PROPAGATION CHARACTERISTICS OF MICROSTRIP LINES (MTLs) WITH DEFECTED GROUND STRUCTURE SLOTS: THEORY AND APPLICATION

摘要

Propagation characteristics, including scattering, dispersion, and loss modeling, of some microstrip lines (MTLs) with defected ground structure (DGS) slots were investigated in this paper. A simple approach was firstly introduced to calculate the slow-wave factors (SWF) of these MTLs with DGS. Based on the above-mentioned theory, a meander MTL structure with periodic DGS slots was proposed and analyzed. The improved SWF and characteristic impedances have been demonstrated, while the bandgap performances have been proved by experimental results. Further, a type of nonuniform DGS slots, which are composed of dual-periodic photonic bandgap structures, was applied to reduce the second-order harmonics and improve the output power of a Ku-band voltage-controlled oscillator. Measurements showed that the second-order harmonics are suppressed by more than - 20dB and the output power is improved by 3-5%.