Using switches to tune the dual-band LNA

hi

i am designing a dual band LNA(2.4GHz and 5.2GHz) , i have to use switches to tune the LNA to a different frequency , how can i make switches ?

i tried using MOSFETs as switches , but when they are ON they r giving very less gain(S21) and when when they are OFF , they are degrading the performance at the other frequency .

did anyone of u designed any dual band LNA ? , plz help

deepak

u need to optimize the W/L of these switches so they don't affect ur circuit

Khouly

hi khouly

how can i optimize the switches, i mean simply by trial and error or can i do it using any software( like hspice ) ?

u need to check how to design a swich , and then simulate the switch alone with any RF simulator , then add the switchs to ur LNA

Try simulate switch with PIN diode.
Search by google for good article.

I did a design on Dual-band front-end myself. If you have any specific questions please contact me. I used common-gate topology and a switch for switching in and out capacitor.