Breakthrough design of power handling capability-enhanced slotted oversized substrate-integrated waveguide power divider/combiner considering corona and thermal effects

Abstract

An analysis and design of a new slotted power divider/combiner (PDC) that utilises an oversized substrate-integrated waveguide (OS-SIW) is presented to enhance power handling capability (PHC). It is interesting to note that, the power capability tolerance can be increased by increasing the width of structure and thickness of the substrate, although it may introduce higher-order modes. The paper is focused on improving PHC of PDC that propagates only the TE₁₀ mode while preventing the propagation of higher-order modes. Additionally, the PHC of the proposed structure is studied in detail. The air breakdown or the corona effect is a physical phenomenon that limits the Peak Power Handling Capability (PPHC) of a device. In slotted microwave components, the corona effect plays a crucial role in determining the PPHC, and it is closely related to environmental conditions such as pressure. Another limiting factor is self-heating, which affects the device's Average Power Handling Capability (APHC). The slotted OS-SIW PDC is designed on Rogers RO4003 laminate with 32mil thickness, offering a low profile with an overall OS-SIW PDC area of 170 × 55 mm². The measured results of the fabricated PDC showcase a range of desirable features. Moreover, the proposed structure in power divider mode exhibits significant improvements in APHC compared to those of the conventional Substrate-Integrated Waveguides structures, with respective enhancements of approximately 8.26% at 10 GHz (with a Fractional Band Width of 58.3%). These advantages are highly beneficial and hold great potential.