Growing evanescent waves in continuous transmission-line grid media

We demonstrate the growth of evanescent waves in a backward-wave medium which consists of a printed continuous transmission-line (TL) grid without any embedded lumped elements (chip or printed) or vias. This proposed medium is referred to as a backward-wave transmission-line (BWTL) grid. When such a BWTL medium is sandwiched between two complementary forward-wave transmission-line (FWTL) grids, growing evanescent waves are supported in the BWTL medium. Analysis and microwave simulations verify the growth of evanescent waves including in the realistic case of lossy TLs. The proposed BWTL medium is easy to construct and inherently scalable with frequency.