- Resonant frequency

- Bandwidth

- Gain

- Directivity

- Efficiency

- VSWR

- S11

It is my proposal but these parameters are not independent. As an example, the Bandwidth can be calculated on the basis of VSWR

Thank you very much Mr Slyusar.

Mouaaz Nahas , At first you need to fix your resonance frequency for comparing different antennas. Then the order of importance will be in the following order

1. S11 or VSWR ( both gives the details about reflection characteristics)

2. Bandwidth

3. Directivity

4. Gain ( usually patch antennas don't have good gain. So many researchers are working in the area of gain enhancement using metamaterials.)

5. Efficiency.

I hope this will help you.

Thank you Mr Manohar, your answer is very useful.

As has been pointed out, vswr is fixed by S11 vswr = (1+|s11|)/(1-|s11|) where s11 is the amplitude ratio, not the power ratio.

also gain is directivity * efficiency

Sidelobe levels and backward radiation are also important parameters.

You also forgot to include price, although the cost of components and energy to make up for having a bad antenna in a communication system often means it is worth paying for a better one.

1. Resonant frequency

2. Bandwidth

3. Directivity

4. Efficiency

5. Gain

5. VSWR

6. S11

According to my observations, if you can properly maintain 1-7, it will be an efficient antenna.

- Resonant frequency

- S11

- Gain

- Efficiency

- VSWR

- Bandwidth

- Directivity

Dear Jayshri Kulkarni madam,

Based on my observations, the antenna's bandwidth is the number of Hz for which the antenna will exhibit VSWR. The product of directivity and efficiency is gain.

VSWR and S11 will give same information as VSWR equal to ratio of (1+ ref/1-ref),so getting either one satisfactory value will naturally gives other value(ref cof 0 correspondence to VSWR 1 and ref coefficient 1corresponends to vswr infinity) so it is VSWR or S11.

The lowest value of S11 (below 10 dB) correspondence to resonance frequency.. so from one graph you obtain information of all three as well as impedance bandwidth.

Next,gain is equals to efficiency times directivity,hence the graph or radiation pattern of gain and directivity will be similar curve.

Hence in my opinion

1.vswr or s11 and resonance frequency

2. directivity and gain

3. Efficiency.

Apart from this, the curve of radiation patterns should be constant for desired bandwidth.

Mouaaz Nahas , it is very difficult to answer this question. As per my opinion the importance of antenna parameters is dependent on application Like for transmitting antennas better impedance matching is compulsory but for receiving antennas that is not a constraint. For some application High beam width is required and for others High gain is required.

Refer to the following papers which have useful relevant information:

Article Eight-Element Compact UWB-MIMO/Diversity Antenna with WLAN B...

Article A Compact CSRR Enabled UWB MIMO Antenna

Dear Mouaaz,

In among all parameters, VSWR should be low and almost near to 1 whereas S11 ( return loss should be also very low ( less than -10db ) in order to get maximum power transfer.

Rest parameters like gain , directivity , BW should be high as much as possible but all these parameter are depend upon other parameter that must be decided by boundary condition ( height of dielectic matetial and its permitivity etc)

The parameter of antenna depends on what application you are working on. Depending on application parameters like type of radiation pattern required(Omni direction for mobile comm and othe comm related applications) gain, bandwidth and efficiency will vary(I am not writing beamwidth as it is inversely related to gain).

The S11 and VSWR gives same information as both are linearly related((1+S11)/(1-S11)=VSWR)

S11signifies how much power is reflected back to port 1, it should be as low as possible at design frequency as we want maximum power to be radiated.

Hope this will clarify your doubt

1. S11 and realized gain plot Vs frequency on the same figure. Include both simulation and measured results. Mention the fractional bandwidth. The plots also indicate the resonant frequency. Realized gain is a function of both directivity and total efficiency, so you don't need to plot directivity separately.

2. Simulated and measured fat field patterns.

3. Simulated and measured radiation and total efficiencies.

4. Co and cross polarization radiation patterns of you have a circularly polarised antenna.