Introduction
Chapter 1 3
Description
The 8480 series power sensors are used for measuring the average power supplied
by an RF or microwave source or device-under-test (DUT). In use, the Power
Sensor is connected to the RF or microwave source and to a compatible power
meter. Suitable and compatible power meters are the EPM series power meters
(E4418B and E4419B), the EPM-P series power meters (E4416A and E4417A) and
the E1416A VXI power meter. Discontinued and obsolete power meters that are
compatible with the 8480 series sensors include the E4418A, E4419A, 435B, 436A,
437B, 438A and 70100A MMS power meter.
The 8480 series power sensors place a 50 ohm load on the RF or microwave source,
except the 8483A which has a 75 ohm load. The power meter indicates the power
dissipated in this load in mW or dBm.
The coaxial power sensors in the 8480 series measure power levels from -70 dBm to
+44 dBm (100 pW to 25 W), at frequencies from 100 kHz to 50 GHz. To cover this
wide dynamic power range, both thermocouple and diode power sensing elements
are used. Both types of power sensing elements have a maximum 50 dB dynamic
range. Thermocouple sensors have a square-law region from -30 dBm to +20 dBm,
and with an attenuator can operate up to +44 dBm. There are three model types of
thermocouple sensors in the 8480 series, covering the complete -30 dBm to
+44 dBm range.
• The A-models cover -30 dBm to +20 dBm.
• The H-models cover from -10 dBm to +35 dBm.
• The B-models cover from 0 dBm to +44 dBm.
Diode detectors (D-models) have the best sensitivity, having an operating range
from -70 dBm to -20 dBm.
Calibration factor (CAL FACTOR) data is provided on a label attached to the power
sensor's cover. Maximum uncertainties of the CAL FACTOR data are listed in the
Specifications section in page 11. This calibration factor is used to adjust the power
meter to suit the particular power sensor and frequency being measured.
NOTE For the B-models in the 8480 series, calibration factor data is valid only when the
sensor is used with the supplied attenuator.
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