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Proceedings ArticleDOI

Infrared thermography for determination of wavelength of microwave signals from interference pattern

27 Apr 2015-pp 774-778
TL;DR: A technique for wavelength measurement of microwaves is demonstrated, where the wavelength is obtained from an interference pattern monitored by an IR Camera, stored in a computer attached to it and processed for wavelength calculation.
Abstract: A technique for wavelength measurement of microwaves is demonstrated. The wavelength is obtained from an interference pattern monitored by an IR Camera. The data captured by the camera is stored in a computer attached to it. This data is then processed for wavelength calculation. In order to show the utility of the above technique, two cases are demonstrated: Case (1) Interference pattern of two patch antennas each radiating at 8 GHz. Case (2) Interference pattern from a single antenna, radiating at 12 Ghz, kept in front of a metallic sheet with two slits. The simulation is carried in CST Microwave Studio software. A good agreement between simulation and experimental results is seen.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the beam width of microwave antennas can be easily determined using infrared thermography using a thin absorption screen made up of some carbon loaded polymer is placed in front of a microwave antenna.

6 citations

Journal ArticleDOI
TL;DR: In this article, a microwave absorption screen made of carbon loaded polymer is kept close in front of the faulty array to increase its temperature, which is identical to electric field intensity profile at the screen location.

5 citations

Journal ArticleDOI
TL;DR: In this article, a thin screen made of carbon fiber reinforced polymers is placed in front of a microwave source, where the electromagnetic waves impinging on the screen are partially absorbed, resulting in temperature rise of the screen.
Abstract: The electric field distribution (magnitude only) near a radiating source (antenna) can be easily determined using infrared thermography. A thin screen (made of carbon fiber reinforced polymers) is placed in front of a microwave source. The electromagnetic waves impinging on the screen are partially absorbed, resulting in temperature rise of the screen. This temperature rise is monitored by an infrared camera. The temperature distribution thus observed is mapped to the electric field strength (magnitude of electric field) of the electromagnetic waves. Points on the screen where the temperature rise is low correspond to weak electromagnetic fields whereas points with high temperature rise correspond to strong electromagnetic fields. In this paper electro-thermal modelling is done so as to obtain the temperature distribution over the screen, when an electromagnetic field is incident on it. This model can conversely be used for finding electromagnetic field distributions from IR thermal images.

2 citations

Journal ArticleDOI
TL;DR: In this paper, a frequency modulated thermal wave imaging (FMTWI) was introduced for the first time for determining power distribution of electromagnetic waves on plane surfaces, which can extract multiple amplitude and phase images from a single run of experiment and can be used qualitatively to detect field leakage near electromagnetic junctions and microstrip feed lines.
Abstract: In this article, Frequency Modulated Thermal Wave Imaging (FMTWI) [1–6] is introduced for the first time for determining power distribution of electromagnetic waves on plane surfaces. The advantage with this technique is that we can extract multiple amplitude and phase images from a single run of experiment. The applied excitation signal in this technique is a frequency modulated chirp signal instead of a single frequency signal used in conventional lock-in infrared (IR) thermography [7–11].The thermal images obtained using FMTWI can be used qualitatively, e.g., to detect field leakage near electromagnetic junctions and microstrip feed lines. As a practical demonstration of this technique, an example of 2 × 2 patch antenna array at 8 GHz is considered. First, amplitude images at various modulation frequencies are obtained. Next, signal to noise ratio (SNR) values at each frequency are calculated. It is seen that SNR is lower at higher frequencies. It is observed that at higher modulation frequenci...

2 citations

References
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Journal ArticleDOI
TL;DR: In this paper, an infrared detection technique is used to measure the electromagnetic fields near apertures of planar and cylindrical structures, and the results are compared with theoretical solutions where applicable.
Abstract: An infrared detection technique is used to measure the electromagnetic fields near apertures of planar and cylindrical structures. Qualitative and quantitative results are presented and compared with theoretical solutions where applicable.

25 citations


"Infrared thermography for determina..." refers background or methods in this paper

  • ...This temperature change ( T) is proportional to the electric field strength as per (1)....

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  • ...Case (2) Interference pattern from a single antenna, radiating at 12 Ghz, kept in front of a metallic sheet with two slits....

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  • ...The temperature change ( T) is related to modulus of Electric field strength E on the screen by (1) as reported in [5] E k T = Δ (1) The principle of the developed technique can be understood from Fig....

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  • ...In order to show the utility of the above technique, two cases are demonstrated: Case (1) Interference pattern of two patch antennas each radiating at 8 GHz....

    [...]

  • ...The simulated results are taken as the square of electric filed magnitude as the temperature change on the screen is proportional to it, as per (1)....

    [...]

Proceedings ArticleDOI
01 Dec 2013
TL;DR: In this article, an example of a patch antenna operating at a frequency of 2.45 GHz is given, in order to show the utility of the infrared thermography using an absorption screen of carbon loaded polymers.
Abstract: The visualization of electromagnetic field intensity can be easily achieved by infrared thermography using an absorption screen of carbon loaded polymers. The electromagnetic waves falling on the absorption screen increase its temperature which is monitored by an infrared camera. The measured temperature profile can further be correlated to the electric field intensity. Measurement of electromagnetic field distribution is typically done by a small scanning antenna and is a time consuming process. Furthermore the scanning antenna will itself disturb the measurement process which is not the case with an absorption screen, even if the screen is kept very near to the electromagnetic wave source. Therefore fields very near to the source can also be visualized and measured. Also the length of the scanning antenna depends on wavelength of electromagnetic field to be measured, therefore it is improper to apply it to measure various fields. In order to show the utility of the above technique, an example of a patch antenna operating at a frequency of 2.45 GHz is given. Initial experiments show good agreement between simulated and measured results.

7 citations

Proceedings ArticleDOI
01 Oct 2010
TL;DR: In this article, a very small change of temperature on an absorption screen illuminated by the electromagnetic wave is measured using an infrared camera with 2-D lock-in processing technique using an absorbent screen made of dielectric material.
Abstract: We have been developing an electromagnetic field intensity measurement system using an absorption screen made of dielectric material. In this developed system, a very small change of temperature on an absorption screen illuminated by the electromagnetic wave is measured using an infrared camera with 2-D lock-in processing technique.

6 citations

Journal ArticleDOI
TL;DR: In this paper, a plane to plane iterative phase retrieval process has been developed and tested with respect to a large number of conflguration parameters such as to flnd an optimal conflgence on a wide frequency range (0.5{20GHz).
Abstract: The framework of our work is the application of a fast method to estimate the radiation pattern of an antenna from the measurement of the electric-fleld magnitude in the near-fleld region using infrared (IR) camera. IR acquisition techniques allows quasi- realtime measurements of the magnitude of the electrical fleld on planar surfaces in near-fleld conditions. However the antennas radiation patterns can only be estimated from near-fleld electrical magnitude and phase measurements. Consequently a classical plane to plane iterative phase retrieval process has been developed and tested with respect to a large number of conflguration parameters such as to flnd an optimal conflguration on a wide frequency range (0.5{20GHz). In order to achieve and validate such a study, some comparisons have been performed on data obtained either by numerical simulation or classical near-fleld technique based upon radio-frequency (RF) probe scanning on simple horn antennas. Among all the studied parameters we will focus onto the in∞uence of the dynamic range of the measurements on the reconstructed radiation patterns and on validations from experimental results.

6 citations