This paper deals with a microwave hygrometer that is based on the sensitivity of air permettivity to humidity. The hygrometer embeds a microwave generator which feeds two different channels. A channel is a holed waveguide, whose permettivity depends on the air humidity, while the other channel is insensitive to the air humidity. The output signals of the two channels are suitably combined in order to obtain the corresponding phase angle, which depends on the permettivity of the air inside the holed waveguide and therefore on the air humidity. Two possible implementations of the proposed principle are described which permit one to obtain an uncertainty of a few percentage of relative humidity in the humidity range of 10% RH to 90% RH and in the temperature range of 5 °C to 40 °C, but with different costs and complexities. The main characteristics of the proposed sensor are a fast response, a low sensitivity with respect to air pollution and the absence of hysteresis phenomena.

A Microwave System for Relative Humidity Measurement / Carullo, Alessio; Ferrero, ANDREA PIERENRICO; Parvis, Marco. - STAMPA. - 1:(1999), pp. 124-129. (Intervento presentato al convegno 16th IEEE Instrumentation and Measurement Technology Conference, IMTC/99 - Measurements for the new Millenium tenutosi a Venice Italy nel 24-26 June) [10.1109/IMTC.1999.776732].

A Microwave System for Relative Humidity Measurement

CARULLO, Alessio;FERRERO, ANDREA PIERENRICO;PARVIS, Marco
1999

Abstract

This paper deals with a microwave hygrometer that is based on the sensitivity of air permettivity to humidity. The hygrometer embeds a microwave generator which feeds two different channels. A channel is a holed waveguide, whose permettivity depends on the air humidity, while the other channel is insensitive to the air humidity. The output signals of the two channels are suitably combined in order to obtain the corresponding phase angle, which depends on the permettivity of the air inside the holed waveguide and therefore on the air humidity. Two possible implementations of the proposed principle are described which permit one to obtain an uncertainty of a few percentage of relative humidity in the humidity range of 10% RH to 90% RH and in the temperature range of 5 °C to 40 °C, but with different costs and complexities. The main characteristics of the proposed sensor are a fast response, a low sensitivity with respect to air pollution and the absence of hysteresis phenomena.
1999
0780352769
9780780352766
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/1409738
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