TECHNICAL FIELD

The present disclosure relates to antenna devices, for example, to printed circuit board (PCB)-based antenna devices, such as stacked patch antenna devices. The disclosure provides an antenna device with at least one first antenna and at least one second antenna, which are distanced from each other by a radiating cavity, which surrounds the at least one first antenna.

BACKGROUND

Stacked antenna devices are usually exploited in many fields of application, due to their low complexity, relatively large operating bandwidths (>10%), dual-polarization operation, and suitability for PCB technology. For example, mm-wave antennas and antenna arrays may be realized by PCB-based antennas that are directly connected to radio frequency (RF) circuitry (also referred to as Antenna on Board (AoB) and Antenna in Package (AiP)) and form the building blocks of mm-wave antenna systems.

A PCB-based stacked antenna device exploits a PCB stack-up, to properly space apart different stacked antennas. This means, however, that several PCB layers operate essentially as mechanical spacers only, and have no other functionality. Therefore, the PCB complexity and cost (e.g., in terms of number of PCB layers, alignment between the layers, number of different classes of plated via holes, etc.), as well as the number of failures in manufacturing, are negatively impacted by this solution.

For example, FIG. 1 shows a stacked patch antenna device. The device comprises a multilayered PCB, which includes a first patch antenna 101. RF signal lines and RF devices may be formed in and/or at the bottom of the PCB. The device also includes a second patch antenna 102. A distance between the first patch antenna 101 and the second patch antenna 102 (as well as the antenna dimensions) is designed to achieve a desired performance in terms of operating bandwidth, and is realized by stacking a certain number of the PCB layers above the first patch antenna 101 and below the second patch antenna, as shown. Compared to a non-stacked patch antenna device (which has only the first patch antenna arranged on atop surface of the PCB), the number of PCB layers is increased. This also increases the manufacturing cost and its complexity.

It can be seen from FIG. 1 that the PCB layers between the first patch antenna 101 and the second patch antenna 102 are essentially used to maintain the second patch antenna 102 at the wanted distance to the first patch antenna 101, and have no other functionality. They thus operate only as mechanical spacers.

SUMMARY

In view of the above, this disclosure aims to provide an antenna device without the abovedescribed issues. For example, an objective is to provide a stacked antenna device that has low complexity and manufacturing cost. To this end, a reduction of the PCB layers is desired compared to an exemplary stacked antenna devices, for instance, as shown in FIG. 1. Other objectives are a high cross-polarization discrimination (XPD) and a wide bandwidth. The antenna device should moreover be compatible with the use of patch-fed antennas.

These and other objectives are achieved by this disclosure, as described in the independent claims. Advantageous implementations are further described in the dependent claims.

A first aspect of this disclosure provides an antenna device comprising: a base structure comprising a first PCB; one or more first antennas supported by a surface of the base structure; an enclosure comprising a support structure arranged on the surface of the base structure and comprising a cover structure arranged on the support structure, wherein the support structure is at least partly conductive, and wherein the enclosure forms a cavity around the one or more first antennas; and one or more second antennas arranged on the cover structure of the enclosure at a distance to the one of more first antennas.

The cavity in the antenna device of the first aspect replaces the PCB layers, which are arranged between first antennas and second antennas, in an exemplary stacked antenna device, e.g., the one shown in FIG. 1. Thus, the number of PCB layers, can be decreased. Also the complexity of the antenna device, and its manufacturing costs, can be lowered in this way. The cavity may be a radiating cavity, which may be achieved because of the at least partly conductive support structure. In this way the bandwidth and the XPD of the antenna device can be increased.

In an implementation form of the first aspect, the one or more first antennas and the one or more second antennas are patch antennas.

Thus, the antenna device of the first aspect is compatible with the use of patch-fed antennas.

In an implementation form of the first aspect, the antenna device further comprises one or more conductive sub-resonating elements and/or one or more conductive resonating elements arranged on the cover structure of the enclosure.

These conductive elements improve impedance matching and control of the XPD, when the antenna device of the first aspect is used for beam-steering.

In an implementation form of the first aspect, the one or more second antennas are arranged inside the cavity on the cover structure, and the one or more conductive sub-resonating elements and/or the one or more conductive resonating elements are arranged outside the cavity on the cover structure.

In an implementation form of the first aspect, the support structure is at least partly conductive, such that the one or more first antennas and the one or more second antennas transfer energy into and from the support structure when radiating.

By the above implementation forms, the bandwidth of the antenna device of the first aspect can be further improved.

In an implementation form of the first aspect, the support structure comprises a metallized plastic part, or a second PCB, or a metal part.

In an implementation form of the first aspect, the cover structure comprises a third PCB or a plastic part. In an implementation form of the first aspect, the support structure and the cover structure are formed by an integral plastic part.

This provides a particularly low complex, cheap, and easy to manufacture antenna device of the first aspect.

In an implementation form of the first aspect, the cover structure comprises a plastic part and the one or more second antennas are formed by a metallization of the plastic part.

In an implementation form of the first aspect, the one or more conductive sub-resonating elements and/or the one or more conductive resonating elements are formed by a metallization of the plastic part.

In an implementation form of the first aspect, the first PCB comprises a plurality of stacked layers, wherein at least one RF circuitry and/or one or more vias connecting the at least one RF circuitry are formed in the stacked layers.

In an implementation form of the first aspect, the base structure comprises the first PCB comprising the stacked layers as a first part, and a separate second part arranged on the first part and carrying the one or more first antennas.

In an implementation form of the first aspect, the second part is a further PCB or a plastic part.

In an implementation form of the first aspect, the base structure and the enclosure are assembled together using at least one of a non-conductive adhesive, a conductive adhesive, soldering, and a mechanical connection; or wherein the base structure and the enclosure are integral.

In an implementation form of the first aspect, the support structure is in galvanic contact with a ground reference of the first PCB or is capacitively coupled to the ground reference. In an implementation form of the first aspect, the one or more first antennas and the one or more second antennas comprise at least one of single-polarized antennas and dualpolarized antennas.

In an implementation form of the first aspect, the one or more first antennas and the one or more second antennas comprise at least one of pin-fed antennas, probe-fed antennas, and slot-fed patch antennas.

In an implementation form of the first aspect, the distance between the one or more first antennas and the one or more second antennas is provided by the cavity.

In an implementation form of the first aspect, the cavity is filled with air.

In an implementation form of the first aspect, the one or more first antennas and the one or more second antennas form an antenna array configured for beam steering.

According to this disclosure, a conventional AoB (or AiP) device may be simplified in terms of its manufacturing cost and complexity, and may also be improved in terms of its performance.

According to this disclosure, a patch-fed radiating cavity antenna device for AoB and AiP may be fabricated, which has improved antenna performance in terms of operating bandwidth, and - particularly when operating in a phased array - better XPD and active impedance matching when steering.

The concept of this disclosure can be applied to single-polarized and dual-polarized stacked patch antennas, or to pin-fed, probe-fed, and/or slot-fed stacked patch antennas.

Starting form an exemplary antenna device as, for example, shown in FIG. 1, the concept of this disclosure is based on the replacement of some or all PCB layers, which are mainly used as mechanical spacers, by a single part (integral base and cover structure), or with an assembly of two or more simple parts (base structure and cover structure), which are able to provide an at least partly conductive or metallized cavity around the first antenna(s). Further, additional degrees of freedom (possible thanks to the cavity) may be exploited according to this disclosure, in order to implement, for instance, the sub-resonating conductive elements to control the XPD.

BRIEF DESCRIPTION OF DRAWINGS

The above described aspects and implementation forms will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which

FIG. 1 shows an example of a stacked patch antenna device.

FIG. 2 shows an antenna device according to this disclosure.

FIG. 3 shows a stacked patch antenna device with cavity and sub-resonating elements, according to this disclosure.

FIG. 4 shows the active S-parameter on a Smith chart for several steering angles evaluated for (a) an exemplary stacked antenna device and (b) an antenna device according to this disclosure.

FIG. 5 shows a radiation pattern @f_min when the main beam of a 7-element array is steered to -60deg for (a) an exemplary stacked antenna device and (b) an antenna device according to this disclosure.

FIG. 6 shows a radiation pattern @f_med when the main beam of a 7 -element array is steered to -60deg for (a) an exemplary stacked antenna device and (b) an antenna device according to this disclosure.

FIG. 7 shows a radiation pattern @f_max when the main beam of a 7 -element array is steered to -60deg for (a) an exemplary stacked antenna device and (b) an antenna device according to this disclosure

FIG. 8 shows an antenna device according to this disclosure with a metallized support structure and a PCB cover structure forming the enclosure. FIG. 9 shows an antenna device according to this disclosure with a metallized support structure and a PCB cover structure forming the enclosure, and a two-part base structure.

FIG. 10 shows an antenna device according to this disclosure with an integral, metallized plastic part forming the enclosure.

FIG. 11 shows an antenna device according to this disclosure with two separate plastic parts forming the enclosure.

FIG. 12 shows assembling sections of an antenna device according to this disclosure.

FIG. 13 shows different exemplary implementations of an antenna device of this disclosure with: (a) a squared cavity and a uniform arrangement of square sub-resonating elements; (b) a circular cavity with a non-uniform arrangement of square sub-resonating elements; (c) a squared cavity and a non-uniform radial arrangement of square sub-resonating elements.

FIG. 14 shows an antenna device according to this disclosure with multiple first and second antennas.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 2 shows an antenna device 200 according to this disclosure. The antenna device 200 comprises a base structure 201, one or more first antennas 202, an enclosure comprising a support structure 203 and a cover structure 204, and one or more second antennas 205.

The base structure 201 comprises a first PCB. For example, the first PCB may comprise a plurality of stacked layers. A least one RF circuitry, and/or one or more vias connecting the at least one RF circuitry, may be formed in the stacked layers of the first PCB. The base structure 201 may also consist of the first PCB, or may comprise the first PCB as first part and a separate second part, for example, a further PCB or plastic part, which is arranged on or below the first part. The one or more first antennas 202 are supported by a surface of the base structure 201, for example, a surface of the first PCB. The one or more first antennas 202 may comprise patch antennas. The one or more first antennas 202 may comprise at least one of single-polarized antennas and dual-polarized antennas. The one or more first antennas 202 may comprise at least one of pin-fed antennas, probe-fed antennas, and slot-fed patch antennas. As shown in FIG. 2 there may be one first antenna 202, however, there may also be multiple first antennas 202, for instance, arranged in an array, as shown later.

The support structure 203 of the enclosure may be arranged on the surface of the base structure 201, and the cover structure 204 may be arranged on the support structure 203. The support structure 203 is at least partly conductive, and the enclosure forms a cavity 206 around the one or more first antennas 201. As an example, the support structure 203 may comprise a metallized plastic part, or a second PCB, or a metal part. As an example, the cover structure 204 may comprise a third PCB or a plastic part.

The one or more second antennas 205 are arranged on the cover structure 204 of the enclosure at a distance to the one of more first antennas 202. The distance between the one or more first antennas 202 and the one or more second antennas 205 may be provided by the cavity 206, which may be filled with air. The one or more second antennas 205 may be are arranged inside the cavity 206 on the cover structure 204 of the enclosure, as shown. However, it is also possible to arrange the one or more second antennas 205 outside the cavity 206 on the cover structure 204. The one or more second antennas 205 may comprise patch antennas. The one or more second antennas 205 may comprise at least one of singlepolarized antennas and dual-polarized antennas. The one or more second antennas 205 may comprise at least one of pin-fed antennas, probe-fed antennas, and slot-fed patch antennas. As shown in FIG. 2 there may be one second antenna 205, however, there may also be multiple second antennas 205, for instance, arranged in an array, as shown later.

The antenna device 200 of the present disclosure is a high-performing and low-cost stacked antenna device with stacked antennas (e.g., a first antenna 202 and second antenna 205), or arrays of stacked antennas (e.g., multiple first antennas 202 and/or multiple second antennas 205). Compared to an exemplary antenna device, as shown in FIG. 1, the antenna device 200 of this disclosure may benefit in terms of cost reduction and higher yield, due to at least one of: a lower number of PCB layers; a lower number of lamination processes; a lower number of via holes and via classes. The antenna device 200 of the present disclosure can be implemented in several different manners.

FIG. 3 shows an antenna device 200 according to this disclosure, which is an implementation of the antenna device 200 of FIG. 2. For instance, the antenna device 200 of FIG. 3 may be a stacked patch antenna device with a cavity 206. Same elements in FIG. 2 and FIG. 3 are labelled with the same reference signs.

The antenna device 200 of FIG. 3 comprises the base structure 201, which here consists of the first PCB as an example, which may connect to an RFIC 302 as illustrated. The antenna device 200 further comprises the support structure 203, which is at least partly conductive, and the cover structure 204 forming the enclosure, at least one first antenna 201 arranged on the surface of the first PCB and in the cavity 206, and at least one second antenna 205 arranged on the cover structure 204 and in the cavity 206.

Further, the antenna device 200 comprises one or more conductive sub-resonating elements 301 arranged on the cover structure 203. Additionally or alternatively, the antenna device 200 could comprise one or more conductive resonating elements arranged on the cover structure 204 (not shown). The conductive sub-resonating elements 301 allow to exploit of additional degrees of freedom, for instance, to control the XPD of the antenna device 200.

In addition, when the first and second antennas 202, 205 of the antenna device 200 of this disclosure are used as phased arrays, a twofold advantage is provided. Firstly, a much more stable active impedance matching is guaranteed when steering, as shown in FIG. 4. In FIG. 4, specifically an active S-parameter on the Smith chart is shown for several steering angles evaluated for (a) an exemplary antenna device as shown in FIG. 1, and (b) the antenna device 200 according to this disclosure.

Secondly, as depicted in FIG. 5, FIG. 6, and FIG. 7, a remarkable improvement of the XPD is provided when steering the beam to large angles, and this advantage is clearly visible on the entire operating bandwidth. In this respect, FIG. 5, FIG. 6, and FIG. 7 show, respectively, a radiation pattern @f_min, a radiation pattern @f_med, and a radiation pattern @f_max, when the main beam of a 7-element array is steered to -60deg for (a) an exemplary antenna device as shown in FIG. 1, and (b) the antenna device 200 according to this disclosure.

FIG. 8 shows an antenna device 200 according to this disclosure, which is an implementation of the antenna device 200 of FIG. 2. Same elements in FIG. 2 and FIG. 8 are labelled with the same reference signs.

The antenna device 200 of FIG. 8 comprises the first PCB as the base structure 201. The first PCB has a reduced number of layers with respect to the exemplary antenna device shown in FIG. 1. Further, the antenna device 200 comprises a first antenna 202 arranged on the first PCB, for instance, belonging to the first PCB. The antenna device 200 further has a metallized support structure 203 of the enclosure, which creates a metal cavity 206 surrounding each and every antenna, with at least the first antenna being able to transfer energy into and from the metallized cavity206. A separated PCB (composed by at least one layer) forms the cover structure 204 applied on top of the metallized support structure 203, holding at least one second antenna 205, and further a certain number of sub-resonating metallized elements 301. The second antenna 205 is arranged inside the cavity 206 on the cover structure 204, and the sub-resonating elements 301 are arranged outside the cavity 206 on the cover structure 204.

FIG. 9 shows an antenna device 200 according to this disclosure, which is an implementation of the antenna device 200 of FIG. 2. Same elements in FIG. 2 and FIG. 9 are labelled with the same reference signs.

The antenna device 200 of FIG. 9 comprises the first PCB, wherein the first PCB has a reduced number of layers compared to the PCB of the exemplary antenna device of FIG. 1. The antenna device 200 further comprises a further PCB 902, which is separate from the first PCB. The first PCB and the further PCB 902 form the base structure 201. The further PCB 902 is arranged on the first PCB. The antenna device 200 comprises a first antenna 202 arranged on or belonging to the further PCB 902, in any case, carried by the further PCB 902. The antenna device 200 also comprises a metallized support structure 203, which creates a cavity 206 surrounding each and every antenna, wherein at least the first antenna 202 is able to transfer energy into and from the metallized cavity 206. A third separated PCB (composed by at least one layer) forms the cover structure 204 and is applied on top of the metallized support structure 203, holding at least one second antenna 205 and a certain number of sub-resonating metallized elements 301. The second antenna 205 is arranged inside the cavity 206 on the cover structure 204, and the subresonating elements 301 are arranged outside the cavity 206 on the cover structure 204.

FIG. 10 shows an antenna device 200 according to this disclosure, which is an implementation of the antenna device 200 of FIG. 2. Same elements in FIG. 2 and FIG. 10 are labelled with the same reference signs.

The antenna device 200 of FIG. 10 comprises the first PCB, as the antenna device 200 of FIG. 8, with the reduced number of layers compared to the antenna device of FIG. 1. The antenna device 200 further comprises a first antenna 202 carried by or belonging to the first PCB. A single plastic part 1002 with selective metallization 1001 implements both the support structure 203 and the cover structure 204. The integral plastic part 1002 forms a metallized cavity 206 surrounding each and every antenna element, with at least the first antenna 202 being able to transfer energy into and from the metallized cavity 206. At least one second antenna 205 and a certain number of sub-resonating metallized elements 301 are formed, for instance, by metallization, on the cover structure 204. The second antenna 205 is formed inside the cavity 206 on the cover structure 204, and the subresonating elements 301 are formed outside the cavity 206 on the cover structure 204.

FIG. 11 shows an antenna device 200 according to this disclosure, which is an implementation of the antenna device 200 of FIG. 2. Same elements in FIG. 2 and FIG. 11 are labelled with the same reference signs

The antenna device 200 of FIG. 11 comprises the first PCB, as the antenna device 200 of FGI. 8, with the reduced number of layers compared to the exemplary antenna device of FIG. 1. A first plastic part 1101 implements the support structure 203 and a part of the base structure 201. The part of the first plastic part 1101 implementing the part of the base structure 201 (together with the first PCB) comprises selective metallization in order to form a first antenna 202. That is, the first antenna 202 in this case is carried by the part of the first plastic part 1101 that is attributed to the base structure 201. A second plastic part 1102 forms the cover structure 204 and has selective metallization forming at least one second antenna 205, and further selective metallization forming a certain number of subresonating metallized elements 301. The second antenna 205 is formed inside the cavity 206 on the cover structure 204, and the sub-resonating elements 301 are formed outside the cavity 206 on the cover structure 204. Further, a metallized cavity 206 surrounding each and every antenna element 202, 205 can be implemented either on the first plastic part 1101 or on the second plastic part 1102, or on both, with at least the first antenna 202 being able to transfer energy into and from the metallized cavity 206. The first plastic part 1101 and the second plastic part 1102 may be obtained by means of a single plastic item.

Notably, any combination of the previously described implementations shown in FIG. 8- FIG. 11 is possible by the concept of this disclosure. Further, the metallized cavity 206, particularly the at least partly conductive support structure 203, can be either in galvanic contact with a ground reference of the first PCB or can be capacitively coupled to this ground reference.

Therefore, the parts composing the antenna device 200 of this disclosure can be assembled in several ways, for instance, by means of: a non-conducting adhesive (e.g. sheet and/or glue); a conductive adhesive (e.g. sheet and/or paste and/or glue); soldering; or a mechanical assembly (e.g. snap-fit and/or screwing and/or rivets).

FIG. 12 shows a sketch representing the assembling sections (according to the implementation of FIG. 9, as an example) of the antenna device 200. For instance, the base structure 201 can be one such section, the support structure 203 another such section, and the cover structure 204 another such section, wherein these sections can be assembled together using one of the aforementioned techniques.

In all antenna devices 200 of this disclosure, the support structure 203 can be made of: a plastic part, which is at least partly metallized; or a low-cost PCB (e.g. FR4), which may be milled and metallized; or a metal part, which may be milled. The cavity 206 formed by the support structure 203 and the cover structure 204 of the enclosure can have any kind of shape (e.g., squared, rectangular, circular, conical...) in this disclosure. The antennas 202, 205 (and other resonating elements) can have different shapes and/or geometries and/or sizes as well. The sub-resonating elements 301 can have different shapes and/or geometries and/or sizes as well, and also different arrangements (e.g., uniform, non-uniform, radial etc.). A couple of examples are depicted in FIG. 13.

In particular, FIG. 13 shows examples of different implementations. In (a), a squared cavity 206 with rounded edges and a uniform arrangement of square sub-resonating elements 301 is shown. In (b), a circular cavity 206 with non-uniform arrangement of square sub-resonating elements 301 and an additional cross-shaped resonating patch is shown. In (c), a squared cavity 206 with rounded edges, a non-uniform radial arrangement of square sub-resonating elements 301, and an additional cross-shaped resonating patch is shown.

FIG. 14 shows an antenna device 200 according to this disclosure, which is an implementation of the antenna device 200 of FIG. 2. Same elements in FIG. 2 and FIG. 11 are labelled with the same reference signs.

While the antenna device 200 of FIG. 2 is exemplarily shown to have at least one first antenna 202 and at least one second antenna 205, the antenna device 200 of FIG. 14 comprises multiple first antennas 202 and multiple second antennas 205. The multiple first antennas 202 are supported by a surface of the base structure 201, and the multiple second antennas 205 are arranged on the cover structure 204 of the enclosure, at a distance to the multiple first antennas 202. The multiple second antennas 205 are formed inside the cavity 206 on the cover structure 204, and multiple sub-resonating elements 301 are formed outside the cavity 206 on the cover structure 204. However, the second antennas 205 could also be on the outside of the cavity 206 on the cover structure 204 together with the subresonating elements 301, or the sub-resonating elements 301 could also be inside the cavity 206 on the cover structure 204. There can also be a mix, where second antennas 205 are formed outside and inside the cavity 206 on the cover structure 204, and/or where subresonating elements 301 are formed outside and inside the cavity 206 on the cover structure 204. In any case, the sub-resonating elements 301 are optional in the antenna device 200 of FIG. 14. The features of the antenna device 200 of FIG. 14 can be mixed or exchanged with those of the antenna devices 200 shown in FIG. 8 - FIG. 11.

The present disclosure, in summary, provides the following benefits. An improved solution for PCB-based stacked antenna devices is provided, in which the radiating section is moved out from the main PCB. This allows to substantially reduce the PCB complexity (e.g., lower number of layers, lower number of laminations, less vias), which may improve the production yield, which leads to reduced costs compared to an exemplary device as shown in FIG. 1.

Further, a remarkable improvement in terms of operating bandwidth is achieved, when considering phased array antennas. Also a very stable active impedance is achieved, when steering the beam, which leads to improved performance and improved efficiency of the antenna device 200.

Further, a remarkable improvement in terms of XPD is achieved, when steering the beam to larger angles, which results in an improved performance. The antenna device 200 also works with both single-ended and differentially fed stacked patch antennas, which makes it applicable to many application scenarios. In addition, the antenna device 200 works with all stacked patch antennas, no matter which is the feeding method (e.g., probe-fed, pin-fed, slot-fed...), which again makes it applicable to many application scenarios.

The present disclosure has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed matter, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.