Higher mode SIW excitation technology and its array application

Abstract

An excitation technology of TE₄₀ mode for substrate integrated waveguide (SIW) and its application in designing a slot antenna array is proposed. In order to excite the TE₄₀ mode, a microstrip power divider and two coupling slots driven by microstrip lines in the longitudinal direction of SIW are designed to convert the electromagnetic field pattern from slot lines to SIW. The advantages of the TE₄₀ mode are not only reducing process complexity but also simplifying the feeding network so as to reduce the production bottlenecks at high frequency. A 16-element slot array antenna fed by the TE₄₀ mode SIW is designed based on the standing wave antenna array principle. Experimental results show that a 4×4 antenna array fed by TE₄₀ mode achieves a maximum radiation gain of 15.2 dBi and 85% radiation efficiency at 10.4 GHz and an impedance bandwidth ranging from 9.95 to 10.6 GHz with |S₁₁| below −10 dB. The achieved results demonstrate the superiority of the higher mode excitation technology and it is reasonable to deduce that other higher modes can be achieved based on the proposed technology.