**3. Simulation Results**

In this section, several simulation experiments are provided. The simulation parameters are: *Gt* = *Gr* = 30 dB, *Gi* = 0 dB, *λ* = 0.03 m, W = 512 MHz, *T* = 25 ns, *L*<sup>1</sup> = −20 dB, *L*<sup>2</sup> = −10 dB, and *R* = 100 km. We suppose the target heading for the radar is an F-16 aircraft, whose variance *σ*<sup>2</sup> *<sup>H</sup>*(*f*), *<sup>f</sup>* <sup>∈</sup> [9.744, 10.252] GHz with azimuth 0.05◦ and elevation 5 ◦ between the radar and the target has been calculated by electromagnetic software, which is shown as the grey dotted line in Figure 1.

In order to verify the superiority of our proposed LPI radar waveform design method, SNR loss is treated as a performance degradation metric for radar and the PIS, which can be defined as *δsnr* = *snropt* − *snrpro*, where *snropt* is the output SNR for the optimized waveforms proposed by Zhu et al. [12], which just considers the maximization of radar detection performance, and *snrpro* is the output SNR for the proposed optimized LPI radar waveforms, which not only consider optimal radar detection performance, but also consider the resolution performance of the radar and interception performance of the PIS. The output SNRs are obtained by matched filtering of the radar and time–frequency analysis of the PIS.

**Figure 1.** Optimized LPI radar waveforms under the constraint of radar detection performance (white Gaussian noise, *PN*<sup>1</sup> <sup>=</sup> *PN*<sup>2</sup> <sup>=</sup> 1.9531 <sup>×</sup> <sup>10</sup>−18, **Ps** <sup>=</sup> <sup>20</sup> kw), the variance of target impulse response *σ*<sup>2</sup> *<sup>H</sup>*(*f*).
