# A 3D-Printed Bent–Twisted Waveguide Filter Using Mixed TE101 and TE102 Mode Resonators

## TL;DR

This paper introduces a 3D-printed waveguide filter that combines bending and twisting functions for improved performance at 20.4 GHz.

## Contribution

The novelty lies in integrating mixed TE101 and TE102 mode resonators to achieve bending and twisting in a lightweight filter design.

## Key findings

- The filter achieves 120° bending and 90° polarization rotation while maintaining low insertion loss.
- A sixth-order Chebyshev bandpass filter centered at 20.4 GHz with 7.84% FBW was successfully fabricated and tested.
- Measured results show strong agreement with simulations, validating the design approach.

## Abstract

This paper presents a waveguide bandpass filter that integrates bending and twisting functions, utilizing mixed TE101 and TE102 mode resonators. Benefiting from the mixed utilization of TE101 and TE102 resonators, the desired stopband suppression and low insertion loss are achieved. To verify the feasibility of this approach, a sixth-order Chebyshev bandpass filter centered at 20.4 GHz is designed, with a bandwidth of 1.6 GHz (FBW = 7.84%) and a return loss of more than 20 dB. The filter also achieves 120° bending in the propagation direction and 90° rotation in polarization. This prototype is fabricated following the stereolithography (SLA) process using photosensitive resin, followed by metallization through electroplating to achieve a lightweight design. The measurements exhibit great consistency with the simulations.