LNA 54 MHz - 860 MHz

[sanketachari]

Hello,

I am final year student of Electronic & communication engineering. My final year project is on building a superhyterodyne receiver.

I am facing a difficulty in designing LNA in Advanced Design System (ADS). For range 54 MHz - 860 MHz can anybody suggest LNA model which can be simulated in ADS ?

Thanks.

 

[BigBoss]

Use CasCode configuration for this bandwidth.There are any Low Noise bipolar transistor in the market and their ADS models are available. Infineon,NXP,NEC etc.
Pay attention its stability and input/output Return Losses.NF can not be NFmin over whole bandwidth.

 

[sanketachari]

Thanks BigBoss.

I have searched about different models & found about the PBR951 RF bipolar transistor. But I am not getting the expected results.


Can you suggest the circuitry for getting appropriate power gain & constant S21 response within the 54-860 MHz ?

If there are other models in ADS, I will like to implement.

Thanks.

 

[vfone]

For this wide frequency range I would recommend a circuit similar to what use internally some MMICs (two bipolar transistors).
This gain-block circuit can give even wider bandwidth and good stability, and the design is relative easier to do, providing input/output of 50 ohms without using complicated impedance matching:

https://www.arrl.org/files/file/Technology/microwave/8702023.pdf

You can chose low power, low noise, high frequency BJTs (Ft few times greater than your maximum frequency) and for their biasing have to search (or better to learn) how to do it.

 

[BigBoss]

I have created a good starting point for you with BFP540ESD from Infineon.( Nonlinearity has not been considered.Just Gain and Noise)
You can continue from this point by carefully examining stability,reflection losses,intermodulation etc.

 

[vfone]

Or you can use this configuration, which in top of flat gain over a wider frequency range (from very low frequencies up to few GHz) provides also good input/output return loss.