Resonance Property of a Novel Vertical Substrate Integrated Waveguide

Millimeter-wave communication plays a more and more important role in the electronic industry. The request for transmission structure is more complex and diversified accordingly. A novel vertical substrate integrated waveguide structure (VSIW) based on multi layers printed circuit board (PCB) is analyzed in this paper. It is composed of substrate, vias and multi copper layers with etched rectangular holes. When top and bottom layers' etched openings shift along the short side of the holes, in the frequency band of 75 GHz to 90 GHz, the cavity resonance mode may be excited. This will greatly degenerate the propagation of the signal. It is proved that this resonance phenomenon is due to that the propagation TE
10
mode converts to the cavity resonant TM
110
mode. Furthermore, an empirical formula for predicting the TM
110
mode resonance frequency using the curve fitting method is proposed. It can fast predict the resonance frequency without time-consuming simulation. The accuracy of the predicted formula is verified by several six-layer VSIW simulation examples.