Low-Cost Microwave Components’ Fabrication in Hybrid Technology of Laminates and Additive Manufacturing on an Example of Miniaturized Suspended Directional Coupler

Abstract

A low-cost approach for the fabrication of low-loss microwave components in hybrid technology of laminates and additive manufacturing is presented in this paper. A standard copper-cladded printed circuit board technology is used in combination with a basic stereolithographic 3D printing technology and industry-standard physical vapor deposition technology of aluminum for manufacturing one of the basic building blocks of microwave systems -a 3-dB coupled-line directional coupler in suspended technique operating at 2.0 GHz band. A thin laminate with the coupler traces' mosaic is suspended inside a metal-coated 3D printed enclosure. The presented study explores the performance of the circuit in terms of total power loss vs. the properties of deposited metallization layer serving as a ground plane. It is shown that when the surface roughness of the 3D printed enclosure is low enough, which can be achieved with the use of a layer of lacquer primer before metal deposition, the conductor-related power losses are lowered to an acceptable level. An exemplary directional coupler was developed along with three variants of the enclosure and the reference one. The measurement results validate the potential of this hybrid technique to deliver fully valuable microwave components at a very low manufacturing cost.

Low-cost fully additively manufactured passive microwave components exploiting available 3D flexibility

“…1 b. In 13 – 15 it was shown that this feature can be utilized for partial realization of compensating elements allowing for frequency characteristic improvement of coupled-line couplers. In the proposed realization, due to the full 3D printing of the coupler and the possibility of truly three-dimensional structure utilization, it is possible to fully realize the compensating elements by varying the air layer and the middle part thickness (see Fig.…”

“…Generally, microwave devices fabricated on standard dielectric materials such as laminates suffer from dielectric loss, thus one of the methods allowing for loss reduction is a suspension of a planar circuit above the ground layer 13 – 15 , 24 as to introduce the lossless air layer. The suspended dielectric stratification utilized for the realization of a low-pass filter is shown in Fig.…”

“…In 4 , 6 – 8 it was shown, that 3D printing technology together with appropriate metallization technique can be utilized for the realization of waveguiding structures, which can feature lower losses than SIW structures, in which an electromagnetic wave fully propagates 9 – 11 or partially 12 within the lossy dielectric substrate. Another approach for the realization of microwave devices was presented in 13 – 15 , where AM technology was used as a substitute for relatively expensive CNC milling for the realization of the metallic enclosure allowing for the suspension of laminate with the etched pattern being a directional coupler. The great advantage of 3D printing technology is the possibility to create truly three-dimensional structures as compared to two-and-one-half-dimensional techniques such as low-temperature cofired-ceramic (LTCC) 5 .…”

“…The high electrical performance is obtained by exploiting the third dimension that is used for the realization of variable thickness air layers. In comparison to previously presented solutions 13 – 15 , no additional microwave laminate is required for the realization of passives and the entire structure can be 3D-printed and metalized, which significantly reduces the cost of production of the microwave elements. The obtained results prove the possibility for realization of fully AM passive microwave components, featuring relatively low-losses and satisfactory electrical properties within the centimeter frequency range.…”

Metallization of Recycled Glass Fiber-Reinforced Polymers Processed by UV-Assisted 3D Printing

“…After the qualitative analysis and surface characterization, some considerations can be made about the possible application fields. Although these coatings were initially used in the electronic and medical sectors [44][45][46], PVD sputtering on 3D-printed parts may be employed for a larger number of applications since it improves the properties of the parts, i.e., wear resistance, durability, and surface aesthetics [30,47]. Moreover, a coating process can also reduce the effects of the 3D printing process such as the staircase effect, which may influence not only the appearance of a 3D printed product but also its functional properties.…”