A novel reconfigurable impedance matching network using DGS and MEMS switches for millimeter-wave applications

This paper presents a novel approach in order to construct low-loss reconfigurable impedance matching networks and tuners using MEMS series-contact switches and periodic defected-ground-structures (DGSs) implemented on coplanar waveguide (CPW) transmission lines. The application of DGSs results in an improved insertion loss and power handling capability compared to the conventional RF MEMS impedance tuning networks. The proposed structure consists of 12 DGSs and RF MEMS series-contact switches producing 4096 (2¹²) impedance states. The tunable matching network was fabricated on an alumina substrate and is only 1.3 times 3.6 mm in size. The measured results demonstrate wide coverage of the Smith chart with a maximum VSWR of 12:1 at 60 GHz. The measured loss of the network when used to match a 10 Omega load to 50 Omega from 22 GHz up to 40 GHz is only 0.5 dB.