Inventors:
Corcos, Dan (Nesher, IL)
Elad, Danny (Haifa, IL) Kaminski, Noam (Kiryat Tivon, IL)
Klein, Bernhard (Zurich, SZ)
Kull, Lukas (Zurich, SZ)
Morf, Thomas (Gross, SZ)
Publication Date:
05/01/2014
Claims:
What is claimed is:
1. An antenna for receiving
terahertz (THz) radiation, comprising: a suspended conductive dipole element
supported by a non-conductive holding arm; and a plurality of reflectors
physically isolated from said dipole element.
2. The antenna according to claim 1, wherein said plurality of reflectors comprises a plane conductor located below said dipole element.
3. The antenna according to claim 2, wherein said plane conductor is located approximately one quarter wavelength below said dipole element.
4. The antenna according to claim 1, wherein said plurality of reflectors comprises first and second metallic reflectors substantially parallel to said dipole element and in the same plane thereof.
5. The antenna according to claim 4, wherein said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
6. An antenna for receiving terahertz (THz) radiation, comprising: a pair of perpendicularly folded suspended conductive dipole elements supported by a non-conductive holding arm; and a plurality of reflectors physically isolated from said dipole elements.
7. The antenna according to claim 6, wherein said plurality of reflectors comprises a plane conductor located below said dipole elements.
8. The antenna according to claim 7, wherein said plane conductor is located approximately one quarter wavelength below said dipole elements.
9. The antenna according to claim 6, wherein said plurality of reflectors comprises two pairs of reflectors, each reflector pair comprising first and second reflectors substantially parallel to a dipole element and in the same plane thereof.
10. The antenna according to claim 9, wherein each said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
11. A detector for detecting terahertz (THz) radiation, comprising: a suspended conductive dipole element supported by a non-conductive holding arm; a plurality of reflectors physically isolated from said dipole element; a load impedance directly coupled to said dipole element and operative to convert said received THz radiation to thermal energy; and a thermal sensor operative to generate an electrical signal in accordance with the heat generated by said load impedance.
12. The detector according to claim 11, wherein said plurality of reflectors comprises a plane conductor located below said dipole element.
13. The detector according to claim 12, wherein said plane conductor is located approximately one quarter wavelength below said dipole element.
14. The detector according to claim 11, wherein said plurality of reflectors comprises first and second metallic reflectors substantially parallel to said dipole element and in the same plane thereof.
15. The detector according to claim 14, wherein said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
16. The detector according to claim 14, further comprising a readout circuit situated around said detector.
17. The detector according to claim 14, further comprising a readout circuit situated around said detector and attached to said reflectors thereby forming a closed RF current loop.
18. A detector for detecting terahertz (THz) radiation, comprising: a pair of perpendicularly folded suspended conductive dipole elements supported by a non-conductive holding arm; a plurality of reflectors physically isolated from said dipole elements; a single load impedance directly coupled to said dipole elements and operative to convert said received THz radiation to thermal energy; and a thermal sensor operative to generate an electrical signal in accordance with the heat generated by said load impedance.
19. The detector according to claim 18, wherein said plurality of reflectors comprises a plane conductor located below said dipole elements.
20. The detector according to claim 19, wherein said plane conductor is located approximately one quarter wavelength below said dipole elements.
21. The detector according to claim 18, wherein said plurality of reflectors comprises two pairs of reflectors, each reflector pair comprising first and second reflectors substantially parallel to a dipole element and in the same plane thereof.
22. The detector according to claim 21, wherein each said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
23. The detector according to claim 18, further comprising a readout circuit situated around said detector.
24. The detector according to claim 18, further comprising a readout circuit situated around said detector and attached to said reflectors thereby forming a closed RF current loop.
2. The antenna according to claim 1, wherein said plurality of reflectors comprises a plane conductor located below said dipole element.
3. The antenna according to claim 2, wherein said plane conductor is located approximately one quarter wavelength below said dipole element.
4. The antenna according to claim 1, wherein said plurality of reflectors comprises first and second metallic reflectors substantially parallel to said dipole element and in the same plane thereof.
5. The antenna according to claim 4, wherein said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
6. An antenna for receiving terahertz (THz) radiation, comprising: a pair of perpendicularly folded suspended conductive dipole elements supported by a non-conductive holding arm; and a plurality of reflectors physically isolated from said dipole elements.
7. The antenna according to claim 6, wherein said plurality of reflectors comprises a plane conductor located below said dipole elements.
8. The antenna according to claim 7, wherein said plane conductor is located approximately one quarter wavelength below said dipole elements.
9. The antenna according to claim 6, wherein said plurality of reflectors comprises two pairs of reflectors, each reflector pair comprising first and second reflectors substantially parallel to a dipole element and in the same plane thereof.
10. The antenna according to claim 9, wherein each said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
11. A detector for detecting terahertz (THz) radiation, comprising: a suspended conductive dipole element supported by a non-conductive holding arm; a plurality of reflectors physically isolated from said dipole element; a load impedance directly coupled to said dipole element and operative to convert said received THz radiation to thermal energy; and a thermal sensor operative to generate an electrical signal in accordance with the heat generated by said load impedance.
12. The detector according to claim 11, wherein said plurality of reflectors comprises a plane conductor located below said dipole element.
13. The detector according to claim 12, wherein said plane conductor is located approximately one quarter wavelength below said dipole element.
14. The detector according to claim 11, wherein said plurality of reflectors comprises first and second metallic reflectors substantially parallel to said dipole element and in the same plane thereof.
15. The detector according to claim 14, wherein said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
16. The detector according to claim 14, further comprising a readout circuit situated around said detector.
17. The detector according to claim 14, further comprising a readout circuit situated around said detector and attached to said reflectors thereby forming a closed RF current loop.
18. A detector for detecting terahertz (THz) radiation, comprising: a pair of perpendicularly folded suspended conductive dipole elements supported by a non-conductive holding arm; a plurality of reflectors physically isolated from said dipole elements; a single load impedance directly coupled to said dipole elements and operative to convert said received THz radiation to thermal energy; and a thermal sensor operative to generate an electrical signal in accordance with the heat generated by said load impedance.
19. The detector according to claim 18, wherein said plurality of reflectors comprises a plane conductor located below said dipole elements.
20. The detector according to claim 19, wherein said plane conductor is located approximately one quarter wavelength below said dipole elements.
21. The detector according to claim 18, wherein said plurality of reflectors comprises two pairs of reflectors, each reflector pair comprising first and second reflectors substantially parallel to a dipole element and in the same plane thereof.
22. The detector according to claim 21, wherein each said first and second reflectors are adapted to function substantially as Yagi-Udi reflectors.
23. The detector according to claim 18, further comprising a readout circuit situated around said detector.
24. The detector according to claim 18, further comprising a readout circuit situated around said detector and attached to said reflectors thereby forming a closed RF current loop.
Description:
FIELD OF THE INVENTION
The
present invention relates to the field of semiconductor imaging devices, and
more particularly relates to a dipole antenna incorporating reflectors and
having low thermal mass for detection of Terahertz (THz) radiation.
BACKGROUND OF THE INVENTION
THz
radiation imaging is currently an exponentially developing research area with
inherent applications such as THz security imaging which can reveal weapons
hidden behind clothing from distances of ten meters or more; or medical THz
imaging which can reveal, for example, skin cancer tumors hidden behind the
skin and perform fully safe dental imaging. Constructing prior art THz
detectors is typically a challenging endeavor since both radiation sources and
radiation detectors are complex, difficult and expensive to make.
THz
radiation is non-ionizing and is therefore fully safe to humans unlike X-ray
radiation. THz imaging for security applications, for example, uses passive
imaging technology, namely the capabilities of remote THz imaging without using
any THz radiation source thus relying solely on the very low power natural THz
radiation which is normally emitted from any room temperature body according to
well-known black body radiation physics. Passive THz imaging requires extremely
sensitive sensors for remote imaging of this very low power radiation. Prior
art passive THz imaging utilizes a hybrid technology of superconductor single
detectors cooled to a temperature of about 4 degrees Kelvin which leads to
extremely complex (e.g., only the tuning of the temperature takes more than 12
hours before any imaging can take place) and expensive (e.g., $100,000 or more)
systems. A detector is desirable that can be used to detect THz radiation and
that has much lower potential cost compared with existing superconducting
solutions. Passive THz imaging, however, requires three orders of magnitude
higher sensitivity compared with passive infrared (IR) imaging, which is a
challenging gap.
SUMMARY OF THE INVENTION
There
is provided a novel and useful THz radiation detector comprising a suspended
dipole antenna and a plurality of reflectors for achieving low thermal mass and
high electrical performance. The reflectors used in the antenna do not
physically contact the dipole element and are used to shape the radiation pattern
in a similar fashion as obtained by well-known Yagi-Uda reflectors. The dipole
element is connected directly to a load resister for generating heat which is
sensed by a sensing transistor/diode. The lack of a mechanical connection of
the reflectors to the dipole antenna element prevents any increase in the
thermal capacitance of the antenna. The detector concentrates THz energy on a
pixel suspended micro-electromechanical systems (MEMS) based platform.
There
is thus provided in accordance with the invention, an antenna for receiving
terahertz (THz) radiation comprising a suspended conductive dipole element
supported by a non-conductive holding arm and a plurality of reflectors
physically isolated from the dipole element.
There
is also provided in accordance with the invention, an antenna for receiving
terahertz (THz) radiation comprising a pair of perpendicularly folded suspended
conductive dipole elements supported by a non-conductive holding arm and a
plurality of reflectors physically isolated from the dipole elements.
There
is further provided in accordance with the invention, a detector for detecting
terahertz (THz) radiation comprising a suspended conductive dipole element
supported by a non-conductive holding arm, a plurality of reflectors physically
isolated from the dipole element, a load impedance directly coupled to the
dipole element and operative to convert the received THz radiation to thermal
energy and a thermal sensor operative to generate an electrical signal in
accordance with the heat generated by the load impedance.
There
is also provided in accordance with the invention, a detector for detecting
terahertz
(THz)
radiation comprising a pair of perpendicularly folded suspended conductive
dipole elements supported by a non-conductive holding arm, a plurality of
reflectors physically isolated from the dipole elements, a single load
impedance directly coupled to the dipole elements and operative to convert the
received THz radiation to thermal energy and a thermal sensor operative to generate
an electrical signal in accordance with the heat generated by the load
impedance.
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