Design of a compact dumbbell-shape twist waveguide with performance of band-pass filtering

A dumbbell-shape 90° step twist waveguide with the performance of band-pass filtering is proposed. Not only could the smooth dumbbell-shape structure be easily manufactured but also avoid high-strength electric field that excited by corner point. Traditional metal waveguide section is replaced by medium substrate. This waveguide can achieve the 90° polarization rotation of electromagnetic wave, also can be regarded as a filter with 190MHz bandwidth. The twist waveguide has the features of high Q factor, small size and low manufacturing costs. The measured insertion loss is 0.9dB and the relative bandwidth compared with the bandwidth of the structure with similar function is broadened by 58%. The total length of the twist section is only 1.6mm and it achieves the miniaturization of device dramatically.