Waveguide-integrated MEMS-based phase shifter for phased array antenna

Zargham Baghchehsaraei (1) , Alexander Vorobyov (2) , Jan Åberg (3) , Erwan Fourn (2) , Ronan Sauleau (2) , Joachim Oberhammer (1)

1 KTH - KTH Royal Institute of Technology [Stockholm]
2 IETR - Institut d'Électronique et des Technologies du numéRique
3 MicroComp Nordic

This study investigates a new concept of waveguide-based W-band phase shifters for applications in phased array antennas. The phase shifters are based on a tuneable bilateral finline bandpass filter with 22 microelectromechanical system (MEMS) switching elements, integrated into a custom-made WR-12 waveguide with a replaceable section, whose performance is also investigated in this study. The individual phase states are selected by changing the configuration of the switches bridging the finline slot in specific positions; this leads to four discrete phase states with an insertion loss predicted by simulations better than 1 dB, and a phase shift span of about 270°. MEMS chips have been fabricated in fixed positions, on a pair of bonded 300 µm high-resistivity silicon substrates, to prove the principle, that is, they are not fully functional, but contain all actuation and biasing-line elements. The measured phase states are 0, 56, 189 and 256°, resulting in an effective bit resolution of 1.78 bits of this nominal 2 bit phase shifter at 77 GHz. The measured insertion loss was significantly higher than the simulated value, which is assumed to be attributed to narrow-band design of the devices as the influences of fabrication and assembly tolerances are shown to be negligible from the measurement results.

Domaines: Micro et nanotechnologies/Microélectronique; Electronique; Electromagnétisme

Zargham Baghchehsaraei, Alexander Vorobyov, Jan Åberg, Erwan Fourn, Ronan Sauleau, et al.. Waveguide-integrated MEMS-based phase shifter for phased array antenna. IET Microwaves Antennas and Propagation, 2014, 8 (4), pp.235-243. ⟨10.1049/iet-map.2013.0256⟩. ⟨hal-01108415⟩