Antenna apparatus

An antenna apparatus is provided. The antenna apparatus includes a cavity element, a radiating element, and a feeding element. The cavity element includes an opening. The radiating element is located in the opening and is disposed at a conductive layer. An outline of the radiating element and the opening form a surround slot. An imaginary rectangle has four sides respectively abutted against an external outline of the surround slot. The feeding element is disposed at another parallel conductive layer. The feeding element includes two sections. There is a coupling spacing is between a section and the radiating element to feed into the radiating element through electric field coupling. A tail end of the section is an open circuit. Another section is an initial section of the feeding element inserted into the opening. There is a shifting spacing between the another section and a central line of the imaginary rectangle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 110148774, filed on Dec. 24, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

The disclosure relates to an antenna technology, and particularly relates to a non-narrowband antenna apparatus.

Description of Related Art

The antenna design affects the antenna performance. The bandwidth is one of the indicators of antenna performance. In order to meet non-narrowband requirements, most antenna architectures are complex and difficult to design.

SUMMARY

The disclosure provides an antenna apparatus. The antenna apparatus includes (but is not limited to) a cavity element, a radiating element, and a feeding element. The cavity element includes an opening. The radiating element is located in the opening and is disposed at a conductive layer. An outline of the radiating element and the opening form a surround slot. An external outline of the surround slot is configured to define an imaginary rectangle, and the imaginary rectangle has four sides respectively abutted against the external outline of the surround slot. The feeding element is disposed at another parallel conductive layer. The feeding element includes two sections. There is a coupling spacing between one section of the two sections and the radiating element to feed into the radiating element through electric field coupling. A tail end of the section is an open circuit. Another section is an initial section of the feeding element inserted into the opening. There is a shifting spacing between the another section and a central line of the imaginary rectangle.

In order for the features and advantages of the disclosure to be more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG.1Ais a perspective view of an antenna apparatus1according to Embodiment 1 of the disclosure,FIG.1Bis a top view of the antenna apparatus1according to Embodiment 1 of the disclosure, andFIG.1Cis a side view of the antenna apparatus1according to Embodiment 1 of the disclosure. Please refer toFIG.1AtoFIG.1C, the antenna apparatus1includes a cavity element10-1, a radiating element30-1, and a feeding element50-1.

The cavity element10-1is a cavity including an opening11-1.FIG.1Atakes a rectangular cavity as an example, but the appearance is not limited thereto. The opening11-1is rectangular. From the perspective ofFIG.1C(for example, a Y-Z plane), a top side of the cavity element10-1abuts a conductive layer M1, and a bottom side of the cavity element10-1abuts a conductive layer M3. It should be noted that conductive layers M1, M2, and M3are parallel to an X-Y plane. The conductive layer M2is located between the conductive layer M1and the conductive layer M3.

The radiating element30-1may be a patch, a microstrip, or other radiators. The radiating element30-1is located in the opening11-1and is disposed at the conductive layer M1. A geometrical shape of an outline of the radiating element30-1is the same as the opening11-1. That is, the radiating element30-1is rectangular. From the perspective ofFIG.1B, an area of the radiating element30-1is smaller than an area of the opening11-1. In addition, the outline of the radiating element30-1and the opening11-1form a surround slot20-1(also referred to as a slot-ring).

From the perspective ofFIG.1C, the feeding element50-1is disposed at the conductive layer M2. The feeding element50-1may be a microstrip line, a stub, or other transmission conductors.

From the perspective ofFIG.1B, the feeding element50-1includes (but is not limited to) sections51-1and52-1. The sections51-1and52-1form a straight stub.

From the perspective ofFIG.1C, a part of the feeding element50-1is located below the radiating element30-1. In other words, regions of the sections51-1and52-1projected onto the conductive layer M1in a vertical direction of the conductive layer M2partially overlaps with the radiating element30-1. For example, the entire section51-1is located directly below the radiating element30-1. There is a coupling spacing CD1between the section51-1and the radiating element30-1. Thereby, the feeding element50-1may feed a radio signal into or out of the radiating element30-1through an electric field coupling manner. A tail end of the section51-1is an open circuit.

From the perspective ofFIG.1B, the section52-1is an initial section of the feeding element50-1inserted into the opening11-1. In addition, there is a shifting spacing SI1between the section52-1and a central line CL1of an imaginary rectangle IR1. In other words, the feeding element50-1is not for centered feeding. It is worth noting that an external outline of the surround slot20-1may be configured to define the imaginary rectangle IR1, and the imaginary rectangle IR1is configured to define a central line of the surround slot20-1. The imaginary rectangle IR1has four sides (for example, opposite sides S111, S112, S121, and S122), and the four sides are respectively abutted against the external outline of the surround slot20-1. The imaginary rectangle IR1is the smallest rectangle that may cover the external outline of the surround slot20-1(that is, an outline of the opening S11-1) on the X-Y plane. That is, the rectangle with the smallest area among all rectangles that may cover the external outline of the surround slot20-1. In other words, a region of the imaginary rectangle IR1projected onto the conductive layer M1may cover the external outline of the surround slot20-1and has the smallest area. For example, assuming that the external outline of the surround slot20-1is also rectangular, the imaginary rectangle IR1will also coincide with the rectangle of the external outline of the surround slot20-1. Assuming that the external outline of the surround slot20-1is also an ellipse, lengths of a long side and a short side of the imaginary rectangle IR1will also be equal to lengths of a long axis and a short axis of the ellipse.

In an embodiment, from the perspective ofFIG.1B, the imaginary rectangle IR1includes two opposite sides S111and S112. The central line CL1is formed at a center of any one of the opposite sides S111and S112. That is, the central line CL1is a perpendicular bisector of the opposite sides S111and S112. The section52-1is inserted into the opening11-1from the opposite side S111, and a tail end511-1of the section51-1is not connected to the opposite side S112(that is, an open circuit is formed). In an embodiment, the shifting spacing SI1is greater than or equal to one-sixteenth of lengths of the opposite sides S111and S112to provide an appropriate non-narrowband range. For example, if the shifting spacing SI1is increased from one-sixteenth of the lengths of the opposite sides S111and S112to one-quarter or more, the non-narrowband range provided by the antenna apparatus1will be increased from a dual-bandwidth range to a wideband range.

In an embodiment, from the perspective ofFIG.1B, a shortest linear distance W from the external outline of the surround slot20-1to an external outline of the radiating element30-1may define one or more widths of the surround slot20-1. The largest width among the one or more widths of the surround slot20-1is less than half of the wavelength of the radio signal of the antenna apparatus1. However, in other embodiments, the largest width among the one or more widths of the surround slot20-1may also be one-quarter of the wavelength, one-eighth of the wavelength, or other lengths.

In an embodiment, from the perspective ofFIG.1B, the imaginary rectangle IR1further includes the opposite sides S121and S122. The tail end511-1of the section51-1does not exceed the central line SCL1of the imaginary rectangle IR1. The central line SCL1is formed at a center of any one of the opposite sides S121and S122. That is, the central line SCL1is a perpendicular bisector of the opposite sides S121and S122. In an embodiment, the lengths of the opposite sides S111and S112are greater than lengths of the opposite sides S121and S122, that is, the section52-1may be inserted into the opening11-1by the long side (the opposite side S111) of the imaginary rectangle IR1, and the central line CL1may be a perpendicular bisector of the long side of the rectangle IR1.

In another embodiment, from the perspective ofFIG.1B, the tail end511-1of the section51-1may exceed the central line SCL1of the imaginary rectangle IR1, but the tail end511-1is still an open circuit (that is, not connected to the opposite side S112).

In addition, from the perspective ofFIG.1C, the antenna apparatus1further includes a ground part40-1. The ground part40-1is disposed at the conductive layer M3parallel to the conductive layer M1. In addition, the ground part40-1is located on the bottom side of the cavity element10-1. In an embodiment, the cavity element10-1is a conductor, which is coupled to the ground part40-1. In an embodiment, the opening11-1is defined by at least one conductive wall surrounding the radiating element30-1. In another embodiment, the opening11-1is defined by multiple parallel conductive vias surrounding the radiating element30-1. The feeding element50-1is, for example, configured to transmit the radio signal. The shortest distance between multiple conductors is less than or equal to half of the wavelength of the radio signal to provide acceptable signal isolation. In an embodiment, the shortest distance between the conductors is less than or equal to one-eighth of the wavelength of the radio signal to provide better signal isolation.

FIG.2Ais a top view of an antenna apparatus2according to Embodiment 2 of the disclosure, andFIG.2Bis a side view of the antenna apparatus2according to Embodiment 2 of the disclosure. Please refer toFIG.2AandFIG.2B. The antenna apparatus2includes a cavity element10-2, a radiating element30-2(disposed at the conductive layer M1), and a feeding element50-2(disposed at the conductive layer M2). The difference from Embodiment 1 is that geometrical shapes of an outline of a radiating element30-2and an opening11-2are ellipses.

Similarly, the outline of the radiating element30-2and the opening11-2form a surround slot20-2. There is a coupling spacing CD2between the feeding element50-2and the radiating element30-2. The two sets of opposite sides S211and S212and S221and S222of an imaginary rectangle IR2are respectively abutted against an external outline of the surround slot20-2. There is a shifting spacing SI2between an initial section of the feeding element50-2and a central line CL2of the imaginary rectangle IR2. In addition, a tail end of the feeding element50-2does not exceed a central line SCL2of the imaginary rectangle IR2.

FIG.3is a top view of an antenna apparatus3according to Embodiment 3 of the disclosure. The antenna apparatus3includes a cavity element10-3, a radiating element30-3, and a feeding element50-3. An outline of the radiating element30-3and an opening11-3form a surround slot20-3. The difference from Embodiments 1 and 2 is that a geometrical shape of an outline of the radiating element30-3is different from the opening11-3of the cavity element10-3. The geometrical shape of the outline of the radiating element30-3is rectangular, but the opening11-3is an ellipse.

FIG.4is a top view of an antenna apparatus4according to Embodiment 4 of the disclosure. Please refer toFIG.4. The antenna apparatus4includes a cavity element10-4, a radiating element30-4, and a feeding element50-4. An outline of the radiating element30-4and an opening11-4form a surround slot20-4. The difference from Embodiments 1 and 2 is that a geometrical shape of the outline of the radiating element30-4is different from the opening11-4of the cavity element10-4. The geometrical shape of the outline of the radiating element30-4is an ellipse, but the opening11-4is rectangular.

FIG.5Ais a top view of an antenna apparatus5according to Embodiment 5 of the disclosure, andFIG.5Bis a side view of the antenna apparatus5according to Embodiment 5 of the disclosure. Please refer toFIG.5AandFIG.5B. The antenna apparatus5includes a cavity element10-5, a radiating element30-5, and a feeding element50-5. An outline of the radiating element30-5and an opening11-5form a surround slot20-5. The difference from Embodiments 1 and 2 is that from the perspective ofFIG.5B, the radiating element30-5is disposed at the conductive layer M2. The feeding element50-5is disposed at the conductive layer M1. In other words, the conductive layer M2where the radiating element30-5is at is located between the conductive layer M1where the feeding element50-5is at and the conductive layer M3on a bottom side of the cavity element10-5. At this time, the feeding element50-5is located above the radiating element30-5.

FIG.6Ais a top view of an antenna apparatus6according to Embodiment 6 of the disclosure, andFIG.6Bis a side view of the antenna apparatus6according to Embodiment 6 of the disclosure. Please refer toFIG.6AandFIG.6B. The antenna apparatus6includes a cavity element10-6, a radiating element30-6, and a feeding element50-6. An outline of the radiating element30-6and an opening11-6form a surround slot20-6. Similarly, from the perspective ofFIG.6B, the radiating element30-6is disposed at the conductive layer M2. The feeding element50-6is disposed at the conductive layer M1. However, the difference from Embodiment 5 is that the cavity element10-6further includes an opening extension part60-6. The opening extension part60-6extends from the opening11-6to a corresponding space of the feeding element50-6to be accommodated by the feeding element50-6.

It is worth noting that the design of the surround slot formed between the cavity element and the radiating element of the embodiments of the disclosure can generate two electric field modes with close frequencies, thereby achieving a non-narrowband. In addition, the feeding element of the embodiments of the disclosure is designed for shifted feeding, which also helps to increase the bandwidth.

FIG.7is an S parameter diagram of the antenna apparatus1according to Embodiment 1 of the disclosure. Please refer toFIG.7. Corresponding shifting spacings of curves702,703, and704are different, wherein the shifting spacing corresponding to the curve702is the shortest, and the shifting spacing corresponding to the curve704is the longest. Take the bandwidth shown in the curve703as an example, compared with centered feeding, that is, the design without any shifting spacing, the bandwidth is increased from 3 GHz to 11 GHz. Therefore, if there is the shifting spacing, the bandwidth can be significantly increased.

FIG.8Ais a top view of an antenna apparatus7according to Embodiment 7 of the disclosure. Please refer toFIG.8A. The antenna apparatus7includes a cavity element10-7, a radiating element30-7, and a feeding element50-7. An outline of the radiating element30-7and an opening11-7form a surround slot20-7. The difference from Embodiment 1 is that a shifting spacing SI7is greater than the shifting spacing SI1. A region of the feeding element50-7projected onto the conductive layer M1in the vertical direction of the conductive layer M2does not overlap with the radiating element30-7, so that the feeding element50-7is exposed. In an embodiment, a region of the feeding element50-7projected onto the conductive layer M1in the vertical direction of the conductive layer M2partially overlaps with the radiating element30-7, so that the feeding element50-7is partially exposed.

FIG.8Bis an S parameter diagram of the antenna apparatus7according to Embodiment 7 of the disclosure. Please refer toFIG.8B. Compared withFIG.7, the bandwidth shown in a curve801is still greater than centered feeding. It can be seen that the user may adjust a length of the shifting spacing according to requirements to achieve the desired bandwidth.

FIG.9Ais a top view of an antenna apparatus8according to Embodiment 8 of the disclosure. Please refer toFIG.9A. The antenna apparatus8includes a cavity element10-8, a radiating element30-8, and a feeding element50-8. An outline of the radiating element30-8and an opening11-8form a surround slot20-8. The difference from Embodiment 1 is that the feeding element forms an L-shaped stub (a tail end thereof extends toward a central line (taking an axis X as an example) of the surround slot20-8). In addition, a region of the feeding element50-8projected onto the conductive layer M1in the vertical direction of the conductive layer M2does not overlap with the radiating element30-8, so that the feeding element50-8is exposed.

FIG.9Bis an S parameter diagram of an antenna apparatus8according to Embodiment 8 of the disclosure. Please refer toFIG.9B. A curve901as shown forms two obvious low points to provide a bandwidth greater than centered feeding.

FIG.10Ais a top view of an antenna apparatus9according to Embodiment 9 of the disclosure. Please refer toFIG.10A. The antenna apparatus9includes a cavity element10-9, a radiating element30-9, and a feeding element50-9. An outline of the radiating element30-9and an opening11-9form a surround slot20-9. The difference from Embodiment 1 is that the feeding element forms an L-shaped stub (a tail end thereof extends toward a direction away from a central line (taking the axis X as an example) of the surround slot20-9). In addition, a region of the feeding element50-9projected onto the conductive layer M1in the vertical direction of the conductive layer M2does not overlap with the radiating element30-9, so that the feeding element50-9is exposed.

FIG.10Bis an S parameter diagram of the antenna apparatus9according to Embodiment 9 of the disclosure. Please refer toFIG.10B. A curve1001as shown forms two obvious low points to provide a bandwidth greater than centered feeding.

FIG.11Ais a top view of an antenna apparatus10according to Embodiment 10 of the disclosure. Please refer toFIG.11A. The antenna apparatus10includes a cavity element10-10, a radiating element30-10, and a feeding element50-10. An outline of the radiating element30-10and an opening11-10form a surround slot20-10. The difference from Embodiment 1 is that the feeding element forms a T-shaped stub (two tail ends thereof respectively extend toward directions close to and away from a central line (taking the axis X as an example) of the surround slot20-10). In addition, a region of the feeding element50-10projected onto the conductive layer M1in the vertical direction of the conductive layer M2does not overlap with the radiating element30-10, so that the feeding element50-10is exposed.

FIG.11Bis an S parameter diagram of the antenna apparatus10according to Embodiment 10 of the disclosure. Please refer toFIG.11B. A curve1101as shown forms two obvious low points to provide a bandwidth greater than centered feeding.

It should be noted that the outlines of the feeding element, the radiating element, and the opening of the above embodiments are all geometrical shapes. Of course, there may still be other changes in shapes.FIG.12is a top view of an antenna apparatus11according to Embodiment 11 of the disclosure. Please refer toFIG.12. The antenna apparatus11includes a cavity element10-11, a radiating element30-11, and a feeding element50-11. An outline of the radiating element30-11and an opening11-11form a surround slot20-11. The difference from the above embodiments is that outlines of the radiating element30-11, the feeding element50-11, and the opening11-11are all irregular shapes. In any case, there is still a shifting spacing SI11between an initial section of the feeding element50-11and a central line CL11of an imaginary rectangle IR11covering the surround slot20-11. Therefore, compared with the antenna design of centered feeding, Embodiment 11 may provide a greater bandwidth.

In summary, in the antenna apparatus of the embodiments of the disclosure, the surround slot is formed between the cavity element and the radiating element, the feeding element feeds through electric field coupling, and there is the shifting spacing (that is, shifted feeding) between the feeding element and the central line of the imaginary rectangle. Therefore, parameters used in the antenna design of the embodiments of the disclosure are relatively simple and easy to optimize. The embodiments of the disclosure can increase the bandwidth, thereby achieving the non-narrowband (for example, the dual-bandwidth range, the multi-bandwidth range, or the wideband range). In addition, the embodiments of the disclosure are less susceptible to the influence of surrounding elements, and the degree of isolation between antenna elements is high.

Although the disclosure has been disclosed in the above embodiments, the embodiments are not intended to limit the disclosure. Persons skilled in the art may make some changes and modifications without departing from the spirit and scope of the disclosure. The protection scope of the disclosure shall be defined by the appended claims.