Ultralow RF Signal Loss in Aerosol Jet Printed Silver Microstrip Lines up to 18 GHz

Abstract

Printed radio frequency (RF) electronic components are often prohibitively lossy due to the materials challenges involved in additively manufacturing metals and dielectrics. We use aerosol jet printing of reactive silver inks to fabricate microstrip transmission lines onto commercial RF boards and subsequently extract the insertion loss of the printed silver through bisect de-embedding of the transmission lines. We directly compare the performance of our printed silver microstrips to conventional copper-clad microstrips to benchmark the efficacy of additive manufacturing against traditional processing methods. With an insertion loss nearing that of conventional copper, reactive silver ink printed traces offer dense continuous metals that can reliably act as conductors for RF applications. In addition to the morphological effects on loss from the printed metal itself, we also observe that the effect of substrate surface texture contributes to unexpected loss that may be mitigated by smoothing the surface or aligning the print direction to minimize these effects. Metallizing passive RF components using reactive inks offers a practical approach which will allow RF designers to take advantage of three-dimensional space. This is possible without sacrificing the necessary high conductivity and low loss needed to produce high performance devices for use within aerospace and communications.INDEX TERMS 3D printing, additive manufacturing, microstrip line, printed circuit board.

Printed Electronics in Radiofrequency Energy Harvesters and Wireless Power Transfer Rectennas for IoT Applications

“…[395] FFF-printed waveguides, chemically post-treated, feature transmission losses compared to other printing methods achieving higher conductivity, e.g., AJP. [282,396] However, low resolution and thick layer height in truly 3D printing techniques restrict them from fabricating active components and high-frequency antennas. 3D printing techniques can be integrated with printed electronics to overcome this limitation.…”

“…Highly conductive patterns printed with AJP are reached by modification of silver–nanoparticle inks by additives influencing ink rheology parameters, [ 233 ] adding another conductive medium, e.g., carbon nanotubes [ 357 ] or rarely used reactive inks achieving the highest conductivity. [ 282 ] High conductivity of printed electronics was achieved using various methods, e.g., by decorating silver nanoparticles for inkjet ink with graphene [ 358 ] or a combination of post‐treatment methods—plasma treatment, thermal annealing, and high pressure—on screen‐printed patterns. [ 359 ]…”

“…However, recent studies investigating resistivity and loss of printed lines in radio frequencies suggest that up to 20GHz AJP is suitable for antenna manufacturing and can successfully print transmission lines with conductivity and losses up to bulk silver. [278][279][280][281][282] It was also investigated that the bending of transmission lines does not affect their transmission properties. [283] The high novelty of this technique, new companies emerging to the market, and examples of high-frequency circuit elements manufactured with AJP depict this technique as highly prospective for RF EH and WPT.…”

Alumina‐Epoxy‐Pore Composites Fabricated by Inkjet Printing for Wireless Communication Technology

“…Through this, we can see that our paper indicates that inkjet printing can be used in a wider range of fields in wireless communication technology. [22][23][24][25][26][27][28] Our research goal is to manufacture a product that complements the disadvantages while inheriting the advantages of commercially available dielectrics. We want to fabricate hybrid composites with pores (air) as a new type of low-loss material for such a goal.…”

Fully 3D printed high performance band-stop filters enabled by three-dimensional design

“…To address what is fundamentally a materials challenge, many novel materials have been created and evaluated with 3D printing techniques. Recent innovations in direct-write metals [12][13][14][15][16][17][18][19][20][21] have led to bulk-like electrical conduction properties from the DC limit up to 20 GHz [22][23][24], which is critical for high performance RF components. Researchers have also made significant progress in identifying chemistries which lead to printable dielectrics that have low loss tangents and tailored dielectric constants [25,26].…”