How to achieve high impedance input on OPAMP without sacrificing bandwidth
An approach to high input impedance buffering with an op-amp is to create a non-inverting unity gain buffer, using a very high input impedance op-amp, such as the Intersil CA3140 (1.5 Tera Ohms), or the Texas Instruments OPA2107 (10 Tera Ohms), both of which have a Gain Bandwidth Product of 4.5 MHz.

 (From Wikipedia)

In a non-inverting unity gain buffer configuration, the input impedance of the buffer is the input impedance of the op-amp itself, and resistance noise is minimized / none. 

One other factor, though, is the input capacitance of these op-amps, 4 pF in the case of both these example op-amps. This capacitance itself would load the incoming signal, if the signal frequency is very high. 

As the question does not state the desired bandwidth, the suitability and capacitance impact of the suggested op-amps can not be verified. Using a spice model for one of these in the simulation may help in this.



Based on subsequent comments, for a 100 MHz unity gain bandwidth desired, the Texas Instruments OPA355 or OPA356 would work, with their GBW of 200 MHz, and input impedance of 10 TeraOhms coupled with capacitance of just 1.5 pF.