Radiation efficiency of microstrip antennas

[jallem]

I had simulated and got >70% for thickness of 30mils.

 

[bingjiang99]

Hello Jallem,

Thank you very much for sharing. Could you let me know what material you used for the simulation (dielectric constant and dielectric loss tangent)?

I used the 60 mil FR406, and the maximal efficiency is about 50%.

Thanks,

I had simulated and got >70% for thickness of 30mils.

 

[jallem]

I used Rogers 4350, er= 3.48, loss tg = 0.004
I used FR4, with er= 4.4, loss tg = 0.02.

 

[bingjiang99]

jallem,

Thank you again. If it is possible, could you upload your file here? I want to find out what my problem is.

Thanks a lot,

I used Rogers 4350, er= 3.48, loss tg = 0.004
I used FR4, with er= 4.4, loss tg = 0.02.

 

[bingjiang99]

I would like to update and clarify some confusions (at least for me):

1) When the wavelength is much bigger than the thickness of the dielectric material, the radiation efficiency can be improve by increasing the thickness of material. Or, the higher frequency will have higher radiation efficiency for the same dielectric material. Most of textbooks discribe this issue in the different way.

2) Dielectric loss is one loss contribute to total low radiation efficiency, but it is not significient as the surface wave, which is the major part in the radiation loss.

3) I still can't understand why the p a tch shape can affect the radiation efficiency. Most of publications discribe that radiation efficiency is almost irrevelant to the shape.

Thanks a lot,

I had simulated and got >70% for thickness of 30mils.

 

[bingjiang99]

Hello Jallem,

What did you do to improve the radiation efficiency? I realized that there is an model error with my original simulation. When I corrected it, the radiation efficiency is only about 25% for FR4 at 915 MHz.

Thanks,

I used Rogers 4350, er= 3.48, loss tg = 0.004
I used FR4, with er= 4.4, loss tg = 0.02.

 

[goo]

Hi guys,

how do u all calculate the radiation effiecncy???is there any equations? i am using FR4 with Er= 4.6 1 oz loss tangnet = 0.02 like that.. thanks


Regards