I propose to use a follower Aop (high input impedance amplifiers) to measure input and output (l and V).

Thank you for including the schematic.

Have you  considered using voltage Standing Wave Ratio devices. 

In my radio work, as K4KKQ Amateur Radio , I do this commonly,

as I tune my antenna systems.

I use the SWR readings to compare Voltage Ratios : input vs. output,

Hi Glen,

Using  a VSWR device is good in case of antenna response but here i am having a shottkey diode.

So i am not sure how the non linear device will affect the reading .

Firstly,

experiments and measurements with Oscilloscopes

can tell you exactly what you need to know.

Secondly,

I would agree with Malaoui except that

OPA usually do not work up at 1GHz.

.,..

Therefore, following Malaoui line of thought, I suggest :

(1) design for a FET amp at the input and FET amp at the output.

(2) design for two RF probes ( diodes down to DC for OpAmp ckt ). 

Attached is a diagram of Anti-Parallel Diodes

which I commonly use to provide function in plus-and-minus direction.

Good luck with your work.

I agree with Glen, also now we can find transistors that work for very high frequencies (> 10Ghz) for example:

- RF FET Transistor 10 GHz   "ATF-34143-TR1G"

and also

- "CPH6021" is a NPN Single RF Transistor, 12V, 100mA, fT=10GHz for High-Frequency Low-Noise Amplifier