Patent Application-DIPOLE ANTENNA WITH REFLECTORS HAVING LOW THERMAL MASS FOR DETECTION OF TERAHERTZ RADIATION

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

http://www.freepatentsonline.com/y2014/0117241.html

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. 

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.