Firstly connect the circuit diagram in esim. In esim first go to new project then give project name then click ok open the schematic of the your project and using place component we can choose the components required to our circuit and place component in the schematic window and connect the circuit connections through wire as per circuit diagram and give component names and input output port names and annotate the circuit and check the ERC if there are no errors then generate netlist.to generate netlist go to spice select default format and click on generate the .cir file is generated
 
For .cir file go to esim workspace and project name and copy file and paste in the skywater130 folder. Edit the .cir file remove all the slash and add .lib "models/sky130.lib.spice" tt and give input voltage delay time, rise time, fall time, time period and pulse width and for plotting the output give plot(inputs/outputs). select the file and right click go to FOSSEE and ngspice-nghdl and then bin and then click on ngspice.exe then open and run the file.



Problems faced:
Case1:
   I have used the transistors present in sky130 as sky130_fd_pr__pfet_01v8 w=1 l=0.5. But I did not the reference output Waveform
Case2:
   This time I tried implementing by changing transistor sizes from the reference paper  A 0.6-V, 0.4-lW bulk-driven operational amplifier with rail-to-rail input/output swing.Then I got cannot find model error.
Case3:
   Next I tried reducing the transistor size as in reference The Recycling Folded Cascode: A General Enhancement of the Folded Cascode Amplifier and tried to implement. I got some output but it is not a sine wave.

Case4:
     I tried changing capacitor and resistor values but still output did not change from previous one.

Case5:
    I changed input from sine to pulse then the output is like noise.

Case6:
    Instead of bulk driven transistor I changed to gate driven transistor  and gave pulse as input but still output is noise.
Case7:
    For gate driven transistor I tried with sine input and I got output as sine wave.
Case 8
I tried increasing resistance and reducing capacitance to improve amplitude but output remained as previous one.




   


   



Implementation:









