A simplified normalization FDTD formula and its application to VIP combline bandpass filters

摘要

In this work new studies on the normalized finite-difference time-domain (FDTD) formula show that its time-domain iteration is done with an expanded dimension. A simple formula is derived to show the resulting variations in the frequency domain. A practical application to the vertical installed planar (VIP) BPF is given, a novel improvement to which includes applying planar fins and fine through-holes to reduce the requirement on an ideal ground circuit. The excellent properties of the modified combline BPF have been shown by the FDTD design as well as the measured ones.