Directional couplers between doubled-sided substrate microstrip lines using virtually-terminated coupling slots

A new planar multilayer quadrature coupler is proposed. This new multilayer coupler consists of two microstrip lines that are coupled through two virtually terminated narrow slots in a common ground plane. Experimental results are in fairly good agreement with theory. With the advantages of compact size and simple design procedure, this new component should have many applications in multilayer microwave integrated circuits.<
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