A novel method for constructing the end-to-end calibration matrix of fully polarimetric radiometer

Ou, Naiming; Bai, Ming; Hu, Anyong; Miao, Jungang; Liu, Yanming; Duan, Chongdi; Lv, Rongchuan

doi:10.1109/icmmt.2012.6230277

Cited by 2 publications

(12 citation statements)

References 13 publications

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“…The FPoR receiver can be operated either as a total power radiometer in the measurement mode or as a Dicke switch in the calibration mode . In the calibration mode, the minimum number of independent observations is five, to determine the unknown gain and offset matrix of the FPoR as follows

([], \begin{matrix} V_{v} \\ V_{h} \\ V_{3} \\ V_{4} \end{matrix}) = ([], \begin{matrix} G_{vv} & G_{vh} & G_{v 3} & G_{v 4} \\ G_{hv} & G_{hh} & G_{h 3} & G_{h 4} \\ G_{3 v} & G_{3 h} & G_{33} & G_{34} \\ G_{4 v} & G_{4 h} & G_{43} & G_{44} \end{matrix}) \cdot ([], \begin{matrix} T_{v} \\ T_{h} \\ T_{3} \\ T_{4} \end{matrix}) + ([], \begin{matrix} O_{v} \\ O_{h} \\ O_{3} \\ O_{4} \end{matrix}),

where V α and T α with α = v , h , 3, and 4 are the output response voltages from the FPoR and the noise temperature from the CNCS, respectively. The subscripts v , h , 3, and 4 are the first, second, third, and fourth Stokes parameters.…”

Section: Proposed Internal Calibration Sourcementioning

confidence: 99%

“…From the vertically and horizontally polarized signals, that is, S v ( h ) , linearly and circularly polarized signals are also estimated from Equation 4 as follows:

([], \begin{matrix} T_{h} \\ T_{LCP} \\ T_{RCP} \\ T_{45^{°}} \\ T_{135^{°}} \\ T_{v} \end{matrix}) = \frac{1}{2 italicRkB} ([], \begin{matrix} (〈〉, {(||, S_{h})}^{2}) \\ (〈〉, {(||, S_{v} e^{- italicjπ / 2} + S_{h})}^{2}) \\ (〈〉, {(||, S_{v} + S_{h} e^{- italicjπ / 2})}^{2}) \\ (〈〉, {(||, S_{v} e^{- italicjπ} + S_{h} e^{- italicjπ})}^{2}) \\ (〈〉, {(||, S_{v} e^{- italicjπ / 2} + S_{h} e^{- j 3 π / 2})}^{2}) \\ (〈〉, {(||, S_{v})}^{2}) \end{matrix}),

where the subscripts h , v , LCP , RCP , 45°, and 135° represent the horizontal, vertical, left‐hand, and right‐hand circular polarizations and the 45° and 135° linear polarizations, respectively. From the calculation in Equation 4, T h , T v ,

T_{3} ((), = T_{135^{°}} - T_{45^{°}})

and T 4 (= T LCP − T RCP ) were obtained from five independent observations based on the control of the SPDT switches and phase shifters to determine the associated unknown gain‐offset matrix by cross‐correlating the vertical and horizontal brightness temperatures …”

Section: Proposed Internal Calibration Sourcementioning

confidence: 99%

“…The calibration of a fully polarimetric radiometer (FPoR) is an important task to provide accurate measurements of the brightness temperatures of remote sensing targets . Recently, the calibration of FPoRs is done using a fully polarimetric calibration standard (FPCS) with approach in the X‐band, Ka‐band, and W‐band . These calibration standards are operated from a mechanical set‐up that rotates a linearly polarized calibration standard and a retardation plate in front of the antenna with periodic calibration.…”

Section: Introductionmentioning

confidence: 99%

“…These calibration standards are operated from a mechanical set‐up that rotates a linearly polarized calibration standard and a retardation plate in front of the antenna with periodic calibration. However, the existing FPCS is not suitable for relatively portable size that operates on a low‐frequency band due to a large antenna . Moreover, it will be sensitive to the physical temperatures of the core components such as the polarizing wire grid and the retardation plate.…”

Section: Introductionmentioning

confidence: 99%

“…In this letter, the internal calibration structure of an FPoR is suggested as a novel calibration methodology from an electrical operation instead of a mechanical structure at S‐band. It can be operated by minimizing ambient temperature effects compared to the external calibration standard . In addition, it can be realized with a relatively compact source size regardless of the frequency band.…”

Section: Introductionmentioning

confidence: 99%

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A correlated noise calibration source for the internal calibration of a fully polarimetric radiometer

Kim

2018

Micro & Optical Tech Letters

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A novel microwave calibration source for a fully polarimetric radiometer (FPoR) is proposed for internal calibration by the electrical operation instead of a mechanical structure at S‐band. The proposed correlated noise calibration source (CNCS) using microwave components can generate vertical and horizontal polarized signals; additionally, linearly and circularly polarized signals (third and fourth Stokes parameters) are also estimated by injecting correlated noise. In contrast to existing mechanical calibration sources, this calibration source can be designed by miniaturization. Based on measured quantities under realistic conditions, the uncertainty was evaluated according to the states of the SPDT switches and phase shifters of the CNCS.

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([], \begin{matrix} V_{v} \\ V_{h} \\ V_{3} \\ V_{4} \end{matrix}) = ([], \begin{matrix} G_{vv} & G_{vh} & G_{v 3} & G_{v 4} \\ G_{hv} & G_{hh} & G_{h 3} & G_{h 4} \\ G_{3 v} & G_{3 h} & G_{33} & G_{34} \\ G_{4 v} & G_{4 h} & G_{43} & G_{44} \end{matrix}) \cdot ([], \begin{matrix} T_{v} \\ T_{h} \\ T_{3} \\ T_{4} \end{matrix}) + ([], \begin{matrix} O_{v} \\ O_{h} \\ O_{3} \\ O_{4} \end{matrix}),

Section: Proposed Internal Calibration Sourcementioning

confidence: 99%

“…From the vertically and horizontally polarized signals, that is, S v ( h ) , linearly and circularly polarized signals are also estimated from Equation 4 as follows:

([], \begin{matrix} T_{h} \\ T_{LCP} \\ T_{RCP} \\ T_{45^{°}} \\ T_{135^{°}} \\ T_{v} \end{matrix}) = \frac{1}{2 italicRkB} ([], \begin{matrix} (〈〉, {(||, S_{h})}^{2}) \\ (〈〉, {(||, S_{v} e^{- italicjπ / 2} + S_{h})}^{2}) \\ (〈〉, {(||, S_{v} + S_{h} e^{- italicjπ / 2})}^{2}) \\ (〈〉, {(||, S_{v} e^{- italicjπ} + S_{h} e^{- italicjπ})}^{2}) \\ (〈〉, {(||, S_{v} e^{- italicjπ / 2} + S_{h} e^{- j 3 π / 2})}^{2}) \\ (〈〉, {(||, S_{v})}^{2}) \end{matrix}),

T_{3} ((), = T_{135^{°}} - T_{45^{°}})

Section: Proposed Internal Calibration Sourcementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A correlated noise calibration source for the internal calibration of a fully polarimetric radiometer

Kim

2018

Micro & Optical Tech Letters

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Double Square Waveguide Directional Coupler for Polarimeter Calibration

Aja

Villa

Fuente

et al. 2019

IEEE Trans. Microwave Theory Techn.

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A novel full-band square waveguide coupler design based on directional couplers which couple the TE10 and TE01 orthogonal modes in a square waveguide is presented. This waveguide coupler is aimed at calibration of polarization receivers. This is composed of a pair of rectangular waveguide directional couplers, which are rotated 90º between them and both are coupled to a main square waveguide through each one of the square section walls. The coupler covers the full frequency band from 10 GHz to 18.9 GHz. It has inherent low cross-polarization, which allows to obtain any known elliptically polarized wave at a square waveguide when a signal is applied to the couplers. The fabricated prototype of this coupler exhibits 31 dB of coupling, with flatness of ±3.8 dB and excellent cross polarization better than 50 dB over the whole band.

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A novel method for constructing the end-to-end calibration matrix of fully polarimetric radiometer

Cited by 2 publications

References 13 publications

A correlated noise calibration source for the internal calibration of a fully polarimetric radiometer

A correlated noise calibration source for the internal calibration of a fully polarimetric radiometer

Double Square Waveguide Directional Coupler for Polarimeter Calibration

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