Thank you for your advice. But I want keep my design as simple as possible and less power consumption because I am going to make this transmitter portable.
I have eventually complete the oscillator, now it comes a problem where i cant find a suitable DC/DC inverter to power up my oscillator. My idea for this oscillator power management would be like this: battery > 12V regulator > 12V DC/DC Inverter > -12V regulator. The output of 12V regulator will be fed to the positive input of the op-amp and the input of the DC/DC Inverter. While the output of -12V regulator will be fed to the negative input of the op-amp.... Any suggestion on the DC/DC inverter that i can use???? Thank you!!!