Patent Description:
More and more radio technologies need to be supported in a mobile device. These technologies may include cellular technologies, such as <NUM>/<NUM>/<NUM> radio, as well as non-cellular technologies. In the coming <NUM> new radio (NR) technology, the frequency range will be expanded from sub-<NUM> to the so-called mmWave frequency, e.g., <NUM>, <NUM>, <NUM> and <NUM>. In mmWave frequency, the antenna array will be used to form beams with higher gain to overcome higher path loss in the propagation media. However, antenna radiation patterns and array beam patterns with higher gain will result in a narrow beam width. Beam steering techniques such as phased antenna array can be utilized to steer the beam towards different direction on demand. However, when it comes to user equipment (UE) such as a mobile terminal, the UE may be used in an arbitrary orientation. Thus, the UE antenna design must exhibit a very wide nearly full spherical beam coverage.

One challenge to implement mmWave antennas for a UE device is to have omnicoverage radiation properties, where mmWave energy is radiated from the sides of the UE device to achieve full spherical coverage. The conventional technique to achieve display side radiation is to locate mmWave antenna arrays next to the display unit. However, the current design trend is to extend the size of the display so that the display cover the whole front face of the UE. This limits the space available for the antenna(s).

Accordingly, it would be desirable to provide an antenna array that addresses at least some of the problems identified above. <CIT> discloses antenna systems and compact antenna systems having multiple antennas. <CIT> antenna devices for millimeter wave (mmWave) communication.

The aspects of the disclosed embodiments are directed to providing an antenna array for a mobile communication device. Further advantageous modifications can be found in the dependent claims.

According to a first aspect the above and further objects and advantages are obtained by an antenna assembly. In one embodiment, the antenna assembly includes a first antenna array disposed on a first side of a substrate and a second antenna array disposed on the second side of the substrate. The first antenna array is made up of a first monopole antenna element and at least one second monopole antenna element. A metal strip member is coupled to the first monopole antenna element and to the at least one second monopole antenna element. The second antenna array comprises a dipole shaped coupler. The first antenna array and the second antenna array are spaced apart by a predetermined distance and occupy a common space. The end of the first monopole antenna element and the metal strip member are separated by a gap (300a) and the end of the second monopole antenna and the metal strip member are separated by the gap. The metal strip member is disposed on a third layer of the substrate and the third layer is different from the first layer and the second layer. The aspects of the disclosed embodiments provide an antenna arrangement that is extremely compact since the geometry of two differently polarized antenna arrays is shared between the antennas. Physically smaller antennas are beneficial given the small volumes available for antennas in devices with big displays.

In a possible implementation form of the antenna assembly, the metal strip member couples an end of the first monopole antenna element opposite a feed point of the first monopole antenna element to an end of the at least one second antenna element opposite a feed point of at least one the second antenna element. The aspects of the disclosed embodiments provided improved bandwidth and efficiency of the first monopole antenna element and the second monopole antenna element by a coupled array mode. The electric fields generated by the first monopole antenna element and the second monopole antenna element are uniform and less frequency dependent due to metal strip member coupling.

In a possible implementation form of the antenna assembly the metal strip member is directly connected to the first monopole antenna element and the at least one second monopole antenna element. The connection with the metal strip member makes the arrangement of the first monopole antenna element and the second monopole antenna element physically smaller. The metal strip member is effectively operating as a part of the first monopole antenna element and the second monopole antenna element.

In a possible implementation form of the antenna assembly the metal strip member and the first monopole antenna are separated by a gap. The metal strip member and the at least one second monopole antenna are separated by the gap. In this manner, the metal strip member is capacitively coupled to the first monopole antenna element and the second monopole antenna element. The aspects of the disclosed embodiments enable the first monopole antenna and the second monopole antenna to be physically smaller. The frequency bands of the monopole antennas are tuned by the first gap and the second gap in order to make the antenna assembly smaller in size.

In a possible implementation form of the antenna assembly, the metal strip member is disposed on a third layer of the substrate, wherein the third layer is different from the first layer and the second layer. The aspects of the disclosed embodiments provide for the metal strip to be capacitively coupled, enabling greater design flexibility.

In a possible implementation form of the antenna assembly an alignment of the first monopole antenna and the at least one second monopole antenna on the substrate is orthogonal relative to an alignment of the metal strip member. The dipole-shaped antenna coupler of the second antenna array uses the metal strip member of the first antenna array as an antenna member. This allows the overall size of the antenna assembly to remain small.

In a possible implementation form of the antenna assembly, the pre-determined distance between first antenna array and the second antenna array is less than approximately two millimeters (mm). The antenna assembly can be implemented on a printed circuit board (PCB) and a typical thickness of the PCB is between <NUM> to <NUM>. Coupling with the metal strip member is reduced when the distance increases beyond this range, which can limit the performance of the antenna assembly.

In a possible implementation form of the antenna assembly, a dielectric block is disposed over a top the second antenna array. The frequency of the second antenna array, or the horizontally polarized antenna, can be tuned in order to make the horizontally polarized antenna, such as the dipole shaped antenna coupler, and the antenna assembly smaller in size.

In a possible implementation form of the antenna assembly, the second antenna array comprises a second dipole shaped antenna coupler. The second dipole shaped antenna coupled is tightly coupled with the first dipole shaped antenna coupler. Tightly coupled or connected antenna arrays achieve wideband performance since neighbouring antenna elements allow the current to remain nearly constant over frequency. This enables the size of the antenna assembly to be physically smaller.

In a possible implementation form of the antenna assembly a first branch of the second dipole shaped antenna coupler is connected to a first feeding line and a second branch of the second dipole shaped antenna coupler is connected to a second feeding line. The second dipole antenna coupler is configured to provide balanced feeding where the different feed lines feed signals with the same magnitude and <NUM> degree phase offset.

In a possible implementation form of the antenna assembly a first branch of the second dipole shaped antenna coupler is connected to a feeding line and a second branch of the second dipole shaped antenna coupler is connected to a ground connection. This enables the second dipole shaped antenna coupler to have unbalanced feeding.

In a possible implementation form of the antenna assembly a polarization of the first antenna array is different from a polarization of the second antenna array. Data throughput is improved by the different polarizations and the multiple input multiple output (MIMO) performance of the antenna assembly.

In a possible implementation form of the antenna assembly the first antenna array is configured as vertically polarized antenna and the second antenna array is configured as a horizontally polarized antenna. Data throughput is improved by the different polarizations and the MIMO performance of the antenna assembly.

According to a second aspect the above and further objects and advantages are obtained by a mobile communication device. In one embodiment, the mobile communication device has a frame member, a display glass member covering a display of the mobile communication device and an antenna assembly according to any one or more of the possible implementation forms.

In a possible implementation form of the mobile communication device the antenna assembly is disposed in a cavity of the frame member between the display glass member and the frame member. The aspects of the disclosed embodiments provide a visually-appealing design of the mobile communication device. The device can include a full-display design with minimal inactive areas on the front surface. The aspects of the disclosed embodiments provide an antenna arrangement that is extremely compact since the geometry of two differently polarized antenna arrays is shared between the two antennas. Physically smaller antennas are beneficial given the small volumes available for antennas in devices with larger or full screen displays.

These and other aspects, implementation forms, and advantages of the exemplary embodiments will become apparent from the embodiments described herein considered in conjunction with the accompanying drawings. It is to be understood, however, that the description and drawings are designed solely for purposes of illustration and not as a definition of the limits of the disclosed invention, for which reference should be made to the appended claims. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

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

Referring to <FIG>, an exemplary antenna assembly <NUM> incorporating aspects of the disclosed embodiments is illustrated. The aspects of the disclosed embodiments are directed to a compact dual polarization connected antenna array, also referred to as a mmWave multi-mode connected antenna array, with wide beam coverage. The antenna assembly <NUM> of the disclosed embodiments is extremely compact since the geometry of two differently polarized antenna arrays is shared between the two antennas. Physically smaller antennas are beneficial given the small volumes available for antennas in mobile devices with big displays. The antenna assembly <NUM> is configured to be integrated into the frame of a mobile device with a full-display, wherein the frame of the mobile device can be made by solid metal. As used herein, the term "full-display" mobile device generally refers to a device with a screen-to-body ratio that is over <NUM> percent, or a bezel less device.

As shown in the example of <FIG>, the antenna assembly <NUM> includes a first antenna array <NUM> and a second array <NUM>. The first antenna array <NUM> is disposed on a first side <NUM> or layer of a substrate <NUM>. The second antenna array <NUM> is disposed on a second side <NUM> or layer of the substrate <NUM>. As will be further described herein, the substrate <NUM> generally comprises a printed circuit board (PCB). The printed circuit board can have any number of layers. In the example of <FIG>, five layers are illustrated, with the antennas disposed on the bottom and top layers. A typical PCB will have at least two metal layers, a maximum number of layers is limited by the height or thickness of the PCB. Although for the purposes of the description herein, the antenna arrays <NUM>, <NUM> will be described with respects to bottom and top sides of the substrate <NUM>. However, the aspects of the disclosed embodiments are not so limited. In alternative embodiments, the antenna arrays <NUM>, <NUM> can be disposed on any suitable layers of the printed circuit board, as will be described further herein.

The first antenna array <NUM> comprises at least a first monopole antenna or antenna element <NUM> and at least a second monopole antenna or antenna element <NUM>. As will be generally understood, the antenna assembly <NUM> can include any number of monopole antenna elements. For example, <FIG> illustrates an embodiment where the first antenna array <NUM> includes eight (<NUM>) monopole antenna elements.

In one embodiment, the second antenna array <NUM> comprises at least one dipole shaped coupler <NUM>. The number of dipole shaped coupler antennas of the second antenna array <NUM> will correspond to the number of monopole antennas of the first antenna array <NUM>.

A metal strip member <NUM> is coupled to and between the first monopole antenna element <NUM> and the at least one second monopole antenna element <NUM>. In one embodiment, as shown in <FIG>, the metal strip member <NUM> is directly connected to and between the first monopole antenna element <NUM> and the at least one second monopole antenna element <NUM> to form an electrically conductive connection. Although the example of <FIG> shows a direct connection of the metal strip member <NUM> to the monopole antenna elements <NUM>, <NUM>, the aspects of the disclosed embodiments are not so limited. In one embodiment, as shown in <FIG>, the metal strip member <NUM> can be capacitively coupled to the monopole antenna elements <NUM>, <NUM> via a capacitive gap 300a.

The first antenna array <NUM> and the second antenna array <NUM> are spaced apart by a predetermined distance and occupy a common space. In the example of <FIG>, the pre-determined distance is a thickness of the substrate <NUM>. A typical thickness of the substrate <NUM> can range to and from between approximately <NUM> to and including <NUM>. The coupling of the second antenna array <NUM> with the metal strip member <NUM> is reduced when the predetermined distance increases beyond this range, which can limit the performance of the antenna assembly <NUM>. In alternative embodiments, the distance between the first antenna array <NUM> and the second antenna array <NUM> can be any suitable distance that enables coupling with the metal strip member and does not limit the performance of the antenna assembly.

For the purposes of the description herein, the first antenna array <NUM> in this example is configured as a vertically polarized antenna array. This vertically polarized antenna array can be either a connected antenna array or a multifeed folded monopole antenna array.

The second antenna array <NUM> in this example, is configured as a horizontally polarized antenna array with dipole shaped couplers that are tightly coupled. The term "tightly coupled" as used herein generally refers to adjacent ends of elements of different dipole shaped couplers being closely spaced. In one embodiment, the spacing between the ends of the elements of adjacent dipole shaped couplers is less than λ/<NUM>. The geometry of the vertically polarized antenna is shared between both the vertically and horizontally polarized antennas.

In the example of <FIG>, the first monopole antenna element <NUM> has a feedpoint <NUM> and an endpoint <NUM>. The second monopole antenna <NUM> includes feedpoint <NUM> and endpoint <NUM>. Generally, each monopole antenna will have a feedpoint and an endpoint. In one embodiment, the endpoint of a monopole antenna comprises a T-shaped endpoint. An example of this is shown in the embodiment of <FIG>, where endpoints <NUM> and <NUM> are in a T-shape form.

Referring also to <FIG>, the first antenna array <NUM> is formed by a number of individual monopole antenna elements, generally illustrated as antenna elements <NUM>-<NUM>. The monopole antenna elements <NUM>-<NUM> are connected or coupled to each other by the metal strip member <NUM>, and a total of eight (<NUM>) feeds <NUM>-<NUM> are used. However, in alternative embodiments the number of individual monopole antenna elements can be anything larger than <NUM>.

In one embodiment, a proper antenna length for the monopole antenna elements is defined such that the electrical length <NUM> is roughly λ/<NUM>. The physical length of the monopole antenna elements can be reduced with the help of a ceramic block with a proper dielectric constant (Dk). In this design, a Dk of <NUM> is used but suitable values are between <NUM> and <NUM>.

In one embodiment, a dummy antenna branch <NUM> is disposed at one end of the antenna array <NUM> and a dummy antenna branch <NUM> is disposed at the other end of the antenna array <NUM>. The dummy antenna branches <NUM>, <NUM> are used to mimic a continuation of the antenna array <NUM>. The dummy antenna branches <NUM>, <NUM> may be directly, electrically or inductively connected to PCB <NUM> as shown in <FIG> or capacitively coupled by providing a capacitive gap 119a between the PCB <NUM> and the dummy antenna <NUM> and <NUM> as illustrated in <FIG>. A direct connection increases the antenna impedance more as compared to the use of the gap 119a.

As shown in <FIG> and <FIG>, the metal strip member <NUM> is connected to and connects the monopole antennas <NUM>-<NUM>. As shown in <FIG>, the metal strip member <NUM>, which can comprise any suitable type of electrically conducting element, couples end <NUM> of the first monopole antenna element <NUM>, which is opposite the feed point <NUM>, to the end <NUM> of the second antenna element <NUM>, opposite the feed point <NUM>.

In the example of <FIG>, the monopole antenna elements <NUM>, <NUM> are T-shaped, forming capacitively loaded monopole antenna elements. A gap 300a, referred to as a capacitive gap, separates the ends <NUM>, <NUM> of the respective monopole antenna elements <NUM>, <NUM> from the metal strip member <NUM>. In this example, the metal strip member <NUM> is capacitively coupled to the respective monopole antenna elements <NUM>, <NUM>. When a capacitive gap is introduced as shown in <FIG>, the metal strip member is floating, i.e., there is no galvanic connection.

The metal strip member <NUM> can be located on the same layer as the first or monopole antenna array <NUM> as shown in <FIG> or <FIG> or any other layer between the monopole antenna array <NUM> and the second antenna array <NUM>. For example, in one embodiment, the metal strip member <NUM> can be disposed on a layer of the substrate <NUM> that is between the layer <NUM> and the layer <NUM>. Where the metal strip member <NUM> is located on a layer of the substrate that is not one of the layers <NUM> or <NUM>, there will also be a vertically oriented or disposed gap between the metal strip member <NUM> and one or more of the first antenna array <NUM> and the second antenna array in addition to the horizontally oriented gap 300a. The size of this vertically oriented gap will be the distance between the particular layer of the substrate <NUM> and the location of the respective antenna array <NUM>, <NUM>.

Referring to <FIG>, a schematic diagram of the second antenna array <NUM> is illustrated, wherein the second antenna array <NUM> is disposed on the second side <NUM> of the substrate <NUM>, or a side of the substrate <NUM> opposing the first antenna array <NUM>. Also referring to <FIG>, the second antenna array <NUM> comprises a dipole shaped coupler <NUM> and at least one other dipole shaped coupler <NUM>. <FIG> illustrates an example of the second or dipole shaped coupler antenna array <NUM> that includes eight dipole shaped coupler elements <NUM>-<NUM>. As will be generally understood, the second antenna array <NUM> can include any suitable number of dipole shaped couplers. The number of dipole-shaped coupler elements of the second antenna array <NUM> has to be the same as the number of monopole antenna elements of the first antenna array <NUM>.

As shown in <FIG>, a spacing <NUM> between adjacent dipole-shaped coupler elements and a length <NUM> of an exemplary dipole-shaped coupler element <NUM> is roughly λ/<NUM>. The physical dimensions of the dipole shaped coupler elements can depend on the dielectric material(s) that are used.

Referring again to <FIG> and <FIG>, the first dipole shaped coupler <NUM> includes a first dipole element <NUM>, a second dipole element <NUM>, and a feed point <NUM>. The at least one other dipole shaped coupler <NUM> includes a first dipole element <NUM>, a second dipole element <NUM> and a feed point <NUM>. The dipole-shaped couplers in <FIG> and <FIG> are tightly coupled in order to create a full wave loop type current distribution.

As shown in <FIG>, the second antenna array <NUM> includes a dummy antenna branch <NUM> at one end of the antenna array <NUM> and a dummy antenna branch <NUM> at the other end of the antenna array <NUM>. The dummy branches <NUM>, <NUM> are used to mimic a continuation of the antenna array <NUM>. The dummy antenna branches <NUM>, <NUM> may be inductively connected to PCB <NUM> as shown in <FIG> or capacitively coupled by providing a capacitive gap 119a between the PCB <NUM> and the dummy antenna <NUM> and <NUM> as shown in <FIG>.

Referring now to <FIG>, which is a partial cross-sectional view of an exemplary user equipment (UE) <NUM>, both the first antenna array <NUM> and the second antenna array <NUM> occupy the same volume <NUM>. In this example, the substrate or PCB <NUM> is located under the display panel <NUM>. The geometry, placement and arrangement of the respective elements of the first antenna array <NUM> and the second antenna array <NUM> relative to one another, as illustrated in <FIG>, enables the first antenna array <NUM>, which in this example, is a vertically polarized antenna, to be shared between both the first antenna array <NUM> and the second antenna array <NUM>. The sharing of the geometry of the first antenna array <NUM> creates differential mode radiating currents on both the vertically polarized and horizontally polarized antenna arrays and improves the performance of the horizontally polarized antenna array.

<FIG> and <FIG> illustrate two different examples configured to provide antenna feeding for the second, or horizontally polarized antenna array <NUM>. In <FIG>, there are mirrored feeds, represented as feed lines <NUM>-<NUM> and <NUM>-<NUM>, disposed on either side <NUM>, <NUM> of a centre-line <NUM> of the dipole-shaped coupler array <NUM>. In the example of <FIG>, the mechanical antenna geometry is mirrored with respect to the center line <NUM>. This makes the antenna array <NUM> operate like one big dipole as presented in <FIG>. Furthermore, this kind of mirrored antenna arrangement will improve the antenna isolation between the two polarizations of antenna arrays <NUM> and <NUM>.

As illustrated in <FIG>, this mirrored feeding scheme is implemented by having <NUM> degree phase difference between the left <NUM> and right <NUM> side feeding of the dipole-shaped coupler array <NUM>. This feeding scheme excites two orthogonal modes, differential and common mode, and excellent isolation, for example, better than <NUM> dB, can be achieved. In the example of <FIG>, the feeding scheme has similar phasing over the feeds.

<FIG> illustrates an example where the dipole shaped antenna coupler <NUM> has balanced feeding. In this example, one branch <NUM> of the dipole shaped antenna coupler <NUM> is connected to a first feed line <NUM>. A second branch <NUM> of the dipole shaped antenna coupler <NUM> is connected to a second feed line <NUM>. The feed lines <NUM> and <NUM> are feeding signals with the same magnitude and <NUM> degree phase offset.

<FIG> illustrates an example of unbalanced feeding of a dipole shaped antenna coupler <NUM>. In this example, one branch <NUM> of the dipole shaped antenna coupler <NUM> is connected to a first feed line <NUM>. The other branch <NUM> of the dipole shaped antenna coupler <NUM> is connected to a ground connection, typically a ground connection of the substrate <NUM>.

<FIG> illustrates an example of an antenna assembly <NUM> incorporating aspects of the disclosed embodiments where the monopole antenna array <NUM> is a multi-feed folded monopole antenna array. In this example, monopole antenna elements <NUM>, <NUM> and <NUM> are illustrated, it being understood that the antenna assembly <NUM> can any number of monopole antenna elements greater than one. The number of monopole antenna elements will be equal to the number of dipole shaped antenna couplers.

In the example of <FIG>, the monopole antenna element <NUM> includes a feed point <NUM> and a folded branch <NUM>. The monopole antenna element <NUM> includes a feed point <NUM> and a folded branch <NUM>. The monopole antenna element <NUM> includes a feed point <NUM> and a folded branch <NUM>. Monopole antennas may have very low impedance level if located close to other metal objects or a ground plane. One way to increase the impedance of a monopole antenna is to introduce an additional branch(es). Increasing the number of branches increases the impedance level. The purpose of the folded branch is to increase the impedance of monopole elements.

<FIG> is a side partial cross-sectional view of a user equipment or device <NUM> incorporating aspects of the disclosed embodiments. In this example, the user equipment <NUM> is a mobile communication device. As shown in <FIG>, an antenna assembly <NUM> incorporating aspects of the disclosed embodiments is disposed within the confines of the metal frame <NUM> of the device <NUM>. In this example, the antenna assembly <NUM> includes a monopole antenna array <NUM> and a dipole shaped antenna coupler array <NUM> disposed with respect to the substrate <NUM>, as is generally described herein with respect to any one or more of <FIG> and <FIG>. Co-existence of the antenna assembly <NUM> with the sub-<NUM> metal frame antenna <NUM> is provided by maintaining a dielectric-filled gap <NUM> between the antenna assembly <NUM> and the metal frame <NUM>.

In the example of <FIG>, a dielectric block <NUM> is shown disposed in conjunction with the antenna assembly <NUM>. In particular, the dielectric block is disposed over the second antenna array <NUM>, which in this example, is the dipole shaped coupler array. In one embodiment, the dielectric constant Dk of the block <NUM> can be in the range of <NUM>-<NUM>. The dielectric block <NUM> shown in <FIG> is optional, and its use will depend upon the implementation. As is shown in <FIG>, the antenna assembly <NUM> can be disposed beneath a display glass <NUM> of the device <NUM>. In this manner, dual polarization beamforming is focused toward the direction of the display glass <NUM>. In this manner, when the user is holding the mobile communication device <NUM>, the user's hand will not interfere with the antenna performance.

Referring to <FIG> and <FIG>, the antenna assembly <NUM> of the disclosed embodiments can be implemented in a Radio Frequency Integrated Circuit (RFIC) or chip <NUM>. As shown in <FIG>, the RFIC <NUM> can be configured to be disposed within an exemplary mobile communication device <NUM>, below the display glass <NUM>.

The aspects of the disclosed embodiments are directed to a dual-polarized connected antenna assembly that includes a monopole antenna array and a dipole shaped coupler antenna array. The monopole antenna array and the dipole shaped coupler antenna array are tightly coupled and occupy the same space or volume. The geometry of the monopole antenna array is shared with the dipole shaped coupler antenna array. The antenna assembly of the disclosed embodiments is configured to provide wide beam coverage with both vertical and horizontal polarization and can be implemented in a solid metal frame mobile device that includes a full display area.

Claim 1:
An antenna assembly (<NUM>) comprising:
a substrate (<NUM>),
a first antenna array (<NUM>) disposed on a first layer (<NUM>) of the substrate (<NUM>), the first antenna array (<NUM>) comprising a first monopole antenna element (<NUM>) and at least one second monopole antenna element (<NUM>);
a second antenna array (<NUM>) disposed on a second layer (<NUM>) of the substrate (<NUM>), the second antenna array (<NUM>) comprising a dipole shaped coupler (<NUM>); and
a metal strip member (<NUM>) coupled to the first monopole antenna element (<NUM>) and to the at least one second monopole antenna element (<NUM>);
wherein the first antenna array (<NUM>) and the second antenna array (<NUM>) are spaced apart by a predetermined distance and occupy a common space,
wherein the end (<NUM>) of the first monopole antenna element (<NUM>) and the metal strip member (<NUM>) are separated by a gap (300a) and the end (<NUM>) of the second monopole antenna (<NUM>) and the metal strip member (<NUM>) are separated by the gap (300a), characterized in that the metal strip member (<NUM>) is disposed on a third layer (<NUM>) of the substrate (<NUM>), wherein the third layer (<NUM>) is different from the first layer (<NUM>) and the second layer (<NUM>).