the MTJ STO to the Balun-LNA is about -3 dB less than the power generated by the unloaded MTJ STO. Based on this loss ($Z_\text{in}$/($Z_\text{in}+R_\text{DC}$) = 10$^{\frac{-3}{20}}$), it can be calculated that the return loss S11=($Z_\text{in}-R_\text{DC}$)/($Z_\text{in}+R_\text{DC}$) at the operating frequency of the MTJ STO (under the applied biasing condition) is . Since $R_\text{DC}$ is close to 50 $\Omega$, the calculated S11 should be similar to the S11 of the Balun-LNA that is characterized with a 50 $\Omega$ termination. The S11 of the Balun-LNA reported in [@Tingsu2014] is about , which verifies the S11 calculated based on the hybrid simulation. As it can be also approximated from Fig. 7, the difference between the simulated PSD signals at the input and output of the Balun-LNA is approximately , which corresponds to the gain of the Balun-LNA reported in [@Tingsu2014]. In summary, the behavior of the proposed MTJ STO model has been validated at circuit- and system- level. The evaluated hybrid simulation demonstrates that the performance of an MTJ STO-based system can be easily, reliably and accurately predicted by the circuit simulator using the proposed MTJ STO Verilog-A model.

Conclusion
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The analytical model of the MTJ STO proposed in of this paper 