No abstract

Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document.When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

No abstract

We report a D-band waveguide diplexer, with two passbands of 130 -134 GHz and 151.5 -155.5 GHz, fabricated using micro laser sintering (MLS) additive manufacturing with stainless-steel. This is the first demonstration of metal 3D printing technology for multi-port filtering device at a sub-THz frequency. For comparison, the same diplexer design has also been implemented using computer numerical controlled (CNC) milling. The diplexer, designed using coupling matrix theory, employs an all-resonator and E-plane split-block structure. The two channels are folded for compactness. A staircase coupled structure is used in one channel to increase the isolation performance. The printed waveguide flanges are modified to adapt to the limited printing volume from the MLS. Effects of fabrication tolerance on the diplexer are investigated. An effective and unconventional electroless plating process is developed. The measured average insertion losses of the gold coated diplexer are 1.31 dB and 1.37 dB respectively. Respective frequency shifts from design values are 0.92% and 1.1%, and bandwidth variations are 4% and 15%. From a comprehensive treatment of the end-to-end manufacture process, the work demonstrates MLS to be a promising fabrication technique for complex waveguide devices at sub-THz frequency range.

No abstract