I hope this link may helps you

Can you specify which type of transistor are you using (thick oxide, thin oxide, nominal Vt etc.)? Is there a loading issue on the input or output? What is your source and load impedance? Is there an issue with fan-in or fan-out?

If you have the PDK document, look for any information regarding fT or fMax specification of the transistor. Try using the transistor with highest fT or fMax although I must caution there are other parameters that also need to be considered depending on your application such as break down voltages etc. If fT or fMax is not available, this can be simulated in SPICE. If you are interested, I can try to find out a good reference for you.

I have experience with TSMC process and if you are clocking a properly designed inverter at 1GHz at 180nm, it should work. Are you using Cadence or some other CAD tool (Tanner?). I would not worry about model file if you are using Cadence with PDK setup for TSMC 180nm process since they usually package the whole eco-system such that the design flow is seamless for the end user. Last time I installed a TSMC supplied PDK in Cadence, I ran a script which asked some high level questions about metal stack and capacitor options, and the script automatically installed the rest of the library and models for me.

Hope this helps.

Thank you for your response. I am using HSPICE for simulation purpose. I have implemented inverter at 2.40GHz using TSMC 180nm model file. When I change frequency to 850MHz it gives ringing effect in output.

Can anyone suggest which CAD tool is suitable for implementation of RF front end design?

Okay I am not sure about the model file issue since I don't use HSPICE very often.

For RF design, Advance Design System (ADS) from Agilent (now Keysight?) is a very powerful tool however it is not tailored for IC design flow. ADS can do:

1) time and frequency domain simulations (such as harmonic balance) etc.

2) perform EM simulations (for passive characterization)

3) Mixed signal simulation with DSP + Analog RF (ADS Ptolomy)

However its' layout tool is only good for building structures in metal layers ONLY such as inductors, MIM capacitors. It does not have any semiconductor layers.

However, Cadence has what is called Golden Gate simulator which essentially ports all these features from ADS into Cadence environment. The RF designers I used to work with frequently used this tool simulate RF designs.

Thank you sir for your advice.

Microwave devices are the most suitable family for microwave applications (GaAs MESFET, HEMT devices and many software packages can be used such as ADS, HSPICE