Theoretical investigations into binomial distributions of photonic bandgaps in microstripline structures

Conventional circular patterned microstrip PBGs have constraints in broad stop‐band response due to high ripple heights in S parameters. In this Letter, a novel configuration with the nonuniform dimensions of circular‐patterned PBGs to improve the rejection bandwidth and the ripples is proposed. The dimensions of the circles are varied proportionally to the amplitude coefficients of the binomial distribution. The S‐parameter versus frequency plot of a 10‐element binomially distributed circular‐patterned PBG array has been presented. The result reveals that the binomial distribution improves the performance by suppressing ripples and generating distinct stop‐band and low‐pass responses and sharp cutoffs. A tandem of two such PBG lines yields even wider and distinct stop‐band and low‐pass responses.