Programmable Zeroth-Order Resonance with Uniform Manipulation Using the Nonlinearity of PIN Diodes

Metamaterial (MTM) operating on zeroth-order resonance (ZOR) is intrinsically suitable for programmable manipulation: It possesses isolated and periodical configuration capable of individually tuning with employed active element PIN diodes; the ZOR is independent of physical length, providing the freedom to utilize an arbitrary unit cell number. Though realizing versatile functionalities, programmable manipulation is not essentially uniform, and even resonance blindness occurs, since the MTM is usually limited to several units for compact size, and more especially, PIN diodes are utilized as an active element with two discrete states 0/1. In this letter, we study the transition zone where the equivalent impedance of PIN diodes is nonlinear to the supplying voltage between 0.6 and 0.7 V. Taking advantages of this nonlinearity, with a compact two-unit-cell MTM, we achieve the programmable functionalities with uniform manipulation without resonance blindness. The proposed programmable ZOR (PZOR) splitting the spectrum into narrow-bandwidth (NB) channels can be applied to NB Internet of Things for 5G in the near future. Moreover, the PZOR with the active element PIN diode needs only less than 1 V supplying voltage, which is significantly lower than other active elements such as microelectromechanical systems (MEMS) or varactors.