  In light of the non-perturbative resonance effects that may occur during
inflation, we introduce a parametrization for the power spectrum of the
stochastic gravitational wave background (SGWB) characterized by narrow-band
amplification. We utilize the universal $\Omega_\text{GW}\propto k^3$ infrared
limit, applicable to a wide array of gravitational wave sources, to devise a
robust yet straightforward parameterization optimized for Markov Chain Monte
Carlo (MCMC) analyses. This parameterization is demonstrated through select
examples where its application is pertinent, and we discuss the advantages of
this approach over traditional parametrizations for narrow-band scenarios. To
evaluate the sensitivity of our proposed model parameters, we apply a mock
likelihood based on the CMB-Stage4 data. Furthermore, we explicate the
computational process for the mapping relationship between the foundational
model parameters and our parameterized framework, using a two-field inflation
model that resonantly amplifies gravitational waves (GWs) as an example.
