Microstrip electronic scan antenna array

• US 5,243,354 A
• Filed: 08/27/1992
• Issued: 09/07/1993
• Est. Priority Date: 08/27/1992
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Babbitt, Richard W., Stern, Richard A.
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US07/935,931
• Time in Patent Office: 376 Days
• Field of Search: 343/700 MS, 343/754, 343/853, 343/846, 333/1.1, 333/24.2
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 3/242 Circumferential scanning

Abstract

A microstrip electronic scan antenna array is provided comprising a hollow elongated octagonal-shaped housing formed by four quadrantially-disposed microstrip patch antenna arrays and four filler panels extending between the patch arrays. Three, independently-switchable microstrip Y-junction circulators are tandem interconnected in a double-ended wye configuration on a common dielectric substrate forming an octagonal end cover for the housing. Each of the three circulators acts as a single pole-double throw switch and the sequence of energization of the four microstrip patch antenna arrays is determined by controlling the sequence and direction of circulator coupling action of the three circulators.

Claims

1. A microstrip electronic scan antenna array comprising:

a plurality of microstrip patch antenna arrays disposed circumferentially about a central axis, each of said microstrip patch antenna arrays radiating a discrete antenna beam at a different selected bearing point about said axis when said array is coupled to a source of millimeter wave energy, said plurality of microstrip patch antenna arrays comprising four microstrip patch antenna arrays; and

selectively operable microstrip circulator means coupled to said plurality of microstrip patch antenna arrays for sequentially coupling each of said plurality of microstrip patch antenna arrays to a source of millimeter wave energy, said selectively operable microstrip circulator means comprising a plurality of separately switchable microstrip Y-junction circulators tandem interconnected in double-ended wye configuration, each of said circulators having an input and two outputs and operating as single pole-double throw switch with respect to millimeter wave energy applied to the circulator input, said plurality of switchable microstrip Y-junction circulators comprising three switchable microstrip Y-junction circulators tandem interconnected in a double-ended wye configuration with one of said three circulators having the input thereof coupled to said source of millimeter wave energy and the two outputs thereof coupled to the inputs of the remaining two of said three circulators, said remaining two circulators having the outputs thereof each coupled to a different one of said four microstrip patch antenna arrays.

2. A microstrip electronic scan antenna array as claimed in claim 1 wherein said four microstrip patch antenna arrays are disposed at quadrantially related bearing points about said axis so that said microstrip electronic scan antenna array has a 360 degree scanning capability when said four microstrip patch antenna arrays are successively coupled to said source of millimeter wave energy in the order of their bearing points about said axis.

3. A microstrip electronic scan antenna array as claimed in claim 2 wherein each of said microstrip patch antenna arrays comprises

a first microstrip transmission line dielectric substrate spaced laterally from and extending substantially parallel to said axis, said substrate having an inner surface facing said axis and an outer surface facing away from said axis,

a first electrically conductive ground plane disposed on the inner surface of said substrate,

a plurality of microstrip antenna radiating elements mounted on the outer surface of said substrate, and

first electrically conductive microstrip conductor means disposed on the outer surface of said substrate and extending to one of the ends of said substrate for electrically interconnecting said plurality of microstrip antenna radiating elements.

4. A microstrip electronic scan antenna array as claimed in claim 3 wherein said plurality of switchable microstrip Y-junction circulators comprises

a second microstrip transmission line dielectric substrate extending transverse said axis at said one ends of said first microstrip transmission line dielectric substrate,

a second electrically conductive ground plane disposed on one surface of said second dielectric substrate,

three wye-shaped ferrite elements tandem interconnected in a double-ended wye configuration and having a coplanar bottom surface, said three ferrite elements being mounted on the other surface of said second dielectric substrate with said bottom surface of said three ferrite elements abutting said second dielectric substrate other surface, each of said three ferrite elements having

a right-prism shaped central portion with three rectangular prism faces and equilateral triangular shaped top and bottom prism bases,

three triangular shaped arm portions extending radially outwardly from said central portion prism faces, each of said ferrite element arm portions having a downwardly sloping top surface which extends from the top prism base of said ferrite element central portion to said other surface of said second dielectric substrate, and

selectively operable magnetic biasing means for applying a reversible direction d.c. magnetic field between the ferrite element central portion top and bottom prism bases, and

second electrically conductive microstrip conductor means disposed on the top prism bases of said ferrite element central portions, the downwardly sloping top surfaces of the ferrite element arm portions and on said other surface of said second dielectric substrate for connecting the free arm portion of that one of said three ferrite elements which has its remaining two arm portions connected to an arm portion of the remaining two ferrite elements to said source of millimeter wave energy and each of the remaining free arm portions of said two remaining ferrite elements to said first electrically conductive microstrip conductor means interconnecting the plurality of microstrip radiating elements of a different one of said four microstrip patch antenna arrays so that said one ferrite element acts as said one microstrip circulator and said two remaining ferrite elements act as said remaining two circulators.

5. A microstrip electronic scan antenna array as claimed in claim 4 wherein said selectively operable biasing means comprises

a laterally extending bore passing through each of the arm portions of each of said three ferrite wye-shaped elements, and

separately controllable control wire means passing through the bores in the arm portions of each of said three ferrite wye-shaped elements for carrying a d.c. control current through each of said bores in the same rotational direction about the longitudinal axis of the central portion of the wye-shaped ferrite element so that a resultant unidirectional magnetic field is established between the top and bottom prism bases of the central portion of the wye-shaped element and the rotational direction of circulator coupling action of the switchable Y-junction microstrip circulator formed by that wye-shaped element can be separately switched by reversing the polarity of said d.c. control current.

6. A microstrip electronic scan antenna array as claimed in claim 5 wherein each of said three ferrite wye-shaped elements is fabricated of a ferrite material having a square hysteresis loop so that the magnetic direction of said resultant unidirectional magnetic field in each of the three ferrite elements may be latched from one state to the opposite state by the application of a control current pulse to the control wire means for each of said three ferrite elements.

7. A microstrip electronic scan antenna array as claimed in claim 6 further comprising

four housing panels each spaced laterally from and extending substantially parallel to said central axis, each of said housing panels extending between a different adjacent pair of the first microstrip transmission line dielectric substrates forming said four microstrip patch antenna arrays so that a hollow elongated octagonal housing is formed about said central axis,

an octagonal-shaped cover disposed substantially perpendicular to said central axis and extending between said four panels and said first dielectric substrates at the other ends of said first dielectric substrates, and

wherein said second microstrip transmission line dielectric substrate is octagonal-shaped and is disposed substantially perpendicular to said central axis with said other surface of said second dielectric substrate facing the hollow interior of said octagonal housing so that said selectively operable microstrip circulator means are disposed within the closed interior of the electronic scan antenna array formed by said second dielectric substrate, said octagonal housing and said cover.

8. A microstrip electronic scan antenna array as claimed in claim 7 wherein said housing panels and said cover are fabricated of a microstrip transmission line dielectric substrate material.

9. A microstrip electronic scan antenna array as claimed in claim 8 wherein

said plurality of microstrip antenna radiating elements forming each of said microstrip patch antenna arrays are disposed in a single column which is substantially parallel to said central axis, so that each of said microstrip patch antenna arrays radiates a fixed antenna beam which is substantially fan-shaped in a plane perpendicular to said central axis.