Low-noise Amplifier for a sensitive radio receiver

[WonderNomad]

I'm designing a low-noise amplifier (LNA) for a sensitive radio receiver. What are the key noise sources I need to consider at the transistor level (e.g., thermal noise, shot noise, flicker noise)? How do different LNA topologies (e.g., common-source, common-gate, common-drain with inductive degeneration) impact the overall noise figure and gain? What are the trade-offs involved in optimizing these parameters?

 

[Baluncore]

Welcome to PF.

I'm designing a low-noise amplifier (LNA) for a sensitive radio receiver.

What frequency band must it cover?

Why are you designing an LNA when they can be purchased?
https://www.ebay.com.au/itm/375533233277?

https://en.wikipedia.org/wiki/Low-noise_amplifier
https://en.wikipedia.org/wiki/Noise_(electronics)

 

[berkeman]

In addition to the buy-vs-build question asked by @Baluncore -- do you have experience designing PCBAs with sensitive radio circuits? What is the application? Will there be digital electronics on the same PCBA? It is *extremely* important to isolate different parts of radio circuits on PCBAs to avoid coupling of noise between sections via shared impedances (like power supply and ground impedance). Are you familiar with techniques such as "Star Grounding" to achieve such isolation?

Also, what level of receiver sensitivity (in dBm) are you shooting for? https://www.repeater-builder.com/tech-info/measuring-sensitivity/measuring-sensitivity.html

 

[tech99]

I was wondering why you have chosen inductive degeneration for common source operation?

 

[marcusl]

It’s all about matching the source impedance to the transistor input impedance that optimizes its noise figure. Pay attention to the Smith chart noise figure circles on the device data sheet.