A compact 3-dB coupler on a dual substrate layer with a rectangular slotted microstrip ground plane

This paper presents a compact 3-dB coupler on a dual substrate layer with a rectangular slotted microstrip ground plane. The coupler is designed for operating frequency at 2.45 GHz using an inexpensive FR-4 substrate. A compact coupler design with dimension of 19 mm x 7.5 mm offers a size reduction of 62% while simultaneously enhanced the bandwidth to 42.7% compared to a conventional coupler.