Low-RCS UWB Planar Monopole Array Antenna Based on the Optimized Design of the Conductor Layers

Using an optimized design of combining traditional copper (Cu) film and novel phase transition film vanadium dioxide (VO2), this communication proposes an ultrawideband (UWB) planar monopole array antenna with excellent stealth performance. The VO2 film exhibits two controllable phases: one with low conductivity of less than 10(3) S/m and the other with high conductivity of more than 10(6) S/m. Since VO2 has lower conductivity than Cu, antenna designs using this material will have lower radiating efficiency as a tradeoff for reducing the radar cross section (RCS). To optimize this tradeoff, careful antenna shape design, and an innovative combination of using VO2+Cu films, the RCS can be reduced in a UWB without significantly decreasing the gain of the array antenna. In this work, Cu is applied in the regions supporting high current density, while phase transition VO2 film is used in areas supporting lower current density. Both the shape and size of the VO2 film are optimized. Compared with the all-Cu film counterpart, the realized gain of the VO2+Cu hybrid film array antenna is decreased only by an average of 0.4 dBi, maintaining the same radiation pattern in the working band of 6-9 GHz, while the monostatic RCS is reduced by about 9 dB on average across the UWB of 4-11 GHz.

Automated summary

This paper proposes an ultrawideband planar monopole array antenna with excellent stealth performance by using a combination of traditional copper film and novel phase transition film vanadium dioxide (VO2). By carefully designing the antenna shape and using an innovative combination of VO2+Cu films, the tradeoff between radiating efficiency and reducing radar cross section (RCS) is optimized, resulting in a decreased gain of only 0.4 dBi and a reduced monostatic RCS of about 9 dB.