Patent Application
20240186690
The present invention relates generally to wireless communication systems, and specifically to a blade antenna system.
Wireless communication is a vitally important aspect of modern commercial and military logistics applications. Commercial and military vehicles require the capability of at least one of transmitting and receiving wireless communications signals, such as to support voice communications between the vehicle and a control center, or to provide wireless control commands (e.g., with respect to unmanned or autonomous vehicles). Such wireless communications are provided to and/or from the vehicle based on vehicle antenna systems that may be distributed across one or more exterior surfaces of the vehicle. For example, a given aircraft, spacecraft, watercraft, or even terrestrial vehicle may require a number of different antennae distributed across the exterior of the vehicle to provide a variety of different aspects of communication. An example of such antenna systems includes conventional blade and whip antennas that include an interface with radio signal processing equipment using an analog interface. As an example, such an interface may include a large diameter coaxial cable with low signal loss characteristics and which may be communicatively coupled to a dedicated radio signal processing device.
One embodiment includes a blade antenna system. The system includes a ground plane and a planar substrate material extending orthogonally from the ground plane. The system also includes conductive material coupled to the planar substrate material in a coplanar or parallel manner. The conductive material can correspond to a radiating conductor. A portion of the planar substrate material between an edge of the conductive material and the ground plane can form a notch. The system further includes a magneto-dielectric material (MDM) arranged parallel with the planar substrate material to cover the notch.
Another embodiment includes a blade antenna system. The system includes a ground plane and a planar substrate material extending orthogonally from the ground plane. The system also includes conductive material coupled to the planar substrate material in a coplanar or parallel manner. The conductive material can correspond to a radiating conductor. An edge of the conductive material can form a nonlinear shape from an approximate middle of the planar substrate material extending to each of opposing ends of the planar substrate material, such that a portion of the planar substrate material between the edge of the conductive material and the ground plane can form a first notch and a second notch on opposing ends of the planar substrate material. The system further includes a magneto-dielectric material (MDM) arranged parallel with the planar substrate material.
Another embodiment includes a blade antenna system. The system includes a printed circuit board (PCB) card extending orthogonally from the ground plane. The PCB card can include a conductive trace portion corresponding to a radiating conductor. A dielectric portion of the PCB card between an edge of the conductive trace portion and the ground plane can form a notch. The conductive trace portion can have a ratio of height to length that is less than one. The system further includes a magneto-dielectric material (MDM) arranged parallel with the planar substrate material.
The present invention relates generally to wireless communication systems, and specifically to a blade antenna system. The blade antenna system can be implemented, for example, on an exterior of a vehicle, such as an aircraft, spacecraft, or automobile. The blade antenna system can be oriented in a manner to reduce drag, and can be arranged with a low profile to conserve space, as described in greater detail herein. As described in greater detail herein, the blade antenna system can be arranged as a monopole antenna that can be coupled to a coaxial cable, such as coupled to a communications transmitter. Therefore, the blade antenna system can transmit and/or receive wireless communication signals provided from and/or to a transceiver respectively.
As an example, the blade antenna system can include a ground plane and a planar substrate material extending orthogonally from the ground plane. The blade antenna system can also include a conductive material coupled to the planar substrate material in a coplanar or parallel manner. The conductive material can correspond to a radiating conductor and a portion of the planar substrate material between an edge of the conductive material and the ground plane can form a notch. As an example, the planar substrate material can correspond to a printed circuit board (PCB) card that is fabricated with a conductive trace portion corresponding to the conductive material. Therefore, the planar substrate material and conductive material can be fabricated in an inexpensive manner and can have a compact form-factor.
As an example, the edge of the conductive material can be nonlinear from an approximate middle of the planar substrate material and extending to each of opposing ends of the planar substrate material. For example, the edge of the conductive material can be formed as a semi-elliptical shape having a semi-minor axis extending along the approximate middle of the planar substrate material. The portion of the planar substrate material can form a gap between the edge of the conductive material and the ground plane. The gap can have a minimum dimension between the conductive material and the ground plane along the planar substrate material. The dimension along the planar substrate material orthogonal to the ground plane can thus increase along the length in a nonlinear (e.g., exponential) manner from the approximate middle of the planar substrate material.
In addition, the blade antenna system can include a magneto-dielectric material (MDM) arranged parallel with the planar substrate material to cover the notch. As an example, the MDM can be any of a variety of commercially available MDMs, and can thus be implemented as a low-cost material. For example, the MDM can be bonded to at least the notch using an adhesive material. As an example, the MDM can be arranged to cover the entirety of the notch, as well as a proper-subset portion of the conductive material. Therefore, the conductive material, the arrangement of the notch, and the MDM can form a radiating element for the blade antenna system operating as a monopole antenna. As a result, as described herein, the blade antenna system can exhibit significantly higher (e.g., approximately three times) the fractional bandwidth at the same center frequency of conventional monopole blade antennas of similar height. Furthermore, the blade antenna system can exhibit a higher product of fractional bandwidth times radiation efficiency relative to a conventional monopole antenna that does not include MDM loading.
The blade antenna system 100 includes a ground plane 102 and a planar substrate material (“PLANAR SUBSTRATE”) 104. The ground plane 102 can be formed from any of a variety of conductive materials that can form a ground connection for the blade antenna system 100. As an example, the ground plane 102 can be mounted approximately flush with a surface of the associated vehicle or platform on which the blade antenna system 100 is attached. For example, a coaxial cable can be provided to the ground plane 102, such that an outer conductor can be conductively coupled to the ground plane 102.
The planar substrate material 104 can extend orthogonally from the ground plane 102, and can thus form the blade structure of the blade antenna system 100. The blade antenna system 100 also includes a conductive material 106 that is coupled to the planar substrate material in a coplanar or parallel manner. The conductive material 106 can correspond to a radiating conductor of the blade antenna system 100. A portion of the planar substrate material 104 that is arranged between an edge of the conductive material 106 and the ground plane 102 can form a notch for the blade antenna system 100. As an example, the conductive material 106 can be provided approximately the same on both sides of the planar substrate material 104. For example, the planar substrate material 104 can be formed as a printed circuit board (PCB) card and the conductive material 106 can be formed as a conductive trace portion of the PCB card. Thus, the coupling of the conductive material 106 to the planar substrate material 104 can encapsulate fabrication of the conductive trace portion as part of the PCB card. The conductive material 106 arranged as a conductive trace portion of a PCB card can thus extend through both sides of the planar substrate material 104 as a unitary material (e.g., copper) conductor. Therefore, the planar substrate material 104 and the conductive material 106 can be fabricated in an inexpensive manner and can have a compact form-factor.
As an example, the edge of the conductive material 106 can be nonlinear from an approximate middle of the planar substrate material 104 and extending to each of opposing ends of the planar substrate material 104. For example, the edge of the conductive material 106 can be formed as a semi-elliptical shape having a semi-minor axis extending along the approximate middle of the planar substrate material 104. A portion of the planar substrate material 104 having a minimum width between the edge of the conductive material 106 and the ground plane 102 can form a gap. The gap can have a minimum dimension between the conductive material 106 and the ground plane 102 along the planar substrate material 104, with the dimension increasing along the length of the planar substrate material 104 orthogonal to the ground plane 102 in a nonlinear (e.g., exponential) manner from the approximate middle of the planar substrate material 104.
In addition, the blade antenna system 100 can include a magneto-dielectric material (MDM) 108 arranged parallel with the planar substrate material 104 to cover the notch. As an example, the MDM 108 can be any of a variety of commercially available MDMs. For example, the MDM 108 may correspond to a composite planar material with a relative dielectric constant εr of approximately 6.5 and a relative permeability μr of approximately 6.0 for frequencies below 1 GHz. As an example, the MDM 108 can be bonded to at least the notch using an adhesive material. As an example, the MDM 108 can be arranged to cover the entirety of the notch, as well as a proper-subset portion of the conductive material 106. Therefore, the conductive material 106, the arrangement of the notch, and the MDM 108 can form a radiating element for the blade antenna system 100 operating as a monopole antenna. As a result, as described herein, the blade antenna system 100 can exhibit significantly higher (e.g., approximately three times) the fractional bandwidth at the same center frequency of conventional monopole blade antennas of similar height. Furthermore, the blade antenna system 100 can exhibit a higher product of fractional bandwidth times radiation efficiency relative to a conventional monopole antenna that includes no MDM loading.
Each of the views 202, 204, and 206 of the blade antenna system is demonstrated as a plan view taken along the −Y axis. In the first view 202, the blade antenna system includes a ground plane 210 and a PCB card 212. The ground plane 210 can be formed from any of a variety of conductive materials, such as copper or aluminum, that can form a ground connection for the blade antenna system. As an example, the ground plane 210 can be mounted approximately flush with a surface of the associated vehicle or platform on which the blade antenna system is attached. In the example of
The PCB card 212 is demonstrated as extending orthogonally in the Z-direction from the ground plane 210 and having a long dimension along the X-axis. Therefore, the structure and orientation of the PCB card 212 forms the blade structure of the blade antenna system. The extension of the blade antenna system along the Z-axis can be minimal (e.g., approximately two inches) relative to the extension along the X-axis (e.g., approximately nine inches). Accordingly, the blade antenna system can have a low-profile to allow for attachment to an associated vehicle, such as in confined exterior locations. Furthermore, because the PCB card 212 is very thin, the resultant blade antenna system be very aerodynamic in the X-direction for operation as a vehicle-mounted blade antenna.
The blade antenna system also includes a conductive trace portion 218 that can be fabricated as part of the PCB card 212. Therefore, the PCB card 212 and the conductive trace portion 218 can be fabricated in an inexpensive manner and can have a compact form-factor. In the example of
In the example of
The portion of the PCB card 212 that is arranged between the edge 222 of the conductive trace portion 218 and the ground plane 210 on either side of the PCB card 212 can form a first notch 226 and a second notch 228 for the blade antenna system. In the example of
ƒ1(x)=gap+b−√{square root over (b)}2(1−(x/a)2 Equation 1
Where: gap is the distance of the gap 224 between the edge 222 of the conductive trace portion 218 and the ground plane 210;
As an example, gap can be approximately 0.031 inches between the edge 222 of the conductive trace portion 218 and the ground plane 210. The length a of the conductive trace portion 218 along the semi-major axis of the semi-elliptical shape can be approximately four inches, and the height b of the conductive trace portion 218 along the semi-minor axis of the semi-elliptical shape can be approximately two inches.
As another example not depicted in the example of
ƒ2(x)=AeBx+C Equation 2
Where: A is a user defined variable;
In Equation 2, the endpoints of the exponential curve are known since the lowest endpoint is defined by ƒ2(0) and the highest endpoint is defined by ƒ2(a), as demonstrated below:
ƒ2(0)=gap=A+C Equation 3
ƒ2(a)=gap+b=AeBa+C Equation 4
Based on Equations 3 and 4 above, one of the three parameters A, B, and C can be user specified to deduce the remaining two parameters. By selecting parameter A to be user specified, then parameters B and C may be calculated, as defined above. However, either of the other variables B and C can be defined instead to allow deduction of the other two of the variables of A, B, and C. As an example, for gap, a, and b to be the same as described above, and A being approximately equal to 0.05 inches, then B can be equal to approximately 0.928 inches−1, and C can be equal to approximately −0.019 inches.
As yet another example not depicted in the example of
Where: exponent p is a user specified variable that defines a taper of the edge 222, where p=1 defines a straight line, p=2 defines a quadratic function, and p=3 defines a cubic function, and where p is not limited to an integer value.
Thus, in any of the examples of Equations 1−5 above, the nonlinear edge 222 can provide for the notches 226 and 228 that can provide for a more broadband impedance match of the blade antenna system. Furthermore, in the examples of Equations 1−5, a ratio of the height b to the overall length of the conductive trace portion 2182xa is less than one. The structural characteristic of the ratio of height b to twice the length a provides for a low-profile antenna structure while maintaining superior antenna operational characteristics. The nonlinear shape of the edge 222 of the conductive trace portion 218 is not limited to the examples described above in Equations 1−5, and can instead by defined by any of a variety of different functions. Accordingly, the shape of the conductive trace portion 218 can be defined in any of a variety of ways to thereby define the shape of the notches 226 and 228.
In the second view 204, the blade antenna system includes an MDM 232 arranged parallel with the PCB card 212 to cover the notches 226 and 228. The MDM 232 may be realized in the form of a sheet material of approximately uniform thickness and uniform material composition. Alternatively, the MDM 232 can be tapered in thickness or tailored spatially in material properties to effect an improved antenna voltage standing-wave ratio (VSWR) or an improved antenna efficiency. As an example, the MDM 232 can be any of a variety of commercially available MDMs. For example, the MDM 232 can be fabricated as a composite material that includes a host dielectric material (e.g., polytetrafluoroethylene (PTFE)) that can include embedded ferrite particles. In the example of
For example, the MDM 232 can be provided on one side or both sides of the blade antenna system. In the example of the MDM 232 being provided on both sides of the PCB card 212, the MDM 232 may have the same thickness on both sides, or it may have dissimilar thicknesses on each side. As an example, the MDM 232 can have a nominal thickness of approximately 0.060 inches on one or both sides of the PCB card 212. Furthermore, the material properties of the MDM 232 on one side of PCB card 212 may be dissimilar from the material properties of the MDM 232 located on the opposite side of PCB card 212 for the purpose of improving antenna bandwidth. Additionally, the material properties of the MDM 232 covering the first notch 226 may be dissimilar from the material properties of the MDM 232 covering the second notch 228, such as to improve antenna bandwidth. Furthermore, the MDM 232 can be provided on both sides of the blade antenna system irrespective of whether the conductive trace portion 218 is provided on one or both sides of the blade antenna system. Therefore, the conductive trace portion 218, the notches 226 and 228, and the MDM 232 can form a radiating element relative to the ground plane 210 for the blade antenna system operating as a monopole antenna.
The inclusion of the MDM 232 as covering the notches 226 and 228 can provide for improved antenna characteristics of the blade antenna system. As an example, the traveling wave antenna characteristic of the blade antenna system is improved relative to conventional antennas that include MDM loading by increasing the electrical length tangential to the ground plane by covering the notches 226 and 228 with the MDM 232. The blade antenna system can exhibit an approximate 35% minimum efficiency over a bandwidth ratio of at least 2:1 (e.g., from approximately 470 MHz to approximately 1080 MHZ). In this example, the fractional bandwidth of the blade antenna system can be approximately 0.787. Therefore, the fractional bandwidth of the blade antenna system can be approximately three times the fractional bandwidth of conventional blade monopole antennas with MDM loading, and it can operate at a center frequency that is approximately five times higher than conventional blade monopole antennas with MDM loading. Furthermore, based on the above exemplary parameters, the blade antenna system can provide for a bandwidth-efficiency product of approximately 0.275, which is significantly higher than conventional MDM-loaded antennas. Accordingly, the blade antenna system can be implemented as a lower-profile and more effective antenna than typical monopole blade antennas.
In the third view 206, the blade antenna system is demonstrated as including a dielectric housing 234. The dielectric housing 234 can be formed of a unitary dielectric material that covers the ground plane 210, the PCB card 212, the conductive trace portion 218, and the MDM 232. As an example, the dielectric housing 234 can be formed from a low loss dielectric material, such as any of a polycarbonate, polyurethane, polymer, fiberglass, or composite dielectric material. The dielectric housing 234 can be formed, for example, via an injection molding process, such as to include a recess to accommodate the ground plane 210, the PCB card 212, and the MDM 232. As another example, the dielectric housing 234 can be formed from an additive manufacturing process with a shape designed to cover the ground plane 210, the PCB card 212, and the MDM 232.
The fourth view 208 provides another perspective of the blade antenna system, as an overhead view in the −Z direction. The fourth view 208 demonstrates that the ground plane 210 can be fabricated in an elliptical shape. Thus, along with the thin profile of the blade structure formed by the PCB card 212, the blade antenna system can exhibit improved aerodynamics along the X axis.
What have been described above are examples of the invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the invention are possible. Accordingly, the invention is intended to embrace all such alterations, modifications, and variations that fall within the scope of this application, including the appended claims. Additionally, where the disclosure or claims recite “a,” “an,” “a first,” or “another” element, or the equivalent thereof, it should be interpreted to include one or more than one such element, neither requiring nor excluding two or more such elements. As used herein, the term “includes” means includes but not limited to, and the term “including” means including but not limited to. The term “based on” means based at least in part on.
