Investigation of coaxial TE01 mode converter from high to low radius ratio structures

Abstract

This paper investigates the characteristics of coaxial waveguide modes in variation to the cross-section geometry and proposes the solutions for broadband and high-purity conversions of lossless coaxial TE01 mode at low terahertz-wave regime. Four-wave, eight-wave, and sixteen-wave rectangular waveguide power dividers/combiners are developed to excite the desired coaxial TE01 mode but to suppress the potential parasitic TE21, TE41, and TE81 oscillations at radius ratios 4.05, 1.64, and 1.36, respectively. Accordingly, the simulated results reveal the broad −1dB back-to-back transmission bandwidth of 13.5 GHz (14.3%), 12.7GHz (13.5%), and 18.7 GHz (19.9%) at W-band. Notably, these three converters with different cross-sections are designed to be capable of concentric integration, which yields a three-channel (3C) high power rotary joint for long-range and high-resolution radar applications.