Characterizing calibration standards using one airline as a transfer standard

Roberts, T.; Martens, J.

doi:10.1109/arftg.2014.6899525

Cited by 2 publications

(2 citation statements)

References 7 publications

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“…Achieving such tight tolerances is an area of active research and we are identifying promising techniques. For instance, the current uncertainty levels could be reduced by incorporating measurements of custom reflection standards, such as well characterized air-dielectric coaxial lines, into the VNA calibration process (Eiø et al 2006;Wübbeler et al 2009;Roberts & Martens 2014).…”

Section: Reduction Of Systematicsmentioning

confidence: 99%

CALIBRATION OF THE EDGES HIGH-BAND RECEIVER TO OBSERVE THE GLOBAL 21 cm SIGNATURE FROM THE EPOCH OF REIONIZATION

Monsalve

Rogers

Bowman

et al. 2017

ApJ

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The EDGES High-Band experiment aims to detect the sky-average brightness temperature of the 21 cm signal from the epoch of reionization in the redshift range   z 14.8 6.5. To probe this redshifted signal, EDGES High-Band conducts single-antenna measurements in the frequency range MHz from the Murchison Radio-astronomy Observatory in Western Australia. In this paper, we describe the current strategy for calibration of the EDGES High-Band receiver and report calibration results for the instrument used in the 2015-2016 observational campaign. We propagate uncertainties in the receiver calibration measurements to the antenna temperature using a Monte Carlo approach. We define a performance objective of 1 mK residual rms after modeling foreground subtraction from a fiducial temperature spectrum using a five-term polynomial. Most of the calibration uncertainties yield residuals of 1 mK or less at 95% confidence. However, current uncertainties in the antenna and receiver reflection coefficients can lead to residuals of up to 20 mK even in low-foreground sky regions. These dominant residuals could be reduced by (1) improving the accuracy in reflection measurements, especially their phase, (2) improving the impedance match at the antenna-receiver interface, and (3) decreasing the changes with frequency of the antenna reflection phase.

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Section: Reduction Of Systematicsmentioning

confidence: 99%

CALIBRATION OF THE EDGES HIGH-BAND RECEIVER TO OBSERVE THE GLOBAL 21 cm SIGNATURE FROM THE EPOCH OF REIONIZATION

Monsalve

Rogers

Bowman

et al. 2017

ApJ

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“…The thru is characterized separately using a series of independent measurements, and the DC resistance of the 50-Ω load is measured with a precision ohmmeter as suggested in [14] and [17]. A different type of method, introduced in [18], improves the characterization of the SOL standards by using a precision airline, which is connected to the calibrated measurement port and terminated with an offset short and a mismatch load. Ripples observed when connecting the airline are mainly due to residual source match and directivity resulting from assuming incorrect values for the calibration SOL parameters.…”

Section: Introductionmentioning

confidence: 99%

One-Port Direct/Reverse Method for Characterizing VNA Calibration Standards

Monsalve

Rogers

Mozdzen

et al. 2016

IEEE Trans. Microwave Theory Techn.

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Abstract-This paper introduces a one-port method for estimating model parameters of VNA calibration standards. The method involves measuring the standards through an asymmetrical passive network connected in direct mode and then in reverse mode, and using these measurements to compute the Sparameters of the network. The free parameters of the calibration standards are estimated by minimizing a figure of merit based on the expected equality of the S-parameters of the network when used in direct and reverse modes. The capabilities of the method are demonstrated through simulations, and real measurements are used to estimate the actual offset delay of a 50-Ω calibration load that is assigned zero delay by the manufacturer. The estimated delay is 38.8 ps with a 1σ uncertainty of 2.1 ps for this particular load. This result is verified through measurements of a terminated airline. The measurements agree better with theoretical models of the airline when the reference plane is calibrated using the new estimate for the load delay.

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Characterizing calibration standards using one airline as a transfer standard

Cited by 2 publications

References 7 publications

CALIBRATION OF THE EDGES HIGH-BAND RECEIVER TO OBSERVE THE GLOBAL 21 cm SIGNATURE FROM THE EPOCH OF REIONIZATION

CALIBRATION OF THE EDGES HIGH-BAND RECEIVER TO OBSERVE THE GLOBAL 21 cm SIGNATURE FROM THE EPOCH OF REIONIZATION

One-Port Direct/Reverse Method for Characterizing VNA Calibration Standards

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