Problem about power MOSFET SWITCH

[New ones]

Hi everybody
I met a problem I dont know how to solve it. In this circuit. Q3 and Q7 worked as a switch.
But when the input voltage reaches to 20Mhz. The input signal will be found at the gate foot of Q3.
Whether I can change this circuit to improvement its work at this frequency. Capacitor between gate and drain make this problem I think. I'm noob. I feel confused about this problem . Please give me some advice~:?::?::?:

 

[ravindragudi]

For the MOSFET Q3, from datasheet it looks like it cannot function at switching frequencies of more than 5.55MHz with typical values. Check the Switching Characteristics in its datasheet.

 

[New ones]

Hi ravindragudi :
Thanks for your reply. How can you get the frequency of 5.55MHz ?I'm noob . Maybe I made you misunderstand my problem . The switch MOSFET period which is the period of control signal at Q3's 1 foot is about 100 us. But the input signal from Q3's 2 foot to Q3's 3 foot is 22MHz. So I don't think my problem thanks to the switching characteristics.