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It depends what you mean by performance and to what accuracy. Also what kind of an antenna are you measuring? Bandwidth and matching is of course easiest to measure with a VNA. To measure the efficiency you need an anechoic chamber or a reverberation chamber.
The basic method of measuring an antenna is to use another reference antenna with known characteristics. In this way you could get some results by hooking up signal generator and a spectrum analyzer. You could also use a SWR meter instead of the spectrum analyzer.
For simple dipoles one doesn't usually need much trimming. If your application is no too critical you could rely on your calculations and just build it.
If you want some good results, I suggest you try to get in contact with some company or school where you could use a VNA and a chamber.
Antenna Gain measurement using a Spectrum Analyzer and a Signal Generator is very straightford and very simple.
Much simple and much accurate than writers try to explain in some books or papers.
- For method of substitution in a anechoic chamber or an open site use for substitution a calibrated Dipole at the frequency that you are looking for.
- Connect the Signal Generator to a directive test antenna that could be a Yagi, Log-periodic, Horn, etc (same polarization with DUT antenna).
- Connect the Spectrum Analyzer to a Dipole (calibrated to the DUT antenna frequency, and mounted on the same polarization as the DUT)
- Set the Signal Generator to relative high carrier level (lets say 0 dBm)
- Set the Spectrum Analyzer detector on average measurement.
- Using the Spectrum Analyzer measure and record for Low, Mid and High (frequencies inside the band of interest) the signal level transmitted by the Signal Generator (you can do more frequencies if you want for better accuracy).
- Replace the Dipole with your DUT antenna and measure the level for the same 3 frequencies. The difference in dB between Dipole and DUT levels represents the Gain of the DUT antenna in dBd.
- For antenna pattern rotate the DUT antenna (usually 15 degrees steps) and record the levels for each step.
- For better accuracy and to minimize the tolerance of +/-1dB of the Spectrum Analyzer, repeat for 3 times the full rotations and do the average of each measurement.
1. measure gain with a spectrum+signal as mentioned by others.
2. you can use a spectrum+signal+coupler to measure the VSWR of the antenna.
3. you can use a spectrum+signa+tripod to measure the radiation pattern (by using zero span in the spectrum).
How to perform pattern measurement with VNA only. The image is professional antenna measurement system offered by MI-Technologies.
Can somebody explain how to perform
Signal Generator and Power Meter/Spectrum Analyzer setup is the same as VNA setup.
Using the VNA and measuring S21, actually you transmit power with one port (as a signal generator) and receive the power with the second port (as a spectrum analyzer or power meter).
The advantage using the VNA is, you can place/read multiple markers and run an Antenna Pattern vs Frequency in one full rotation.
1.single frequency
use the VNA in CW mode, this way the X-axis is time that can be synchronized with the turntable, the graph you will get on the VNA will be the radiation pattern
2.multi frequency
you do the following algorithm:
turn the table to point 1->measure S21->turn to pint2->measure S21->etc
now you have a table in your computer and you plot the pattern.
every antenna range I know is using the VNA, unless it's a big outdoor one where you will need very long cables and then you use a signal and spectrum.
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