what should be the ground plane dimension of microstrip antenna

[sameerccs11]

hello
this is sameer again
i want to ask about the ground plane dimension. the length of patch is 32.85 and the width of 49.27 so what shud be the dimension of the ground plane.

regards

sameer

 

[enjunear]

hello
this is sameer again
i want to ask about the ground plane dimension. the length of patch is 32.85 and the width of 49.27 so what shud be the dimension of the ground plane.

regards

sameer

Ideally, as much as you can afford.

When designing microstrip transmission lines, you typically keep adjacent conductors a minimum of 2-times the width of the trace, away. So if you had a 10 mil wide 50 ohm line, you'd keep adjacent conductors at least 20 mils away. This gives gives you room so that the E-fields do not cross (significantly), and you don't get significant coupling of signals between the lines. A similar concept can be applied to the patch antenna. If your 2x tracewidth is 20 mils, then I'd probably double that again to make sure you have a enough ground plane behind your patch antenna to terminate the E-field lines produced by the patch.

You should probably fabricate a few versions of the antenna layout, evaluate how each performs, and what minimum directivity/gain you want to achieve.

 

[sameerccs11]

hello thnx for reply

u know i m working to enhance the gain and uptill i have designed to microstrip antenna and i got one conclusion that for having a good gain ground plain plays the imp role. i m saying this bcoz when i was increasing the ground plane size the gain was also increase. but then ground plane became so large and the patch was so small. so i m confuse how much dimension i shud consider.

regards sameer

 

[Hi-Tone]

This should be the minimum if its a patch antenna:

Length = 6 * height of PCB + Length of patch.
Width = 6 * height of PCB + Width of patch.

You may obtain better results if the dimentions are bigger.

 

[enjunear]

hello thnx for reply

u know i m working to enhance the gain and uptill i have designed to microstrip antenna and i got one conclusion that for having a good gain ground plain plays the imp role. i m saying this bcoz when i was increasing the ground plane size the gain was also increase. but then ground plane became so large and the patch was so small. so i m confuse how much dimension i shud consider.

regards sameer

Your gain should continue to increase with more ground plane area, but you will reach a point where the gain flattens out. Theoretically, an infinite ground plane is the best solution, but that's not practical (or realistic). You may need to pick a size of ground plane based on your installation/mounting considerations. So start looking at other requirements of your design that will drive it's size, and maximize the ground plane based on those constraints (since bigger looks to be better, make it as big as possible/reasonable).