Your first one is good and quite close. This is the correct way to say it: "I am interested in your field (Instrument Amplifier) and I would appreciate it if you would accept my request." Good luck

Hi Mohamad, You need a linking verb to show a relationship between the subject "I" and the adjective "interested". Hence, the first sentence is correct. If you still prefer to use the second sentence, you still need a linking verb. In this case, you can write: I have (linking verb) interest in your field...... Hope this helps. Cheers, Lance