Patent Description:
In accordance with the present invention, there is provide a radio frequency antenna element as defined by claim <NUM>.

With this particular arrangement, RF signals having a circular polarization may be coupled to and/or from the antenna element via the single feed circuit. The three conductors can be spaced from each other and disposed such that they provide polarization alignment when they are disposed within an array antenna having a triangular lattice spacing.

The antenna element having three conductors and disposed in an array antenna on the triangular lattice results in the ability to provide an array antenna having more radiating elements per area without resulting in grating lobes as compared with antenna elements disposed on rectangular lattices. Thus, the number of active device channels required to realize a desired level of gain for a particular antenna element or array of antenna elements may be reduced. The single feed used to realize the right-hand circular polarized (RHCP) antenna element can reduce the number of active devices needed by half compared to a dual feed architecture. Thus, an antenna element having three conductors (or arms) may be used to provide a low profile, circularly polarized, antenna element suitable for use in an array antenna having a triangular lattice shape and configured to generate circular polarization using a single feed and able to maintain circularly polarized performance over a broad scan volume. A broad scan volume may refer to scan volumes that cover all scan angles out to a <NUM>° scan angle (i.e., <NUM>° scan cone) or greater with respect to a boresight axis of the respective antenna element or array antenna. A circular polarized performance can be maintained up to a <NUM>° scan volume.

For example, the antenna element can be sized such that it is compact and thus may be easier to accommodate within a unit cell of an array antenna with enough room to also accommodate vertical transitions to active devices. IThe structure of the antenna element includes ground vias to form a grounded structure where the entire radiator circuit is DC grounded. Thus, improving high frequency performance and inhibiting propagation of surface waves. High frequency may refer to a frequency in the range of about <NUM> to about <NUM> (e.g., from the S-band range to the Q-band range). High frequency may refer to frequencies above the Q-band frequency range. It should be appreciated that the antenna elements as described herein can be scaled to a variety of different frequencies with such frequencies selected based upon the needs of a particular application in which the antenna or antenna element is being used as well as upon manufacturing technologies (e.g., printed wiring board (PWB) technology).

The feed circuit includes a signal port, antenna ports, a feed line and can include multiple delay lines to provide to each of the three conductors, which connect to the antenna element, RF signals having approximately equal amplitudes and a phase relationship (e.g., ideally distributed at <NUM>°/<NUM>°/<NUM>° respectively) such that the signal provided to each arm of an antenna element is phase shifted by approximately <NUM>° from an adjacent arm. The feed circuit design produces a phase shift of approximately <NUM>° between RF signals provided to adjacent ones of antenna element conductors by means adapted from Marchand balun design, but that produces the necessary approximate <NUM>° phase difference (instead of approximately <NUM>° used in a conventional Marchand balun) by creating an asymmetry in the length of the two short circuited stubs that realize the RF chokes in the feed circuit. The feed circuit properties, such as but not limited to, the length, width (i.e., impedance) and/or shape of the feed and delay lines can be selected to provide the appropriate phase shift and amplitude distribution between RF signals provided to adjacent conductors. Thus, the feed circuit as described herein can provide approximately equal RF signals to three conductors by exciting signal vias coupled to each of the conductors with RF signals <NUM>° out of phase relative to an adjacent one of the three conductors. This feed circuit is also compact enough to fit within the radiator unit cell lattice, which is not possible with a feed circuit provided from a traditional three-way reactive divider with delay lines.

Three conductors may be provided having similar geometric shape. The antenna elements include a first signal via coupling the first antenna port to a first conductor of the three conductors, a second signal via coupling the second antenna port to a second conductor of the three conductors and a third signal via coupling the third antenna port to a third conductor of the three conductors.

A first ground via is formed extending from the first conductor to a first ground plane, a second ground via is formed extending from the second conductor to the first ground plane and a third ground via is formed extending from the third conductor to the first ground plane.

A plurality of leakage vias can be disposed having a geometric relationship with respect to each other. Each of the plurality of leakage vias can couple the first ground plane to a second ground plane.

The antenna element comprises two layers such that the three conductors are disposed in a first layer and the plurality of leakage vias are disposed in a second layer.

The feed circuit further may include a feed line (e.g., signal path) coupling the signal port to the second signal via, wherein the feed line provides the RF signals to each of the first, second and third signal vias having equal amplitudes and having an approximately <NUM> degree phase shift relative to the RF signals provided to an adjacent one of the first, second and third signal vias. The feed circuit may include a first delay line having a first length, a second delay line having a second length and a third delay line having a third length. The first delay line may couple the first ground via to the first signal via, the second delay line may couple the second ground via to the second signal via and the third delay line may couple the second signal via to the third signal via.

A portion of the feed line can be disposed proximate to a portion of the first delay line to couple the feed line to the first delay line such that the first delay serves as a ground reference to the feed line. The first delay line and second delay line can be spaced a predetermined distance from each other. The predetermined distance can be selected such that it produces the approximately <NUM> degree phase shift between the RF signals provided to the first and second signal vias.

The predetermined distance can be selected such that a combined power factor of the RF signals provided to the second signal via and third via is two times greater than a power factor of the RF signals provided to the first signal via.

A length of the third delay line can be selected to produce the approximately <NUM> degree phase shift between the RF signals provided to the second signal via and third signal via.

The array antenna includes a substrate having first and second opposing surfaces and a plurality of antenna elements disposed on the first surface of said substrate.

Each of the plurality of antenna elements includes three conductors physically spaced apart from each other and arranged so as to be responsive to RF signals at a desired frequency range, and a feed circuit having a signal port, and first, second and third antenna ports. Each of the first, second and third antenna ports coupled to a respective one of the three conductors, said feed circuit configured such that in response to an RF signal provided to the signal port thereof, said feed circuit provides at each of the first, second and third antenna ports, RF signals having equal amplitudes and phases shifted by approximately <NUM> degrees.

Each of the antenna elements includes a first signal via coupling the first antenna port to a first conductor of the three conductors, a second signal via coupling the second antenna port to a second conductor of the three conductors and a third signal via coupling the third antenna port to a third conductor of the three conductors. Each of the antenna elements include a first ground via extending from the first conductor to a first ground plane, a second ground via extending from the second conductor to the first ground plane and a third ground via extending from the third conductor to the first ground plane.

Each of the antenna elements may include a plurality of leakage vias disposed having a geometric relationship with respect to each other, each of the plurality of leakage vias coupling the first ground plane to a second ground plane. In embodiments, each of the antenna elements includes two layers such that the three conductors are disposed in a first layer and the plurality of leakage vias are disposed in a second layer.

A feed line coupling the signal port to the second signal via may be included in each of the antenna elements. The feed line can provide the RF signals to each of the first, second and third signal vias having approximately equal amplitudes and having an approximately <NUM> degree phase shift relative to the RF signals provided to an adjacent one of the first, second and third signal vias.

Each of the antenna elements may include a first delay line having a first length, a second delay line having a second length, and a third delay line having a third length. The first delay line may couple the first ground via to the first signal via, the second delay line may couple the second ground via to the second signal via, and the third delay line may couple the second signal via to the third signal via.

A portion of the feed line can be disposed proximate to a portion of the first delay line to couple the feed line to the first delay line such that the first delay serves as a ground reference to the feed line.

The first delay line and the second delay line can be spaced a predetermined distance from each other. The predetermined distance can be selected such that it produces the approximately <NUM> degree phase shift between the RF signals provided to the first and second signal vias. A length of the third delay line can be selected to produce the approximately <NUM> degree phase shift between the RF signals provided to the second signal via and third signal via.

The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below.

The foregoing features may be more fully understood from the following description of the drawings in which:.

Now referring to <FIG>, an array antenna (or more simply "array") <NUM> includes a plurality of so called "tripole current loop" antenna elements 104a-104p. Each of the antenna elements 104a-104p are provided from three conductors 106a-106c (also referred to herein as "arms") disposed in a predefined spaced relation on a first surface 102a of a substrate <NUM>. In particular, conductors 106a-106c are disposed having a triangular relationship with respect to a center point. That is, each conductor or arm in an element is spaced apart and is rotated by an angle of about <NUM>° with respect to the other conductors which comprise the element.

As illustrated in <FIG>, array <NUM> is provided having a triangular lattice. That is, antenna elements 104a-104p can be disposed on substrate <NUM> having a triangular lattice spacing (for clarity, a triangular grid <NUM> is superimposed over the example array illustrated in <FIG>; it should be appreciated that grid <NUM> is not part of the array <NUM>, but rather is only included for clarity). As illustrated in <FIG>, each of antenna elements 104a-104p are disposed at one of a plurality of vertices <NUM> (or nodes) of triangular grid <NUM>. Thus, antenna elements 104a-104p are disposed at various points along a triangular grid <NUM>.

In the illustrative embodiment of <FIG>, arms of antenna elements 104a, 104b, 104c, 104d are aligned at least along line 109a and arms of antenna elements 104d, 104i, <NUM>, 104o are aligned at least along line 109b. Further, and as noted above, conductors 106a-106c which make up each of antenna elements 104a-104p, are disposed having a triangular relationship (i.e., <NUM>° relationship) with respect to each other, and in the illustrative embodiment of <FIG>, a center point between the three conductors is aligned with at least one of the plurality of vertices <NUM> (or node) of triangular grid <NUM>.

Conductors 106a-106c may be provided from any electrical conductor (e.g., a metallic material) or any material electrically responsive to RF signals provided thereto. Conductors 106a-106c may be formed having the same or substantially same geometric shape. In other embodiments, one or more of conductors 106a-106c may have different geometric shapes. Conductors 106a-106c may be formed in a variety of different shapes, including but not limited to any regular or irregular geometric shape. In some embodiments, the thickness (or width) of conductors 106a-106c can be varied to modify (e.g., improve) design performance. The shape and/or properties of conductors 106a-106c can be selected based, at least in part, on the dimensions of array antenna <NUM> and/or a particular application of array antenna <NUM>. For example, the shape of conductors 106a-106c can be modified to change a performance characteristic and/or frequency band within which the respective antenna element <NUM> or array antenna <NUM> operates. Such performance characteristics include, but are not limited to, return and insertion loss, gain, and/or axial ratio characteristics the respective antenna element <NUM> or array antenna <NUM>.

Substrate <NUM> comprises a dielectric material. In some embodiments, substrate <NUM> may include multiple layers some of which may be a dielectric material and some of which may be a non-dielectric material, as will be discussed in greater detail below with respect to <FIG> and <FIG>.

Referring now to <FIG>, an array antenna unit cell <NUM> (hereinafter unit cell) includes three conductors 106a-106c disposed on a first surface 102a of a substrate <NUM> so as to form antenna element <NUM> on first surface 102a of substrate <NUM>. It should be appreciated that antenna element <NUM> may be the same as or substantially similar to at least one of the plurality of antenna elements 104a-104p of <FIG>. In the illustrative embodiment of <FIG>, unit cell <NUM> is provided having six (<NUM>) sides. Unit cells having other shapes, may of course, also be used.

Unit cell <NUM> further includes a ground plane <NUM> disposed on a second, opposite surface 102b of substrate <NUM>. A second substrate <NUM> may be disposed over a second surface 108b of ground plane <NUM>. Each of conductors 106a-106c is coupled to ground <NUM> through a ground via as will be described in more detailed below with respect to <FIG>.

Thus, array antenna <NUM> of <FIG> may include a plurality of unit cells, each having antenna elements comprising three conductors 106a-106c positioned such that they are disposed adjacent to each other and physically spaced apart in a center of the respective unit cell.

Conductors 106a-106c are disposed on first surface 102a of substrate <NUM> and spaced apart from each other. Thus, a gap 105a-105c exists between each of conductors 106a-106c such that the conductors 106a-106c are not in physical contact.

Conductors 106a-106c can, for example, be spaced apart from each other and arranged along first surface 102a so as to be responsive to radio frequency (RF) signals at a desired frequency range. In some embodiments, the spacing between conductors 106a-106c can be selected based at least in part on performance requirements and/or frequency band requirements of a particular application in which a respective antenna element <NUM> and/or array antenna <NUM> is used. For example, changing the spacing (e.g., changing the gap) between conductors 106a-106c can change the return loss and insertion loss performance, gain, and/or axial ratio characteristics of a respective antenna element <NUM> and/or array antenna <NUM>. In some embodiments, antenna element <NUM> and conductors 106a-106c can be configured to be responsive to RF signals in the Q band frequency range (e.g., <NUM>-<NUM>). However, it should be appreciated that antenna element <NUM> and conductors 106a-106c can be configured to be responsive to RF signals in a variety of different frequency ranges, based at least in part upon the needs of a particular application in which antenna element <NUM> is used.

As illustrated in <FIG>, conductors 106a-106c are disposed having a triangular relationship (i.e., <NUM>° relationship) with respect to each other. Such an arrangement allows a center point between the three conductors to be aligned at one of the plurality of vertices (or nodes) <NUM> (<FIG>) of a triangular grid (e.g., triangular grid <NUM> of <FIG>) so as to provide an array having a triangular lattice structure. In an embodiment, the use of three conductors 106a-106c having a spaced triangular relationship provides for polarization alignment between conductors 106a-106c and a triangular lattice of an array antenna which may be formed by antenna elements provided from conductors 106a-106c and substrate <NUM>. The polarization alignment of conductors 106a-106c can provide for a more predictable change over scan in mutual coupling between antenna elements in an array antenna, such as between antenna elements <NUM> of array antenna <NUM> of <FIG>. The more predictable change over scan can provide an improved scan performance, particularly at far scan angles.

The use of three conductors 106a-106c (instead of four as in traditional quad pole designs) reduces the footprint required by conductors 106a-<NUM> within unit cell <NUM> and facilitates inclusion of additional circuitry within unit cell <NUM>. Additionally, the use of the triangular lattice instead of a rectangular lattice provides a large unit cell area that is substantially grating lobe free, which also provides more space for feed circuitry and vertical vias. This additional area for circuitry can become very important at higher frequencies where a particular application of an antenna element or array antenna is required by grating lobe physics to be on a smaller lattice to maintain scan performance. For example, conductors 106a-106c can be sized and provided within unit cell <NUM> with enough spacing to accommodate vertical transitions to active devices (not shown). The shape and triangular relationship between the three spaced conductors or arms 106a-106c which form the antenna element allows the antenna element to be used in an array having a triangular lattice. This, in turn, allows for fewer antenna elements 104a-104p to be used within an array antenna of a given size (area) as compared to a similarly sized array having a rectangular lattice structure. Such a decrease in the number of antenna elements maintains antenna gain while reducing overall array cost (because fewer active devices and components are required to support fewer channels, simplifying packaging of components on the array and reducing component cost).

Referring now to <FIG> and <FIG> in which like elements are provided having like reference designations, each of conductors 106a-106c include at least one signal via 120a-120c and at least one ground via 124a-124c to couple the respective conductors to a feed circuit <NUM> and a ground plane (e.g., ground plane <NUM> of <FIG>) respectively. For example, a first signal via 120a and a first ground via 124a are coupled to conductor 106a. A second signal via 120b and a second ground via 124b are coupled to conductor 106b. A third signal via 120c and a third ground via 124c are coupled to conductor 106c. Thus, a tripole antenna element configured to generate circular polarizations can be provided having a single feed, here feed circuit <NUM>.

Feed circuit <NUM> includes a signal path <NUM> coupled to first, second and third antenna ports 121a-121c through signal paths <NUM>, <NUM>, <NUM> and signal vias 120a-120c with paths <NUM>, <NUM>, <NUM> corresponding to delay lines. Signal path <NUM> is coupled to port <NUM> (e.g., signal port interface) where a vertical RF via transition couples feed circuit <NUM> to various circuit portions of which the respective antenna element is a part. For example, in one embodiment, port <NUM> couples feed circuit <NUM> to active devices mounted on a printed wiring board (PWB). In some embodiments, signal path <NUM> may be referred to herein as a feed line.

A first end of first signal via 120a is coupled to first conductor 106a and a second end of signal via is coupled to feed circuit <NUM>. In this way, RF signals may be coupled between the antenna element and port <NUM>. Similarly, second signal via 120b has a first end coupled to second conductor 106b and a second end coupled feed circuit <NUM> and third signal via 120c has a first end coupled to third conductor 106c and a second end coupled to feed circuit <NUM>. Thus, feed circuit <NUM> can provide RF signals to each of first, second and third conductors 106a-106c.

The feed circuit <NUM> is formed and configured to provide RF signals having equal amplitudes and phases shifted by <NUM>° to conductors 106a-106c. For example, signal path <NUM> and each of delay lines <NUM>, <NUM>, <NUM> can be positioned, spaced and/or sized such that feed circuit <NUM> provides RF signals to first, second and third conductors 106a-106c respectively that are phase shifted <NUM>° from RF signals provided to an adjacent (or neighboring) one of first, second and third conductors 106a-106c. Thus, each of the arms may be excited from signals provided through the three signal vias 120a-120c.

In this illustrative embodiment, feed circuit <NUM> is provided from a pair of conductor signal layers (i.e. as a two-layer feed) which provides <NUM>, <NUM> and <NUM> degree phase shifted equal amplitude signals to antenna element arms 106a-106c.

Signal path <NUM> includes a coupling region <NUM> in which path <NUM> serves as a ground to signal path <NUM>. Coupling region <NUM> directs one-third of the power fed from a first end of signal path <NUM> (i.e. a port <NUM>) to conductor 106b and two-thirds of the power propagates along path portion 132b toward conductors 106a, 106b. At signal via 120c, the remaining power is split equally such that one-third of the total power provided at input port <NUM> is provided to conductor (or arm) 106c and one-third of the power is provided to conductor (or arm) 106a via signal path <NUM>. It should be appreciated that paths <NUM>, <NUM>, <NUM> may be provided having a width selected such that the signal path acts as an RF choke. Thus, each of the arms 106a-106c receive signals having an equal amount of signal power with relative phase shifts of <NUM>°/<NUM>°/<NUM>° for right hand circuit polarization (RHCP).

As illustrated in <FIG>, a first end of feed line <NUM> is configured to couple RF signals to and/or from port <NUM>, which, in turn, couples signals to and/or from various portions of an RF system of which antenna element <NUM> is a part. For example, port <NUM> may be provided as an interface that couples feed circuit <NUM> to the various portions of an RF system (e.g., passive or active devices and/or circuits) through a vertical via transition. Thus, feed line <NUM> couples signals between the respective antenna ports and input/output port <NUM>.

Feed circuit <NUM> includes a first delay line <NUM> coupling second signal via 120b to a second ground via 124b. A second delay line <NUM> couples third signal via 120c to a third ground via 124c, and a third delay line <NUM> couples third signal via 120c to first signal via 120a.

Feed line <NUM> couples to third signal via 120c with third signal via 120c coupled to first signal via 120a through third delay line <NUM>. Thus, feed line <NUM> can be configured to provide RF signals having a greater power factor to third signal via 120c as compared to the RF signal provided to second signal via 120b, as third signal via 120c is coupled to first signal via 120a and shares (e.g., splits) the RF signals with first signal via 120a. In one embodiment, a combined power factor of RF signals provided to third and first signal vias 120c, 120a can be two times greater than a power factor of RF signals provided to second signal via 120b.

First delay line <NUM> and second delay line <NUM> can be spaced apart from each other a predetermined distance such that the predetermined distance produces a <NUM>° phase shift between the RF signals provided to second signal via 120b and third signal via 120c. It should be appreciated that the predetermined distance between first delay line <NUM> and second delay line <NUM> can be selected to achieve a variety of different phase shifts.

Third delay line <NUM> can be formed such that it splits RF signals between third signal via 120c and first signal via 120a. For example, a length, width (e.g., impedance) and/or shape (here an upside down L shape) of third delay line <NUM> can be selected such that it produces an approximately <NUM>° phase shift between the RF signals provided to third signal via 120c and first signal via 120a. Thus, each of first, second and third signal vias 120a-120c can be excited with RF signals approximately <NUM>° out of phase relative to an adjacent signal via.

In some embodiments, first, second, and third delay lines <NUM>, <NUM>, <NUM> can be formed having different lengths, different impedances (e.g., different widths) and/or different shapes. For example, first, second, and third delay lines <NUM>, <NUM>, <NUM> can be configured to act as an RF choke. The width of first, second and third delay lines <NUM>, <NUM>, <NUM> can be selected to achieve an appropriate impedance. In some embodiments, first, second, and third delay lines <NUM>, <NUM>, <NUM> can be selected such that they appear as an open circuit. In the illustrative embodiment of <FIG>, the properties of first, second and third delay lines <NUM>, <NUM>, <NUM> can be selected to provide RF signals to each of the three conductors 106a-106c having equal amplitude but <NUM>° out of phase relative to an adjacent one of conductors 106a-106c.

It should be appreciated that shapes, impedances, lengths and/or spacing between first, second and third delay lines <NUM>, <NUM>, <NUM> can vary and can be selected and formed to produce a required phase shift (here approximately <NUM>°) between RF signals provided to different signal vias for a particular application of an antenna element.

Each of conductors 106a-106c is coupled to ground plane (e.g., ground plane <NUM> of <FIG>) through at least one of ground vias 124a-124c. For example, and as illustrated in <FIG>, first ground via 124a couples a surface of first conductor 106a to a ground plane, second ground via 124b couples a surface of second conductor 106b to the ground plane, and third ground via 124c couples a surface of third conductor 106c to the ground plane.

A plurality of leakage vias 122a-<NUM> can be formed in antenna element <NUM> to prevent RF leakage through a feed layer, such as the feed layer between feed circuit <NUM> and conductors 106a-106c. For example, and as will be described in greater detail with respect to <FIG>, leakage vias 122a-<NUM> can be formed in a different layer of antenna element <NUM> than ground vias 124a-124c and can form a cavity such that energy is transferred to (e.g., up to) conductors 106a-106c and doesn't leak through a stripline layer disposed adjacent to the feed layer of antenna element <NUM>. In the illustrative embodiment of <FIG>, leakage vias 122a-<NUM> are formed generally in a circular shape, however it should be appreciated that leakage vias 122a-<NUM> can be formed in a variety of different shapes (e.g., rectangular, spherical, etc.) to prevent leakage. Further, the number of leakage vias 122a-<NUM> can be selected based at least in part on a dimensions of a respective antenna element and its respective components and/or a frequency of RF signals being provided. For example, in an embodiment, the size of the cavity created by leakage vias 122a-<NUM> can be used to tune the respective antenna element or array antenna.

Referring now to <FIG>, conductors 106a-106c are formed over a first surface 140a of a first dielectric region <NUM> forming an antenna circuit <NUM>. Feed line <NUM> and first and second delay lines <NUM>, <NUM> can be formed within a second dielectric region <NUM> as part of feed circuit <NUM>. In an embodiment, second dielectric region <NUM> can be formed proximate to a second surface 108b of ground plane <NUM> (here below ground plane <NUM>) of antenna element <NUM>. Signals vias 120a-120c can be formed through first dielectric region <NUM> and a portion of second dielectric region <NUM> to couple a surface of conductors 106a-106c to feed line <NUM>. For example, in an embodiment, antenna circuit <NUM> is formed adjacent to a first surface 108a of ground plane <NUM> (here above ground plane <NUM>) and feed circuit <NUM> is formed adjacent to second surface 108b of ground plane <NUM> (here below ground plane <NUM>).

In the illustrative embodiment of <FIG>, first signal via 120a extends from first conductors 106a to a first antenna port 121a, second signal via 120b extends from second conductors 106b to a second antenna port 121b, and third signal via 120c extends from third conductor 106c to a third antenna port 121c. In an embodiment, each of first, second and third antenna ports 121a-121c can be part of the signal path for antenna element <NUM>. For example, each of first, second and third antenna ports 121a-121c can be coupled to feed line <NUM> to provide RF signals to first, second and third signal vias 120a-120c, respectively. In some embodiments, first antenna port 121a can be coupled to the second region <NUM> of second delay line <NUM> to receive RF signals, second port 121b can be coupled to the first delay line <NUM> to receive RF signals and third antenna port 121c can be capacitively coupled to feed line <NUM> to receive RF signals. In an embodiment, first, second and third antenna ports 121a-121c may optionally include impedance tuning features (e.g., copper etched pads) added in some embodiments to improve loss performance.

As illustrated in <FIG>, ground vias 124a-124c are formed through first dielectric region <NUM> to couple a surface of conductors 106a-106c to ground plane <NUM>. Second dielectric region <NUM> is below second surface 108b of ground plane <NUM>. Leakage vias 122a-<NUM> can be formed within second dielectric region <NUM>. In some embodiments, leakage vias 122a-<NUM> can be formed through second dielectric region <NUM> such that they extend from ground plane <NUM> to an additional ground plane formed proximate to a second surface 142b of second dielectric region <NUM>.

For example, and referring now to <FIG>, a second ground plane <NUM> can be formed proximate to (here under) a second surface 142b of second dielectric region <NUM>. Further, and as illustrated in <FIG>, leakage vias 122a-<NUM> can be formed to couple a surface of first ground plane <NUM> to a surface of second ground plane <NUM>. Thus, leakage vias 122a-<NUM> can form a cavity proximate to (here under) couplings between signals vias 120a-120c can conductors 106a-106c to prevent leakage.

In the illustrative embodiment of <FIG>, conductors 106a-106c are disposed proximate to a first surface 140a of first dielectric region <NUM>. Signal vias 120a-120c extend from a surface of conductors 106a-106c to feed line <NUM> and delay lines <NUM>, <NUM>, <NUM> and thus through first dielectric region <NUM> and a portion of second dielectric region <NUM>. For example, signal vias 120a-c can extend through first dielectric region <NUM> and a portion of second dielectric region <NUM> to couple to components of feed circuit <NUM>, described above. In some embodiments, one or more openings may be formed in ground plane <NUM> such that signal vias 120a-120c can extend through and couple to delay lines <NUM>, <NUM>, <NUM>, respectively.

Ground vias 124a-124c extend from a surface of conductors 106a-106c to ground plane <NUM>.

Referring now to <FIG>, a structure <NUM> having a manifold <NUM> coupled to an antenna element <NUM>. In an embodiment, antenna element <NUM> may be the same as or substantially similar to antenna element <NUM> as described above with respect to <FIG>. In some embodiments, structure <NUM> may include a printed wiring board (PWB) stack up having manifold <NUM> and antenna element <NUM> and power and control layers support active devices.

Manifold <NUM> may include circuitry operable to couple or otherwise convey an electrical signal (e.g., RF signal) to antenna element <NUM> or an array antenna having a plurality of antenna elements <NUM>.

In the illustrative embodiment of <FIG>, antenna element <NUM> includes conductors <NUM> formed on a first surface 640a of a first layer <NUM>. Conductors <NUM> are coupled to a first ground plane <NUM> through one or more ground vias <NUM>. Conductors <NUM> are coupled to a feed circuit <NUM> through one or more signal vias <NUM>.

Ground plane <NUM> is generally disposed between first dielectric region <NUM> and a second layer dielectric region <NUM> of antenna element <NUM>. Feed circuit <NUM> may include a feed line, one or more delay lines, a signal port and antenna ports to provide RF signals to conductors <NUM>. Feed circuit <NUM> can be formed within second layer <NUM>. One or more leakage vias <NUM> can be formed such that they extend from first ground plane <NUM> to a second ground plane <NUM>. In some embodiments, second ground plane <NUM> may be a component of manifold <NUM>. In other embodiments, second ground plane <NUM> may be formed as a component of antenna element <NUM>.

Claim 1:
A radio frequency, RF, antenna element (104a-p) comprising:
a substrate (<NUM>) having first (102a) and second opposing surfaces;
three conductors (106a-c) disposed on the first surface of said substrate, said three conductors being physically spaced apart from each other and being arranged so as to form an antenna element responsive to RF signals at a desired frequency range;
a feed circuit (<NUM>) having a signal port and first, second and third antenna ports (121a-c), each of the first, second and third antenna ports coupled to a respective one of the three conductors through a respective one of first, second, and third signal vias (120a-c); and
a first ground via (124a) extending from a first conductor of the three conductors to a first ground plane (<NUM>), a second ground via (124b) extending from a second conductor of the three conductors to the first ground plane and a third ground via (124c) extending from a third conductor of the three conductors to the first ground plane;
wherein said feed circuit is configured such that in response to an RF signal provided to the signal port thereof, said feed circuit provides at each of the first, second and third antenna ports, RF signals having equal amplitudes and phases shifted by <NUM> degrees.