Analysis of Coupling between CPW-Fed Slot Antennas Using FDTD with PML Boundary Conditions

Seppo SAARIO  Yongxi QIAN  Eikichi YAMASHITA  

IEICE TRANSACTIONS on Electronics   Vol.E80-C   No.12   pp.1608-1613
Publication Date: 1997/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Microwave and Millimeter Wave Technology
coupling,  slot antenna,  FDTD,  PML,  imaging array,  

Full Text: PDF(533.9KB)>>
Buy this Article

A rigorous analysis of coupling between two twin-slot antennas using the Finite Difference Time Domain (FDTD) method is reported for the first time. The Phase Cancellation Effect (PGE) is used to reduce the coupling due to the TM0 surface wave mode between the Coplanar Waveguide (CPW) fed cascade-connected twin-slot antennas. To confirm the effectiveness of this approach, coupling between single-slot and twin-slot elements separated by λ0/2 was analysed. The coupling between the two single-slot antennas was S21 = -30.2 dB. For the case of two twin-slot antennas, the coupling was found to be -37.8 dB, 7.6 dB below that of the single-slot antennas. The phase cancellation effect of surface waves is significant in reducing coupling between two twin-slot antennas, in addition to minimising power loss into substrate modes. A memory optimised implementation of the FDTD method with the Berenger Perfectly Matched Layer (PML) Absorbing Boundary Condition (ABC) was used for the numerical analysis.