This paper discusses radiation phenomena in a metamaterial transmission line based on series capacitive gaps and CSRRs periodically loading a host microstrip line and acting as a leaky-wave antenna. The analysis performed for different distances between CSRRs and the substrate edges shows that in narrow substrates destructive interference occurs between free-space leaky wave radiation and surface wave modes, reflected at substrate edges.
Eggermont, S., & Huynen, I. (2010). Substrate Edge Effects in Leaky Wave Antenna Based on Complementary Split Ring Resonators. 4th European Conference on Antennas and Propagation (EuCAP 2010), 4 pp. https://hdl.handle.net/2078.5/221183