Near electric field in microstrip/coplanar circuits and antennas - simulation and measurement

Abstract

A detailed investigation of the near electric field distributions in electromagnetic circuits such as microstrip/coplanar circuits and patch antennas is very useful for physical understanding, studies of electromagnetic coupling effects for EMC and EMI and for optimization of electromagnetic circuit designs. The aim of this paper is to show how to simulate and measure the near electric field distributions in microstrip/coplanar circuits and patch antennas. The full-wave analysis is carried out by using a finite-difference time domain technique, commercial-software Sonnet10.2 and its measurement is carried out by using a very small probe antenna. The leakage phenomenon which is not obtained by the simulation using a conventional FD-TD is observed by measurement of near electric field distributions of resonance modes of microstrip/coplanar resonator and patch antennas. It is considered that this leakage-phenomenon is caused by the electromagnetic coupling between the resonance mode of microstrip resonator and the surface wave TM 0 mode of covered dielectric slab that propagates from DC. The proposed measurement system offers a valid means for predictions in the theoretical analysis of more complicated discontinuity problems. Thus, the proposed measurement system offers a valid means for predictions in the theoretical analysis of more complicated discontinuity problems.