Coaxial transition with very large diameter ratio of inner conductor using equal amplitude in-phase feeding

Abstract This paper presents a novel design for a broadband coaxial transition featuring a large inner conductor radius ratio. To establish the equivalence between a two-port matching network and the even mode of a symmetrical power splitting network, an equivalent circuit model of an ideal Tee junction is proposed. Subsequently, a highly integrated impedance transition model is developed by employing a double splitting strategy. Subsequently, a highly integrated impedance transition model is developed by employing a double splitting strategy. By adopting a symmetrical, in-phase, and equal-amplitude feeding strategy, the challenges associated with impedance matching and spurious mode suppression are effectively addressed. Furthermore, a symmetrical and equal amplitude in phase feeding strategy are introduced to the great challenges of impedance matching and spurious suppression can be overcome. In addition, the design complexity is alleviated by using the equivalence between the wrapped waveguide and a coaxial to reduce the numerical burden. A typical design example with the radius ratio of the inner conductor up to 1:25 is designed and fabricated. The simulated and measured results have proven the feasibility of the proposed method. It can be applied to broadband rotary joints that demand large hollow space through the center.