Electronically scanned ferrite line source

• US 5,955,998 A
• Filed: 01/05/1996
• Issued: 09/21/1999
• Est. Priority Date: 08/14/1995
• Status: Expired due to Term

• Current Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Original Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Inventors: Williams, Wyman L., Roberts, Roger G., Alexander, Jeff M.
• Primary Examiner(s): Wimer, Michael C.
• Application Number:
  US08/583,707
• Time in Patent Office: 1,355 Days
• Field of Search: 343/768, 343/770, 343/771, 343/853, 342/371, 342/374, 333/24.1
• US Class Current: 343/768
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 3/36 with variable phase-shifters

Abstract

A ferrite scanning line source is formed of a ferrite toroid and one or more dielectric slabs mounted to a side of the toroid. A signal propagating through the waveguide is phase shifted by the magnetization of the toroid. The further down the toroid the signal propagates the greater the phase shift that is applied to the signal. Radiators or coupling ports are formed by slots cut in a wall of the waveguide. The phase of the signal radiating from each slot in the line source is shifted from the signals emanating from the preceding and following slot in the line source. By properly locating the slots along the line source, a composite beam formed by the energy radiating from each slot may be titled (scanned) to a desired direction. In addition, the amount of phase shift applied to the signal by the waveguide depends on the magnetic state of the phase shifter. By changing the magnetic state of the phase shifter, by using a latch wire, the direction of the beam emanating from the line source can be scanned, such as by ±20°. Phased array antenna systems are formed of groups of radiating elevation line sources that are fed signals by a group of azimuth line sources coupled by microstrips to the elevation line sources.

Claims

1. An electronically scanned ferrite line source comprising:

a linear waveguide having a hollow ferrite toroid, at least one dielectric slab external to the toroid and adjacent a first wall of the toroid, and a conductive skin covering outer surfaces of the toroid and slab; and

a plurality of slots etched on the conductive skin adjacent the dielectric slab, where the slots are parallel to an axis of the waveguide.

2. An electronically scanned ferrite line source as in claim 1 wherein the slots radiate energy into free space.

3. An electronically scanned ferrite line source as in claim 1 having a latch wire extending through the ferrite toroid and said latch wire is adapted to receive a voltage time integral signal to selectably set the magnetic state of the ferrite toroid.

4. An electronically scanned ferrite line source as in claim 1 wherein said slots are rectangular and have a long dimension parallel to a longitudinal axis of the toroid.

5. An electronically scanned ferrite line source as in claim 1 wherein the toroid has a longitudinal cavity that is rectangular in cross section.

6. An electronically scanned ferrite line source as in claim 1 wherein the slots are spaced apart by a distance approximately twice the wavelength of a signal propagating in the line source.

7. An electronically scanned ferrite line source as in claim 1 wherein the dielectric slab is a composite slab formed of a plurality of dielectric slabs stacked together.

8. An electronically-scanned ferrite line source as in claim 7 wherein a first slab of said plurality of dielectric slabs is adjacent the first wall of the toroid and a second slab of said plurality of dielectric slabs is separated from the toroid by the first slab.

9. An electronically scanned ferrite line source as in claim 8 wherein the first slab has a dielectric constant relatively high as compared to a dielectric constant of the second slab.

10. An electronically scanned ferrite line source for spatially scanning a beam of electromagnetic energy comprising:

a linear waveguide having a hollow ferrite toroid, at least one dielectric slab external to the toroid and adjacent to a first sidewall of the toroid, and a conductive metal skin covering outer surfaces of the toroid and slab;

wherein a plurality of slot apertures are etched in the skin adjacent the dielectric slab, and the slot apertures are parallel to an axis of the waveguide;

an impedance matched terminal load for at least one end of the waveguide;

a signal port to the waveguide, and

a current carrying latch wire extending through said toroid.

11. An electronically scanned ferrite line source as in claim 10 wherein the slot apertures etched on the metal skin radiate energy into free space.

12. An electronically scanned ferrite line source as in claim 10 wherein said latch wire is adapted to receiving a voltage-time integral signal and the voltage-time integral signal is represented by:

##EQU3## where t₁ and t₂ represent the start and stop time of the signal, U is voltage and φ

is the desired magnetic flux setting.

13. An electronically scanned ferrite line source as in claim 10 wherein said slot apertures are rectangular in cross-section and have a long dimension parallel to a longitudinal axis of the toroid.

14. An electronically scanned ferrite line source as in claim 10 wherein the toroid has a longitudinal cavity rectangular in cross section.

15. An electronically scanned ferrite line source as in claim 10 wherein the slot apertures are separated by a distance approximately twice a wavelength of a signal propagating in the line source.

16. An electronically scanned ferrite line source as in claim 10 wherein the at least one dielectric slab is a pair of dielectric slabs stacked together.

17. An electronically scanned ferrite line source as in claim 16 wherein a first slab of said pair of dielectric slabs is adjacent the first sidewall of the toroid and a second slab of said pair of dielectric slabs is separated from the toroid by the first slab.

18. An electronically scanned ferrite line source as in claim 17 wherein the first slab has a dielectric constant relatively high as compared to a dielectric constant of the second slab.

19. An electronically scanned phase array antenna comprising:

an electronically scanned linear ferrite line source including;

a hollow ferrite toroid having a first wall;

at least one dielectric slab adjacent the first wall of the toroid, where the slab is external to the toroid;

a conductive skin covering outer surfaces of the toroid and slab;

a plurality of radiating slots etched on the conductive skin adjacent the slab and parallel to an axis of the toroid, wherein said slots radiate electromagnetic energy to collectively form a transmission beam propagating in a beam direction;

a latch wire for setting the magnetic state of the toroid, and

a signal coupling port for receiving signals for transmission from the line source;

a signal generator for sequentially supplying a plurality of frequency beam signals, wherein each signal has a substantially different wavelength, and

a signal and latch wire driver that sequentially applies each of the signals to the signal coupling port to change the beam direction from one scan angle to another, and sequentially sets the magnetic state of the toroid by applying current to the latch wire to further change the direction of the beam direction.

20. An electronically scanned phase array antenna as in claim 19 wherein the plurality of frequency beam signals includes a low frequency signal, a center frequency signal and a high frequency signal.

21. An electronically scanned ferrite line source antenna device for spatially scanning a beam of electromagnetic energy comprising:

a linear waveguide having a ferrite toroid, at least one dielectric slab disposed external to and adjacent a first sidewall of the toroid, and a conductive metal skin covering outer surfaces of the toroid and slab, wherein said skin includes coupling slots etched in a surface adjacent the slab;

an impedance matched terminal load for at least one end of the waveguide;

a signal port to the waveguide;

a current carrying latch wire extending through said waveguide;

a pair of microstrips coupled to each of the coupling slots where said microstrips are mounted on a substrate juxtaposed to a front face of an outer one of said dielectric slab, and each of said pair of microstrips are coupled to opposite ports of a 90°

hybrid coupler, and each of said pair of microstrips extend beyond the hybrid coupler such that the first of the pair of microstrips terminates at a terminal load and the second of the pair of microstrips terminates at an antenna aperture.

22. An electronically scanned ferrite line source antenna coupling comprising:

first and second ferrite line sources each having a linear ferrite toroid and at least one dielectric slab adjacent a first wall of each toroid, and a plurality of coupling slots etched in a conductive skin covering the toroid and slab, where said first ferrite line source is adapted to be fed a signal for transmission for an antenna and said second ferrite line source is adapted to be fed a signal received by the antenna;

a microstrip substrate juxtaposed over the slots of each of said first and second ferrite line sources, wherein at least one microstrip is electromagnetically coupled to each one of said coupling slots, and each of said microstrip is connected to first or second port of a circulator and a third port of the circulator adapted to be coupled to an antenna radiating element.

23. An electronically scanned ferrite line source antenna coupling as in claim 22 wherein the first port of the circulator is coupled via one of said microstrip to the first ferrite line source and the second port of the circulator is coupled via a second one of said microstrip to the second ferrite line source.

24. A multibeam antenna system comprising:

an elevation array of electronically scanned ferrite line sources each having a linear waveguide having a ferrite toroid and, at least one dielectric slab adjacent an external surface of a side wall of the toroid, a conductive skin covering outer surfaces of the toroid and slab, and a plurality of radiating slots etched in the skin adjacent the slab to radiate signals in the waveguide out to free space;

an azimuth array of electronically scanned ferrite line sources each having a linear waveguide having a ferrite toroid and, at least one dielectric slab adjacent a side wall of the toroid, a conductive skin covering outer surfaces of the toroid and slab, and a plurality of coupling slots etched in the skin adjacent the slab to transfer beam signals fed into each of the waveguides to a coupling to the elevation array of electronically scanned ferrite line sources, wherein each slot in each of the azimuth ferrite line sources is coupled to a respective one of the elevation line sources.

25. A multibeam antenna system as in claim 24 wherein the coupling between the azimuth array and elevation array is a network of microstrips having a plurality of branches each coupled to a one of the coupling slots in the azimuth array, wherein said branches for each of the coupling slots corresponding to the respective one of the elevation line sources are combined to a coupling to the respective elevation line source.