The case study that radio frequency PA+FEM guides stray is differred
[introduction] the conduction that radio frequency PA+FEM adds screen to overspread stray is poorer (23 harmonic of DCS) , because of,knowing is He Yuan, ask grant instruction!
Problem: The conduction that radio frequency PA+FEM adds screen to overspread stray is poorer (23 harmonic of DCS) , because of,knowing is He Yuan, ask grant instruction!
Likelihood reason 3:
1.Match package to suffer Shielding Cover to so that impedance slanted,be affected
Pursue as follows:
If Shielding Cover follows,match package too close its parasitism effect changes its inductance or capacitance is worth, so that impedance changes that,conduct harmonic to greaten of course. Especially inchoate 0402 component are easier such but 0201 component are met rarely now such.
2.Leak of RF question mark arrives the Vcc of PA
When the screen on your lid is overspread, PA can go to radiate of RF question mark or coupling screen overspreads upper part, that is to say the TX dispatch number that screen hood just can have remain.
If screen cover ground connection is good so meeting all sheds the TX question mark of these remain to GND;
If screen cover ground connection is good so the TX question mark of these remain, one part sheds GND to be able to be reflexed again partly;
If mark of catoptric TX question is hit to the Vcc of PA that of course TX function with respect to deterioration.
3.Screen cover leaves with PA too close the parasitism effect between changed PA character
Means of test and verify:
Saw rarely the first kind now do not carry so
The 2nd kind word is OK such test and verify pursue as follows:
Because you say when adding screen to overspread, its conduct stray to be able to have been compared, accordingly, if adding screen,you use this kind of means below cover state. Its conduct stray to become with when adding screen to overspread, differ euqally, that murderer may be to come from this reason.
Notable is, that DC Block wants to add, avoid the direct current source of Vcc, answer fill to arrive PA or CMW500.
The 3rd kind word was not adding screen to overspread a state to fall
Stick an adhesive plaster first in PA upper part, put a sheet metal casually again. Same, when you say to did not add screen to overspread, its conduct stray to be able to have been compared.
Accordingly, if adding screen to overspread a state to fall, you use this kind of means.
If its conduct stray to become,follow when adding screen to overspread, differ euqally, that murderer may be to come from this reason.
Solution:
Saw rarely the first kind now, do not carry so.
The 2nd kind word
Because the murderer is to come from fill of RF question mark to enter Vcc, so you are in Vcc there. Put electric capacity of a be born, let fill shed GND into the RF question mark of Vcc.
Since you advocate frequency is DCS is told with the capacitance of 0201, you put a 18 PF.
The 3rd kind can change a structure only
Should follow screen shade the distance is pulled between PA big, it is direct put in a skylight-leave a blank in a publication to show that sth has been censored of PA upper part otherwise.
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