Quadrature Hybrid Miniaturization on Single-Layer Substrate

This paper presents an exact design technique to obtain formulas for compact quadrature hybrid coupler. We minimize the physical size based on even-and odd mode analysis. The proposed structure is relatively simple as the coupler can be fabricated on a single-layer printed circuit board. After finishing the design, full prototype of proposed coupler is fabricated and tested to validate the design. The obtained results reveal that we can reduce the coupler size up to 60% from the conventional one while maintaining its characteristics such as return loss, insertion loss and phase difference between through and coupled ports. Key-Words: even-odd mode; quadrature hybrid coupler; miniaturization; 3G and LTE