Rectangular to Large Diameter Conical Corrugated Waveguide Converter Based on Stacked Rings

This paper considers the design and manufacture, using stacked rings, of a standard corrugated antenna for the WM-380 band for use as a converter from a WM-380 rectangular aperture to a large diameter conical corrugated waveguide. In-house mode matching software is utilised for the design and three prototypes manufactured using stacked rings. The level of agreement of the stacked ring prototypes with the design predictions for the return loss and HE11 modal coupling is measured and found to demonstrate high levels of agreement

Rectangular to Large Diameter Conical Corrugated Waveguide Converter Based on Stacked Rings

This paper considers the design and manufacture, using stacked rings, of a standard corrugated antenna for the WM-380 band for use as a converter from a WM-380 rectangular aperture to a large diameter conical corrugated waveguide. In-house mode matching software is utilised for the design and three prototypes manufactured using stacked rings. The level of agreement of the stacked ring prototypes with the design predictions for the return loss and HE11 modal coupling is measured and found to demonstrate high levels of agreement

Rectangular waveguides for applications using terahertz signals

A waveguide for transmitting signals at terahertz (THz) frequencies, wherein said waveguide comprises at least a matrix and an insert piece having a waveguide channel, wherein said piece is inserted in said matrix

Grafted-to Polymeric Layers Enabling Highly Adhesive Copper Films Deposited by Electroless Plating on Ultra-Smooth Three-Dimensional-Printed Surfaces

A process has been developed to produce highly adhesive metallic layers onto polymeric surfaces. It is specifically aimed at ultra-smooth polymeric substrates produced by stereolithography (SLA) with applications in the field of radiofrequency components. By combining the wet deposition of an azide-based primer and high molecular weight polyacrylic acid (PAA), a dense polyelectrolyte layer can be grafted to various plastic surfaces. Conformal metallization is achieved by electroless plating. Adhesion of the metal layer to the plastic substrate is promoted by specific affinity and chelating binding of the grafted layer to the catalyst, its robust anchoring to the plastic substrate by covalent bonds via nitrene insertion, and deep interpenetration with the metal layer. This process is highly versatile since it is effective on various polymeric substrates, environmentally friendly and chromium-free, and adaptable to three-dimensional (3D) geometries. It has been shown to provide high adhesion onto surfaces with nanometric roughness without using surface roughening techniques. This method has been extended to produce micrometric metallic patterns by selective electroless metallization. Patterns of grafted-to PAA were printed by aerosol jet printing, and the electroless copper bath was adapted to achieve selectivity of the electroless copper on the chosen patterns. The printing and plating process also aims to be compatible with the surfaces of 3D-printed plastics and composites

Polymer-Based Additive Manufacturing of High-Performance Waveguide and Antenna Components

In this paper, a lightweight horn antenna array demonstrator is designed and fabricated by means of an additive manufacturing (AM) process that has been optimized for complicated passive radio-frequency (RF) components. The presented design comprises a complex waveguide feeding network (WFN) which aims to exploit the increased flexibility offered by this novel fabrication technique. This WFN concept could be easily extended to larger antenna arrays with higher gain for full-size telecommunication applications. The electromagnetic performance of the featured structure is validated by means of full-wave numerical simulations. Fabricated prototypes of the WFN and of the complete antenna array are tested and are found to exhibit a promising agreement with the simulation results

W-Band Waveguide Filters Fabricated by Laser Micromachining and 3-D Printing

This paper presents two W-band waveguide bandpass filters, one fabricated using laser micromachining and the other 3-D printing. Both filters are based on coupled resonators and are designed to have a Chebyshev response. The first filter is for laser micromachining and it is designed to have a compact structure allowing the whole filter to be made from a single metal workpiece. This eliminates the need to split the filter into several layers and therefore yields an enhanced performance in terms of low insertion loss and good durability. The second filter is produced from polymer resin using a stereolithography 3-D printing technique and the whole filter is plated with copper. To facilitate the plating process, the waveguide filter consists of slots on both the broadside and narrow side walls. Such slots also reduce the weight of the filter while still retaining the filter's performance in terms of insertion loss. Both filters are fabricated and tested and have good agreement between measurements and simulations