An Oversized Air‐Filled Substrate‐Integrated Waveguide Balanced‐Delta‐Port Magic‐T Power Divider/Combiner With Improved Power Handling Capability

ABSTRACT This paper presents a new approach to designing transmission line (TL) and power divider/combiner (PDC) using an oversized air‐filled substrate‐integrated waveguide (OS‐AFSIW). Our approach enhances the average power handling capability and reduces the loss. By strategically increasing the width of proposed TL, we achieve improved power handling capability. However, this approach can introduce higher‐order modes, which can be detrimental. Therefore, this paper focus on designing a balanced delta port magic‐T PDC configuration within the OS‐AFSIW that exclusively supports the fundamental TE 10 mode and effectively suppresses the unwanted higher‐order modes. This paper conducted a thorough analysis of the proposed PDC's average power handling capability, resulting in excellent agreement between fabricated and simulated results. The OS‐AFSIW PDC was implemented on an FR4 and low‐profile Rogers RO4003 laminate with a thickness of 32 mil, resulting in a compact design with a footprint of 144.63 × 58.4 mm 2 . The fabricated PDC exhibits outstanding performance characterised by input and output return losses exceeding 10 dB, good isolation across the entire Ku‐band (offering a fractional bandwidth of 28.57%), and significantly reduced loss compared to conventional air‐filled structures. Notably, at 15 GHz, our design demonstrates impressive improvements of approximately 35% in the loss and 17% in the Average Power Handling Capability (APHC), which is a significant advantage for practical applications.