Using a spectrum analyzer, the bandwidth of the antenna can be observed by measuring the radiated power when stepping a carrier across the frequency band of interest.
This can be easily done with the SmartRF Studio version 7, refer to Figure 12 for the screen dump of SmartRF Studio whilst performing a frequency sweep on CC1110.
For the 2.4 GHz frequency sweep measurement, a 2.4 GHz antenna must be connected to the spectrum analyzer so the radiated power can be measured from the AUT.
The results show that the antenna has approximately 2 dB variation in output power across the 2.4 GHz frequency band and max radiation at the centre of this band.
This kind of measurement can however also be very useful even if an anechoic chamber is not available.
たとえ無反響の部屋が利用できないとしても、この種の測定値はしかし非常に役に立つこともありえます。
Performing such a measurement in an ordinary lab environment will give a relative result, which shows whether the antenna has optimum performance in the middle of the desired frequency band.