Method for bypassing LNA
I have designed an UWB LNA 4-10 GHz. I want to design a switch to bypass it when it is not needed. I put a transistor in bypass path and switch it off and on.
However, the problem is it totally ruins the circuit !
I tried optimizing two circuits simultaneously with same parameters (off and on circuit) for S11 and NF goal and I used resistance or inductance to match but still it gets bad results and the main problem is S11 !
Do you have any methods or switch structures for this purpose ?
I think you should turn off the LNA first then a design a non-dissipated SPDT switch with CMOS transistors.if your LNA is differential, you should design a DPDT switch to bypass the LNA.
I turn off the LNA with 0 biasing.
What is non-dissipated SPDT ? can you provide some example or tutorial ?
There are 2 types of switch.Dissipating(Non-Reflecting) and Reflecting.
There is a terminating resistor in a Non-Reflecting ( Dissipating) so that when switch is OFF ( ON) state, the common pin is terminated by a resistance to prevent reflections or undesired termination.In the second type switch, there isn't any resistor, switch acts as a ON/OFF toggle switch.
https://cdn.macom.com/datasheets/MASW-007075.pdf
and
https://cdn.macom.com/datasheets/MASWSS0157.pdf
Thank you for help. But these are Data sheet. I need CMOS desgin and integrated circuit.
I have posted for you enlightening,You can realize your own switches with your process too..
Why ? anything that is high quality is likely to be made with other materials
here is one that goes to 50 GHz so well covers your 10 GHz
https://cdn.macom.com/datasheets/MA4AGSW2_rev5.pdf