Enabling RF/Microwave Devices and Antennas using Negative-Refractive-Index Transmission-Line (NRI-TL) Metamaterials

Negative-Refractive-Index Transmission-Line (NRI-TL) Metamaterials comprise transmission lines loaded periodically with series capacitors and shunt inductors, such that the phase flow and power flow are contra-directional on the lines. These NRI-TL media exhibit properties that can be utilized for miniaturizing microwave devices and antennas. A compact antenna, power divider and branch-line coupler are presented to demonstrate the miniaturization techniques enabled by NRI-TLs. Moreover, a compact NRI-TL coupled-line coupler exhibiting complex modes and arbitrary coupling levels along with high directivity is summarized. Finally, a generalized NRI-TL is described that exhibits two left-handed and two right-handed bands, which can be exploited for realizing dual-band & quad-band RF/Microwave components. Moreover, this generalized NRI-TL can be designed to exhibit two distinct frequencies where the corresponding propagation constant vanishes.