NOVEL INTEGRATED RF AND mm-WAVE COMPONENTS FOR B5G NETWORKS

As wireless communication systems move toward 5G and beyond, the need for high data speeds, low latency, and wide coverage has led to the widespread use of massive MIMO architectures, especially in the sub-6 GHz n78 band (3.4–3.8 GHz). This frequency allows for multi-gigabit user data rates and great fronthaul throughput; however, it needs very complicated antenna arrays with a lot of transceiver chains. This makes it much harder to put together RF front-end parts, notably filters, which need to be small, high-performance, and able to handle high power levels. Traditional filter technologies, like ceramic resonators, are small but don't handle heat or power well enough to be used in macro base-station applications where the power sent can be several watts per channel. Traditional hollow waveguide filters, on the other hand, have a great quality factor and can handle a lot of power, but they are big and hard to fit into modern planar and densely packed RF designs. Substrate Integrated Waveguide (SIW) technology is a good middle ground because it combines the excellent power handling and electromagnetic shielding of waveguides with the small size and ease of manufacture of planar circuits. Also, as we move toward beyond-5G and 6G systems, there are strict criteria for size, loss, and integration at higher frequencies. This pushes for the co-design of filters and antennas into single structures. In this setting, combined filter–antenna solutions based on SIW show promise as a way to cut down on footprint and connection losses while still keeping good selectivity, efficiency, and power handling. Consequently, this research concentrates on the development of SIW-based filters and antenna structures specifically designed for high-performance and power-resilient RF front-ends in next-generation wireless communication systems. Substrate Integrated Waveguide (SIW) technology has emerged as an effective solution for modern wireless front-ends due to its ability to combine the high power handling capability, low radiation loss, and electromagnetic shielding of conventional waveguides with the compactness and ease of integration of planar circuits. These characteristics make SIW particularly suitable for highly integrated 5G and beyond-5G systems, where dense antenna arrays and high transmit power impose stringent requirements on passive RF components. Within this framework, SIW inline filter topologies are especially attractive, as they enable compact implementations while offering enhanced selectivity through the controlled introduction of transmission zeros. Such filters provide improved out-of-band rejection without increasing circuit order or footprint, which is critical in space-constrained massive MIMO architectures. Building upon this capability, SIW technology also facilitates the realization of dual-polarized antennas with shared apertures, allowing polarization diversity and compact array configurations while maintaining high isolation and efficient radiation characteristics. Motivated by these advantages, this work first investigates SIW inline filter structures to achieve high selectivity and robust power handling. Subsequently, a dual-polarized shared-aperture antenna is designed using SIW techniques to ensure compatibility in terms of geometry, fabrication, and electromagnetic behavior. One of the best-performing SIW filters developed in the earlier stage of this research is then selected and integrated with the antenna, resulting in a compact filtering-antenna structure with reduced interconnect losses and improved system-level performance. Finally, dedicated power handling measurements are carried out on the proposed SIW filter to experimentally validate its suitability for high-power base station applications.