# Axes

An axis is a dimension which data is calculated along. Typically an axes contain the set of physical points where data is calculated, the frequency or position where the data is calculated. A full list is given in Table 1. Any of these axes may be added to a DataSet.

As an example, we pull in a near field from a horn antenna and print out the different axes.
Note: That the near field specifies three spatial dimensions and a frequency dimension.
nf = pf.NearField.GetDataSet("Horn.StandardConfiguration1.NearField1")
for index, axis in pairs(nf.Axes) do
print(string.format("axis[%d]: %s axis with %d values [%E to %E] %s",
index,
axis.Name,
axis.Count,
axis.Values[1],
axis.Values[#axis.Values],
axis.Unit))
end
axis[1]: Frequency axis with 1 values [1.645000E+009 to 1.645000E+009] Hz
axis[2]: X axis with 21 values [-2.600000E-001 to 2.600000E-001] m
axis[3]: Y axis with 21 values [-2.000000E-001 to 2.000000E-001] m
axis[4]: Z axis with 1 values [4.600000E-001 to 4.600000E-001] m
Analysing the example, one can see that the near field was calculated at a single frequency and at a single height. The other two spatial dimensions form a rectangle, making it clear that the near field is a flat surface at a fixed height and frequency. Each axis also indicates the unit in which the axis is measured. The spatial axes are measured in metre (m), while the frequency axis is measured in Hertz (Hz).
Note: That the data type for all of the axes are scalar. In other words, all of the axis values in this instance contain real values.
Table 1. Axis types for the Axes field
Axis type Axes field
Position X
Y
Z
Theta
Phi
Rho
R
Frequency axis Frequency
Other axes Arbitrary
Index
MediumNames
PortNumber
Solution
S-parameter
Undefined
Time