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How to determine tone 1 and tone 2 in ADE IIP3 simulation (hb) for a 60 GHz LNA?

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JLHW

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Hi, rookie post here, the LNA I'm simulating in Cadence ADE is operating at a carrier frequency of 60 GHz. I'm using hb analysis.

I'm aware of the formula 2f1 - f2 = fc, but:

1. Is there a formula/method/rule of thumb to specify either f1 or f2?

2. Is it correct that I set frf1 (tone 1) as 60 GHz?

3. I'm also aware of similar previous posts, but they are not in 60 GHz, are their channel spacing still valid for 60 GHz?

Thanks.
 

2*f1-f2 or 2*f2-f1 are Third Order Intermodulation Products and IF these Products fall down into Bandwidth, 3OIP measurement is meaningful.
So, here is the question : What is your Bandwidth and do all those 3OIP fall down into Bandwidth ?? Carrier Frequency is not a matter, the essential here do Disturbing Products Impact the Receiving?
 

My bandwidth is (65.97-52.17) GHz = 13.8 GHz

May I know how to determine whether OIP3 falls into bandwidth?
 

My bandwidth is (65.97-52.17) GHz = 13.8 GHz
May I know how to determine whether OIP3 falls into bandwidth?

Now you will answer your question by yourself..
How you should choose f1 and f2 so that which combination ( 2*f1-f2 or 2*f2-f1) of 3OIM fall into Frequency Bandwidth ( between 52.17-64.97 GHz) ?
 

Okay, I've chosen f1=59.5 GHz and f2=59 GHz and run the hb analysis. Then at the main form, I chose 59.5 GHz as 1st order freq and 60.5 GHz as 3rd order freq, the result is as shown:

12.PNG

May I know are the two frequencies acceptable in this analysis?
 

Thanks

I've tested with other values by playing with other harmonics within the bandwidth in the direct plot form, and the results will differ, so may I know how can we decide which harmonics to produce the right IP3?

also, if I set the frequency for P1dB plot at 60 GHz, will it contradict the results with my current setup for IP3?
 
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-There is no such definition "Right IP3".. This specification already varies within Bandwidth in a moderate tolerance..
 

Alright, thanks for the clarification, then I'll leave my IP3 plot as it is shown here.

BTW, If I set the frequency for P1dB plot at 60 GHz, will the P1dB curve contradict with my current setup for IP3 since the frequencies are already different for both plots?
 

Alright, thanks for the clarification, then I'll leave my IP3 plot as it is shown here.
BTW, If I set the frequency for P1dB plot at 60 GHz, will the P1dB curve contradict with my current setup for IP3 since the frequencies are already different for both plots?
Not really.. You can choose same frequency for P1dB too and two plots can be layed down on a same chart..But simulation set-up will be surely different.
 

Okay, so right now, I have two testbenches for the same LNA circuit, one for P1dB sim, another for IP3.

for P1dB, I've set my frf1 variable in ADE as 60 GHz and for IP3, frf1=59.5 GHz, frf2=59 GHz as mentioned previously.

The result of P1dB is as shown:

13.PNG

I've heard about the rule of thumb that P1dB power is roughly 10 dB lower than IIP3, but my IIP3 is 33.1 dBm and OIP3 is 38.91 dBm, way higher than the rule of thumb suggested. is this normal for a V-band LNA and will it affect the linearity of my LNA?
 
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If OIP3 is 38.91dBm, P1dB is not correct or vice versa. 9.6dB difference should theoretically be between them but this difference is huge..
I don't know what you're doing but there is surely be an error..
 

Then we focus on the P1dB simulation first:

If my LNA is operating at 60 GHz, should I put frf1 = 60 GHz for my hb analysis?
 

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