Performing component verification in the field using a rugged vector network analyzer: Page 3 of 5

May 07, 2014 //By Rolland Zhang, Agilent Technologies
The installation and maintenance of specialized systems—radio networks, satellite ground stations, radars—often requires in-field verification and adjustment of filters, diplexers, duplexers and antennas. Although the preferred tool is a vector network analyzer (VNA), typical benchtop units are neither portable nor rugged enough for field use.
Getting accurate, repeatable results in the field

A FieldFox analyzer can be configured for cable-and-antenna test (CAT), vector network analysis and spectrum analysis—individually or in combination—with maximum frequency coverage that ranges from 4 GHz to 26.5 GHz. To survive field use, the analyzers are durable enough to comply with MIL-PRF-28800F, which includes water resistance and a dust-free design, and type tested under IP53 (dust and rain). FieldFox has also been type-tested for operation in explosive environments according to MIL-STD-810G, Method 511.5 Procedure 1. As an added element of user safety and convenience, the analyzers can be controlled and monitored remotely through an iOS app.

Configuring for the required results

The minimalist configuration for field use is the CAT analyzer. With these capabilities, the instrument measures magnitude-only S-parameters and reports values such as return loss, VSWR and insertion loss. These are useful when characterizing antenna components and transmission line systems including cables and waveguides.

As a VNA, FieldFox can be configured for either transmission-and-reflection measurements (forward only) or full two-port measurements (forward and reverse). In either case, the analyzer can measure the full set of complex-valued (magnitude and phase) S-parameters.

In a transmission/reflection (T/R) configuration, the DUT must be disconnected and reconnected to make measurements in the reverse direction. Because the full two-port configuration includes an internal switch matrix, the device-under-test (DUT) need be connected only once. A full two-port unit provides the highest level of measurement accuracy because it allows the characterization and removal of all systematic measurement errors.


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