In this paper a novel 1-bit phase shifter topology based on dual input Low Noise Amplifier (LNA) for Active Reflective Intelligent Surfaces (Active RIS) is presented. The proposed solution is advantageous when the LNA has to be switched between two different radio-frequency (RF) sources. In particular, the Active RIS receiving (RX) patch antenna has two opposite feed points in order to obtain a 0° and 180° phase shifted signals entering the dual input LNA. A 1-bit digital enable (EN) signal is used to select one of the two inputs at a time, making the LNA behaves as pseudo-switch. Experiments were carried out on a fabricated prototype. The reported results show good agreement with simulations, thus validating the LNA operation. The LNA is based on a 130 nm SiGe BiCMOS technology, operating between 20 and 30 GHz with a 13 dB gain and 3 dB noise figure.

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.