Question about the gain of micrpstrip array antenna.

I have simulated a 4X4 units array antenna,but the gain of the antenna just like this:

.Who can tell me the reason? What should I make change about the model?

What hope does anyone realistically have of being able to help you without considerably more detail about the antenna, how the 16 antennas are fed,. etc etc.

Dave

we cant talk about antenna with out know frequency and type and distance of antennas

It is my fault that I do not give you the detail information about the antenna.It is feed by microstrip line with equal power divider.The distance of the array antenna's units at the horizontal direction is 0.8λ while at the vertical direction is 1λ.I adjust the distance between 0.5λ~1.0λ,but I still can not let the S11 and the gain to my goal.I want the gain reach 20dB.The resonant frequency is 12.5GHz and the bandwidth is from 11~14GHz.I can give you the model,but I can not upload it at the moment, because it is not at my hand now.I will upload it later.I hope that you can give me some useful advice.Thanks~

---------- Post added at 15:44 ---------- Previous post was at 15:43 ----------

It is feed by microstrip line with equal power divider.The distance of the array antenna's units at the horizontal direction is 0.8λ while at the vertical direction is 1λ.I adjust the distance between 0.5λ~1.0λ,but I still can not let the S11 and the gain to my goal.I want the gain reach 20dB.The resonant frequency is 12.5GHz and the bandwidth is from 11~14GHz.

about S11 your problem your power divider and antenna matching so its not related to your array and about gain its related to your simulation and distance between elements and i think u should reduce them i u sen d your i able to talk more about this

Hi,this is my model,you can have a look and tell me some advice.

i saw your design but i will simulated it today but your simulation had some problem i think u will achieve good result if u design it by lump port

---------- Post added at 10:51 ---------- Previous post was at 09:10 ----------

i checked your simulation i cant understand part of your design

my contact : ferdows_j@yahoo.com

Firstly,thanks that you can have time to check my design.Then which part you cannot understand you can tell me and i will explain to you.I will send email to you later.

checchangfu

There is a minimum distance that needs to be maintained between elements if you want to avoid grating lobes and this distance is dependent on the scan angle of the arrays.

generally speaking its always good to stick to less than half a lambda distance between elements.

Hope that helps

Regards
Elchiquito

i think your ground insert to your substrate its made me confuse when i check it part by part

The ground is not insert to sub,the middle sub is just air sub.

i checked your simulation and pls contact me with that email