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US-12627071-B1 - Magnetoelectric antenna structures

US12627071B1US 12627071 B1US12627071 B1US 12627071B1US-12627071-B1

Abstract

Provided herein are various magnetoelectric dipole antenna arrays and multi-array arrangements for handling radio frequency signals. In one example, an antenna array includes a baseplate conductively coupled to sets of plate elements by support members that position the plate elements at selected distances offset from a surface of the baseplate. Antenna probes are arranged in orthogonal pairs positioned within gaps between a corresponding set of plate elements, with each antenna probe comprising a conductive strip having a feed section coupled to a radio frequency connection through the baseplate, a transverse section generally parallel with the baseplate, and a terminal section directed back toward the baseplate. Dielectric structures for each pair of antenna probes comprise a dielectric material having channels that recess the conductive strips therein and a dielectric spacer positioned between overlapping transverse sections of the antenna probes.

Inventors

  • Elie Germain TIANANG
  • James F. Mulvey
  • Andrew Jason Kee
  • Erik Lier

Assignees

  • LOCKHEED MARTIN CORPORATION

Dates

Publication Date
20260512
Application Date
20240110

Claims (20)

  1. 1 . An antenna assembly, comprising: plate elements coupled to support members that establish selected offset distances from a baseplate for the plate elements; a pair of probes arranged orthogonally and positioned within gaps between corresponding plate elements; and dielectric structures for the probes comprising a dielectric material having channels that recess conductive material forming the probes therein and a dielectric spacer positioned between overlapping portions of the probes.
  2. 2 . The antenna assembly of claim 1 , wherein each probe comprises a conductive strip having a feed section coupled to a corresponding radio frequency connection, a transverse section generally parallel with the baseplate, and a terminal section directed back toward the baseplate; and wherein the overlapping portions of the probes comprise at least a portion of the transverse sections.
  3. 3 . The antenna assembly of claim 2 , wherein the dielectric material comprises a foam material having the channels formed therein that recess the conductive strips of the probes flush with a surface of the foam material, and having bores configured to route feed lines between the radio frequency connections and corresponding feed sections of the conductive strips.
  4. 4 . The antenna assembly of claim 1 , wherein the dielectric spacer comprises a high-K dielectric material selected to reduce multipaction between the probes.
  5. 5 . The antenna assembly of claim 1 , wherein the support members individually establish the selected offset distances to achieve performance targets for at least one among axial ratio, bandwidth, group delay, and transmission losses.
  6. 6 . The antenna assembly of claim 1 , comprising: riser structures on a back surface of the baseplate that provide individual pathlengths among corresponding radio frequency connections through the baseplate and establish selected phase relationships among the probes.
  7. 7 . An antenna arrangement, comprising: a central antenna array surrounded by peripheral antenna arrays; wherein each among the central antenna array and the peripheral antenna arrays include a corresponding set of antenna structure instances, each antenna structure instance comprising: plate elements coupled to support members that establish selected offset distances from a baseplate for the plate elements; probes arranged in orthogonal pairs positioned within gaps between a corresponding set of plate elements; and dielectric structures for the probes comprising a dielectric material having channels that recess conductive material forming the probes therein and a dielectric spacer positioned between overlapping portions of the probes.
  8. 8 . The antenna arrangement of claim 7 , wherein each probe comprises a conductive strip having a feed section coupled to a corresponding radio frequency connection, a transverse section generally parallel with the baseplate, and a terminal section directed back toward the baseplate; and wherein the overlapping portions of the probes comprise at least portions of the transverse sections.
  9. 9 . The antenna arrangement of claim 8 , wherein, for each antenna structure instance, the dielectric material comprises a foam material having the channels formed therein that recess the conductive strips of the probes flush with a surface of the foam material, and having bores configured to route feed lines between the radio frequency connections and corresponding feed sections of the conductive strips.
  10. 10 . The antenna arrangement of claim 7 , wherein, for each antenna structure instance, the dielectric spacer comprises a high-K dielectric material selected to reduce multipaction between the probes.
  11. 11 . The antenna arrangement of claim 7 , wherein each among the central antenna array and the peripheral antenna arrays comprise separate hexagonal shaped baseplates abutted at corresponding edges to form the antenna arrangement.
  12. 12 . The antenna arrangement of claim 7 , wherein the central antenna array is configured to handle higher power transmissions than the peripheral antenna arrays, and comprises an antenna array for a radionavigation system; and wherein the peripheral antenna arrays each comprise extended coverage electronically steerable arrays (ESAs).
  13. 13 . The antenna arrangement of claim 7 , wherein, for each antenna structure instance, the support members individually establish the selected offset distances to achieve performance targets for at least one among axial ratio, bandwidth, group delay, and transmission losses.
  14. 14 . The antenna arrangement of claim 7 , comprising: riser structures on a back surface of the baseplates for each antenna structure instance that provide individual pathlengths among corresponding radio frequency connections through the baseplate and establish selected phase relationships among the probes.
  15. 15 . An antenna, comprising: plate elements coupled to a baseplate by support members that establish selected offset distances for the plate elements from the baseplate; probes comprising conductive members arranged in an orthogonal pair positioned within gaps between the plate elements; and a dielectric structure having channels that recess at least a portion of the conductive members of the probes therein and a dielectric spacer positioned between overlapping portions of the probes.
  16. 16 . The antenna of claim 15 , wherein each conductive member comprises a feed section coupled to a radio frequency connection through the baseplate, a transverse section generally planar with the plate elements, and a terminal section directed back toward the baseplate.
  17. 17 . The antenna of claim 15 , wherein the support members individually establish the selected offset distances to achieve performance targets for at least one among axial ratio, bandwidth, group delay, and transmission losses.
  18. 18 . The antenna of claim 15 , wherein the dielectric material comprises a foam material having the channels formed therein that recess the conductive members of the probes flush with a surface of the foam material.
  19. 19 . The antenna of claim 15 , wherein the probes and of plate elements are sized to support radio frequency transmission bands of at least one among L-band, ultrahigh frequency (UHF) band, and microwave frequency band.
  20. 20 . The antenna of claim 15 , comprising: riser structures on a back surface of the baseplate that provide individual pathlengths among radio frequency connections through the baseplate and establish selected phase relationships among the probes.

Description

RELATED APPLICATIONS This application is a continuation of, and claims priority to, U.S. patent application Ser. No. 17/952,913, entitled “MAGNETOELECTRIC ANTENNA ARRAY,” and filed Sep. 26, 2022. TECHNICAL BACKGROUND Various radio frequency antenna arrangements have been developed for microwave frequency applications, such as use on space-deployed craft for communications and ranging. Some example antenna arrangements include dipole, slot, helix, horn, Yagi, microstrip, and patch antennas, each with various limitations on packaging, bandwidth, cross-polarization, and radiation pattern directivity. Many emerging applications for microwave radio frequency (RF) transmissions include arrays of dozens or hundreds of antenna elements, useful for applications such as electronically-steerable arrays (ESAs), which establish packaging or sizing requirements that exclude certain antenna styles or types. Also, when deployed into vacuum environments, such as orbit or space, multipaction effects can limit power handling capabilities of many antenna types. Magnetoelectric (ME) dipole antennas have been developed which include antenna arrangements having two I-shaped or U-shaped orthogonal probes surrounded by four conductive plates that are positioned above a ground plane situated in a box-style of reflector. The surfaces of the conductive plates in the ME dipole antenna act as ground planes, while energized probes transmit/receive RF signals by way of associated RF connectors. Portions of the probes located between gaps in the conductive plates couple the RF energy carried by the antenna. However, existing ME dipole antennas suffer from several limitations, including multipaction and structural fragility which make them unsuitable for most space-deployed applications. Multipaction, or the multipactor effect, is a resonance effect for electrons in vacuum that can exist in response to RF fields accelerating electrons in the voids in waveguides or antenna devices which then impact the nearby surfaces. Under certain conditions, these accelerated electrons can liberate additional electrons from the impacted surfaces, leading to a runaway effect of an exponentially increasing quantity of electrons being accelerated and freed. Multipaction results in various operational degradations, such as high losses, signal distortions, and ultimately equipment failures, particularly in space-deployed devices. Overview Provided herein are various magnetoelectric (ME) dipole antenna arrays and multi-array arrangements for handling radio frequency signals. Array antennas based on legacy helix or patch antennas are not readily available with low profile, low mass, large bandwidth, high power handling, and dual polarization. Furthermore, when antenna arrays are deployed for space applications, multipaction effects can reduce performance and power handling of many legacy RF and antenna solutions, and any selected antenna needs sufficient ruggedization to survive launch and deployment processes. Passive intermodulation (PIM) is also a limiting factor for high power RF applications. The examples discussed herein include enhanced ME dipole arrays, which can be optimized to meet various performance goals. For example, the ME dipole arrays discussed herein can be ruggedized for space applications and have reduced multipaction, along with various optimizations for increased bandwidth, low axial ratio (cross-polarization), and low pattern group delay. When deployed in space applications, such as on radionavigation satellites, such ME dipole antennas can be a fraction of the protrusion profile of helix antennas, and half the weight of microstrip patch arrays. In one example, a magnetoelectric antenna array includes a baseplate conductively coupled to sets of plate elements by support members that position the plate elements at selected distances offset from a surface of the baseplate. Antenna probes are arranged in orthogonal pairs positioned within gaps between a corresponding set of plate elements, with each antenna probe comprising a conductive strip having a feed section coupled to a radio frequency connection through the baseplate, a transverse section generally parallel with the baseplate, and a terminal section directed back toward the baseplate. Dielectric structures for each pair of antenna probes comprise a dielectric material having channels that recess the conductive strips therein and a dielectric spacer positioned between overlapping transverse sections of the antenna probes. In another example, a magnetoelectric antenna arrangement includes a central antenna array surrounded by peripheral antenna arrays. Each among the central antenna array and the peripheral antenna arrays include a corresponding set of antenna structure instances. Each antenna structure instances can be as described above. For instance, an antenna instance includes a baseplate conductively coupled to a set of plate elements by support members that position the plate ele