Design and EM Behavioral Study of PET Films for Improved Stealthiness

Different types of stealth films and their electromagnetic (EM) behavioral characteristics have been studied to fulfil the stealth requirements of today’s electronic warfare (EW) for military mission success. The EM performance of stealth films has been measured using two different measurement methods: wave guide measurement (WGM) and open area test site (OATS). Polyethylene terephthalate (PET) (sample B1) has been used as the base material to design and fabricate composite stealth films, films N (PET + conductive paint), S (PET + conductive paint + fumed silica), Q (PET + conductive paint + aluminum), and P (PET + conductive paint + aluminum + fumed silica). The conductive paint and fumed silica are used to design and fabricate small unmanned aerial vehicle (sUAV) model stealth frames. The detailed parametric studies of these films and frames have been analyzed in terms of EM wave parameters, S11 (reflection coefficient), S21 (transmission coefficient), I1 (input power at port 1), O1 (output power at port 1), O2 (output power at port 2), P in (input power incident on sample specimen), Pre fle (reflected power at a point close to the transmitter), P trans (power transmitted through the sample), SE refle (shielding effectiveness of reflection loss), SE abs (shielding effectiveness of absorption loss), SE tot (total shielding effectiveness), and RCS ( σ ) (radar cross-section). These parameters have been verified in the X-band frequency operation in the 8- to 12-GHz frequency range. Using these stealth films and frames, the minimum values of S11, S21, and SE tot of − 40 dB, − 0.6 dB, and 0.7 dB, respectively, in WGM and − 75 dB, − 76 dB, and − 75 dB, respectively, in OATS, were achieved. Further, the achieved RCS reduction level falls in the range of 0.09–1.5 m 2 over the 8–10.1 GHz frequency range, and in the range 1.6–4 m 2 above 10.1 GHz and up to 12 GHz, as presented in this paper. The experimental results give a good agreement between the design material and their EM behaviors, so their suitability for stealth applications is justified.