Hybrid couplers are important devices that combine or divide signals in various microwave applications. Wideband performance, low losses and small size are key features in most modern radar and communication systems. This paper presents a new geometry for single-ridge, air-filled waveguide quadrature hybrid couplers at the X/Ku band on a single layer using multiple pairs of slots cut on a common ridge coupling section. Bandwidth can be progressively extended by increasing the number of slot pairs. Two designs characterized by compact size and state-of-the-art performance are proposed, leading to a fractional bandwidth up to 46.88% and a maximum dimension of 1.18 wavelengths. A tolerance analysis is presented to highlight the design robustness and reliability.