Communications: radio wave antennas – Antennas – Wave guide type
Reexamination Certificate
1999-09-30
2001-06-26
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
Wave guide type
C359S237000, C385S002000
Reexamination Certificate
active
06252557
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to photonic sensors, and more particularly to electro-optic antennas and sensors for wideband reception and processing of electromagnetic signals.
2. Related Art
Array antennas for reception and transmission of electromagnetic signals are well known in the art. One important objective in the refinement of this type of antenna is to increase the operational bandwidth of the antenna.
Traditional arrays use conventional antenna elements. One disadvantage of this type of element is that it is usually limited to a small operational bandwidth. Further, these elements require some sort of transmission line, such as coaxial cable, microstrip, or stripline, to connect to each antenna element and a feed network. For antenna arrays having many elements, this approach results in structures that are quite heavy and large. Another disadvantage that results from this approach is an increase in backplane complexity. A further disadvantage is the substantial signal losses that are incurred on the transmission lines, as the desired frequency of operation is increased.
One conventional approach to increasing bandwidth is to use a “spiral” antenna element within the array. One disadvantage of this approach is that such spiral elements become large as the frequency of operation is reduced. Further, the spacing of these elements increases, resulting in a physically large structure. Further, this large spacing has adverse effects on the operation of the array. A further disadvantage is the backplane complexity mentioned above.
Another conventional approach is to use electrically small antennas to get around the spacing issue. However, the efficiency of this class of antennas is usually very poor.
SUMMARY OF THE INVENTION
The present invention is a photonics sensor and array for the reception and processing of RF signals. In one embodiment, the present invention is an antenna comprising: a first electro-optically active optical waveguide; a first planar electrode substantially parallel to the first waveguide; a second electro-optically active optical waveguide; a second planar electrode substantially parallel to the second waveguide, the first and second planar electrodes being substantially adjacent and coplanar; and a third planar electrode substantially parallel to the first and second planar electrodes and disposed such that the first waveguide lies between the first and third planar electrodes, and the second waveguide lies between the second and third planar electrodes.
In another embodiment, the present invention is an antenna comprising: first and second planar electrodes being substantially adjacent and coplanar; a first electro-optically active optical waveguide disposed between the planar electrodes; and a second electro-optically active optical waveguide substantially parallel to the first waveguide.
In another embodiment, the present invention is an antenna comprising: a plurality of cells, each cell comprising: a first electro-optically active optical waveguide; a first planar electrode substantially parallel to the first waveguide; a second electro-optically active optical waveguide; a second planar electrode substantially parallel to the second waveguide, the first and second planar electrodes being substantially adjacent and coplanar; and a third planar electrode substantially parallel to the first and second planar electrodes and disposed such that the first waveguide lies between the first and third planar electrodes, and the second waveguide lies between the second and third planar electrodes.
In another embodiment, the present invention is an antenna comprising: a plurality of cells, each cell comprising: first and second planar electrodes being substantially adjacent and coplanar; a first electro-optically active optical waveguide disposed between the planar electrodes; and a second electro-optically active optical waveguide substantially parallel to the first waveguide.
An optical source may be coupled to a first end of each of the waveguides. An output optical waveguide may be coupled to the second end of each of the first and second waveguides. A photodetector may be coupled to the output waveguide. A coupler may electrically connect the first and third planar electrodes, whereby the first and third planar electrodes may be kept at substantially the same electrical potential. The present invention may further comprise a polymer layer in which the waveguides are formed and to which the planar electrodes are attached. The first planar electrode may be arranged so that an incident electromagnetic signal will impinge upon the first planar electrode.
The third planar electrode may comprise a first portion and a second portion and may be disposed such that the first waveguide lies between the first planar electrode and the first portion of the third planar electrode, and the second waveguide lies between the second planar electrode and the second portion of the third planar electrode.
REFERENCES:
patent: 3944330 (1976-03-01), Tsunoda et al.
patent: 5278924 (1994-01-01), Schaffner
patent: 5285308 (1994-02-01), Jenkins et al.
patent: 5347601 (1994-09-01), Ade et al.
patent: 5359449 (1994-10-01), Nishimoto et al.
patent: 5363230 (1994-11-01), Djupsjobacka
patent: 5488677 (1996-01-01), Tokano
patent: 5543805 (1996-08-01), Thaniyavarn
patent: 5568574 (1996-10-01), Tanguay, Jr. et al.
patent: 5613020 (1997-03-01), Uchida et al.
patent: 5615037 (1997-03-01), Betts et al.
patent: 5638468 (1997-06-01), Tokano et al.
patent: 5799116 (1998-08-01), Yamamoto
patent: 5862276 (1999-01-01), Karras
patent: 5866807 (1999-03-01), Cummings
Choi et al. “Measurement of low frequency electric field using Ti:LiNbO3” IEE, 1993 pp. 7-10.
Young Electro-Optic E-Field Sensors for Shielding Measurements up to 18GHz; IEEE, pp. 87-91, 1995.
Harvey et al. “Optical up-conversion for passive millimetre-wave imaging”, SPIE, vol. 3064; 1997.
Anderson William W.
Plugge Richard J.
Alemu Ephren
Le Hoang-anh
Lockheed Martin Corporation
Swidler Berlin Shereff & Friedman, LLP
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