3-D-Printed Two-Dielectric Rectangular Waveguide TE₁₀–TE₂₀ Mode Converter

Abstract

In this work a novel TE10–TE20 mode converter for rectangular waveguide (RW) is presented. The proposed structure is conceived as a device that can be inserted in an empty straight section of a RW to yield the desired mode conversion. The converter is formed by a single ‘V’ shaped two-dielectric compact solid that can be scaled according to the frequency of operation and to fit inside the targeted RW section. It is a very low-cost light structure easy to fabricate compared to conventional alternatives of mode converters. To demonstrate the advantages of the proposed design and show its performance, a RW TE10–TE20 mode converter has been designed, simulated and measured at a center frequency of 10.7 GHz in a WR-137. It has been implemented by using additive manufacturing techniques and two materials with different dielectric permittivity. Simulated results show a mode conversion efficiency higher than 85% for a frequency bandwidth between 10.1 GHz and 11.7 GHz, and a mode purity higher than 98% for a frequency range between 9.5 GHz and 11.6 GHz. Back-to-back conversion measurements performed using WR-90 to WR-137 adapters and two of the proposed converter designs, are used to demonstrate the response of the novel TE10–TE20 mode converter. Also, the measurement of the H-plane radiation pattern of a TE20 fed WR-137 aperture is provided to corroborate the good performance of the proposed mode converter. The comparison between these measurements and electromagnetic simulations are in good agreement and show a band of operation between 10.1 GHz and 11.1 GHz.

Keywords

• Additive manufacturing
• mode converter
• rectangular waveguide
• slab waveguide