Patent Description:
It is often desirable to increase the operational antenna bandwidth of a wireless communication system. Mobile communication devices typically have multiple antenna systems that are each required to be thin to fit within a thin form factor of the mobile communication device (e.g., a smartphone, tablet computer, etc.). Typical antenna bandwidth enhancements include enlarging a radiating aperture of the antenna system. For example, parasitic elements may be added in proximity of a main radiating element. The dimensions of the parasitic elements are usually on the order of a half wavelength of an operational frequency to support resonance. In certain implementations, such dimensions may be difficult to maintain within the thin form factor required in modern mobile communication devices.

<CIT> discloses an antenna apparatus including a dielectric substrate, a ground plate, a patch antenna provided with a patch radiating element, and a plurality of EBGs (Electromagnetic Band Gaps). The EBGs are composed of patch-shaped patterns formed on a surface of the substrate and connecting conductors electrically connecting the patch-shaped patterns and the ground plate. Each EBG is arranged to provide an EBG absent region having no EBG on the surface of the substrate. The patch radiating element is arranged within the EBG absent region. The EBG absent region is formed such that distances (absent distances) in a dominant polarized wave direction changes into a plurality of types depending on the position on a vertical patch line, where the distances range, to the boundary of the region, from an arbitrary position on the virtual patch line which is perpendicular to the dominant polarized wave direction of the patch antenna.

<CIT> discloses an integrated repeater with a meta-structure antenna. A repeater comprises a relay amplifier, a donor antenna and a service antenna which are integrally formed. Each of the service and the donor antennas includes a main patch and at least one or more wave absorbers that are located around the main patch. The wave absorber is a radio absorber based on a meta-material structure, and has a first resonant frequency generation unit of which an input and an output are connected perpendicularly, a second resonant frequency generation unit of which an input and an output are connected parallel to each other, and an effective permittivity.

<CIT> discloses substrates and methods to fabricate and use millimeter wave Sievenpiper EBG structures such that the conductive portions are internal to an LTCC package.

<NPL>" discloses a high gain patch antenna realized by using negative permeability electromagnetic metamaterials. A number of metamaterial cells on the substrate around the patch antenna is further disclosed.

<CIT> discloses a built-in transmitting and receiving integrated radar antenna whose coverage of a horizontal radiation pattern is widened and whose space factor is improved by integrating high-frequency circuit component onto an antenna substrate while suppressing unnecessary waves. A first dielectric substrate is formed into a three-layered structure in which a bias line of an MIC is disposed between a second layer and a third layer and a second ground plane is disposed between the first layer and the second layer. Also, the second ground plane is conductively connected with isolated through-holes, so that a domain in which a feeding port is disposed is isolated from a domain in which the bias line is disposed.

<CIT> discloses an apparatus comprising an antenna formed on a substrate, and a high impedance surface (HIS). The HIS has a plurality of cells formed on the substrate that are arranged to form an array that substantially surrounds at least a portion of the antenna. Each cell generally includes a ground plane, first plate, second plate, and an interconnect. The ground plane is formed on the substrate, while the first plate is formed over and coupled to the ground plane. The first plate for each cell is also arranged so as to form a first checkered pattern for the array. The second plate is formed over and is substantially parallel to the first plate. The first and second plates are also substantially aligned with a central axis that extends generally perpendicular to the first and second plates hand have a interconnect formed there between. The second plate for each cell is also arranged so as to form a second checkered pattern for the array.

<CIT> discloses an apparatus comprising a first radiator and a first plurality of metamaterial structures formed in a first plane of a dielectric substrate, and a second radiator and a second plurality of metamaterial structures formed in a second plane of the dielectric substrate.

Enabling disclosure for the claimed invention can be found in <FIG> and <FIG> as well as in the corresponding parts in the description below. The remaining embodiments may be considered as useful for understanding the invention outside the scope of the claims unless they also relate to conductive loop structures as in the context of the present claims.

An example of an apparatus according to the disclosure is defined in claim <NUM>.

Implementations of such an apparatus may include one or more of the following features. The maximum width of each of the plurality of metamaterial structures may be in a range between one-fifth and one-twentieth of the wavelength of the operational frequency. The first radiator may be operably coupled to a feedline and the second radiator is a parasitic element. The second radiator may be disposed in a third area on the surface of the dielectric substrate, such that at least a portion of the plurality of metamaterial structures may be disposed in a fourth area surrounding the third area on the surface of the dielectric substrate. The first radiator may be a metallic patch. The plurality of metamaterial structures may form at least two concentric perimeters in the second area around the first radiator. The plurality of metamaterial structures may form at least three concentric perimeters in the second area around the first radiator. The operational frequency may be within a range from <NUM> gigahertz to <NUM> gigahertz.

Items and/or techniques described herein may provide one or more of the following capabilities, as well as other capabilities not mentioned. An antenna array may be fabricated in an integrated circuit in an electronic device. The bandwidth of an antenna array may be enhanced by changing the dielectric constant of the substrate near the elements of the antenna array. A Gradient-Index (GRIN) metamaterial may be used to modify the dielectric constant of substrate around an antenna element. The composition and arrangement of the GRIN metamaterial may be designed to create antenna gain and directivity improvements. For example, use of the GRIN metamaterial may increase bandwidth and impedance match at far out scan angles The GRIN metamaterial may include periodic metamaterial structures to create different dielectric constants. The metamaterial structures are substantially smaller than the wavelength of the antenna operating frequency. The metamaterial structures may be metallic and may increase the metal density of the antenna structure which may reduce warping and thickness variation issues in a Printed Circuit Board (PCB) manufacturing process. Further, it may be possible for an effect noted above to be achieved by means other than that noted, and a noted item/technique may not necessarily yield the noted effect.

Techniques are discussed herein for, among other things, improving the bandwidth performance of an antenna assembly in a mobile device. For example, many mobile devices include millimeter-wave (MMW) modules to support higher RF frequencies (e.g., <NUM>th Generation and/or certain Wi-Fi specifications). Increasing the bandwidth performance of an antenna system may enable higher data transfer speeds across a wider spectrum of the RF frequencies. Antenna bandwidth enhancement may be realized using substrates constituted of materials with different dielectric constants. In an embodiment, a layered stack-up may utilize gradient-index (GRIN) metamaterials including periodic metallic structures to create the different dielectric constants. In addition to modifying the dielectric constant of a substrate, the periodic metallic metamaterial structure also increases the metal density in the antenna structure which can reduce warping and thickness variation issues in PCB manufacturing processes. The disclosed designs utilize GRIN metamaterials (i.e., metamaterials) in the near-field region of a radiating source, as opposed to other solutions which typically use metamaterials in a plane wave environment in a far-field region.

Referring to <FIG>, a wireless device <NUM> capable of communicating with different wireless communication systems <NUM> and <NUM> is shown. Wireless system <NUM> may be a Code Division Multiple Access (CDMA) system (which may implement Wideband CDMA (WCDMA), cdma2000, or some other version of CDMA), a Global System for Mobile Communications (GSM) system, a Long Term Evolution (LTE) system, a <NUM> system, etc. Wireless system <NUM> may be a wireless local area network (WLAN) system, which may implement IEEE <NUM>, etc. For simplicity, <FIG> shows wireless system <NUM> including one base station <NUM> and one system controller <NUM>, and wireless system <NUM> including one access point <NUM> and one router <NUM>. In general, each system may include any number of stations and any set of network entities.

Wireless device <NUM> may also be referred to as a user equipment (UE), a mobile device, a mobile station, a terminal, an access terminal, a subscriber unit, a station, etc. Wireless device <NUM> may be a cellular phone, a smart phone, a tablet, a wireless modem, a personal digital assistant (PDA), a handheld device, a laptop computer, a smartbook, a netbook, a cordless phone, a wireless local loop (WLL) station, a Bluetooth device, etc. Wireless device <NUM> may be equipped with any number of antennas. Further, other wireless devices (whether mobile or not) may be implemented within the systems <NUM> and/or <NUM> as the wireless device <NUM> and may communicate with each other and/or with the base station <NUM> or access point <NUM>. For example, such other devices may include internet of thing (IoT) devices, medical devices, home entertainment and/or automation devices, etc. Multiple antennas may be used to provide better performance, to simultaneously support multiple services (e.g., voice and data), to provide diversity against deleterious path effects (e.g., fading, multipath, and interference), to support multiple-input multiple-output (MIMO) transmission to increase data rate, and/or to obtain other benefits. Wireless device <NUM> may be capable of communicating with wireless system <NUM> and/or <NUM>. Wireless device <NUM> may also be capable of receiving signals from broadcast stations (e.g., a broadcast station <NUM>). Wireless device <NUM> may also be capable of receiving signals from satellites (e.g., a satellite <NUM>), for example in one or more global navigation satellite systems (GNSS).

In general, wireless device <NUM> may support communication with any number of wireless systems, which may employ radio signals including technologies such as WCDMA, cdma2000, LTE, GSM, <NUM>, GPS, etc. Wireless device <NUM> may also support operation on any number of frequency bands.

Wireless device <NUM> may support operation at a very high frequency, e.g., within millimeter-wave (MMW) frequencies from <NUM> to <NUM> gigahertz (GHz). For example, wireless device <NUM> may operate at <NUM> for <NUM>. Wireless device <NUM> may include an antenna system to support operation at MMW frequencies. The antenna system may include a number of antenna elements, with each antenna element being used to transmit and/or receive signals. The terms "antenna" and "antenna element" are synonymous and are used interchangeably herein. Generally, each antenna element may be implemented with a patch antenna or a strip-type antenna. A suitable antenna type may be selected for use based on the operating frequency of the wireless device, the desired performance, etc. In an exemplary design, an antenna system may include a number of patch and/or strip-type antennas supporting operation at MMW frequency. Other radiator geometries and configurations may also be used. For example strip-shape antennas such as single-end fed, circular, and differential fed structures may be used.

Referring to <FIG>, an exemplary design of a wireless device <NUM> with a <NUM>-D antenna system <NUM> is shown. In this exemplary design, antenna system <NUM> includes a <NUM>×<NUM> array <NUM> of four patch antennas <NUM> (i.e., radiators) formed on a single plane corresponding to a back surface of wireless device <NUM>. While the antenna system <NUM> is visible in <FIG>, in operation the patch array may be disposed on a PC board or other assembly located inside of a device cover <NUM>. An antenna element may be used to transmit and/or receive signals. The antenna element may have a particular antenna beam pattern and a particular maximum antenna gain, which may be dependent on the design and implementation of the antenna element. Multiple antenna elements may be formed on the same plane and used to improve antenna gain. Higher antenna gain may be desirable at MMW frequency since (i) it is difficult to efficiently generate high power at MMW frequency and (ii) attenuation loss may be greater at MMW frequency. These limitations may be exacerbated by the presence of a back cover or other housing element or device component between a MMW antenna element and the other devices. The patch antenna array <NUM> has an antenna beam <NUM>, which may be formed to point in a direction that is orthogonal to the plane on which patch antennas <NUM> are formed or in a direction that is within a certain angle of orthogonal, for example up to <NUM> degrees in any direction from orthogonal. Wireless device <NUM> can transmit signals directly to other devices (e.g., access points) located within antenna beam <NUM> and can also receive signals directly from other devices located within antenna beam <NUM>. Antenna beam <NUM> thus represents a line-of-sight (LOS) coverage of wireless device <NUM>.

For example, an access point <NUM> (i.e., another device) may be located inside the LOS coverage of wireless device <NUM>. Wireless device <NUM> can transmit a signal to access point <NUM> via a line-of-sight (LOS) path <NUM>. Another access point <NUM> may be located outside the LOS coverage of wireless device <NUM>. Wireless device <NUM> can transmit a signal to access point <NUM> via a non-line-of-sight (NLOS) path <NUM>, which includes a direct path <NUM> from wireless device <NUM> to a wall <NUM> and a reflected path <NUM> from wall <NUM> to access point <NUM>.

In general, the wireless device <NUM> may transmit a signal via a LOS path directly to another device located within antenna beam <NUM>, e.g., as shown in <FIG>. This signal may have a much lower power loss when received via the LOS path. The low power loss may allow wireless device <NUM> to transmit the signal at a lower power level, which may enable wireless device <NUM> to conserve battery power and extend battery life.

The wireless device <NUM> may transmit a signal via a NLOS path to another device located outside of antenna beam <NUM>, e.g., as also shown in <FIG>. This signal may have a much higher power loss when received via the NLOS path, since a large portion of the signal energy may be reflected, absorbed, and/or scattered by one or more objects in the NLOS path. Wireless device <NUM> may transmit the signal at a high power level in an effort to ensure that the signal can be reliably received via the NLOS path.

Referring to <FIG>, an exemplary design of a wireless device <NUM> with a <NUM>-D antenna system <NUM> is shown. In this exemplary design, antenna system <NUM> includes (i) a <NUM>×<NUM> array <NUM> of four patch antennas <NUM> formed on a first plane corresponding to the back surface of wireless device <NUM> and (ii) a <NUM>×<NUM> array <NUM> of four patch antennas <NUM> formed on a second plane corresponding to the top surface of wireless device <NUM>. As depicted in <FIG>, the second plane is at a <NUM> degree angle respective to the first plane. The <NUM> degree angle is exemplary only and not a limitation as other orientations between one or more antenna arrays maybe be used. The antenna array <NUM> has an antenna beam <NUM>, which may be formed to point in a direction that is orthogonal to the first plane on which patch antennas <NUM> are formed or in a direction that is within a certain angle of orthogonal, for example up to <NUM> degrees in an direction from orthogonal. Antenna array <NUM> has an antenna beam <NUM>, which points in a direction that is orthogonal to the second plane on which patch antennas <NUM> are formed in the illustrated embodiment. Antenna beams <NUM> and <NUM> thus represent the LOS coverage of wireless device <NUM>. While the arrays <NUM> and <NUM> are each illustrated as a <NUM>×<NUM> array in <FIG>, one or both may include a greater or fewer number of antennas, and/or the antennas may be disposed in a different configuration. For example, one or both of the arrays <NUM> and <NUM> may be configured as a <NUM>×<NUM> array.

An access point <NUM> (i.e., another device) may be located inside the LOS coverage of antenna beam <NUM> but outside the LOS coverage of antenna beam <NUM>. Wireless device <NUM> can transmit a first signal to access point <NUM> via a LOS path <NUM> within antenna beam <NUM>. Another access point <NUM> may be located inside the LOS coverage of antenna beam <NUM> but outside the LOS coverage of antenna beam <NUM>. Wireless device <NUM> can transmit a second signal to access point <NUM> via a LOS path <NUM> within antenna beam <NUM>. Wireless device <NUM> can transmit a signal to access point <NUM> via a NLOS path <NUM> composed of a direct path <NUM> and a reflected path <NUM> due to a wall <NUM>. Access point <NUM> may receive the signal via LOS path <NUM> at a higher power level than the signal via NLOS path <NUM>.

The wireless device <NUM> shows an exemplary design of a <NUM>-D antenna system comprising two <NUM>×<NUM> antenna arrays <NUM> and <NUM> formed on two planes. In general, a <NUM>-D antenna system may include any number of antenna elements formed on any number of planes pointing in different spatial directions (including a single plane in which multiple antenna elements radiate in different directions). The planes may or may not be orthogonal to one another.

Referring to <FIG>, an exemplary design of a patch antenna <NUM> suitable for MMW frequencies is shown. The patch antenna <NUM> includes a radiator such as a conductive patch <NUM> formed over a substrate <NUM>. In an example, the patch <NUM> has a dimension (e.g., <NUM> × <NUM>) selected based on the desired operating frequency. The substrate <NUM> has a dimension (e.g., <NUM>×<NUM>). Smaller dimensions of patches and substrates may be used. In an example, a feedpoint <NUM> is located near the center of patch <NUM> and is the point at which an output RF signal is applied to patch antenna <NUM> for transmission. Multiple feed points may also be used to vary the polarization of the patch antenna <NUM>. For example, at least two conductors may be used for dual polarization (e.g., a first conductor and a second conductor may be used for a horizontal-pol feed line and a vertical-pol feed line). The locations and number of the feedpoints may be selected to provide the desired impedance match to a feedline. Additional patches may be assembled in an array (e.g., 1x2, 1x3, 1x4, 2x2, 2x3, 2x4, 3x3, 3x4, etc.. ) to further provide a desired directivity and sensitivity.

Referring to <FIG>, a side view and top view of an example patch antenna array in a wireless device <NUM> is shown. The wireless device <NUM> includes a display device <NUM>, a device cover <NUM>, and a main device printed circuit board (PCB) <NUM>. The device cover <NUM> is typically made of a plastic material such as polycarbonate or polyurethane. In some devices, the cover may be constructed of a glass or a ceramic structure. Other nonconductive materials are also used for device covers. A MMW module PCB <NUM> is operably coupled to the main device PCB <NUM> via one or more ball grid array (BGA) conductors 522a-b. The MMW module PCB <NUM> may include a plurality of patches 524a-d and corresponding passive patches 526a-b to form a wideband antenna. In general, a stack of patches (e.g., 524a, 526a) may include an actively driven element and one or more passive or parasitic elements. The MMW module PCB <NUM> also includes signal and ground layers which further increase the thickness (e.g., height) of the PCB <NUM>. An integrated circuit (RFIC) <NUM> is mounted to the MMW module PCB <NUM> and operates to adjust the power and the radiation beam patterns associated with the patch antenna array 524a-d. The RFIC <NUM> is an example of an antenna controller means. For example, the integrated circuit <NUM> may be configured to utilize phase shifters and/or hybrid antenna couplers to control the power directed to the antenna array and to control the resulting beam pattern, for example so as to drive the patches <NUM> as a phased array.

Referring to <FIG>, a uniform substrate patch antenna <NUM> includes a metallic patch <NUM> disposed in a first area on a first substrate <NUM>. In an example, the first substrate <NUM> may be a PCB material such as FR-<NUM>, BT, FR-<NUM>, etc., with a first dielectric constant (e.g., <NUM>, <NUM>, <NUM> at <NUM>-<NUM>). The PCB material is an example only and not a limitation as other substrates with different dielectric constants may be used. In general, the dielectric constant of the substrate around an antenna structure may impact the performance of the antenna. Referring to <FIG>, for example, a mixed substrate patch antenna <NUM> includes the metallic patch <NUM> disposed in a first area on the first substrate <NUM>. The metallic patch <NUM> and the first substrate <NUM> are surrounded by a second area comprising a second substrate <NUM>. The dielectric constant of the second substrate <NUM> is different from the dielectric constant of the first substrate <NUM>. In an example, the dielectric constant of the first substrate <NUM> is <NUM> and the dielectric constant of the second substrate <NUM> is <NUM>. Referring to <FIG>, a frequency response graph <NUM> relating to the patch antennas in <FIG> is shown. The graph <NUM> includes a signal strength axis <NUM> (in dB) and a radio frequency axis <NUM> (in GHz). A first data set <NUM> indicates the frequency response of the uniform substrate patch antenna <NUM>, and a second data set <NUM> indicates the frequency response of the mixed substrate patch antenna <NUM>. A comparison highlight area <NUM> is provided to demonstrate the bandwidth enhancement realized by the mixed substrate patch antenna <NUM>. Specifically, the mixed dielectric substrate increases the antenna S11 (e.g., standing wave ratio) at less than - 10dB for a wider frequency range as compared to a uniform substrate patch antenna. The frequency response curves (e.g., the first data set <NUM>, and the second data set <NUM>) are examples only and may change with different dielectric values as well as different substrate and patch geometries.

Referring to <FIG>, an example substrate <NUM> with metamaterial structures is shown. The substrate <NUM> includes a metallic patch <NUM> disposed in a first area of a dielectric substrate <NUM>, and a plurality of metamaterial structures <NUM> disposed on and/or within a second area of the dielectric substrate <NUM> (e.g., FR-<NUM>, BT, FR-<NUM>, etc.). The second area of the substrate706 surrounds the first area of the substrate <NUM> and is within the near field of the metallic patch <NUM>. In some embodiments, the term "surround" may be used to refer to a configuration which is not fully enclosed, while in other embodiments the term "surround" refers to a configuration that fully encloses another portion or area. The metallic patch <NUM> may be a square metal patch or other type of radiator such as a strip antenna. The metamaterial structures <NUM> may be small metallic structures (e.g., squares, crosses, circles, etc.) disposed in the near field of the metallic patch <NUM> in a periodic pattern. In general, the term near field means a region in the immediate vicinity of a radiating antenna that is not the far field of the antenna. A definition of the near field may include the region in which the energy radiated from the antenna is predominately a reactive field (e.g., the E- and H- fields are out of phase with one another). The dimensions (e.g., maximum width) of the metamaterial structures <NUM> are electrically small in physical size as compared to the wavelength of the operational frequency of the metallic patch <NUM>. A periodic pattern may be defined as a repeating pattern of metamaterial structures on a single plane of a substrate with each metamaterial structure being a neighbor to at least two other metamaterial structures on two axes, the distances to each of the neighboring metamaterial structures being approximately equal. The dielectric constant of a portion of the substrate on or in which the metamaterials are formed may be increased due to the presence of the periodic pattern of metamaterial structures. In an example, the maximum width of each of the metamaterial structures is less than half of a wavelength of the operational frequency. The dimensions and/or period of the positions of the metamaterial structures <NUM> may be varied to change the dielectric constant of the PCB substrate <NUM>. The example substrate <NUM> provides similar bandwidth enhancements as the mixed substrate patch antenna <NUM>. That is, the metamaterial structures <NUM> effectively change the dielectric constant of the PCB substrate <NUM> in the areas the metamaterial structures <NUM> are disposed. The net electrical result of including the metamaterial structures is similar to the results achieved by using the second dielectric constant of the second substrate <NUM> in the mixed substrate patch antenna <NUM>.

Referring to <FIG>, a frequency response graph <NUM> of an example metamaterial structure is illustrated. The graph <NUM> includes a resistance/reactance axis <NUM>, a frequency axis <NUM>, a frequency response curve <NUM> and a stable operation region <NUM>. The graph <NUM> represents an example frequency response of an example metamaterial structure (e.g., a individual small metal structure such as one of the metamaterial structures <NUM>). The metamaterial structure resonates at a first resonant frequency f<NUM>. At frequencies less than the first resonant frequency (e.g., << f<NUM>), the frequency response is approximately flat as depicted in the stable operation region <NUM>. The metamaterial structures described herein are designed to operate within the stable operation region <NUM> for transmission/reception frequencies of the patch <NUM> (or other radiator which is disposed near the metamaterial structure). For example, the dimensions of the metamaterial structures are typically in a range of <NUM>/<NUM>th to <NUM>/<NUM>th the size of the wavelength of the frequency of the antenna radiator.

Referring to <FIG>, a patch antenna with examples of different metamaterial structures are shown. <FIG> provides a general overview of different metamaterial structures and <FIG> provide more detailed views of the embodiments. While the metal structures in <FIG> are generally depicted as squares, other geometric shapes (e.g., circles, rectangles, polygons, etc.) may be used. A single patch baseline antenna <NUM> is an example of a uniform substrate patch antenna <NUM> as described in <FIG> including a metallic patch and a first substrate. The single patch baseline antenna <NUM> provides reference bandwidth performance as comparison for the example antenna designs depicted in <FIG>. A patch antenna with a wall <NUM> includes a single metal patch and a uniform substrate surrounded by a continuous metal wall. A patch antenna with a first metal pattern <NUM> includes a single patch with a metamaterial including two concentric perimeters (e.g., rings) of metal structures disposed on or in a substrate around the patch. A patch antenna with a second metal pattern <NUM> includes a single patch with a metamaterial including three concentric perimeters of metal structures disposed on or in a substrate around the patch. A patch antenna with a third metal pattern <NUM> includes a single patch with a metamaterial including four concentric perimeters of metal structures disposed on or in a substrate around the patch. A patch antenna with loop rings <NUM> includes a single patch with a metamaterial including a plurality of metallic loop rings disposed in a substrate around the patch. A patch antenna with symmetrical loop rings <NUM> includes a single patch with a metamaterial including a plurality of symmetric metallic loop rings disposed in a substrate around the patch. As depicted in Table <NUM> below, the example patch antennas depicted in <FIG> provide different bandwidth performance and different metal density values.

Referring to <FIG>, a frequency response graph <NUM> depicting the antenna bandwidth performance for each of the examples depicted in <FIG> is shown. The graph <NUM> includes a signal strength axis <NUM> (in dB) and a frequency axis <NUM> (in GHz). The graph <NUM> includes a plurality of response curves associated with the designs depicted in <FIG> and are the basis for the bandwidth performance provided in Table <NUM>. In an example, the response curves may be generated with a modeling software such as High Frequency Simulation Software (HFSS) from Ansys, Inc. For example, a first response curve 902a is based on the performance of the single patch baseline antenna <NUM>. A second response curve 904a is based on the patch antenna with a wall <NUM>. A third response curve 906a is based on the patch antenna with a first metal pattern <NUM>. A fourth response curve 908a is based on the patch antenna with a second metal pattern <NUM>. A fifth response curve 910a is based on the patch antenna with a third metal pattern <NUM>. A sixth response curve 912a is based on the patch antenna with loop rings <NUM>.

Referring to <FIG>, illustrations of the example patch antennas depicted in <FIG> are shown with at least a top view and a side view. The patch antennas are examples only as other configurations of radiators and metamaterial may be used to enhance the bandwidth of an antenna system. Further, while the examples in <FIG> show four metal layers, fewer layers (e.g., only one layer) or additional layers may be used. Referring to <FIG>, a top view and side view of the single patch baseline antenna <NUM> are shown. The single patch baseline antenna <NUM> includes the metallic patch <NUM> and the first substrate <NUM>. The first substrate <NUM> may include one or more additional metallic patches 602a. For example, as depicted in 10A, the metallic patch <NUM> is an active radiator and receives an input from a feedline 602b. The additional metallic patches 602a may be passive (e.g., parasitic) radiators. In an embodiment, antenna polarization may be realized by providing an additional feed signal to the metallic patch <NUM> or one of the additional metallic patches 602a. The first substrate <NUM> may include a feed layer <NUM> including at least one feedline 1002a configured to provide an RF signal to the metallic patch <NUM>. The first substrate <NUM> may also include an interconnect layer <NUM> configured to operably couple the antenna <NUM> to a MMW module PCB <NUM>, an RFIC <NUM>, or other circuits and devices as required in a wireless communications device.

Referring to <FIG>, a top view and a side view of a patch antenna with a wall <NUM> are shown. The antenna <NUM> includes a metallic patch <NUM> operably coupled to a feedline 602b. The metallic patch <NUM> is disposed on a PCB substrate <NUM>. A solid metallic wall <NUM> is disposed around the metallic patch <NUM> and the PCB substrate <NUM>. In an example, the wall <NUM> may be approximately <NUM>-<NUM> thick with a height equal to the width of the PCB substrate <NUM>. In other embodiments, the wall may instead be formed of a plurality of vias. The PCB substrate <NUM> may include a feed layer (not shown in <FIG>) and the interconnect layer <NUM>. Additional parasitic or active radiators may also be included within the PCB substrate <NUM>.

Referring to <FIG>, a top view and a side view of a patch antenna with a first metal pattern <NUM> are shown. The antenna <NUM> includes a metallic patch <NUM> operably coupled to a feedline 702b. The metallic patch <NUM> and a plurality of metamaterial structures <NUM> are disposed on and within a PCB substrate <NUM>. In an example, the metallic patch <NUM> is approximately <NUM> in length and <NUM> in width (e.g. +/- <NUM>%) and may be deposited in a PCB manufacturing process such as High Density Interconnect (HDI) or other such sequential lamination processes. Each of the plurality of metamaterial structures <NUM> may be approximately <NUM> to <NUM> in length and width (e.g., +/- <NUM>%) and may be deposited during the manufacturing process. In general, the spacing between each of the metamaterial structures <NUM> are kept at approximately equal values to form a periodic pattern. For example, the metamaterial structures <NUM> are arranged in two concentric perimeters around the metallic patch <NUM>. A first concentric perimeter 705a includes equally spaced metamaterial structures <NUM> around the exterior boundary of the PCB substrate <NUM>, and a second concentric perimeter 705b includes equally spaced metamaterial structures <NUM> inside of the first concentric perimeter 705a as shown in <FIG>. The spacing between the first concentric perimeter 705a and the second concentric perimeter 705b is equal to the spacing between the metamaterial structures <NUM> on either of the concentric perimeters 705a-b. The period and size of the metamaterial structures <NUM> may be varied to change the dielectric constant of the PCB substrate <NUM>. In addition to repeating the pattern in the x-y plane, as indicated in <FIG>, the pattern is repeated along the z-axis such that more than one plane within the PCB substrate <NUM> may include a metallic patch and a plurality of metamaterial structures. For example, both the metallic patch <NUM> and the plurality of metamaterial structures <NUM> are repeated three times at equal intervals throughout the depth <NUM> of the PCB substrate <NUM>. The additional metallic patches within the depth <NUM> of the PCB substrate <NUM> may be passive radiators or may be configured to receive an RF signal (i.e., active radiator). The PCB substrate may include a feed layer <NUM>, such as a microstrip line 1002a, which includes a feedline 702b that is operably coupled to the metallic patch <NUM> with one or more via connects. In an example, an additional feedline may be coupled to the metallic patch <NUM> or one of the additional metallic patches within the PCB substrate <NUM> to provide dual polarization capabilities.

Referring to <FIG>, a top view and a side view of a patch antenna with a second metal pattern <NUM> are shown. The antenna <NUM> includes a metallic patch <NUM> operably coupled to a feedline 1020b. The metallic patch <NUM> and a plurality of metallic metamaterial structures <NUM> are disposed on and within a PCB substrate <NUM>. In an example, the metallic patch <NUM> is approximately <NUM> in length and <NUM> in width (e.g. +/- <NUM>%) and each of the plurality of metallic metamaterial structures <NUM> may be approximately <NUM> to <NUM> in length and width (e.g., +/- <NUM>%). The metallic patch <NUM> and plurality of metallic metamaterial structures <NUM> may be deposited during the manufacturing process. The spacing between each of the metallic metamaterial structures <NUM> are kept at approximately equal values to form a periodic arrangement. As an example, the metallic metamaterial structures <NUM> are arranged in a periodic pattern including three concentric perimeters 1025a-c around the metallic patch <NUM>. As depicted in <FIG>, the pattern of the metallic metamaterial structures <NUM> may also be repeated at equal vertical intervals within the PCB substrate <NUM>. For example, the interior portion <NUM> of the PCB substrate <NUM> comprises three layers, with each layer including both a metallic patch <NUM> and a plurality of metallic metamaterial structures <NUM>. The additional metallic patches in the interior portion <NUM> may be passive radiators or may be configured to receive an RF signal (i.e., active radiator). The PCB substrate may include a feed layer <NUM>, such as a microstrip line 1002a, which includes a feedline 1020b that is operably coupled to the metallic patch <NUM> with one or more via connects. In an example, an additional feedline may be coupled to the metallic patch <NUM> or one of the additional metallic patches within the PCB substrate to provide dual polarization capabilities. In an example, the bottom metallic patch in the interior portion <NUM> is operably coupled to a feedline.

The dimensions, shape and patterns of the metallic patch <NUM> and metallic metamaterial structures <NUM> are examples only and not limitations. Other dimensions, shapes and patterns may be used to enhance the bandwidth performance of an antenna system. For example, the metamaterial structures may be in one pattern on one side of the metal patch and a different pattern on another side of the metal patch. Variations in the dimensions, shapes and/or patterns of the metal patch and metamaterial structures may be used to increase gain / directivity of an antenna system. In general, the addition of the metamaterial structures to the PCB substrate may provide antenna bandwidth enhancements when the physical size of the individual metamaterial structures is smaller than the wavelength of the operational frequency of the antenna (i.e., within the stable operation region <NUM>), and the metamaterial structures are disposed in a periodic pattern on and/or within the PCB substrate. The addition of the metallic metamaterial structures also provides the advantage of increasing the metal density of an antenna system which may be beneficial to PCB construction because it can reduce warpage in the antenna assembly.

Referring to <FIG>, a top view, a side view and a perspective view of a patch antenna with loop rings <NUM> are shown. The antenna <NUM> includes a metallic patch <NUM> operably coupled to a feedline 1030b. The metallic patch <NUM> and a plurality of metallic metamaterial structures <NUM> are disposed on and within a PCB substrate <NUM>. In an example, the metallic patch <NUM> is approximately <NUM> in length and <NUM> in width (e.g. +/- <NUM>%) and each of the plurality of metallic metamaterial structures <NUM> may be approximately <NUM> to <NUM> in width and <NUM> to <NUM> in length (e.g., +/- <NUM>%). The interior portion <NUM> of the PCB substrate <NUM> may include multiple layers with each layer including a metallic patch and a plurality of metallic metamaterial structures. One or more of the metallic metamaterial structures <NUM> may be electrically coupled to a metamaterial structure in an adjacent layer with two conducting vias 1034a to form a conductive loop structure. For example, two metamaterial structures <NUM> may form a top portion and a bottom portion of a loop ring, such that two conducting vias 1034a connect the respective ends of the metamaterial structures <NUM> to form the ring structure. Thus, as depicted in <FIG>, four layers of metamaterial structures <NUM> create two layers of loop rings within the PCB substrate <NUM>. The metallic patch <NUM>, the plurality of metallic metamaterial structures <NUM>, and the conducting vias 1034a may be deposited during the manufacturing process. The spacing between each of the metallic metamaterial structures <NUM> are kept at approximately equal values to form a periodic arrangement. The PCB substrate <NUM> may include four layers of metal patches <NUM> as previously described. The PCB substrate <NUM> may include a feed layer <NUM>, such as a microstrip line 1002a, which includes a feedline 1030b that is operably coupled to the metallic patch <NUM> with one or more via connects. In an example, an additional feedline may be coupled to the metallic patch <NUM> or one of the additional metallic patches within the PCB substrate to provide dual polarization capabilities. In an example, the bottom metallic patch in the interior portion <NUM> is operably coupled to a feedline.

Referring to <FIG>, a top view, a side view and a perspective view of a patch antenna with symmetrical loop rings <NUM> are shown. The antenna <NUM> includes a metallic patch <NUM> operably coupled to a feedline 1040a. The metallic patch <NUM> and a plurality of metallic metamaterial structures <NUM> are disposed on and within a PCB substrate <NUM>. In an example, the metallic patch <NUM> is approximately <NUM> in length and <NUM> in width (e.g. +/- <NUM>%) and each of the plurality of metallic metamaterial structures <NUM> may be approximately <NUM> to <NUM> in width and <NUM> to <NUM> in length (e.g., +/- <NUM>%). The interior portion <NUM> of the PCB substrate <NUM> may include multiple layers with each layer including a metallic patch and a plurality of metallic metamaterial structures. One or more of the metallic metamaterial structures <NUM>, <NUM> may be electrically coupled to a metamaterial structure in an adjacent layer with two or more conducting vias 1046a to form a conductive loop structure. For example, two metamaterial structures <NUM> may form a top portion and a bottom portion of a loop ring, such that two conducting vias 1046a connect the respective ends of the metamaterial structures <NUM> to form the ring structure. The metallic metamaterial structures <NUM> located in the corners of the antenna <NUM> are square-loop shaped and are coupled to an adjacent layer with four conducting vias 1046a. In an example, the square-loop shaped metamaterial structures <NUM> may not be coupled to adjacent layers. As compared to the patch antenna with loop rings <NUM> depicted in <FIG>, the loop rings in the patch antenna with symmetrical loop rings <NUM> present a symmetric orientation relative to the metal patch <NUM>. The PCB substrate <NUM> may include four layers of metal patches <NUM> as previously described. The PCB substrate <NUM> may include a feed layer <NUM>, such as a microstrip line 1002a, which includes a feedline 1040a that is operably coupled to the metallic patch <NUM> with one or more via connects. In an example, an additional feedline may be coupled to the metallic patch <NUM> or one of the additional metallic patches within the PCB substrate to provide dual polarization capabilities. In an example, the bottom metallic patch in the interior portion <NUM> is operably coupled to a feedline.

Referring to <FIG>, with further references to <FIG>, examples of metal patch geometries are shown. In general, the size and shape of a metal patch radiator may be varied based on frequency, bandwidth and beam forming requirements. This geometry of the metal patches previously described are examples only and not limitations as other radiator shapes and configurations may be used. For example, a patch antenna array may be comprised of one or more patches including shapes such as a square patch <NUM>, a circle patch <NUM>, an octagon patch <NUM>, and a triangle patch <NUM>. Other shapes may also be used, and an antenna array may include patches with differing shapes. The properties of a patch antenna may be varied by changing the boundaries of the individual patches. For example, a square patch with single notches <NUM>, a square patch with multiple notches <NUM> such as depicted in <FIG>, and a square with parallel notches <NUM> may be used as a radiator. The square patch geometry is an example only and not a limitation as other shapes may include one or more notches such as a circle with notches <NUM>, an octagon with notches <NUM>, and a triangle with notches <NUM>. The shape and locations of the notches may vary. For example, the notches may be semicircles, triangles, or other shaped areas of material that are removed from the patch. A patch antenna may include one or more parasitic radiators disposed in proximity to the patch. For example, a patch with one set of parasitic radiators <NUM> and a patch with two sets of parasitic radiators <NUM> may be used. The metamaterial structures may be disposed around the combination of the patch and the parasitic radiators. The geometry, number, and locations of the parasitic radiators may vary based on antenna performance requirements.

Referring to <FIG>, with further reference to <FIG>, examples of antenna arrays with different metamaterial structures are shown. A first antenna array <NUM> includes a plurality of metal patches on a uniform substrate. The first antenna array <NUM> is comprised of four single patch baseline antennas <NUM> in a 2x2 array. The first antenna array <NUM> provides a baseline by which bandwidth improvements of arrays with metamaterial structures may be measured. The example single metal patch antennas and metamaterial structures described at <FIG> may be extended into multi-radiator arrays such as patch antenna arrays <NUM>, <NUM>. For example, a second antenna array <NUM> includes four patch antennas with a second metal pattern arranged in a 2x2 array. The metamaterial structures are disposed between each of the metal patches. The metal patches and metamaterial structures are based on the patch antenna with second metal pattern described in <FIG>. For example, a first metal patch may be disposed in a first area and a first pattern of metamaterial structures may be disposed in a second area surrounding the first area. A second metal patch may be disposed in a third area and a second pattern of metamaterial structures may be disposed in a fourth area. At least a portion of the second and the fourth areas is between the first and the third areas. In another example, a third antenna array <NUM> includes four patch antennas with loop rings arranged in a 2x2 array. The 2x2 configuration is an example only and not a limitation as other arrays (e.g., 1x2, 1x3, 1x4, 2x3, 2x4, 3x3, 3x4, 4x4, etc.) may be used. The antenna arrays are also not limited to metal patches as strip radiators and dipole configurations may be used as active and parasitic elements. The addition of the metallic metamaterial to the PCB substrate within the near field of the antenna modifies the dielectric constant of the substrate and may be used to provide bandwidth improvements to an antenna system. An implementation of a gradient-index metamaterial may be used with a wide range of antenna configurations and is not limited to a particular antenna geometry or array structure. For example, metamaterial structures strip-shape antennas such as single-end fed, circular, and differential fed structures may be used.

Specific details are given in the description to provide a thorough understanding of example configurations (including implementations). However, configurations may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the configurations. This description provides example configurations only, and does not limit the scope, applicability, or configurations of the claims. Rather, the preceding description of the configurations provides a description for implementing described techniques.

Also, as used herein, "or" as used in a list of items prefaced by "at least one of" or prefaced by "one or more of" indicates a disjunctive list such that, for example, a list of "at least one of A, B, or C," or a list of "one or more of A, B, or C," or "A, B, or C, or a combination thereof" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C), or combinations with more than one feature (e.g., AA, AAB, ABBC, etc.).

As used herein, unless otherwise stated, a statement that a function or operation is "based on" an item or condition means that the function or operation is based on the stated item or condition and may be based on one or more items and/or conditions in addition to the stated item or condition.

Components, functional or otherwise, shown in the figures and/or discussed herein as being connected, coupled (e.g., communicatively coupled), or communicating with each other are operably coupled. That is, they may be directly or indirectly, wired and/or wirelessly, connected to enable signal transmission between them.

Having described several example configurations, various modifications, alternative constructions, and equivalents may be used without departing from the disclosure. For example, the above elements may be components of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of operations may be undertaken before, during, or after the above elements are considered. Accordingly, the above description does not bound the scope of the claims.

Claim 1:
An apparatus (<NUM>, <NUM>) comprising:
a dielectric substrate (<NUM>, <NUM>) having a first area and a second area disposed around the first area;
a first radiator <NUM>, <NUM>) disposed on a surface of the dielectric substrate (<NUM>, <NUM>), in the first area, the first radiator (<NUM>, <NUM>) being configured to transmit and receive radio signals at an operational frequency;
a first plurality of metamaterial structures (<NUM>, <NUM>) disposed in a periodic pattern on the surface of the dielectric substrate (<NUM>, <NUM>) in the second area and within a near field of the first radiator (<NUM>, <NUM>), wherein a maximum width of each of the first plurality of metamaterial structures (<NUM>, <NUM>) is less than half of a wavelength of the operational frequency; and
a second radiator and a second plurality of metamaterial structures disposed on a second plane within the dielectric substrate (<NUM>, <NUM>), the second radiator being disposed in the first area of the dielectric substrate (<NUM>, <NUM>) under the first radiator (<NUM>, <NUM>), and the second plurality of metamaterial structures being disposed in the second area of the dielectric substrate (<NUM>, <NUM>) under the first plurality of metamaterial structures (<NUM>, <NUM>);
wherein the first radiator (<NUM>, <NUM>) and the first plurality of metamaterial structures (<NUM>, <NUM>) are disposed on a first plane of the dielectric substrate (<NUM>, <NUM>), wherein each of the first plurality of metamaterial structures (<NUM>, <NUM>) are electrically coupled to a metamaterial structure of the second plurality of metamaterial structures in an adjacent layer with two conducting vias (1034a, 1046a) to form a conductive loop structure.