Electromagnetic Field Analysis Using the Analogy between H-Plane Waveguide- and Modified NRD-Type Planar Circuit

A detailed investigation of the electromagnetic field distributions inside waveguide circuits is very useful for physical understanding, for optimization of high-frequency circuit designs, and for studies of electromagnetic coupling effects for EMC and EMI. The aim of this paper is to show how to simulate and measure the electromagnetic field distributions inside waveguide-and modified NRD-type planar circuits, making use of a kind of analogy existing between H-plane waveguide- and modified NRD-type planar circuits. A electromagnetic analysis is carried out by using the FDTD or the normal mode expansion technique and measurements are carried out by using very a small probe antenna. The measurement results are in good agreement with those of the numerical analysis using the FDTD or the normal mode expansion method. Thus, the proposed measurement system offers a valid means for establishing the behaviors of more complicated discontinuity problems.