Three-dimensional (3D) printing, additive manufacturing (AM), digital manufacturing, and free-form fabrication are some of the synonymous expressions commonly used to identify the new class of processes through which objects are built by selectively adding material, usually layer by layer, instead of subtracting material, as in conventional machining techniques like chemical etching, laser-cutting, milling, and electroerosion [1].

This letter presents a simple and cheap metal-plating procedure for plastic 3-D printed microwave components. The devices are built using a Stereolithographic printer and then metalized by a two-step process consisting in a silver-painted substrate followed by copper electrodeposition. The method achieves good adhesion of the metal to the plastic body and high conductivity. Resonators and X -band filters have been fabricated and tested, showing excellent performance in terms of dimensional accuracy and low loss, with quality factors better than 6500. The technique can be usefully employed for fast and cheap prototyping of microwave components at least up to the X -band.

In this paper, we describe how to define and build a set of known loads to be used in near-field microwave microscopy. Such loads are necessary to set up a microwave calibration kit, enabling local quantitative measurements by the microscope. The proposed protocol is validated through the microscopy system we have recently developed that combines a scanning tunneling microscope and a 70-GHz vector network analyzer.

Microwave microscopy has recently attracted intensive effort, owing to its capability to provide quantitative information about the local composition and the electromagnetic response of a sample. Nonetheless, the interpretation of microwave images remains a challenge as the electromagnetic waves interact with the sample and the surrounding in a multitude of ways following different paths: microwave images are a convolution of all contributions. In this work we show that examining the time evolution of the electromagnetic waves allows us to disentangle each contribution, providing images with striking quality and unexplored scenarios for near-field microscopy.

This letter presents an innovative topology of evanescent mode filters with mixed electromagnetic coupling finalized to take full advantage of additive manufacturing techniques. A four-pole filter with two transmission zeroes was designed starting from a suitable equivalent circuit. The filter was built using a 3-D printer and measured. The good experimental results show the usefulness of the solution when in-line topologies are required.

Additive manufacturing (AM) has proven to be a very interesting technology for a wide range of applications. In this paper, a stereolithography (SLA) 3-D printer has been used for the manufacturing of a new class of filters whose resonators consist of two mushroom-shaped posts transversely placed in a cavity. Each resonator implements a transverse doublet able to produce two poles and two transmission zeros in the upper stopband. The two mushroom stems are connected through a metal wire, whose the position and shape allow the control of the doublet parameters. Higher order filters are obtained by cascading doublet resonators through metal wires in an in-line configuration. This results in filters with nonconventional geometry that can be manufactured thanks to the high flexibility of AM technology. Structures manufactured by SLA are in plastic; thus, a metallization process is required. Here, the filters manufactured have been electroplated with copper. A four-pole filter with four transmission zeros has been designed and manufactured in order to demonstrate the feasibility of the structure proposed.