In RF circuit design, which ground method is better?

Hi,

In RF circuit design, using microstrip,
which gound methos is better?

(1) Use Via to ground; (layer 2 is ground layer)

(2) Use 1/4 of wavelength (open stub).


Please give a short explaination.

Thanks.

I think :
below 2GHz use via to grond
above 2GHz use 1/4 of wavelength(open stub)

Hi: I think it really depends upon many things. If it is narrow bandwidth, you may be able to achieve very good ground at a particular frequency usng 1/4 lambda. However, the 1/4 lambda stub will not work for wide bandwidth. Grounding via should give reasonable good ground over relatively wide frequency range from 0 to some high frequncy. However, it will have some inductance there and this inductance will become more and more important at high frequency. Regards.