General Guided-Wave Impedance-Matching Networks with Waveguide-Metamaterial Elements

A plasmonic based nanocircuit transplants the lumped property of classical electronic circuits to optical frequencies, providing a circuit paradigm for optics and photonics. To broaden the material and frequency selections, the concept of a waveguide metamaterial is applied to design lumped elements by utilizing the waveguide's structural dispersion to emulate the natural material's dispersion. Here, as an important application of the physics of waveguide metamaterials, a general type of impedance-matching network directly integrated with a waveguide is investigated for various matching occasions of guided waves, outperforming the classical ones using waveguide membranes. Three representative matching examples are analyzed to validate the feasibility, namely, transmission discontinuities, active power amplifiers, and antennas. The numerical and experimental results confirm the impedance-matching applications of the waveguide metamaterial and suggest the potential merits of low loss and low crosstalk for the proposed waveguide-integrated matching networks in terahertz integrated-circuit designs.