Question About Antenna Performance
How can one measure antenna performance besides evaluating its impedance, SWR and return-loss?
What is the best type of antenna to be used for 433.92MHz signal?
...and how can one boost up an RF signal?
The measurements you cite deal with the connection to the antenna.
Consider that the purpose of an antenna is to radiate and or collect signals. You can also make measurements that relate to the radiation. Gain, beamwidth, sidelobe level, polarization, etc. refer to these characteristics.
VSWR is good to see how much power is reflected back from the antenna input.
No reflected power doesn?t means that all the power is radiated. There are a lot of factors which contribute to the radiation: antenna efficiency (losses), antenna resistance, antenna type, etc.
What antenna is good for 433MHz is a generic question. The best antenna for this frequency is a Long Yagi with 30 elements :D But for ISM applications probably small loop antennas are most suitable.