Abstract
For quasi-one-dimensional (Q1D) waveguides of width a and with stubs attached periodically, it is shown that the photonic gaps with periodic dielectric contrast can be many times larger than those of a Q1D quarter-wave structure for sufficiently short a. Similar photonic gaps, without dielectric contrast, result from destructive interference. When a double stub is inserted in a finite waveguide it can lead simultaneously to transmittance resonances in the gaps and antiresonances in the bands that widen, respectively, into new bands and gaps when more stubs are inserted. © 1996 The American Physical Society.