WO2019152429A1

WO2019152429A1 - Antenna assemblies including stacked patch antennas

Info

Publication number: WO2019152429A1
Application number: PCT/US2019/015706
Authority: WO
Inventors: Reza Azadegan
Original assignee: Laird Technologies, Inc.
Priority date: 2018-02-01
Filing date: 2019-01-29
Publication date: 2019-08-08

Abstract

According to various aspects, exemplary embodiments are disclosed herein of antenna assemblies (e.g., vehicular antenna assemblies, etc.) including stacked patch antennas. In an exemplary embodiment, an antenna assembly includes a dielectric spacer, a first patch antenna, and a second patch antenna. The second patch antenna is stacked on top of the first patch antenna with the dielectric spacer disposed between the first and second patch antennas.

Description

ANTENNA ASSEMBLIES INCLUDING STACKED PATCH ANTENNAS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims is a PCT International Application that claims priority to and the benefit of U.S. Provisional Application No. 62/625,147, filed on February 1, 2018, and also claims priority to and the benefit of U.S. Provisional Application No. 62/700,716 filed on July 19, 2018. The entire disclosures of the above applications are incorporated herein by reference.

FIELD

[0002] The present disclosure generally relates to antenna assemblies ( e.g ., vehicular antenna assemblies, etc.) including stacked patch antennas.

BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] Various different types of antennas are used in the automotive industry, including AM/FM radio antennas, Satellite Digital Audio Radio Service (SDARS) antennas (e.g., SiriusXM satellite radio, etc.), Global Navigation Satellite System (GNSS) antennas, cellular antennas, etc. Multiband antenna assemblies are also commonly used in the automotive industry. A multiband antenna assembly typically includes multiple antennas to cover and operate at multiple frequency ranges.

[0005] Automotive antennas may be installed or mounted on a vehicle surface, such as the roof, trunk, or hood of the vehicle to help ensure that the antennas have unobstructed views overhead or toward the zenith. The antenna may be connected (e.g, via a coaxial cable, etc.) to one or more electronic devices (e.g, a radio receiver, a touchscreen display, navigation device, cellular phone, etc.) inside the passenger compartment of the vehicle, such that the multiband antenna assembly is operable for transmitting and/or receiving signals to/from the electronic device(s) inside the vehicle. DRAWINGS

[0006] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0007] FIG. 1 is a perspective view of an exemplary embodiment of a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas. FIG. 1 also shows a slot in the top radiating patch element and a single feed for both the driven radiating patch element of the top patch antenna and the parasitically coupled radiating patch element of the bottom patch antenna.

[0008] FIG. 2 is a cross-sectional view of the antenna assembly shown in FIG. 1, and showing the stacked patch antennas, a dielectric spacer represented by the gap separating the top patch antenna from the bottom patch antenna, and the feed. FIG. 2 also shows the z (vertical) axis and the origin of the coordinate system.

[0009] FIG. 3 is a perspective view of an exemplary embodiment of a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas. FIG. 3 also shows a slot in the top radiating patch element and a single feed for both the driven radiating patch element of the top patch antenna and the parasitically coupled radiating patch element of the bottom patch antenna. Example dimensions in millimeters (mm) are also provided in FIG. 3 according to this exemplary embodiment.

[0010] FIG. 4 is an exploded perspective view of an exemplary embodiment of a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer positionable between the top and bottom patch antennas. FIG. 4 also shows a slot in the top radiating patch element and a single feed for both the driven radiating patch element of the top patch antenna and the parasitically coupled radiating patch element of the bottom patch antenna.

[0011] FIG. 5 is a Smith Chart showing simulated antenna input impedance at a feed probe for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS. [0012] FIG. 6 is a line graph showing simulated return loss Sl l in decibels

(dB(S(l,l)) versus frequency in Gigahertz (GHz) of antenna input impedance at a feed probe for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS.

[0013] FIG. 7 is a Smith Chart showing simulated antenna input impedance with a simple matching network as the input for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS.

[0014] FIG. 8 is a line graph showing simulated return loss Sl l in decibels

(dB(S(l,l)) versus frequency in gigahertz (GHz) of antenna input impedance with a simple matching network as the input for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS.

[0015] FIG. 9 is a line graph of simulated average gain in decibels (dB) versus frequency in gigahertz (GHz) for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS.

[0016] FIG. 10 is a line graph of simulated axial ratio in decibels (dB) versus frequency in gigahertz (GHz) for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS.

[0017] Corresponding reference numerals indicate corresponding (but not necessarily identical) parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0018] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0019] Exemplary embodiments are disclosed herein of dual band circularly polarized antenna assemblies including stacked patch antennas. The antenna assembly may be configured to be operable for receiving satellite signals ( e.g ., signals within the GPS Ll and L2 bands, other satellite navigation system frequencies, SDARS signals, etc.) according to exemplary embodiments. Exemplary embodiments may allow for changing the sense of circular polarization from right hand to left hand or vice versa to thereby change the frequency bands of operation. For example, the dimensions and substrate properties of an antenna assembly disclosed herein may be changed or predetermined so that right hand circular polarization ( e.g ., for GPS, etc.) is changed to left hand circular polarization (e.g., for satellite radio, etc.), which thus changes the frequency bands of operation.

[0020] In exemplary embodiments, an antenna assembly generally includes stacked patch antennas. A dielectric spacer (e.g, foam, elastomer, plastic, etc.) is disposed between the top and bottom patch antennas. The dielectric spacer is an intervening component such that the top patch antenna is not disposed directly on the bottom patch antenna. For example, the lower surface of the top patch antenna’s dielectric substrate is not disposed directly on or in physical contact with the upper surface of the radiating patch element of the bottom patch antenna.

[0021] The dielectric spacer may create spacing between the top and bottom patch antenna that controls the coupling between the top and bottom patch antennas, which, in turn, controls the higher operating frequency band (Ll) in exemplary embodiments. Also, the top and bottom patch antennas may be configured to operate at the lower operating frequency band (L2) in exemplary embodiments, and then the Ll frequency band may be achieved by controlling the space/coupling between the top and bottom patch antennas.

[0022] A slot may be provided in the top radiating patch element along the top patch antenna. The slot may have a stepped configuration defined by two or more rectangular slot portions that are adjacent, adjoin, or overlap each other along at least a portion of their longer sides. The slot may comprise a step slotline including one or more rectangular slot portions, steps, cutouts, etc. For example, two rectangular square slots may be introduced on the top patch antenna, which slots may be defined by the area of the top patch antenna from which the metallization has been removed. The introduction of the slots perturbs the symmetry of the patch antenna and creates two degenerate modes for exciting circular polarizations. As another example, chamfering is another method that may be used to perturb the symmetry of the patch antenna and create circular polarization. In exemplary embodiments, both methods of introducing slots and chamfering may be used to perturb the symmetry of the top patch antenna. [0023] A single feed or connector may be used for both the driven radiating patch element of the top patch antenna and the parasitically coupled radiating patch element of the bottom patch antenna. An end of the feed may electrically contact the top radiating patch element at an end of the slot. The feed may extend from the top radiating patch element through the dielectric substrates of the top and bottom patch antennas to a ground plane ( e.g ., metallization, etc.) along a lower surface of the dielectric substrate of the bottom patch antenna. The feed or connector may electrically connect and provide a galvanic connection between the top radiating patch element and the ground plane without any direct galvanic connection between the feed or connector and the bottom radiating patch element.

[0024] A metallization may cover the entire area (or substantially the entire area) of the lower surface of the dielectric substrate of the bottom patch antenna. In this exemplary embodiment, the top patch antenna does not include a metallization along the lower surface of the dielectric substrate of the top patch antenna.

[0025] The antenna assembly may be configured to be operable for receiving satellite signals (e.g., signals within the GPS Ll and L2 bands, other satellite navigation system frequencies, SDARS signals, etc.) according to exemplary embodiments. For example, the top driven radiating patch element may be configured to cover a lower frequency band (e.g, GPS lower band L2 (1227.60 MHz), etc.). And with parasitic coupling between the top and bottom radiating patch elements, the parasitically coupled top and bottom patch radiating elements may be configured to cover an upper frequency band (e.g, GPS upper band Ll (1575.42 MHz), etc.).

[0026] In an exemplary embodiment, a vehicular antenna assembly generally includes a step slotline perturbed stack patch antenna that is dual band and circularly polarized. The vehicular antenna assembly may be configured to be operable with the relatively closely spaced GPS lower band L2 (1227.60 MHz) and higher band L2 (1575.42 MHz). For example, two rectangular square slots may be introduced on the top patch antenna, which slots may be defined by the area of the top patch antenna from which the metallization has been removed. The introduction of the slots perturbs the symmetry of the patch antenna and creates two degenerate modes for exciting circular polarizations. As another example, chamfering is another method that may be used to perturb the symmetry of the patch antenna and create circular polarization. In exemplary embodiments, both methods of introducing slots and chamfering may be used in the top patch antenna. [0027] The top and bottom patch antennas may be configured to operate at the lower operating frequency band (L2) in exemplary embodiments, and then the Ll frequency band may be achieved by controlling the space/coupling between the top and bottom patch antennas. The top patch antenna may be configured to be operable at L2 such that the top patch antenna can couple to the bottom patch antenna. The bottom patch antenna may be configured to solely operate at L2. Note that two patch antennas (or resonators in general) need to be at the same resonant frequency to couple. In exemplary embodiments, the top patch antenna is also configured to be operable at Ll in order to have a wider bandwidth at Ll to cover the correction bands which is adjacent to the Ll band. Accordingly, exemplary embodiments may include a top patch antenna configured to be operable at L2 such that it can couple to the bottom patch that is already operable at L2, to thereby generate operation for or within the Ll band. The top patch antenna may also be configured to be operable at Ll because the bandwidth at Ll obtained through the coupling mechanism alone may not be sufficient to provide the required bandwidth.

[0028] To ensure that the top patch antenna can support both Ll and L2, the dielectric substrate of the top patch antenna may be made of a different material with a smaller dielectric constant than the dielectric substrate of the bottom patch antenna. The normal mode of the top patch antenna on the outer perimeters does not need to perturbed by slots for operating at Ll, and the perturbed modes by the stepped slots provide operation for L2. In exemplary embodiments, one or more rectangular ( e.g ., square, etc.) slots on the top patch antenna may provide perturbation for circular polarization and also size reduction (e.g., miniaturization, etc.).

[0029] With reference now to the figures, FIGS. 1 and 2 illustrate an exemplary embodiment of an antenna assembly 100 embodying one or more aspects of the present disclosure. The antenna assembly 100 is configured to be operable with circular polarization and operable for receiving satellite signals in multiple bands (e.g, signals within the GPS Ll and L2 bands, other satellite navigation system frequencies, SDARS signals, etc.). In this exemplary embodiment, the antenna assembly 100 is configured to be operable with the GPS Ll and L2 bands. As disclosed herein, the antenna assembly 100 may be reconfigured or modified (e.g, change dimensions and/or substrate properties, etc.) to switch the sense of circular polarization from right hand circular polarization (e.g, for GPS, etc.) to left hand circular polarization (e.g, for satellite radio, etc.) or vice versa for different frequency bands. [0030] As shown in FIGS. 1 and 2, the antenna assembly 100 includes first and second (or top and bottom) stacked patch antennas 104, 108.

[0031] A dielectric spacer 112 (broadly, an electrical insulator, an electrical isolator, or a dielectric) is disposed between the top and bottom patch antennas 104, 108. The dielectric spacer 112 is represented by the gap (FIG. 2) separating the top patch antenna 104 from the bottom patch antenna 108. The dielectric spacer 112 may comprise foam, elastomer, plastic, air, other dielectric material, other electrical insulator, plastics, dielectric conductive materials, etc. In some embodiments, a double sided dielectric adhesive tape and/or a dielectric adhesive may be used between the dielectric spacer 112 and the patch antennas 104, 108.

[0032] The top patch antenna 104 includes a substrate 116 made of a dielectric material, for example, a ceramic ( e.g ., aluminum oxide (AI2O3) ceramic, organic ceramic fiberglass reinforced laminate, etc.), FR4 composite material, which includes woven fiberglass cloth with an epoxy resin binder that is flame resistant, etc. An electrically-conductive material may be disposed along the upper surface of the substrate 120 to form an antenna structure or top radiating patch element 120 (e.g., l/2-antenna structure, etc.) of the top patch antenna 104.

[0033] The bottom patch antenna 108 includes a substrate 124 made of a dielectric material, for example, a ceramic (e.g, aluminum oxide (AI2O3) ceramic, organic ceramic fiberglass reinforced laminate, etc.), FR4 composite material, which includes woven fiberglass cloth with an epoxy resin binder that is flame resistant, etc. An electrically-conductive material may be disposed along the upper surface of the substrate 124 to form an antenna structure or bottom radiating patch element 128 (e.g, l/2-antenna structure, etc.) of the bottom patch antenna 108. A ground plane may be along the lower surface of the dielectric substrate 124. In this exemplary embodiment, a metallization 132 may cover the entire area (or substantially the entire area) of the lower surface of the dielectric substrate 124 of the bottom patch antenna 108.

[0034] Also in this exemplary embodiment, the top patch antenna 104 does not include a metallization along the lower surface of the dielectric substrate 116 of the top patch antenna 104. Accordingly, the dielectric spacer 112 may thus be referred to as an intervening component disposed between the lower surface of the dielectric substrate 116 of the top patch antenna 104 and the upper surface of the radiating patch element 128 of the bottom patch antenna 108. [0035] The dielectric spacer 112 may be configured to prevent or inhibit direct physical contact between the lower surface of the top patch antenna’s dielectric substrate 116 from physically contacting the upper surface of the radiating patch element 128 of the bottom patch antenna 108. Due to its thickness ( e.g ., 1 mm, etc.), the dielectric spacer 112 raises the top patch antenna 104 such that the lower surface of the top patch antenna 104 is spaced apart from the upper surface of the bottom patch antenna 108. The dielectric spacer 112 creates and maintains a distance or gap (e.g., 1 mm air gap, etc.) between the top patch antenna 104 and the bottom patch antenna 108.

[0036] The dielectric spacer 112 may have length and/or width dimensions equal to, greater than, or less than corresponding dimensions of the patch antennas 104, 108. For example, FIG. 4 illustrates an exemplary embodiment in which the dielectric spacer 312 comprises a plastic circular washer having an outer diameter less than the length and width of the bottom patch antenna 308, which allow a connector 336 to pass alongside an outer perimeter of the washer instead of through the center opening of the washer, etc.

[0037] The dielectric spacer 112 may create spacing between the top and bottom patch antennas 104, 108 that controls the coupling between the top and bottom patch antennas 104, 108, which, in turn, controls the higher operating frequency band (Ll). Also, the top and bottom patch antennas 104, 108 may be configured to operate at the lower operating frequency band (L2), and then the Ll frequency band may be achieved by controlling the space/coupling between the top and bottom patch antennas 104, 108.

[0038] A connector or feed 136 is used for both the radiating patch element 120 of the top patch antenna 104 and the radiating patch element 128 of the bottom patch antenna 108. The combined feed 136 may be used to increase bandwidth. The connector or feed 136 may be used to electrically connect the antenna assembly 100 to a communication link, which, in turn, may be connected to an electronic device (e.g, an in-dash touchscreen display, etc.) inside a passenger compartment of a vehicle. The connector or feed 136 may comprise an uninsulated pin or an insulated pin (e.g, a metal conductor with an EMI shield around it, etc.).

[0039] The connector or feed 136 may extend from the top radiating patch element 120 through the dielectric substrates 116, 124 of the top and bottom patch antennas 104, 108, respectively, to the ground plane 132 along the lower surface of the dielectric substrate 124 of the bottom patch antenna 108. The feed or connector 136 may electrically connect and provide a galvanic connection between the top radiating patch element 120 and the ground plane 132 without any direct galvanic connection between the feed or connector 136 and the radiating patch element 128 of the bottom patch antenna 108.

[0040] As shown in FIG. 1, the top patch antenna 104 includes a slot 140 in or along the radiating patch element 120. An upper end portion of the connector or feed 136 may be electrically connected with the radiating patch element 120 at a location adjacent or at an end portion of the slot 140.

[0041] The slot 140 is generally an absence of the electrically-conductive material (e.g., metal, etc.) that defines the radiating patch element 120. By way of example, the radiating patch element 120 may be initially formed with the slot 140, or the slot 140 may be formed by removing electrically-conductive material or metallization, such as by etching, cutting, stamping, etc. In still yet other embodiments, the slot 140 may be formed by adding electrically nonconductive or dielectric material, such as by printing, etc.

[0042] In an exemplary embodiment, the slot 140 may be configured such that the antenna assembly 100 may include or be referred to as a step slotline perturbed stack patch antenna. The step slotline perturbed stacked patch antenna may be configured to be operable with the relatively closely spaced GPS lower band L2 (1227.60 MHz) and higher band L2 (1575.42 MHz).

[0043] In this exemplary embodiment, the slot 140 may have a stepped configuration defined by two or more rectangular slot portions 144, 148 that are adjacent, adjoin, or overlap each other along at least a portion 152 of their longer sides. The slot 140 may comprise a step slotline that including one or more rectangular slot portions, steps, or cutouts. The slot 140 may have a stairstep configuration (e.g, generally define two adjacent steps, etc.), a rectangular S- shape, a rectangular Z-shape, etc.

[0044] The introduction of the rectangular slot portions 144, 148 perturbs the symmetry of the top patch antenna 104 and creates two degenerate modes for exciting circular polarizations. Chamfering is another method that may be used to perturb the symmetry of the top patch antenna 104 and create circular polarization. For example, two opposing comers of the rectangular top patch antenna 104 may be chamfered as shown in FIG. 1. Accordingly, both methods of introducing slots and chamfering are used to perturb the symmetry of the top patch antenna 104 in the exemplary embodiment shown in FIG. 1. [0045] The antenna assembly 100 may be configured to be operable for receiving satellite signals ( e.g ., signals within the GPS Ll and L2 bands, SDARS signals, other satellite navigation signals, etc.) according to exemplary embodiments. For example, the top driven radiating patch element 120 may be configured to cover a lower frequency band (e.g., GPS lower band L2 (1227.60 MHz), etc.). And with parasitic coupling between the top and bottom radiating patch elements 120, 128, the parasitically coupled top and bottom patch radiating elements 120, 128 may be configured to cover an upper frequency band (e.g, GPS upper band Ll (1575.42 MHz), etc.).

[0046] In an exemplary embodiment, the antenna assembly 100 is configured to be operable with the GPS Ll and L2 bands. Alternatively, the antenna assembly 100 may be reconfigured or modified (e.g, change dimensions and/or substrate properties, etc.) to switch the sense of circular polarization from right hand circular polarization (e.g, for GPS, etc.) to left hand circular polarization (e.g, for satellite radio, etc.) or vice versa for different frequency bands. In other exemplary embodiments, the antenna assembly 100 may be configured to be operable with other GNSS frequencies and/or with other dual band circular polarizations given that the separation is not more than an octave.

[0047] In this exemplary embodiment, the top and bottom patch antennas 104, 108 may be configured to operate at the lower operating frequency band (L2), and then the Ll frequency band may be achieved by controlling the space/coupling via the dielectric spacer 112 between the top and bottom patch antennas 104, 108. The top patch antenna 104 may be configured to be operable at L2 such that the top patch antenna 104 can couple to the bottom patch antenna 108. The bottom patch antenna 108 may be configured to solely operate at L2. The top patch antenna 104 may also be configured to be operable operate at Ll in order to have a wider bandwidth at Ll to cover the correction bands which is adjacent to the Ll band. Accordingly, the top patch antenna 104 may be configured to be operable at L2 such that it can couple to the bottom patch antenna 108 that is already operable at L2, to thereby generate operation for the Ll band. The top patch antenna 104 may also be configured to be operable at Ll because the bandwidth at Ll obtained through the coupling mechanism alone may not be sufficient to provide the required bandwidth.

[0048] To ensure that the top patch antenna 104 can support both Ll and L2, the dielectric substrate 116 of the top patch antenna 104 may be made of a different material with a smaller dielectric constant than the dielectric substrate 124 of the bottom patch antenna 108. The normal mode of the top patch antenna 104 on the outer perimeters does not need to perturbed by slots for operating at Ll, and the perturbed modes by the stepped slots provide operation for L2. The one or more rectangular ( e.g ., square, etc.) slots 144, 148 on the top patch antenna 104 may provide perturbation for circular polarization and also size reduction (e.g., miniaturization, etc.).

[0049] The antenna assembly 100 may be mounted inside or outside of a vehicle or elsewhere. For example, the antenna assembly 100 may be mounted on an exterior vehicle surface, such as the roof, trunk, or hood of the vehicle to help ensure that the antenna has unobstructed views overhead or toward the zenith.

[0050] FIG. 3 illustrates an exemplary embodiment of an antenna assembly 200 embodying one or more aspects of the present disclosure. The antenna assembly 200 may include features similar or identical to the corresponding features of the antenna assembly 100. For example, the antenna assembly 200 generally includes first and second (or top and bottom) stacked patch antennas 204, 208. A dielectric spacer 212 is disposed between the top and bottom patch antennas 204, 208.

[0051] The top patch antenna 204 includes a slot 240 in or along the radiating patch element 220. An upper end portion of a connector or feed 236 may be electrically connected with the radiating patch element 220 at a location adjacent or at an end portion of the slot 240.

[0052] The connector or feed 236 is used for both the radiating patch element 220 of the top patch antenna 204 and the radiating patch element 228 of the bottom patch antenna 208. The connector or feed 236 may extend from the top radiating patch element 220 through the dielectric substrates 216, 224 of the top and bottom patch antennas 204, 208, respectively, to the ground plane 232 along the lower surface of the dielectric substrate 224 of the bottom patch antenna 208. The feed or connector 236 may electrically connect and provide a galvanic connection between the top radiating patch element 220 and the ground plane 232 without any direct galvanic connection between the feed or connector 136 and the radiating patch element 228 of the bottom patch antenna 208.

[0053] In this particular exemplary embodiment, the antenna assembly 200 is configured (e.g, shaped, sized, material selection, etc.) to be operable with circular polarization and operable for receiving GPS signals within the GPS Ll band (1575.42 MHz) and GPS L2 band (1227.60 MHz). The top driven radiating patch element 220 is configured to cover the GPS lower band L2 (1227.60 MHz). And with parasitic coupling between the top and bottom radiating patch elements 220, 228, the parasitically coupled top and bottom patch radiating elements 220, 228 are configured to cover the GPS upper band Ll (1575.42 MHz).

[0054] Continuing with this example, the substrate 216 of the top patch antenna 204 may be made of a different material with a smaller dielectric constant than the substrate 224 of the bottom patch antenna 208, which helps to ensure that the top patch antenna 204 can support both Ll and L2. For example, the dielectric substrate 224 of the bottom patch antenna 208 may have dimensions of 45 mm x 45 mm x 3.5 mm, may be formed from aluminum oxide (AI2O3) ceramic, and may have a dielectric constant (e_r) of 9.8 and a tan delta (dissipation factor or tan(5)) of less than 0.0009. Also by way of example, the dielectric substrate 216 of the top patch antenna 204 may have dimensions of 45 mm x 45 mm x 4 mm, may be formed from Taconic RF-60 organic ceramic fiberglass reinforced laminate, and may have a dielectric constant (e_r) of 6.15 and a tan delta (dissipation factor or tan(5)) of less than 0.0028.

[0055] The dielectric spacer 212 may have a thickness of about 1 mm. The total height of the stacked patch antennas 204, 208 may be about 8.5 mm, which is the sum of the substrate heights (3.5 mm + 4 mm) and dielectric spacer thickness of 1 mm. Accordingly, the antenna assembly 200 is thus relatively compact 45 mm x 45 mm x 8.5 mm in this exemplary embodiment. This relatively compact size may allow the antenna assembly 200 to be usable for different antenna platforms. The dimensions, materials, and properties are provided herein as examples only as alternative embodiments may be configured differently, such as larger, smaller (e.g., 40 mm x 40 mm x 8.5 mm), from different materials, have different properties (e.g. , higher or lower dielectric constant, different tan(5), etc.), and/or with a difference sense of circular polarization, etc. The size of the substrates and thus the antenna assembly will depend, at least in part, on the value of the dielectric constants of the materials used for the upper and lower substrates. For example, materials having larger dielectric constant values may be used for a smaller size antenna assembly.

[0056] In this exemplary embodiment, the antenna assembly 200 is configured to be operable with circular polarization and operable for receiving signals within the GPS Ll and L2 bands. In alternative embodiments, an antenna assembly may be configured differently for receiving SDARS signals or signals at other satellite navigation system frequencies, such as Global Navigation Satellite System (GNSS) signals or frequencies (e.g, BeiDou Navigation Satellite System (BDS), the Russian Global Navigation Satellite System (GLONASS), other satellite navigation system frequencies, etc.), etc. For example, the antenna assembly 200 may be configured to be used for any dual band circular polarizations given that the separation is not more than an octave.

[0057] FIG. 4 illustrates an exemplary embodiment of an antenna assembly 300 embodying one or more aspects of the present disclosure. The antenna assembly 300 may include features similar or identical to the corresponding features of the antenna assembly 100. For example, the antenna assembly 300 generally includes first and second (or top and bottom) stacked patch antennas 304, 308. A dielectric spacer 312 is disposed between the top and bottom patch antennas 304, 308. In this exemplary embodiment, the dielectric spacer 312 is a plastic circular washer having a thickness of 1 mm. Alternative embodiments may include other dielectric spacers configured differently, such as thicker, thinner, and/or made from other materials ( e.g ., foam, elastomer, etc.).

[0058] The top patch antenna 304 includes a slot 340 in or along the radiating patch element 320. An upper end portion of a connector or feed 336 may be electrically connected with the radiating patch element 320 at a location adjacent or at an end portion of the slot 340.

[0059] FIGS. 5 through 10 illustrate simulated performance results for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS. These results shown in FIGS. 5 through 10 are provided only for purposes of illustration and not for purposes of limitation.

[0060] More specifically, FIG. 5 is a Smith Chart showing simulated antenna input impedance at a feed probe for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas.

[0061] FIG. 6 is a line graph showing simulated return loss Sl l in decibels (dB(S(l,l)) versus frequency in Gigahertz (GHz) of antenna input impedance at a feed probe for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas.

[0062] FIG. 7 is a Smith Chart showing simulated antenna input impedance with a simple matching network as the input for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas, where the results of the simulation were obtained by Ansys HFSS.

[0063] FIG. 8 is a line graph showing simulated return loss Sl l in decibels (dB(S(l,l)) versus frequency in gigahertz (GHz) of antenna input impedance with a simple matching network as the input for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas.

[0064] FIG. 9 is a line graph of simulated average gain in decibels (dB) versus frequency in gigahertz (GHz) for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas. Generally, FIG. 9 shows that the antenna assembly demonstrates desired or good circularly polarized gain for the GPS Ll and L2 bands.

[0065] FIG. 10 is a line graph of simulated axial ratio in decibels (dB) versus frequency in gigahertz (GHz) for a dual band circularly polarized antenna assembly including stacked patch antennas and a dielectric spacer between the top and bottom patch antennas. Generally, FIG. 10 shows that the antenna assembly demonstrates desired or good axial ratio for the GPS Ll and L2 bands.

[0066] In an exemplary embodiment, an antenna assembly generally includes a dielectric spacer, a first patch antenna configured to be operable with a first one or more frequencies, and a second patch antenna stacked on top of the first patch antenna with the dielectric spacer disposed between the first and second patch antennas. The second patch antenna is configured to parasitically couple with the first patch antenna such that the first and second patch antennas, when parasitically coupled, are operable with a second one or more frequencies different than the first one or more frequencies. A feed is configured to be operable with the first one or more frequencies and the second one or more frequencies.

[0067] The first patch antenna may include a first dielectric substrate and a first radiating patch element along the first dielectric substrate. The second patch antenna may include a second dielectric substrate, a second radiating patch element along the second dielectric substrate, and a slot along the second radiating patch element.

[0068] The slot may be configured such that the antenna assembly is a step slotline perturbed stack patch antenna with the first one or more frequencies including a GPS lower band L2 and/or a frequency of about 1227.60 MHz and the second one or more frequencies including a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

[0069] The slot may include first and second rectangular slot portions that are adjacent, adjoin, or overlap each other along at least a portion of their adjacent longer sides. The slot may have a stairstep configuration.

[0070] An end portion of the feed may be electrically connected to the second radiating patch element of the second patch antenna at a location adjacent or at an end portion of the slot.

[0071] The feed may extend from the second radiating patch element through the second dielectric substrate and the first dielectric substrate to a ground plane along a lower surface of the first dielectric substrate. The feed may bypass and not extend through the dielectric spacer.

[0072] The dielectric spacer may be disposed between a lower surface of the second dielectric substrate and an upper surface of the first radiating patch element.

[0073] The dielectric spacer may be against the lower surface of the second dielectric substrate and the upper surface of the first radiating patch element. The dielectric spacer may inhibit direct physical contact between the lower surface of the second dielectric substrate and the upper surface of the first radiating patch element. The dielectric spacer may create and maintain a distance between the lower surface of the second dielectric substrate and the upper surface of the first radiating patch element.

[0074] The dielectric spacer may create and maintain a distance between the first patch antenna and the second patch antenna.

[0075] The antenna assembly may include only a single feed mechanism including the feed for the first one or more frequencies and the second one or more frequencies.

[0076] The antenna assembly may include only a single feed mechanism including the feed for providing dual band circularly polarized radiation.

[0077] The antenna assembly may include only one feed for the first one or more frequencies and the second one or more frequencies.

[0078] The antenna assembly may include only one feed for providing dual band circularly polarized radiation. [0079] When the second patch antenna is not parasitically coupled to the first patch antenna, the antenna assembly may be configured to be operable with a GPS lower band L2 and/or a frequency of about 1227.60 MHz. When the first and second patch antenna are parasitically coupled, the antenna assembly may be configured to be operable with a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

[0080] The first one or more frequencies include a GPS lower band L2 and/or a frequency of about 1227.60 MHz. The second one or more frequencies include a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

[0081] The antenna assembly may be configured to be operable with right hand circular polarization such that the antenna assembly is operable with Global Positioning System (GPS) signals, whereby the first one or more frequencies include a GPS lower band L2 (1227.60 MHz) and the second one or more frequencies include a GPS upper band Ll (1575.42 MHz).

[0082] The antenna assembly may be configured to be operable with left hand circular polarization such that the antenna assembly is operable for receiving satellite digital audio radio services (SDARS) signals and/or with frequencies from 2320 MHz to 2345 MHz.

[0083] The antenna assembly may comprise a vehicular antenna assembly. When the second patch antenna is not parasitically coupled to the first patch antenna, the vehicular antenna assembly may be configured to be operable with the first one or more frequencies including a GPS lower band L2 and/or a frequency of about 1227.60 MHz. When the first and second patch antenna are parasitically coupled, the vehicular antenna assembly may be configured to be operable with the second one or more frequencies including a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

[0084] In an exemplary embodiment, a dual band circularly polarized stacked patch antenna assembly generally includes a dielectric spacer, a first patch antenna, and a second patch antenna. The first patch antenna includes a first dielectric substrate and a first radiating patch element along the first dielectric substrate. The second patch antenna includes a second dielectric substrate, a second radiating patch element along the second dielectric substrate, and a slot along the second radiating patch element. The second patch antenna is stacked on top of the first patch antenna with the dielectric spacer disposed between the first and second patch antennas. A single feed is configured to be operable for providing dual band circularly polarized radiation. The stacked patch antenna assembly is operable, via the second patch antenna, with a first one or more frequencies. The stacked patch antenna assembly is also operable, via the first patch antenna and the second patch antenna when parasitically coupled, with a second one or more frequencies different than the first one or more frequencies.

[0085] A vehicular antenna assembly may include the dual band circularly polarized stacked patch antenna assembly. The first one or more frequencies include a GPS lower band L2 and/or a frequency of about 1227.60 MHz. The second one or more frequencies include a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

[0086] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms, and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well- known technologies are not described in detail. In addition, advantages and improvements that may be achieved with one or more exemplary embodiments of the present disclosure are provided for purpose of illustration only and do not limit the scope of the present disclosure, as exemplary embodiments disclosed herein may provide all or none of the above mentioned advantages and improvements and still fall within the scope of the present disclosure.

[0087] Specific dimensions, specific materials, and/or specific shapes disclosed herein are example in nature and do not limit the scope of the present disclosure. The disclosure herein of particular values and particular ranges of values for given parameters are not exclusive of other values and ranges of values that may be useful in one or more of the examples disclosed herein. Moreover, it is envisioned that any two particular values for a specific parameter stated herein may define the endpoints of a range of values that may be suitable for the given parameter (i.e., the disclosure of a first value and a second value for a given parameter can be interpreted as disclosing that any value between the first and second values could also be employed for the given parameter). For example, if Parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that parameter X may have a range of values from about A to about Z. Similarly, it is envisioned that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example, if parameter X is exemplified herein to have values in the range of 1 - 10, or 2 - 9, or 3 - 8, it is also envisioned that Parameter X may have other ranges of values including 1 - 9, 1 - 8, 1 - 3, 1 - 2, 2 - 10, 2 - 8, 2 - 3, 3 - 10, and 3 - 9.

[0088] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”,“an” and“the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms“comprises,”“comprising,”“including,” and“having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0089] When an element or layer is referred to as being “on”, “engaged to”, “connected to” or“coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being“directly on,”“directly engaged to”, “directly connected to” or“directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion ( e.g .,“between” versus“directly between,” “adjacent” versus“directly adjacent,” etc.). As used herein, the term“and/or” includes any and all combinations of one or more of the associated listed items.

[0090] The term“about” when applied to values indicates that the calculation or the measurement allows some slight imprecision in the value (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If, for some reason, the imprecision provided by“about” is not otherwise understood in the art with this ordinary meaning, then“about” as used herein indicates at least variations that may arise from ordinary methods of measuring or using such parameters. For example, the terms“generally”,“about”, and“substantially” may be used herein to mean within manufacturing tolerances. [0091] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as“first,”“second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0092] Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”,“above”,“upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as“below” or“beneath” other elements or features would then be oriented“above” the other elements or features. Thus, the example term“below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0093] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements, intended or stated uses, or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. An antenna assembly comprising:

a dielectric spacer;

a first patch antenna configured to be operable with a first one or more frequencies, the first patch antenna including a first dielectric substrate and a first radiating patch element along the first dielectric substrate; and

a second patch antenna stacked on top of the first patch antenna with the dielectric spacer disposed between the first and second patch antennas, the second patch antenna including a second dielectric substrate, a second radiating patch element along the second dielectric substrate, and a slot along the second radiating patch element, the second patch antenna configured to parasitically couple with the first patch antenna such that the first and second patch antennas, when parasitically coupled, are operable with a second one or more frequencies higher than the first one or more frequencies; and

a feed configured to be operable with the first one or more frequencies and the second one or more frequencies.

2. The antenna assembly of claim 1, wherein the second dielectric substrate has a dielectric constant less than a dielectric constant of the first dielectric substrate.

3. The antenna assembly of claim 1 or 2, wherein the slot is configured such that the antenna assembly is operable as a step slotline perturbed stack patch antenna with the first one or more frequencies including a GPS lower band L2 and/or a frequency of about 1227.60 MHz and the second one or more frequencies including a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

4. The antenna assembly of any one of the preceding claims, wherein:

the slot includes first and second rectangular slot portions that are adjacent, adjoin, or overlap each other along at least a portion of their adjacent longer sides; and/or

the slot has a stairstep configuration.

5. The antenna assembly of any one of the preceding claims, wherein an end portion of the feed is electrically connected to the second radiating patch element of the second patch antenna at a location adjacent or at an end portion of the slot.

6. The antenna assembly of any one of the preceding claims, wherein the feed extends from the second radiating patch element through the second dielectric substrate and the first dielectric substrate to a ground plane along a lower surface of the first dielectric substrate.

7. The antenna assembly of claim 6, wherein the feed bypasses and does not extend through the dielectric spacer.

8. The antenna assembly of any one of the preceding claims, wherein the second radiating element is rectangular and includes at least two opposing chamfered comers.

9. The antenna assembly of any one of the preceding claims, wherein the dielectric spacer is configured to create and maintain spacing between the first and second patch antennas to control parasitic coupling between the first and second patch antennas.

10. The antenna assembly of any one of the preceding claims, wherein the slot along the second radiating patch element perturbs a symmetry of the second patch antenna and thereby creates two degenerate modes for exciting circular polarizations.

11. The antenna assembly of any one of the preceding claims, wherein the second radiating patch antenna element includes one or more chamfered corners that perturb a symmetry of the second patch antenna and thereby creates circular polarization.

12. The antenna assembly of any one of the preceding claims, wherein the antenna assembly includes only a single feed mechanism including the feed for the first one or more frequencies and the second one or more frequencies.

13. The antenna assembly of any one of claims 1 to 11, wherein the antenna assembly includes only a single feed mechanism including the feed for providing dual band circularly polarized radiation.

14. The antenna assembly of any one of claims 1 to 11, wherein the antenna assembly includes only one said feed for the first one or more frequencies and the second one or more frequencies.

15. The antenna assembly of any one of claims 1 to 11, wherein the antenna assembly includes only one said feed for providing dual band circularly polarized radiation.

16. The antenna assembly of any one of the preceding claims, wherein:

when the second patch antenna is not parasitically coupled to the first patch antenna, the antenna assembly is configured to be operable with a GPS lower band L2 and/or a frequency of about 1227.60 MHz; and

when the first and second patch antenna are parasitically coupled, the antenna assembly is configured to be operable with a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

17. The antenna assembly of any one of claims 1 to 15, wherein:

the first one or more frequencies include a GPS lower band L2 and/or a frequency of about 1227.60 MHz; and

the second one or more frequencies include a GPS upper band Ll and/or a frequency of about 1575.42 MHz.

18. The antenna assembly of any one of claims 1 to 15, wherein:

the antenna assembly is configured to be operable with right hand circular polarization such that the antenna assembly is operable with Global Positioning System (GPS) signals, whereby the first one or more frequencies include a GPS lower band L2 (1227.60 MHz) and the second one or more frequencies include a GPS upper band Ll (1575.42 MHz); or the antenna assembly is configured to be operable with left hand circular polarization such that the antenna assembly is operable for receiving satellite digital audio radio services (SDARS) signals and/or with frequencies from 2320 MHz to 2345 MHz.

19. A dual band circularly polarized stacked patch antenna assembly including the antenna assembly of any one of the preceding claims.

20. The dual band circularly polarized stacked patch antenna assembly of claim 19, wherein the feed is a single feed configured to be operable for providing dual band circularly polarized radiation such that the stacked patch antenna assembly is operable, via the second patch antenna, with the first one or more frequencies and operable, via the first patch antenna and the second patch antenna when parasitically coupled, with the second one or more frequencies.

21. A vehicular antenna assembly comprising the antenna assembly of any one of the preceding claims.

22. A dual band circularly polarized stacked patch antenna assembly comprising: a dielectric spacer;

a first patch antenna including a first dielectric substrate and a first radiating patch element along the first dielectric substrate;

a second patch antenna including a second dielectric substrate, a second radiating patch element along the second dielectric substrate, and a slot along the second radiating patch element, the second patch antenna stacked on top of the first patch antenna with the dielectric spacer disposed between the first and second patch antennas; and

a single feed configured to be operable for providing dual band circularly polarized radiation such that the stacked patch antenna assembly is operable, via the second patch antenna, with a first one or more frequencies and operable, via the first patch antenna and the second patch antenna when parasitically coupled, with a second one or more frequencies different than the first one or more frequencies.

23. A vehicular antenna assembly including the dual band circularly polarized stacked patch antenna assembly of claim 22, wherein: