Power measurement system for 1 mW at 1 GHz

Clague, Fred R.

doi:10.6028/nist.tn.1345

Cited by 6 publications

(5 citation statements)

References 1 publication

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“…The uncertainty due to the voltmeter measurements of stage 4 is 0.000 15 dB at 30 MHz, based on the voltmeter manufacturer's specifications. The thermistor mounts used in the system are dual-element bolometers and have nonlinearity of about 0.04% at the 1 mW power level due to the rf-dc substitution error that occurs because the two elements are not identical [2]. This gives the uncertainty of 0.000 87 dB.…”

Section: Measurement Results and Its Uncertaintiesmentioning

confidence: 99%

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A broadband attenuation standard

Lee¹,

Kim

Park

et al. 2003

Meas. Sci. Technol.

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Section: Measurement Results and Its Uncertaintiesmentioning

confidence: 99%

“…insertion loss of the splitter and 3 dB attenuator. The input power of the thermistor mounts is controlled to be 1-10 mW, which is in the best linear region of the thermistor mounts [2]. The output power of a splitter is measured by the thermistor mount and an NIST type IV power meter which is connected to an external dc voltmeter.…”

Section: System Descriptionsmentioning

confidence: 99%

A broadband attenuation standard

Lee¹,

Kim

Park

et al. 2003

Meas. Sci. Technol.

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“…The substituted dc power, P dc , is calculated from measured voltages and is given by

P_{dc} = \frac{{V_{off}}^{2} - {V_{on}}^{2}}{R_{0}},

where V off is the output voltage with no rf power applied, V on is the output voltage with rf power applied, and R 0 is the operating resistance of the thermistor mount. Figure 3 shows the measurement sequence for a power calculation [6]. An initial V off is taken; rf power is then applied and V on is measured; rf power is removed and a final V off is taken.…”

Section: Measurement Methodsmentioning

confidence: 99%

“…The NIST calibration of the effective efficiency is done at 10 mW; therefore, this error is of concern when measurements are made below this power. Direct measurements were performed on similar thermistor mounts [6] resulting in a nonlinearity of about 0.04% at the 1 mW level.…”

Section: Uncertainty Analysismentioning

confidence: 99%

High power CW wattmeter calibration at NIST

Rebuldela¹,

Jargon²

1992

J. RES. NATL. INST. STAN.

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The National Institute of Standards and Technology has established a measurement capability to support high power systems and devices. The automated wattmeter calibration system operates at power levels of 1 to 1000 W for frequencies from 1 to 30 MHz and 1 to 500 W from 30 to 400 MHz. A cascaded coupler technique is used to extend power measurements to high levels which are traccable to a 10 mW standard thermistor mount. This technique uses an arrangement of nominal 10, 20, 30, 40, and 50 dB couplers with sidearm power meters. The initial step transfers the calibration of the 10 mW standard to the 10 dB coupler/power meter. The standard is then replaced with a wattmeter to be calibrated. RF power is increased 10 dB and the calibration is transferred to the adjacent 20 dB eoupler/power meter. This sequence is repeated with the remaining coupler/power meters until the wattmeter is calibrated at the desired power levels and frequencies. Power ratios calculated from simultaneous power measurements made at each transfer are used to calculate the incident power at the wattmeter. Due to nonideal components, corrections are made for nonlinearities, mismatch, and other errors. Two types of wattmeters have been evaluated at selected frequencies and power levels. Total uncertainties are based on the random and systematic components.

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“…When we measure the attenuation of 20 dB, leakage uncertainty is smaller than 0.0001 dB. The effect of uncertainty in the voltage measurement can be determined by taking the total differential of the expression for power [6]. From the specification sheet of Agilent 3458A DVM, we get the uncertainty, caused by voltage measurement, of 0.0029 dB.…”

Section: K-band Attenuation Standardmentioning

confidence: 99%

Novel attenuation standards at microwave frequencies and evaluation of their uncertainty

Lee¹,

Kim²,

Kang³

et al. 2007

Meas. Sci. Technol.

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We have developed two coaxial-type microwave attenuation standards using the power ratio transfer method. One standard operates in the frequency range of 18 GHz to 26.5 GHz, and has a dynamic range of 80 dB. Its expanded uncertainty (k = 2) is estimated to be 0.01 dB/80 dB. The other operates in the frequency range of 26.5 GHz to 40 GHz, and has a dynamic range of 60 dB and an expanded uncertainty of 0.009 dB/60 dB. We present an example for calibration of a 40 dB step attenuator using the attenuation standard in a series radio-frequency substitution scheme. The expanded uncertainty (k = 2) is 0.01 dB including the mismatch uncertainty.

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Power measurement system for 1 mW at 1 GHz

Cited by 6 publications

References 1 publication

A broadband attenuation standard

A broadband attenuation standard

High power CW wattmeter calibration at NIST

Novel attenuation standards at microwave frequencies and evaluation of their uncertainty

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