Do I require to measure IIP2, IIP3 , IMD3 of low noise amplifier

Dear Sir,
I have designed low noise amplifier at 1.3GHz using linear Avago ATF 54143 microwave transistor, have measured the gain as 16dB , noise figure as 0.70 dB ,input and output return loss as -11dB, and stability as 1.4130. What is my doubt is , do I require to measure the IIP2, IIP3, P1dB, IMD3 , and power dissipation of low noise amplifier at 1.3 GHz.Any how Avago ATF54143 transistor used that is linear transistor.I have read lot of IEEE papers regarding on low noise amplifier design, most of them used the CMOS transistors and they have measured IIP2, IIP3 , IMD3,P1dB compression point, and power disipation.What is my quesition is,do I require to measure IIP2, IIP3, IMD3, P1dB, and power disipation for my designed low noise amplifier at 1.3 GHz using ATF54143 transistor. I designed using the software AWR MWO, can you help me anybody.

At least you should measure OIP3 to get an information about the linearity.
Linearity is important especially when it's used in amplifying terresterial signals because there are many jamming or unwanted signals in the air and if your amplifier does not have sufficient linearity, it will mix the signals and your output will be "dirty".

BigBoss Sir,
We must measure the IIP3,IIP2,OIP3, IMD3 and dissipation power also. I thought that any how I am using linear transistor, linearity is not a mandatory. Now I realised that we must measure the above said parameter. What I noticed in the many IEEE papers, they measured IIP3 is -6dBm ,-5dBm,
+6dBm, 10dBm. But my design IIP3 has come as 214dBm (0dBm at the input), I have plotted frequency vs Pout , output power has come 19 dBm(Input power is 0 dBm) .I want to make confirm that above obtained values are correct or not. If it is not correct, how we cross verify these values. Can we plot Freq vs IIP3 or Input power vs Output power to measure IIP3 , IIP2 , P1 dB and IMD3. Which one is best , how to measure the dissipated power at the output of the low noise amplifier.How much value is acceptable for IIP3 , IIP2,IMD3, P1dB like that they must come below 10dBm, is there any rule. .

LInearity parameters are rarely measured on a low-noise amplifier with a gain below 20 dB. You never indicated what signal level your LNA should handle. In a good receiver, stages AFTER the LNA are important in linearity considerations.

With your LNA, you should indicate the typical signal power at its input. Depending on application it may be something above -100 dBm. If it becomes > -30 dBm, then LNA linearity should be considered.

IP2 and IP3 (input or output) are more related to the system design. As a stand alone device, for an LNA doing a simple P1dB measurement will give you information about the linearity of the device.
Most of the time for LNAs is valid the rule: IP3(dBm) = P1dB + 10dB. To get this equation valid, the LNA should use proper bias filtering.

Dear vfone and jiripolika,
From your all suggestions, I must measure IIP3, IIP2, OIP3, P1dB. From my first postings itself, I have designed LNA at 1.3GHz and got gain as 16dB and Noise figure as 0.7 dB. Howmuch input power I have to feed it ,can you help me anybody.

btv_murthy said:

Dear vfone and jiripolika,
From your all suggestions, I must measure IIP3, IIP2, OIP3, P1dB. From my first postings itself, I have designed LNA at 1.3GHz and got gain as 16dB and Noise figure as 0.7 dB. Howmuch input power I have to feed it ,can you help me anybody.

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Everything depends on the system requirements. If you "must", test the P-1 dB of your LNA. It can be around -10 to +10 dBm output. Then you can test the IM by two-tone method at the same and a 10 dB lower level Other IM quantities are derived from these two.