TABLE OF CONTENTS The maximal changes of amplitude and phase of the measured field along an antenna will appear for the radial component of the field, i.e., for E parallel to h, then:
Making use of the Schwartz inequality, after integration, we have (4.5):
If the measuring antenna fulfils the condition h < < R and h < < ?, this represents the calibration's conditions, and the emf induced in the antenna e' is:
Dividing formula (4.6) by formula (4.5) gives:
or:
The error of the E-field measurement resulting from averaging of the measured field by the measuring antenna we define as:
where ? 1E = an error expressing the field's phase changes along the antenna:
and ?' 2E = an error representing the amplitude changes along the antenna:
Formula (4.9) reflects measurement errors caused by two factors limiting the accuracy, i.e., averaging the phase of the measured field along the antenna and averaging the amplitude. We will analyze briefly the first of them here while the latter will be discussed in more detail in section 4.3 of this chapter.
The possibility of the field spatial distribution measurement, especially under conditions of multi-path propagation and interference, and the measurement of the maximal and minimal magnitudes of the field strength (while standing waves appear) requires the use of probes equipped with antennas whose sizes are much less than the wavelength. While it would be most convenient to use point antennas (zero-dimensional...
