frequency lambda 2.4ghz
ya, elektr0 I had the same confusion. If the physical dimension of your antenna is same for two different frequency, you have far-field far away for high frequency.
If you have an antenna which is one wavelength long at 2.4 GHz frequency your farfiled starts from around 240 mm away. However, farfield for the same antenna at 24 GHz starts from 2400 mm away. Important thing you need to observe is that, your antenna at 24 GHz frequency is 10 wavelengths long, that's why far-field goes farther away.
I assume your confusion came from this kind of experience: you have seen for low frequency (e.g, 900 MHz) large distance is needed for pattern measuement (large anechoic chamber), however, for high frequency (e.g, 24 GHz) you need smaller distance (small anechoic chamber). The fact is, the antennas which are used in high frequency are physically smaller than those which are used for low frequency.
I guess this explanation helps.