about the trend about SAW filter

[triple_core]

Hi,

I got my PhD thesis from EPCOS. The topic ist about integration of a RF power amplifier and a SAW filter in a ultra small package(0.5mm*0.5mm) for mobile phone application. The critical point is that the signal isolation from output of Amp to output of SAW filter must smaller than -60dB. So that I should make a passiv circuit between amp and SAW and make simulation about the electrical magnetic wave(using e.g. EM-Sim).

I studied master about circuit design and don't know much about HF-design. Does anyone know the trend of my topic. I mean, because of the one-chip solution from e.g. by Infineon, if my module has the chance after 3 years?

Thanks

 

[khouly]

i have already seen , PA and TX saw filters and duplexers integrated in one package from triquent

so other companies have made it ,

i think the PA will continue to be off chip ,

khouly

 

[biff44]

I am not sure I fully follow the quesiton, but the problem is putting it all in the same package. The SAW filter requires a ground connection at input and output. The Amplifier requires a ground connection at the active device. Since these are all in the same package, any RF currents from those three points have the potential for passing through the same package lead inductance, and giving rise to a common mode RF leakage path. Even a 0.1 nH would be enough to screw up a 60 dB isolation.

 

[triple_core]

Thanks for your answer.

As my supervisor said, our company has also this product of the size 1.2mm*0.8mm. between PA and SAW there are enough places, so that it is possible, using metal film to separate the two. But in my design, it is impossible.

Any way, do you mean, it's not a good PhD. thesis? I'm worried about it.

i have already seen , PA and TX saw filters and duplexers integrated in one package from triquent

so other companies have made it ,

i think the PA will continue to be off chip ,

khouly

Added after 15 minutes:

Thanks. Maybe you are right.
I studied analog circuit design, but I don't have any knowledge about rf. So I dont really understand you mean. I hope you can answer my new quesitions again.

What do you mean the RF current? Is it current or radiation? As my supervisor mean, I should make 3D electrical magnetic simulation, because the distance between PA and SAW is ultra small.

The AC-current through the ground is not significant. We have already the compensation circuit.

I am not sure I fully follow the quesiton, but the problem is putting it all in the same package. The SAW filter requires a ground connection at input and output. The Amplifier requires a ground connection at the active device. Since these are all in the same package, any RF currents from those three points have the potential for passing through the same package lead inductance, and giving rise to a common mode RF leakage path. Even a 0.1 nH would be enough to screw up a 60 dB isolation.

 

[khouly]

the pacakge parasitics can couple the RF currents , to ur isolation will not be good ,

specially , the PA in the new pacakage will be very close to the filter

i think it is a challenging to make such samll pacakge

khouly