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How to simulate class-E power amplifier in ADS2009

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kudzus

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Hello, Dear friends

I want to simulate the classical class-E power amplifier. I set the DC voltage Vdd=25 V, output power Po=6 W; the quality factor QL=7; and the operational frequency f=1MHz. The transistor is IRF510.

The parameters are calculated as: R= 60.0834; Lf=69.938u; Cf=453p; C=486pF(the transistor output capacitor is 250p); and the chock is 416u. I added all this elements into the ADS. However, only the switching voltage is correct. The maximum value of the output voltage is wrong. The waveform of the switching current is wrong.

How to correct the circuit to output the right switching voltage and current? (I thoght an input matching needed, But how to design the input matching network?
Another question is the QL is selected as 7. In real design, how to exactly control the quality factor?

circuit.pngcurrent.pngvoltage.png)
 

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chuckey

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In most circuits the UNLOADED Q of an inductor is made as high as possible as Q =ωL/R the R represents a loss. The LOADED Q of the circuit, is the ratio of the reactance to the reistance and so is determined mainly by the load. i.e. You can get a L with a Q of 100, put a 100 ohm resistor in series with it, the CIRCUIT will have a Q of 5 (depending on ωL). If you have a tuned circuit in the collector (or drain) with a Q of 100, its loss is infinite, no load no power transfer, now if you couple that tuned circuit to something else so its loaded Q is 50, its loss is 50%, but you get a signal with good selectivity. If its a power amplifier, the coupling to the load will be tighter, so the loaded Q is 10, its loss will now be 10%, but with only a little selectivity, just to reject harmonics? But in all cases the individual components will be made to have a high a Q as possible.
Frank
 

kudzus

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Thank you very much for your detailed explanation. I misunderstood the differences of unload Q and load Q (Although I "read" the relative papers and textbooks). As a matter of fact, the Q of the resonator in power amplifier is the load Q. Since the Q is defined by the equation sqrt(L/C)/R, the Q will be determined if the values of L, C and R is set before.

Sincerely thank chuckey again for your help.
 

Faridha Fitriati Khurnia

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hello, help me please
i'm new to ADS, and i have project to design class E power amplifier, but i don't know how to simulate it. what i mean is that i don't know how to use Harmonic Balance and LSSP, can help me please.

this is my ADS design, i found it in a paper.
 

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