The design of transverse slot arrays fed by the meandering strip of a boxed stripline

This paper contains the description, analysis, and experimental validation of a new feeding method for exciting transverse slots in a boxed stripline. The feed is provided by running the strip at an angle centrally underneath the transverse slot. The amount of power coupled to the slot is controlled by the angle between the strip and the slot. The electric field generated in the slot is assumed to be an equiphase, half cosinusoid. Based on this assumption, an equation for the resonant resistance of the transverse slot is derived. A comparison of theoretical predictions and experimental results serves to justify the assumption. An antenna design procedure is next presented. This procedure includes an accounting of the external mutual coupling between slots. The active impedance of each slot in the presence of other slots is described by a pair of design equations. These equations relate the active slot impedance to the physical parameters of the circuit. An equispaced, eight element, array was designed to give a broadside 20 dB Dolph-Chebyshev pattern. Experimental results on pattern and input impedance were good.