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Which transistor would best suit for 8.3 - 8.7 GHz X-Band LNA design?

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vedagarbhamsandeep

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Could someone tell me which Transistor would best suit for 8.3 - 8.7 GHz ? and also a design approach to meet the requirements.
Gain: 45dB
Gain Stability: 0.5dB
Output Impedance 50 ohms
I/O VSWR: < 1.3
DC Power: 12V

Any related documents to obtain the same would be of great help. I would be using Ansoft Designer and CST. Please comment on the same.

How many stages of LNA would be required to obtain the target Gain ? and also what Bandpass Filter (my choice is hairpin filter as of now) will be best suited ?
 

imado_60

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lna design using ansoft designer

Try BFR949f
 

neazoi

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x-band

vedagarbhamsandeep said:
Could someone tell me which Transistor would best suit for 8.3 - 8.7 GHz ? and also a design approach to meet the requirements.
Gain: 45dB
Gain Stability: 0.5dB
Output Impedance 50 ohms
I/O VSWR: < 1.3
DC Power: 12V

Any related documents to obtain the same would be of great help. I would be using Ansoft Designer and CST. Please comment on the same.

How many stages of LNA would be required to obtain the target Gain ? and also what Bandpass Filter (my choice is hairpin filter as of now) will be best suited ?

To get so much gain at this frequency you need a multi stage amplifier. You mention that this is an LNA but there is no indication about the NF of the amplifier you need to construct. What is its use? A very low noise can be accomplished by the MGF4919G and the NE3210S01 as can be seen in the gk-electronics.gr website, but they are expensive.
I would say these are among the best transistors as far as concern NF in these frequencies.
Note: NF is defined almost totally by the first stage of your amplifier, i.e. the first transistor, so you probably only need 1 of these.
The rest can be higher noise ones without affecting the performance of the LNA too much. See here for a calculator: https://www.microwave.gr/content/cascades/mcl_nf_calc.html
 

PalashJain

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lna design in edaboard

hello everyone
i am a ug student and doing a project on low noise amp
i want the basic tutorial + design circuit for the same.




thanx
 

neazoi

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low noise amplifier x-band

An LNA is no different than a preamplifier. So any small signal amplifier/preamplifier tutorial will be fine for you. The only thing with LNAs is that the first stage needs to use a low noise active device (transistor), so you have to look for a low noise transistor/MMIC for the frequency you want.
And you need to define what low noise means to you. If 3db total NF can be defined as a low noise amplifier by your project supervisor, then you can just use an MMIC at lower microwaves. See www.gk-electronics.gr for short data and samples on some MMICs.
Noise figures of <1db are more difficult and expensive to achieve.
 

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