Additive manufacturing and metallization of high-frequency communication devices

Abstract

Additive manufacturing (AM) can be applied to new scenarios where traditional subtractive techniques limit geometry and assembling freedom. One of these scenarios is the development of high-frequency devices for communication systems, where AM offers the capability to develop high-complexity geometries, reducing the devices’ weight and cost. This is extraordinarily convenient for recent small satellites where size, weight, and integration are vital. This work presents an AM process specially optimized to develop communication devices. Industry needs have been studied, and materials and manufacturing techniques have been chosen accordingly. Two communication devices, a band-pass filter and a horn antenna, have been developed using two VAT photopolymerization (VPP) processes and different resins. Printed devices were metallized using a two-step process based on a first electroless metallisation and a final galvanic plating. The manufactured pieces were sandblasted prior to metallization to increase plating adhesion and reduce surface roughness. Finally, several dimensional analyses were performed to evaluate the effect of finishing and plating on the manufacturing process using scanning electron microscopy, profilometry, and contact metrology. The electromagnetic response of developed devices is excellent and comparable with commercial devices manufactured with subtractive techniques. A preliminary tolerance analysis was carried out to approximate the systematic deviation of the overall manufacturing process, considering the erosion of sandblasting and the thickness of copper plating. These deviations were compensated in the design step to improve the dimensional accuracy of the band-pass filter.