849605B - Circularly polarized antenna using single radiator - Google Patents

Abstract

The invention discloses a circularly polarized antenna using single radiator, which comprises a substrate, a feed network, a metal layer and a single radiator. The substrate has opposite first and second surfaces, the feed network and the metal layer are respectively formed on the first and second surfaces of the substrate, and the metal layer has first to fourth slots arranged in a ring or sequentially rotated. The single radiator is located above the first to fourth slots of the metal layer to correspond to the first to fourth slots, and the area of the single radiator covers the area of the first to fourth slots of the metal layer.

Description

Circular polarized antenna using a single radiator

The present invention relates to a circular polarization antenna technology, and in particular to a circular polarization antenna using a single radiator.

With the rapid development of wireless communication systems or wireless communication devices, circularly polarized (CP) antennas have been widely used in wireless communication systems or wireless communication devices. Because circularly polarized antennas allow communication between transmitters and receivers, and the requirements for polarization direction are not as strict as those for linearly polarized antennas, and there is no need to align the antenna in the same way as linearly polarized antennas to transmit or receive signals. At the same time, compared with linearly polarized antennas, circularly polarized antennas are less sensitive to multipath fading and signal interference.

Furthermore, the main disadvantage of circular polarized antennas with sequentially-rotated radiators is that the number of radiators is too large, resulting in a large overall size and manufacturing cost of the circular polarized antenna, and usually having a narrow axial ratio (AR) bandwidth and beamwidth. However, circular polarized antennas with wide axial ratio (AR) bandwidth, low impedance bandwidth or high gain are crucial to maintaining the overall performance of wireless communication systems or wireless communication devices.

Therefore, how to provide an innovative circular polarized antenna using a single radiator to solve any of the above problems has become a major research topic for technical personnel in this field.

The circular polarized antenna using a single radiator of the present invention comprises: a substrate having a first surface and a second surface opposite to each other; a feed network and a metal layer formed on the first surface and the second surface of the substrate respectively, wherein the metal layer has a first slot, a second slot, a third slot and a fourth slot arranged in a ring shape or rotated in sequence; and a single radiator located in the metal layer arranged in a ring shape or rotated in sequence. Above the first slot, the first slot, the second slot, the third slot and the fourth slot that rotate sequentially, wherein a single radiator corresponds to the first slot, the second slot, the third slot and the fourth slot that are arranged in a ring shape or rotate sequentially on the metal layer at the same time, and the area of the single radiator covers the area of the first slot, the second slot, the third slot and the fourth slot that are arranged in a ring shape or rotate sequentially on the metal layer.

Therefore, the present invention provides an innovative circular polarization antenna using a single radiator to obtain equivalent or better circular polarization (CP) performance as that of a conventional antenna using four radiators. Alternatively, the present invention can correspond a single radiator of the circular polarization antenna to the first to fourth slots of the metal layer to simultaneously cover the area of the first to fourth slots of the metal layer. Therefore, compared with the traditional circular polarization antenna using four radiators to produce a large area, the area of the single radiator used in the present invention can be significantly smaller than the overall area of the traditional four radiators (e.g., only 1/4 of the area), which is beneficial to reducing the overall size and manufacturing cost of the circular polarization antenna.

Alternatively, the present invention adopts a circular polarization antenna with a single radiator, which can not only reduce the structural complexity and overall size of the traditional circular polarization antenna with four radiators, but also maintain the polarization and beam width characteristics of the circular polarization antenna, and also obtain better advantages in the operating bandwidth of the circular polarization antenna. Alternatively, the present invention adopts a circular polarization antenna with a single radiator, which can have a wider axial ratio (AR) bandwidth, a wider beam width (beamwidth), a lower impedance bandwidth and/or a higher gain.

In order to make the above features and advantages of the present invention more clearly understandable, the following examples are given and detailed descriptions are provided in conjunction with the attached drawings. The following description will partially explain the additional features and advantages of the present invention, and these features and advantages will be partially known from the description or can be learned through the practice of the present invention. It should be understood that both the general description above and the detailed description below are exemplary and explanatory, and are not intended to limit the scope of the present invention.

1: Circular polarization antenna

10: Substrate

11: First surface

12: Second surface

20: Feedback network

30:Metal layer

31: First slot

32: Second slot

33: The third slot

34: Fourth slot

40: Gap

50: Single radiator

60: Support parts

A:Signal connection port

B1: First distributor

B2: Second distributor

B3: The third distributor

C1: First phase adjustment circuit

C2: Second phase adjustment circuit

C3: The third phase adjustment circuit

C4: Fourth phase adjustment circuit

C5: Fifth phase adjustment circuit

C6: Sixth phase adjustment circuit

H1,H2:Height

P1,P2,P3:arrow

L1: Length

L2, L3: Width

W1,W2:Width

Figure 1 is a side view schematic diagram of the circular polarization antenna using a single radiator described in the present invention.

FIG2 is a schematic diagram of a circular polarization antenna using a single radiator as described in the present invention, viewed from above a single radiator.

FIG3 is a schematic diagram of a circular polarization antenna using a single radiator as described in the present invention, viewed from above the metal layer.

FIG4 is a schematic diagram of the circular polarization antenna using a single radiator described in the present invention, viewed from below the feed network.

FIG5 is a waveform diagram of the measured and simulated signals in terms of echo loss (S11) and frequency in the circular polarization antenna using a single radiator described in the present invention.

FIG6 is a waveform diagram of the measured and simulated signals in terms of axial ratio (AR) and frequency in the circular polarization antenna using a single radiator described in the present invention.

FIG7 is a schematic diagram showing the dependence of the axial ratio (AR) of the measured signal and the angles of the two main cutting planes at different frequencies in the circularly polarized antenna using a single radiator described in the present invention.

FIG8 is a waveform diagram showing the gain and frequency of the measured and simulated signals in the circular polarization antenna using a single radiator described in the present invention.

The following describes the implementation of the present invention through a specific concrete implementation form. People familiar with this technology can understand other advantages and effects of the present invention from the content disclosed in this manual, and can also implement or use it through other different specific equivalent implementation forms.

FIG1 is a side view schematic diagram of a circular polarization antenna 1 using a single radiator 50 according to the present invention. As shown in the figure, the circular polarization antenna 1 may include a substrate 10, a feed network 20, a metal layer 30, a gap 40, a single radiator 50 and at least one (such as multiple) supporting members 60, etc.

The substrate 10 may have a first surface 11 and a second surface 12 opposite to each other. The feed network 20 of the circular polarized antenna 1 may be formed on the first surface 11 of the substrate 10, and the feed network 20 may be connected to a signal transmitter or a signal receiver (not shown). The metal layer 30 of the circular polarized antenna 1 may be formed on the second surface 12 of the substrate 10, and the metal layer 30 may have a first slot 31, a second slot 32, a third slot 33, and a fourth slot 34 arranged in a ring shape or rotated in sequence (see FIGS. 2 to 4), and the first slot 31 to the fourth slot 34 may all penetrate the metal layer 30 to expose a portion of the second surface 12 of the substrate 10 respectively. The shapes of the first slot 31, the second slot 32, the third slot 33 and the fourth slot 34 of the metal layer 30 can be hourglass-shaped (i.e., wider at both ends and narrower in the center), etc., so as to facilitate the first slot 31, the second slot 32, the third slot 33 and the fourth slot 34 of the metal layer 30 to be used as signal excitation slots of the circular polarization antenna 1.

The gap 40 of the circular polarization antenna 1 can be formed between the metal layer 30 and the single radiator 50, so that the metal layer 30 and the single radiator 50 are separated by the gap 40 to prevent each other from contacting each other, thereby avoiding affecting the normal operation of the circular polarization antenna 1 or the single radiator 50. The single radiator 50 can be located above the first slot 31, the second slot 32, the third slot 33, and the fourth slot 34 of the metal layer 30 that are arranged in a ring or rotated in sequence, so that the single radiator 50 can send the circular polarization signal of the circular polarization antenna 1 or receive any external signal (such as a wireless signal). A single radiator 50 corresponds to the first slot 31, the second slot 32, the third slot 33 and the fourth slot 34 of the metal layer 30 which are arranged in a ring shape or rotated in sequence and are all in the shape of an hourglass at the same time, so that the area of the single radiator 50 covers (is larger than) the area of the first slot 31, the second slot 32, the third slot 33 and the fourth slot 34 of the metal layer 30 which are arranged in a ring shape or rotated in sequence and are all in the shape of an hourglass. The support member 60 is disposed between the metal layer 30 and the single radiator 50, so that the support member 60 supports the single radiator 50 above the first slot 31, the second slot 32, the third slot 33 and the fourth slot 34 of the metal layer 30, and also facilitates the formation of a gap 40 between the metal layer 30 and the single radiator 50.

In one embodiment, the substrate 10 is, for example, a single substrate made of dielectric materials, a glass fiber epoxy substrate (FR-4), a printed circuit board (PCB), etc. The height H1 (thickness) of the substrate 10 can be 0.8 millimeters (mm), the dielectric constant (εr) of the substrate 10 can be 4.4, the loss tangent (tan δ) of the substrate 10 can be 0.02, and the shape of the substrate 10 can be rectangular or square, etc. The feed network 20 can be a signal feed network, a signal distribution network, a signal phase adjustment network, etc., and the "source" in the feed network 20 represents a signal source or a signal.

In one embodiment, the metal layer 30 may be made of copper, etc., the gap 40 may be an air gap, etc., the height H2 of the gap 40 may be 25 mm, the single radiator 50 may be made of metal (such as copper), etc., and the support member 60 may be made of insulating material, etc. For example, the support member 60 may be composed of a square support member, two L-shaped support members, or four columnar support members, so that the support member 60 is disposed between the metal layer 30 and the single radiator 50.

FIG. 2 is a top view of the circular polarized antenna 1 using a single radiator 50 described in the present invention, viewed from above the single radiator 50 (see arrow P1 in FIG. 1 ), and FIG. 1 is also referred to for explanation.

As shown in FIG. 2 , the metal layer 30 may have a first slot 31, a second slot 32, a third slot 33, and a fourth slot 34 arranged in a ring or rotated in sequence, and the shapes of the first slot 31 to the fourth slot 34 of the metal layer 30 may all be hourglass shapes (i.e., wider at both ends and narrower in the center), etc. The first slot 31 and the third slot 33 of the metal layer 30 are symmetrical or parallel to each other, and the second slot 32 and the fourth slot 34 of the metal layer 30 are symmetrical or parallel to each other. The adjacent first slot 31 and the second slot 32 of the metal layer 30 are perpendicular to each other, the adjacent second slot 32 and the third slot 33 of the metal layer 30 are perpendicular to each other, the adjacent third slot 33 and the fourth slot 34 of the metal layer 30 are perpendicular to each other, and the adjacent fourth slot 34 of the metal layer 30 is perpendicular to the first slot 31.

The single radiator 50 can be used as the top layer of the circular polarization antenna 1 to keep the excitation electric field of the single radiator 50 symmetrically distributed, and the single radiator 50 can be arranged above the first slot 31 to the fourth slot 34 of the metal layer 30 to transmit the circular polarization signal of the circular polarization antenna 1 or receive any external signal (such as a wireless signal).

In one embodiment, the shape of the substrate 10, the metal layer 30 or the single radiator 50 may be a polygon (such as a square), the length and width W1 of the substrate 10 or the metal layer 30 may both be 150 millimeters (mm), the length and width W2 of the single radiator 50 may both be 115 millimeters (mm), and the length, width W1, and area of the metal layer 30 may be greater than or equal to the length, width W2, and area of the single radiator 50. The single radiator 50 corresponds to the first slot 31, the second slot 32, the third slot 33 and the fourth slot 34 of the metal layer 30 at the same time, and the area of the single radiator 50 covers (is larger than) the areas of the first slot 31, the second slot 32, the third slot 33 and the fourth slot 34 of the metal layer 30.

FIG. 3 is a top view schematic diagram of the circular polarization antenna 1 using a single radiator 50 of the present invention viewed from above the metal layer 30 (see arrow P2 in FIG. 1 ), and FIG. 4 is a top view schematic diagram of the circular polarization antenna 1 using a single radiator 50 of the present invention viewed from below the feed network 20 (see arrow P3 in FIG. 1 ), and FIG. 1 is referred to for explanation at the same time.

The combination of the feed network 20, the first slot 31 to the fourth slot 34 of the metal layer 30 and the single radiator 50 can jointly adjust the signal transmitted by the feed network 20 into a circularly polarized signal, or jointly adjust the external signal (such as a wireless signal) received by the single radiator 50 into a circularly polarized signal.

In one embodiment, the signal connection end A of the feed network 20 of the circular polarization antenna 1 can be connected to a signal transmitter (not shown), so that the phase of the signal provided by the signal transmitter is adjusted by the feed network 20 to 0 degree phase, 90 degree phase, 180 degree phase and 270 degree phase respectively, so that the adjusted signal passes through the substrate 10, the first slot 31 to the fourth slot 34 of the metal layer 30, the gap 40 and the single radiator 50 in sequence to form a circular polarization signal, so that the single radiator 50 can send the circular polarization signal.

In another embodiment, the signal connection end A of the feed network 20 of the circular polarized antenna 1 can be connected to a signal receiver (not shown), and the single radiator 50 can receive any external signal (such as a wireless signal), so that the signal (such as a wireless signal) received by the single radiator 50 passes through the gap 40, the first slot 31 to the fourth slot 34 of the metal layer 30, the substrate 10 and the feed network 20 in sequence, and then the feed network 20 adjusts the phase of the signal (such as a wireless signal) to 0 degree phase, 90 degree phase, 180 degree phase and 270 degree phase respectively to form a circular polarized signal and then transmits it to the signal receiver.

For example, the feed network 20 of the circular polarization antenna 1 may be composed of a signal connection terminal A, a plurality of distributors, and a plurality of phase adjustment circuits. The signal connection terminal A may be connected to one of the plurality of distributors, and the plurality of distributors may be respectively connected to the plurality of phase adjustment circuits, so that the phase of the signal may be respectively adjusted to 0 degree phase, 90 degree phase, 180 degree phase, and 270 degree phase by the plurality of distributors and the plurality of phase adjustment circuits.

In the embodiments shown in FIG. 3 and FIG. 4 , the feed network 20 of the circular polarized antenna 1 may have a signal connection terminal A, a first distributor B1, a second distributor B2, a third distributor B3, a first phase adjustment circuit C1, a second phase adjustment circuit C2, a third phase adjustment circuit C3, a fourth phase adjustment circuit C4, a fifth phase adjustment circuit C5, and a sixth phase adjustment circuit C6, but is not limited thereto.

The signal connection end A of the feed network 20 can be connected to a signal transmitter or a signal receiver, etc. The first distributor B1, the second distributor B2 or the third distributor B3 can distribute a signal into two signals. The combination of the first distributor B1 to the third distributor B3 and the first phase adjustment line C1 to the sixth phase adjustment line C6 can jointly adjust the phase of the signal from the signal transmitter or the single radiator 50 to 0 degree phase, 90 degree phase, 180 degree phase and 270 degree phase respectively.

The first distributor B1 can be connected to the signal connection end A, the first phase adjustment line C1 and the second phase adjustment line C2 respectively, the second distributor B2 can be connected to the second phase adjustment line C2, the third phase adjustment line C3 and the sixth phase adjustment line C6 respectively, and the third distributor B3 can be connected to the first phase adjustment line C1, the fourth phase adjustment line C4 and the fifth phase adjustment line C5 respectively. The second distributor B2 can correspond to or be symmetrical to the third distributor B3, and the shapes of the second distributor B2 and the third distributor B3 (similar to U or C shape) are the same or similar. The first distributor B1, the second distributor B2 or the third distributor B3 can be a signal distributor or a power distributor, and the power distributor can be a Wilkinson power divider, etc.

The second phase adjustment line C2 may be adjacent to and longer than the first phase adjustment line C1, the fourth phase adjustment line C4 may be adjacent to and longer than the fifth phase adjustment line C5, the sixth phase adjustment line C6 may be adjacent to and longer than the third phase adjustment line C3, and the ends of the third phase adjustment line C3 to the sixth phase adjustment line C6 may respectively extend to correspond to the narrow central area (central position) of the first slot 31 to the fourth slot 34 of the metal layer 30. The third phase adjustment line C3 may correspond to or be symmetrical to the fifth phase adjustment line C5, and the shapes of the third phase adjustment line C3 and the fifth phase adjustment line C5 are the same or similar (similar to a U-shape or an L-shape). The fourth phase adjustment circuit C4 may correspond to or be symmetrical to the sixth phase adjustment circuit C6, and the shapes of the fourth phase adjustment circuit C4 and the sixth phase adjustment circuit C6 are the same or similar (similar to N shape).

In the embodiment of FIG. 3 , the length L1, width L2 and width L3 of the first slot 31, the second slot 32, the third slot 33 or the fourth slot 34 of the metal layer 30 may be 56 mm, 20 mm and 18 mm respectively, and the shape of the first slot 31 to the fourth slot 34 of the metal layer 30 may be an hourglass shape (i.e., wider at both ends and narrower in the center), etc., so that the first slot 31 to the fourth slot 34 of the metal layer 30 are used as signal excitation slots of the circular polarization antenna 1. The first slot 31 to the fourth slot 34 of the metal layer 30 can generate mutually orthogonal electric fields on a single radiator 50 by sequential rotation (physical rotation). At the same time, the hourglass-shaped first slot 31 to fourth slot 34 of the metal layer 30 help maximize the coupling and minimize the back radiation of the circular polarization antenna 1, and are also beneficial to the broadband application of the circular polarization antenna 1.

In the embodiment of FIG. 4 , the sequentially rotating feed network 20 may use the first distributor B1, the second distributor B2 and the third distributor B3 (such as a Wilkinson power distributor) to provide a good amplitude balance of the signal between the first slot 31 to the fourth slot 34 of the metal layer 30. The lengths of the first phase adjustment line C1 to the sixth phase adjustment line C6 may be appropriately adjusted to achieve a 90-degree phase shift of the signal at adjacent phases, and the resistor (R) value for achieving isolation in the first distributor B1, the second distributor B2 or the third distributor B3 (such as a Wilkinson power distributor) may be 100 ohms.

The circularly polarized antenna 1 using a single radiator 50 described in the present invention can be applied to various wireless communication systems, wireless communication networks or wireless communication devices such as Global Positioning System (GPS), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), satellite communication, Radio Frequency Identification (RFID) reader, Radio Frequency Identification (RFID) tag, etc., and can also be applied to various communication products or antenna products such as smart phones, base stations, wireless sharing devices, transmitters (such as signal transmitters), receivers (such as signal receivers), portable antennas, radio frequency front-end transceiver modules, etc.

For example, the following Figures 5 to 8 are based on the application of the circular polarization antenna 1 of the present invention in the ultra high frequency (UHF) radio frequency identification (RFID) frequency band, but are not limited to this. The circular polarization antenna 1 can also be applied to various different frequency bands.

FIG5 is a waveform diagram of the "measured" and "simulated" signals in terms of echo loss (S11) and frequency in the circular polarization antenna 1 using a single radiator 50 described in the present invention, and refer to FIG1 to FIG4 for explanation.

As shown in FIG. 5 , the present invention uses the echo loss (S11) of the circular polarization antenna 1 signal "measured" by the vector network analyzer as a function of the frequency of the signal, and compares the echo loss (S11) of the circular polarization antenna 1 signal "simulated" with the simulation result of the frequency. The circularly polarized antenna 1 provides an impedance bandwidth with an S11 lower than -10 dB for signals from 0.615 GHz (10 ⁹ Hz) to 1.350 GHz, and achieves an excellent S11 performance of lower than -20 dB in the general ultra-high frequency radio frequency identification (UHF RFID) frequency band.

FIG6 is a waveform diagram of the "measured" and "simulated" signals in the circular polarization antenna 1 using a single radiator 50 in the present invention in terms of axial ratio (AR) and frequency, and is also explained with reference to FIG1 to FIG4.

As shown in FIG6 , the circular polarization antenna 1 provides an axial ratio (AR) bandwidth of less than 3 dB (0.800 to 1.100 GHz) and an axial ratio (AR) bandwidth of less than 1 dB (26.80%) (0.840 to 1.100 GHz) in the universal ultra-high frequency radio frequency identification (UHF RFID) band. Such excellent performance proves the effectiveness of the circular polarization antenna 1 proposed in the present invention in generating circular polarization (CP) performance on a single radiator 50, and the measured results of the circular polarization antenna 1 are very consistent with the simulation results.

FIG. 7 is a schematic diagram showing the dependence of the axial ratio (AR) of the measured signal in the circular polarization antenna 1 using a single radiator 50 and the angles of two main cutting planes (such as the XZ plane and the YZ plane) at different frequencies described in the present invention, and is also explained by referring to FIG. 1 to FIG. 4 .

As shown in Figure 7, at 0.915 GHz, the beamwidth with an axial ratio (AR) of 3 dB was measured to have an angle (θ) of 82 degrees on the "XZ plane" and an angle (θ) of 53 degrees on the "YZ plane".

FIG8 is a waveform diagram of the gain and frequency of the "measured" and "simulated" signals in the circular polarization antenna 1 using a single radiator 50 described in the present invention, and is also explained by referring to FIG1 to FIG4.

As shown in FIG8 , in the universal ultra-high frequency radio frequency identification (UHF RFID) frequency band, the circularly polarized antenna 1 of the present invention achieves a minimum gain of, for example, 7 dBic and a maximum gain (peak value) of 8.3 dBic.

In summary, the circularly polarized antenna using a single radiator described in the present invention has at least the following features, advantages or technical effects.

1. The circular polarization antenna of the present invention uses a single radiator to obtain equivalent or better circular polarization (CP) performance than the traditional four radiators.

Second, the present invention can correspond a single radiator of the circular polarization antenna to the first to fourth slots of the metal layer, so as to cover the area of the first to fourth slots of the metal layer at the same time. Therefore, compared with the traditional circular polarization antenna using four radiators to produce a large area, the area of the single radiator used in the present invention can be significantly smaller than the overall area of the traditional four radiators (such as only 1/4 of the area), which is beneficial to reduce the overall size and manufacturing cost of the circular polarization antenna.

3. The circular polarization antenna of the present invention uses a single radiator, which not only reduces the structural complexity and overall size of the traditional circular polarization antenna using four radiators, but also maintains the polarization and beam width characteristics of the circular polarization antenna, and can also obtain better advantages in the operating bandwidth of the circular polarization antenna.

4. The circularly polarized antenna of the present invention using a single radiator can have a wider axial ratio (AR) bandwidth, a wider beam width, a lower impedance bandwidth and/or a higher gain, and can also be applied to various communication systems, communication products or antenna products with different bandwidths.

5. The feed network of the circularly polarized antenna of the present invention can provide unique phase and azimuth settings to facilitate the circularly polarized antenna to produce better circular polarization (CP) performance.

6. The metal layer of the circular polarization antenna of the present invention adopts the first to fourth slots in the shape of an hourglass, which is conducive to the maximum coupling and minimum back radiation of the circular polarization antenna signal, and is also conducive to the broadband application of the circular polarization antenna.

7. The feed network of the circular polarized antenna of the present invention adopts a distributor (such as a Wilkinson power distributor) to provide a good amplitude balance of the signal between the first slot to the fourth slot of the metal layer.

8. The circular polarization antenna feed network of the present invention adopts a phase adjustment circuit to facilitate proper adjustment of the length of the phase adjustment circuit and also facilitate the realization of a 90-degree phase shift of the signal at adjacent phases.

9. A gap is formed between the metal layer of the circular polarization antenna of the present invention and the single radiator, so as to prevent the metal layer and the single radiator from contacting each other by separating the metal layer and the single radiator through the gap, thereby avoiding affecting the normal operation of the circular polarization antenna or the single radiator.

10. A support member is provided between the metal layer and the single radiator of the circular polarization antenna of the present invention, so as to facilitate supporting the single radiator above the first to fourth slots of the metal layer by the support member, and also facilitate forming a gap between the metal layer and the single radiator.

The above implementation forms are only illustrative of the principles, features and effects of the present invention, and are not intended to limit the scope of implementation of the present invention. Anyone familiar with this technology can modify and change the above implementation forms without violating the spirit and scope of the present invention. Any equivalent changes and modifications completed using the content disclosed by the present invention should still be covered by the scope of the patent application. Therefore, the scope of protection of the present invention should be as listed in the scope of the patent application.

1: Circular polarization antenna

10: Substrate

11: First surface

12: Second surface

20: Feedback network

30:Metal layer

31: First slot

32: Second slot

33: The third slot

34: Fourth slot

40: Gap

50: Single radiator

60: Support parts

H1,H2:Height

P1,P2,P3:arrow

Claims (9)

A circular polarized antenna using a single radiator includes: a substrate having a first surface and a second surface opposite to each other; a feed network and a metal layer formed on the first surface and the second surface of the substrate respectively, wherein the metal layer has a first slot hole, a second slot hole, a third slot hole and a fourth slot hole arranged in a ring shape or rotated in sequence; and a single radiator located above the first slot hole, the first slot hole, the second slot hole, the third slot hole and the fourth slot hole arranged in a ring shape or rotated in sequence of the metal layer, wherein the single radiator simultaneously corresponds to the first slot hole, the first slot hole, the second slot hole, the third slot hole and the fourth slot hole arranged in a ring shape or rotated in sequence of the metal layer. The first slot, the second slot, the third slot and the fourth slot, and the area of the single radiator covers the area of the first slot, the second slot, the third slot and the fourth slot arranged in a ring or rotated in sequence on the metal layer; wherein the shapes of the first slot, the second slot, the third slot and the fourth slot of the metal layer are all hourglass shapes, and the single radiator corresponds to the first slot, the second slot, the third slot and the fourth slot which are all hourglass shapes at the same time, and the area of the single radiator covers the area of the first slot, the second slot, the third slot and the fourth slot which are all hourglass shapes. A circular polarization antenna using a single radiator includes: a substrate having a first surface and a second surface opposite to each other; a feed network and a metal layer formed on the first surface and the second surface of the substrate respectively, wherein the metal layer has a first slot, a second slot, a third slot and a fourth slot arranged in a ring shape or rotated in sequence; and a single radiator located above the first slot, the first slot, the second slot, the third slot and the fourth slot arranged in a ring shape or rotated in sequence of the metal layer, wherein the single radiator corresponds to the metal layer at the same time. The first slot hole, the second slot hole, the third slot hole and the fourth slot hole of the metal layer are arranged in a ring shape or rotated in sequence, and the area of the single radiator covers the area of the first slot hole, the second slot hole, the third slot hole and the fourth slot hole of the metal layer that are arranged in a ring shape or rotated in sequence; wherein, the first slot hole and the third slot hole of the metal layer are symmetrical or parallel to each other, the second slot hole and the fourth slot hole of the metal layer are symmetrical or parallel to each other, the adjacent first slot hole and the second slot hole of the metal layer are perpendicular to each other, and the adjacent third slot hole and the fourth slot hole of the metal layer are perpendicular to each other. The circularly polarized antenna as described in claim 1 or 2, wherein the feed network, the first slot to the fourth slot of the metal layer and the single radiator jointly adjust the signal transmitted by the body source network into a circularly polarized signal, or jointly adjust the signal received by the single radiator into a circularly polarized signal. The circularly polarized antenna as described in claim 1 or 2, wherein the feed network adjusts the phase of the signal to 0 degree, 90 degree, 180 degree and 270 degree respectively, so that the adjusted signal passes through the substrate, the first slot to the fourth slot of the metal layer and the single radiator in sequence to form a circularly polarized signal. A circularly polarized antenna as described in claim 1 or 2, wherein the signal received by the single radiator passes through the first slot to the fourth slot of the metal layer, the substrate and the feed network in sequence, so that the phase of the signal is adjusted by the feed network to 0 degree phase, 90 degree phase, 180 degree phase and 270 degree phase respectively to form a circularly polarized signal. The circularly polarized antenna as described in claim 1 or 2, wherein the feed network is composed of a signal connection end, a plurality of distributors and a plurality of phase adjustment circuits, the signal connection end is connected to one of the plurality of distributors, and the plurality of distributors are respectively connected to the plurality of phase adjustment circuits, so that the phase of the signal is respectively adjusted to 0 degree phase, 90 degree phase, 180 degree phase and 270 degree phase by the plurality of distributors and the plurality of phase adjustment circuits. A circular polarization antenna using a single radiator includes: a substrate having a first surface and a second surface opposite to each other; a feed network and a metal layer formed on the first surface and the second surface of the substrate respectively, wherein the metal layer has a first slot hole, a second slot hole, a third slot hole and a fourth slot hole arranged in a ring shape or rotated in sequence; and a single radiator located above the first slot hole, the first slot hole, the second slot hole, the third slot hole and the fourth slot hole arranged in a ring shape or rotated in sequence of the metal layer, wherein the single radiator simultaneously corresponds to the first slot hole, the second slot hole, the third slot hole and the fourth slot hole arranged in a ring shape or rotated in sequence of the metal layer, and the area of the single radiator covers the metal layer. The area of the first slot, the second slot, the third slot and the fourth slot arranged in a ring or rotated in sequence in the layer; wherein the feed network has a first distributor, a second distributor, a third distributor, a first phase adjustment line, a second phase adjustment line, a third phase adjustment line, a fourth phase adjustment line, a fifth phase adjustment line and a sixth phase adjustment line, the first distributor is respectively connected to the first phase adjustment line and the second phase adjustment line, the second distributor is respectively connected to the second phase adjustment line, the third phase adjustment line and the sixth phase adjustment line, and the third distributor is respectively connected to the first phase adjustment line, the fourth phase adjustment line and the fifth phase adjustment line. A circularly polarized antenna as described in claim 1, 2 or 7, wherein a gap is formed between the metal layer and the single radiator, so that the metal layer and the single radiator are separated by the gap. The circular polarization antenna as described in claim 1, 2 or 7 further includes at least one support member disposed between the metal layer and the single radiator, so as to support the single radiator above the first slot, the second slot, the third slot and the fourth slot of the metal layer by the at least one support member.

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