How to Improve Gain in microstrop meander line antenne using CST software

Dear All

I am new member here, i try to do simulation of Microstrip Meander Line using CST software.Substrate FR4.
Resonant Frequency is 345 MHz. I have a problem with gain and radiation efficiency are very low (the gain is -13 dB and Radiation efficiency is -17 ). How to improve these parameter?

Thanks for your attention and advice

Regards
Sugeng

Your question lacks physical design details. How can we improve?

Read here for insight. http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA418159
check 1/4λ design details and confirm then S parameter results.

Generally the following steps can be considered:
1. Increase mess to check convergence.
2. Increase the space between antenna and boundary to check boundary sets are ok.
3. tune antenna size to get a return loss better than -6dB
4. Change the dielectric and metal to loss less to check antenna loss.

Kayaoo

perhaps also run simulation to measure sensitivity of phase shift on layout and tweak layout gap and track radius for equal distribution of phase shift from straight paths and corners. The result is to reduce change of group delay which affects rise in return loss. Visual analysis of layout of phase shift of fringes will indicate ares of opportunity. Also affects of dielectric thickness and loss tangent values can be tested for sensitivity with typical tolerances if 15%.