TECHNICAL FIELD

The disclosure relates to an antenna pair, an antenna element comprising at least two antenna pairs, and an antenna structure comprising a plurality of antenna elements.

BACKGROUND

Electronic devices, in particular smaller wireless devices such as smartphones and tablets, should not only have a small form factor but also be provided with as large displays and as much battery as possible while still leaving space for a antenna modules facilitating more and more radio signal technology such as millimeter-wave antennas.

In order to achieve stable omnicoverage, i.e. stable communication in all directions and orientations, it can be preferable to use dual-polarized millimeter-wave antennas. However, current solutions, utilizing stacked patch elements, face issues such as inadequate gain, poor cross-polarization ratio when in array configuration, array performance losses when low-band and high-and elements are interleaved in array configuration, surface wave excitation, and poor filtering responses.

Hence, there is a need for antennas that have a small footprint as well as good antenna performance and directivity.

SUMMARY

It is an object to provide an improved antenna pair and antenna structure. The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description, and the figures.

According to a first aspect, there is provided an antenna pair comprising a first planar inverted- F antenna stack; a second planar inverted-F antenna stack; a coupling arrangement configured to couple the first planar inverted-F antenna stack electromagnetically to the second planar inverted-F antenna stack. Such a solution facilitates dual resonance as well as increased directivity. Additionally, bandwidth may be increased.

In a possible implementation form of the first aspect, the antenna pair further comprises a differential feed structure configured to feed a first signal to the first planar inverted-F antenna stack and a second phase-shifted signal to the second planar inverted-F antenna stack, facilitating broadside radiation and improving cross-polarization ratio.

In a further possible implementation form of the first aspect, the antenna pair further comprises a common feed structure configured to feed a first signal to the first planar inverted-F antenna stack and the second planar inverted-F antenna stack, simplifying the structure of the antenna pair.

In a further possible implementation form of the first aspect, the first planar inverted-F antenna stack and the second planar inverted-F antenna stack each comprise a first planar inverted-F antenna comprising a first radiating element; a second planar inverted-F antenna comprising a second radiating element, the second planar inverted-F antenna being superimposed onto the first planar inverted F-antenna, the first radiating element and the second radiating element each being a /4 patch element; a probe feed coupled to the first radiating element; and a ground probe coupled to the first radiating element and the second radiating element; the coupling arrangement coupling an open end of the first radiating element to an open end of the second radiating element, improving cross-polarization ratio as well as bandwidth. Furthermore, directivity and gain may be improved due to a larger effective antenna aperture.

In a further possible implementation form of the first aspect, the first planar inverted-F antenna stack and the second planar inverted-F antenna stack further comprise a third planar inverted-F antenna comprising a third radiating element, the ground probe being coupled to the first radiating element, the second radiating element, and the third radiating element, increasing the resonance range available.

In a further possible implementation form of the first aspect, the first radiating element is configured to generate a first resonance frequency, the second radiating element is configured to generate the first resonance frequency or a second resonance frequency, and the third radiating element is configured to generate a third resonance frequency, increasing the resonance range available.

According to a second aspect, there is provided an antenna element comprising a first antenna pair according to the above and a second antenna pair according to the above, the first antenna pair and the second antenna pair being configured to emit radiation in a low-frequency band, the first antenna pair being configured to enable a radiation pattern having a first polarization, and the second antenna pair being configured to enable a radiation pattern having a second polarization, a cross-shaped coupling arrangement wherein a first section of the coupling arrangement couples the first and second planar inverted-F antenna stacks of the first antenna pair, and wherein a second section of the coupling arrangement couples the first and second planar inverted-F antenna stacks of the second antenna pair.

Such a solution facilitates increased directivity as well as increased low-frequency bandwidth. Furthermore, the solution allows an antenna element that has relatively thin form factor, while still having a wide band covering necessary 5G frequency bands.

In a possible implementation form of the second aspect, a width of the cross-shaped coupling arrangement is at least 150 pm as seen in a plane parallel with the first radiating elements and the second radiating elements of the first antenna pair and the second antenna pair, facilitating a small form factor without reducing the performance within the high-frequency band.

In a further possible implementation form of the second aspect, the antenna element further comprises a third antenna pair according to the above and a fourth antenna pair according to the above, the third antenna pair and the fourth antenna pair being configured to emit radiation in a high-frequency band, each planar inverted-F antenna stack of the third antenna pair and the fourth antenna pair being arranged between one planar inverted-F antenna stack of the first antenna pair and one planar inverted-F antenna stack of the second antenna pair, allowing low- frequency band and high-frequency band elements to be collocated the same antenna volume.

In a further possible implementation form of the second aspect, the low-frequency band comprises frequencies between 1 GHz and 6 GHz, allowing the solution to be used in e.g. base stations. In a further possible implementation form of the second aspect, the low-frequency band comprises frequencies between 24.25-29.5 GHz and the high-frequency band comprises frequencies between 37-43.5 GHz, allowing the antenna element to be used in 5G millimeterwave systems.

According to a third aspect, there is provided an antenna structure comprising a plurality of antenna elements according to the above, wherein the antenna elements are arranged in the form of an array or a matrix. Such a solution allows an antenna structure with improved gain, increased directivity, as well as increased low-frequency bandwidth. Furthermore, the solution allows an antenna element that has relatively small form factor, while still having a wide band covering necessary 5G frequency bands. For example, the characteristics of the antenna structure, when being used as a broadside antenna, is greatly improved when used for millimeter-wave frequencies, e.g. 60 GHz. Furthermore, the antenna structure may generate a filtering response to both the low-frequency band and the high-frequency band, i.e., function as a filtenna.

In a possible implementation form of the third aspect, the antenna elements are arranged as a 1x4 array or a 2x2 matrix. By using a 1x4 array, the element pitch for both the low-frequency band and the high-frequency band may be optimized. Furthermore, the antenna structure may be used for broadside radiation or end-fire radiation. By using a 2x2 matrix, gain and bandwidth may be optimized.

In a further possible implementation form of the third aspect, the antenna structure comprises at least one further antenna element configured to emit radiation in the low-frequency band or in the high-frequency band, each further antenna element being interspersed between two adjacent antenna elements, and configured to strengthen specific radiation if so needed.

According to a fourth aspect, there is provided an electronic apparatus comprising at least one antenna structure according to the above, wherein the antenna structure is configured to emit broadside radiation and/or end-fire radiation, allowing identical antenna structures to be used for broadside radiation as well as end-fire radiation.

In a possible implementation form of the fourth aspect, the electronic apparatus further comprises a cover element forming an outer surface of the electronic apparatus, the antenna structure being arranged adjacent the cover element, allowing the antenna structure to not only take up very little space but to also arrange it in juxtaposition with a glass backcover.

These and other aspects will be apparent from the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments, and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Fig. 1 shows a schematic side view of an antenna pair in accordance with an example of the embodiments of the disclosure;

Fig. 2 shows a schematic side view of a further antenna pair in accordance with an example of the embodiments of the disclosure;

Fig. 3 shows a schematic top view of an antenna element in accordance with an example of the embodiments of the disclosure;

Fig. 4 shows a schematic top view of a further antenna element in accordance with an example of the embodiments of the disclosure;

Fig. 5 shows a schematic top view of an antenna structure in accordance with an example of the embodiments of the disclosure;

Fig. 6 shows a schematic top view of a further antenna structure in accordance with an example of the embodiments of the disclosure;

Fig. 7 shows a schematic side view of an electronic apparatus and an antenna structure in accordance with an example of the embodiments of the disclosure.

DETAILED DESCRIPTION

Figs. 1 and 2 show an antenna pair 1 comprising a first planar inverted-F antenna stack 2, a second planar inverted-F antenna stack 3, and a coupling arrangement 4 configured to couple the first planar inverted-F antenna stack 2 electromagnetically to the second planar inverted-F antenna stack 3.

As shown in Figs. 1 and 2, each antenna pair 1 comprises a first planar inverted-F antenna stack 2 and a second planar inverted-F antenna stack 3. The first planar inverted-F antenna stack 2 may be arranged adjacent a first corner of a ground plane 17 and the second planar inverted-F antenna stack 3 may be arranged adjacent a diagonally opposite, second corner of the ground plane 17, i.e. the first planar inverted-F antenna stack 2 and the second planar inverted-F antenna stack 3 of one antenna pair 1 may be arranged diagonally relative a rectangular ground plane 17 as illustrated in Fig. 3.

A coupling arrangement 4 is configured to couple the first planar inverted-F antenna stack 2 electromagnetically to the second planar inverted-F antenna stack 3.

The first planar inverted-F antenna stack 2 and the second planar inverted-F antenna stack 3 may each comprise a first planar inverted-F antenna 7 comprising a first radiating element 7a and a second planar inverted-F antenna 8 comprising a second radiating element 8a, the second planar inverted-F antenna 8 being superimposed onto the first planar inverted F- antenna 7. The distance between the first planar inverted F-antenna stack 7 and the second planar inverted-F antenna stack 8 is configured to result in an as large effective antenna aperture as possible.

The first radiating element 7a and the second radiating element 8a may each be a /4 patch element. A probe feed 9 may be coupled to the first radiating element 7a, and a ground probe 10 may be coupled to the first radiating element 7a and the second radiating element 8a, as illustrated in Figs. 1 and 2. The coupling arrangement 4 couples an open end of the first radiating element 7a to an open end of the second radiating element 8a.

As suggested in Figs. 1 and 2 by means of broken lines, the first planar inverted-F antenna stack 2 and the second planar inverted-F antenna stack 3 may further comprise a third planar inverted- F antenna 11 comprising a third radiating element I la. In such an embodiment, the ground probe 10 is coupled to the first radiating element 7a, the second radiating element 8a, and the third radiating element I la.

The first radiating element 7a, of the first planar inverted-F antenna 7, may be configured to generate a first resonance frequency, while the second radiating element 8a, of the second planar inverted-F antenna 8, may be configured to generate the first resonance frequency or a second resonance frequency. The third radiating element I la may be configured to generate a third resonance frequency. The antenna pair 1 may also comprise a differential feed structure 5 configured to feed a first signal to the first planar inverted-F antenna stack 2 and a second phase-shifted signal to the second planar inverted-F antenna stack 3. The antenna pair 1 may instead comprise a common feed structure 6 configured to feed a first signal to the first planar inverted-F antenna stack 2 and the second planar inverted-F antenna stack 3. The feed structures 5, 6 are configured to transmit signals to the radiating elements 7a, 8a, I la of the antenna stacks 2, 3. The common feed structure 6 may be configured to excite a first polarization. The differential feed structure 5 may be configured to excite a second polarization.

Figs. 3 and 4 show embodiments of an antenna element 12 comprising a first antenna pair la and a second antenna pair lb. The first antenna pair la and the second antenna pair lb are configured to emit radiation in a low-frequency band.

The first antenna pair la is configured to enable a radiation pattern having a first polarization, and the second antenna pair lb is configured to enable a radiation pattern having a second polarization. The polarization may be slanted.

The first antenna pair la may be arranged such that its antenna stacks 2, 3 are arranged adjacent the first corner of the ground plane 17 and the diagonally opposite, second comer of the ground plane 17. The second antenna pair lb may be arranged such that its antenna stacks 2, 3 are arranged adjacent a third comer of the ground plane 17 and a diagonally opposite, fourth corner of the ground plane 17. The diagonal extent of the first antenna pair la and the second antenna pair lb is illustrated in Fig. 3 by means of rectangular shapes drawn with broken lines, forming an X-shape.

The antenna stacks 2, 3 may be arranged such that at least one side of the radiating elements 7a, 8a is parallel with the sides of the ground plane 17, and/or such that at least one side of the radiating elements 7a, 8a extend at 45° to the sides of the ground plane 17. The radiating elements 7a, 8a may be hexagonal or, e.g., rectangular.

Fig. 3 also shows that the first antenna pair la and the second antenna pair lb may be arranged such that the first section 4a and the second section 4b of the coupling arrangement 4 intersect, or the coupling arrangement 4 has its center, adjacent the center of the ground plane 17. The coupling arrangement 4 may be cross-shaped. The first section 4a of the coupling arrangement 4 couples the first and second planar inverted-F antenna stacks 2, 3 of the first antenna pair la, and the second section 4b of the coupling arrangement 4 couples the first and second planar inverted-F antenna stacks 2, 3 of the second antenna pair lb. The width of the cross-shaped coupling arrangement 4 may be at least 150 pm as seen in a plane Pl parallel with the first radiating elements 7a and the second radiating elements 8a of the first antenna pair la and the second antenna pair lb.

The antenna element 12 may further comprise a third antenna pair 1c and a fourth antenna pair Id, the third antenna pair 1c and the fourth antenna pair Id being configured to emit radiation in a high-frequency band. The high-frequency band radiation may have linear polarization.

The third antenna pair 1c may be arranged such that the first planar inverted-F antenna stack 2 is arranged adjacent a first side edge of the ground plane 17, between the first corner and the fourth comer of the ground plane 17, and the second planar inverted-F antenna stack 3 is arranged adjacent an opposite, second side edge of the ground plane 17, between the third corner and the second comer of the ground plane 17. Correspondingly, the fourth antenna pair 1c may be arranged such that the first planar inverted-F antenna stack 2 is arranged adjacent a third top edge of the ground plane 17, between the first corner and the third comer of the ground plane 17, and the second planar inverted-F antenna stack 3 is arranged adjacent an opposite, fourth bottom edge of the ground plane 17, between the second comer and the fourth comer of the ground plane 17. The extent of the third antenna pair 1c and the fourth antenna pair Id is illustrated in Fig. 4 by means of rectangular shapes drawn with broken lines, forming a crossshape.

As illustrated in Figs. 4 to 6, each planar inverted-F antenna stack 2, 3 of the third antenna pair 1c and the fourth antenna pair Id may be arranged between one planar inverted-F antenna stack 2, 3 of the first antenna pair la and one planar inverted-F antenna stack 2, 3 of the second antenna pair lb. The first antenna pair la, the second antenna pair lb, the third antenna pair 1c, and the fourth antenna pair Id may be shifted in a clockwise fashion, such that e.g. the planar inverted-F antenna stacks 2, 3 of the first antenna pair la and the second antenna pair lb are arranged adjacent the first and second side edges of the ground plane 17, and the planar inverted-F antenna stacks 2, 3 of the third antenna pair 1c and the fourth antenna pair Id are arranged adjacent the corners of the ground plane. The ground probe 14 may be arranged at the edge of the ground plane 17 or at a X/4 (quarter- wave) distance to the ground plane edge 17.

The low-frequency band may comprise frequencies between 1 GHz and 6 GHz. The low- frequency band may comprise frequencies between 24.25-29.5 GHz and the high-frequency band comprise frequencies between 37-43.5 GHz, i.e. the antenna element 12 may be configured to operate at multiple frequency bands.

Figs. 5 and 6 show embodiments of an antenna structure 13 comprising a plurality of antenna elements 12, wherein the antenna elements 12 are arranged in the form of an array as shown in Fig. 5, or a matrix, as shown in Fig. 6. The antenna elements 12 may be arranged as a 1x4 array or a 2x2 matrix, however, any conceivable arrangement such as a 16x16 matrix is possible. The antenna structure 13 may be particularly suitable for use as a broadside antenna for millimeterwave frequencies, e.g. 60 GHz.

The antenna structure 13 may comprise at least one further antenna element 14, as illustrated in Fig. 7. The further antenna element 14 may be configured to emit radiation in the low-frequency band or in the high-frequency band, and each further antenna element 14 is arranged such that it is interspersed between two adjacent antenna elements 12.

An electronic apparatus 15 is illustrated in Fig. 7 by a broken line. The electronic apparatus 15 may be a handheld device such as a smartphone or a tablet, or stationary apparatus such as a base station. The electronic apparatus 15 comprises at least one antenna structure 13, and the antenna structure 13 is configured to emit broadside radiation and/or end-fire radiation.

The electronic apparatus 15 may comprise a cover element 16 forming an outer surface of the electronic apparatus 15. The cover element 16 may be a dielectric backcover, e.g. made o fglass. The cover element 16 may also be a display panel. The antenna structure 13 is arranged adjacent the cover element 16, with a dielectric gap therebetween or in direct contact with the cover element 16.

The various aspects and implementations have been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

The reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this disclosure. As used in the description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.