Patent ID: 12244069

DETAILED DESCRIPTION

Some example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as being limiting as to the scope, applicability or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Furthermore, as used herein, the term “or” is to be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, operable coupling should be understood to relate to direct or indirect connection that, in either case, enables functional interconnection of components that are operably coupled to each other.

Referring now toFIG.1, a cross dipole antenna100of an example embodiment is shown. The cross dipole antenna assembly100may include a first pair of dipole arms110and a second pair of dipole arms120that may be printed on a flexible substrate130of dielectric material. In the depicted example, the four arms of the first and second pairs of dipole arms110and120may each be conductors that have an L or V shape that is geometrically identical. However, the four arms of the first and second pairs of dipole arms110and120may be arranged with their apexes proximate to each other. Meanwhile, the four arms of the first and second pairs of dipole arms110and120may also orthogonally cross each other in the substrate plane. The four arms of the first and second pairs of dipole arms110and120may also have feed points140,142,144and146at respective four corners of a centrally located square shape.

FIG.2illustrates how the feed points140,142,144and146(each of which may be disposed at a proximal end of a radially outwardly extending conductor) may be utilized in one example embodiment. In this regard, the feed points140,142,144and146may be operably coupled to a radio, each other, and/or other external components via coaxial cables. For example, four coax cables may be perpendicular to the substrate130, which may be used to feed the four arms of the cross dipole antenna100at the feed points140,142,144and146. In an example embodiment, two central pins of two neighboring coax cables (e.g., feed points140and142) may be electrically connected to two neighbor arms crossing these cables at the feed points (Coax A and B), and the two shields of the cables that may be electrically connected to the other two neighboring arms on the same side. The shields of another two cables without central pins (called dummy cables) may also be connected electrically to the arms at the feed points (e.g., feed points144and146) which may already be connected to the pins of the first two cables (Dummy Coax A and B). The two orthogonal crossed dipoles may thus be formed. The orthogonal crossed dipoles may each have a coax cable feed, and each coax cable feed may be powered by RF signals with ϕ=π/2 phase difference to radiate either a right-hand CP wave or a left-hand CP wave.

The polarized wave dynamics in the cross dipole antenna100may be described by the normalized Jones vector:

❘"\[LeftBracketingBar]"ψ〉=(ψxψy)=(cos⁢θ⁢ej⁢αsin⁢θ⁢ej⁢α±ϕ),
where α is the polarization angle, ϕ is the polarization offset, and the wave may oscillate in the XY plane. For example if:

ϕ=π2
then the Jones vector becomes:

❘"\[LeftBracketingBar]"ψ〉=12⁢(1±j)⁢ej⁢α
and the antenna pattern becomes circularly polarized if the element is fed with this condition. With −j producing Right-Hand Circularly Polarized (RHCP) pattern and +j Left-Hand Circularly Polarized Pattern.

An antenna backing cavity may be introduced in the form of metal bounded region between the element and the ground plane, the fields created within this cavity may be expressed as a sum of transverse electric and transverse magnetic components in normal to the ground plane Z direction (TEZand TMZ, respectively) via vector potential components FZand AZ:

AZ(ρ,ϕ,z)⁢∑n=-∞∞∑q=0∞A~zec(ρ,n,q)⁢e-j⁢n⁢ϕ⁢cos[q⁢πLz⁢c⁢(z-z1⁢c)]FZ(ρ,ϕ,z)⁢∑n=-∞∞∑q=0∞F~zes(ρ,n,q)⁢e-j⁢n⁢ϕ⁢sin[q⁢πLz⁢c⁢(z-z1⁢c)]A~zec=ℱz⁢cosF~zes=ℱz⁢sin,
in terms of exponential Fourier cosine and sine series in z. And where z1cand z2cmay be physical cavity wall locations, and Lzc=(z2c−z1c). These fields may impact the overall antenna radiation pattern, and as shown, may depend on the geometry of the backing cavity. Example embodiments may therefore provide a structure for a cross dipole antenna100that achieves these objectives, as shown by the exemplary structures described herein.

As noted above, the cross dipole antenna100is printed on the flexible substrate130. This renders the cross dipole antenna100capable of being adapted to the shape of a base component upon which the cross dipole antenna100may be mounted. Thus, for example, if the cross dipole antenna100is mounted to a curved, domed, or otherwise not flat structure, the cross dipole antenna100may take the shape of or dictated by the corresponding mounting structure. In some example embodiments, the mounting structure may be or produce a domed or mushroom shape. This, of course increases the depth dimension of the cross dipole antenna100, and may therefore require the use of a spacer at a center portion thereof.FIG.3illustrates a cylindrically shaped dielectric spacer200, which may serve as the spacer mentioned above. Notably, the dielectric spacer200includes channels210formed therein that correspond to the feed points140,142,144and146of the cross dipole antenna100to permit the coax cables described above to pass therethrough.

Referring now toFIGS.4-6, the cross dipole antenna100ofFIG.1may be mounted on a metallic plate300. The metallic plate300may have any desirable outline shape for mounting the cross dipole antenna100thereon. However, in this example, the outline shape of the metallic plate300is flat, but includes slots310that are formed closer together than the length of the cross dipole antenna100. Thus, the cross dipole antenna100can be mounted with its ends inserted into the slots310and the dielectric spacer200at its center to form a domed or mushroom shape. In particular, for example, the flexible substrate130with printed respective first and second pairs of dipole arms110and120may be bent with a certain curvature radius matching that provided by fitting the ends into the slots310of the metallic plate300. Thus, the distal ends of the substrate130(e.g., the ends opposite the feed points140,142,144and146) may be inserted into the slots310that may be prefabricated on the top portion of the metallic plate300. The distal ends of the substrate130may then be soldered to the metallic plate300to retain the cross dipole antenna100on the metallic plate300.

This mounting strategy holds the cross dipole antenna100in a way that forms a raised printed cross dipole element construction that creates a dome structure an optimizes gain away from the zenith. The dome or mushroom shape also creates a backing cavity320between the metallic plate300and an antenna body330by spacing the metallic plate300apart from the antenna body330. The metallic plate300acts as a secondary ground plate (with the fuselage or other portion of the structure to which the antenna body330is mounted forming a primary ground plane). The metallic plate300with the cross dipole antenna100affixed thereon may thus be mounted, with an optimized height, on the antenna body330under a radome (represented by dashed line340inFIG.5). By manipulating the shape and height of the secondary (mushroom) ground plane formed by the metallic plate300, the antenna pattern shape of the cross dipole antenna100may be effectively optimized as shown inFIG.6.

Thus, according to an example embodiment, a cross dipole antenna element may be provided. The antenna element may include a flexible substrate, a first pair of dipole arms disposed on the flexible substrate, a second pair of dipole arms disposed on the flexible substrate, a plurality of feed points disposed at a center portion of the flexible substrate and between the first and second pairs of dipole arms, a metallic plate forming a ground plane for the antenna element, and a dielectric spacer disposed between the center portion of the flexible substrate and the metallic plate. The first and second pairs of dipole arms may be operably coupled to the metallic plate at distal ends of the first and second pairs of dipole arms relative to the center portion.

In some embodiments, the antenna element may include additional components/modules, optional features, and/or the components/features described above may be modified or augmented. Some examples of modifications, optional features and augmentations are described below. It should be appreciated that the modifications, optional features and augmentations may each be added alone, or they may be added cumulatively in any desirable combination. In this regard, for example, the first and second pairs of dipole arms may extend away from the center portion by a first length defined between the distal ends, and slots may be formed in the metallic plate separated by a second length that is less than the first length. The distal ends of the first and second pairs of dipole arms may be operably coupled to the metallic plate at the slots. In some cases, the distal ends of the first and second pairs of dipole arms may be soldered to the metallic plate at the slots. In an example embodiment, the first and second pairs of dipole arms may each include conductors having a V or L shape, where the apexes of the V or L shape are disposed proximate to the feed points. In some cases, the dielectric spacer may have a cylindrical shape with channels formed therein corresponding to the feed points. In an example embodiment, the flexible substrate may be affixed to the metallic plate to form a dome or mushroom shape. In some cases, the metallic plate may be disposed a predetermined distance from an antenna body to form a backing cavity between the metallic plate and the antenna body. In an example embodiment, the metallic plate may form a secondary ground plane and a fuselage of an aircraft forms a primary ground plane for the antenna element. In some cases, an antenna pattern generated by the antenna element may be circularly polarized. In an example embodiment, feed points disposed opposite each other may be operably coupled to each other.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits or solutions to problems are described herein, it should be appreciated that such advantages, benefits and/or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be thought of as being critical, required or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.