Concurrent multi-band Sawless receiver for wireless communications and GNSS applications

Abstract

In modern wireless communication, software-defined radio (SDR), and multiband passive receivers are pivotal for supporting diverse frequencies, and standards. SDR provides a flexible architecture that accommodates multiple protocols through software, eliminating the need for costly hardware modifications. This flexibility is critical in meeting the increasing demand for data transmission across various frequency bands. Among multiband passive receivers, N-path mixing-based designs stand out as compact, and power-efficient solutions, eliminating bulky surface acoustic wave (SAW or Saw) filters and enabling seamless integration with SDR. Their reconfigurability and broad frequency selectivity make them ideal for multiband, and multimode applications. This thesis comprehensively explores the N-path receiver, including modeling, simulation, and experimental validation, emphasizing its reconfigurability, high linearity, and low noise figures (3–6 dB). The innovative omission of a conventional Low Noise Amplifier (LNA) before the mixer significantly reduces power consumption while maintaining robust performance through effective harmonic rejection. Key performance metrics—conversion gain, sensitivity (noise figure), selectivity (out-of-band rejection), linearity (IIP2, IIP3, and -1 dB compression point), and impedance matching demonstrate excellent selectivity across a wide frequency range (0.1–0.9 GHz) without requiring additional matching networks. Tests with modulated signals validate the receiver’s adaptability to diverse signal types. Addressing the complexities of modern wireless systems, this research focuses on Sawless passive receivers (N-path receivers), offering a smaller footprint, and lower power consumption. Enhanced adaptability to future frequency bands and standards is achieved through digital signal processing. Innovative techniques in harmonic rejection and concurrent reception are also introduced. By employing a single clock with four phases, the design simplifies the architecture while enabling selective harmonic tuning through adjustable local oscillator pulse widths. This approach supports high RF frequencies using low clock frequencies, improving signal reception and minimizing power usage. The streamlined architecture eliminates the need for additional harmonic-selective circuits, simplifying the receiver while maintaining high performance. The findings underline the promise of passive mixer-based architectures as compact, power-efficient, and reconfigurable solutions, offering a scalable foundation for next-generation multiband, and multimode wireless networks. These advancements support evolving frequency bands, and standards, setting the stage for innovative communication systems.