Questions about microstrip antenna arry~

[chenchangfu]

Questions about microstrip antenna array~

I designed a 4X4 microstrip antenna array, from the simulated result the gian is 18db and it is just so-so,but the central frequency has a big offset (from 12.5GHz offset to 11.5GHz and the S11 is also worse). I have attemptted to change the distances between the elements but I still can not get a satisfactory result. Who can tell which resaon can cause this problem? Thanks~

 

[WimRFP]

Try to understand what you have built (that is knowing the behavior of the radiating structure and the feed network inclusive power dividers). Look to current and/or voltage distribution whether it is as you expected. Mostly some scaling and/or change in trace width (that is change in characteristic impedance of transmission line sections) will do the job when it is just a matching issue (and other things are OK).

Changing distance between elements will have effect on S11, but will affect radiation pattern (and gain) also.

 

[ferdows]

hi
pls attach your antenna with out antenna it hard to judgement and for increase your bandwidth better you change first antenna