Agilent Technologies 8510 manual Lower/minimum frequency

Therefore, for the WR-62 waveguide standard defi- nition table, offset loss of zero ohm/sec is entered for all four standards.

Lower/minimum frequency

Lower frequency defines the minimum frequency at which the standard is to be used for the purposes of calibration.

Note

When defining coaxial offset standards, it may be necessary to use banded offset shorts to specify a single standard class. The lower and upper fre- quency parameters should be used to indicate the frequency range of desired response. It should be noted that lower and upper frequency serve a dual purpose of separating banded standards which comprise a single class as well as defining the over- all applicable frequency range over which a cali- bration kit may be used.

In waveguide, this must be its lower cut-off fre- quency of the principal mode of propagation. Waveguide cutoff frequencies can be found in most waveguide textbooks. The cutoff frequency of the fundamental mode of propagation (TE10) in rectan- gular waveguide is defined as follows.

f = c 2a

c = 2.997925 x 1010 cm/sec.

a = inside width of waveguide, larger dimension in cm

As referenced in offset delay, the minimum fre- quency is used to compute the dispersion effects in waveguide.

For the WR-62 waveguide example, the lower cutoff frequency is calculated as follows.

f = c = 2.997925 x 1010 cm/s = 9.487 GHz

2a 2 x 1.58 cm

c = 2.997925 x 1010 cm/s a = 1.58 cm

The lower cut-off frequency of 9.487 GHz is entered into the table for all four WR-62 waveguide standards.

15