scholarly journals Printable Materials for the Realization of High Performance RF Components: Challenges and Opportunities

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Eva S. Rosker ◽  
Rajinder Sandhu ◽  
Jimmy Hester ◽  
Mark S. Goorsky ◽  
Jesse Tice

Printing methods such as additive manufacturing (AM) and direct writing (DW) for radio frequency (RF) components including antennas, filters, transmission lines, and interconnects have recently garnered much attention due to the ease of use, efficiency, and low-cost benefits of the AM/DW tools readily available. The quality and performance of these printed components often do not align with their simulated counterparts due to losses associated with the base materials, surface roughness, and print resolution. These drawbacks preclude the community from realizing printed low loss RF components comparable to those fabricated with traditional subtractive manufacturing techniques. This review discusses the challenges facing low loss RF components, which has mostly been material limited by the robustness of the metal and the availability of AM-compatible dielectrics. We summarize the effective printing methods, review ink formulation, and the postprint processing steps necessary for targeted RF properties. We then detail the structure-property relationships critical to obtaining enhanced conductivities necessary for printed RF passive components. Finally, we give examples of demonstrations for various types of printed RF components and provide an outlook on future areas of research that will require multidisciplinary teams from chemists to RF system designers to fully realize the potential for printed RF components.

2011 ◽  
Vol 393-395 ◽  
pp. 1024-1028 ◽  
Author(s):  
Hong Zhang ◽  
Jun Wei Wang ◽  
Sheng Zhong Dong ◽  
Fang Xu Xu ◽  
Sheng Hou Wang

The optimization of extraction of cordycepin from fruiting body of Cordyceps militaris YCC-01 by water extraction, ethanol extraction, ultrasonic extraction, and synergistic extraction is studied in this paper. The optimal conditions, water extraction at 85°C for 2.5h plus ultrasonic extraction at 600W for 35min, were determined through high performance liquid chromatography (HPLC). The dried fruiting body of cordycepin content was 9.559 mg/g by this synergistic extraction method. The yield was 66.2% higher than the control group 85°C water extraction 2.5h and 11.3% higher than the room temperature ultrasonic extraction 35min. This method has a short extraction time, low cost, low loss of active ingredients and other characteristics with good prospects.


2000 ◽  
Vol 624 ◽  
Author(s):  
Jie Zhang ◽  
Irina Shmagin ◽  
James Skinner ◽  
John Szczech ◽  
Daniel Gamota

ABSTRACTIn today's electronic industry, manufacturers are continuously improving capital utilization, developing flexible manufacturing processes, reduce changeover time and improving yield and throughput. Interest in rapid prototyping and 3-D fabrication capabilities are rapidly increasing, and a number of candidate direct writing technologies are in development to meet these demands.This work studies material systems used by data driven materials deposition (DDMD) technologies for potential low temperature reel-to-reel high volume manufacturing on low cost substrates. Characterization results of fabricated discrete and RF devices using commercially available micro dispensing and ink jet systems will be discussed. Material rheological properties, deposition process characterization, deposition repeatability, fabricated device reliability and electrical performance will be presented. The test vehicles contain resistors and capacitors, transmission lines, open and short series stub filters, and half-wavelength resonators. The material/substrate compatibility will be demonstrated through environmental conditioning of the test vehicles. In addition, a cost estimate for using micro dispensing technologies was conducted to compare current manufacturing technologies to DDMD.


2021 ◽  
Vol 7 (31) ◽  
pp. eabh3530
Author(s):  
Chunhuan Zhang ◽  
Haiyun Dong ◽  
Chuang Zhang ◽  
Yuqing Fan ◽  
Jiannian Yao ◽  
...  

Flexible photonics is rapidly emerging as a promising platform for artificial smart skins to imitate or extend the capabilities of human skins. Organic material systems provide a promising avenue to directly fabricate large-scale flexible device units; however, the versatile fabrication of all-organic integrated devices with desired photonic functionalities remains a great challenge. Here, we develop an effective technique for the mass processing of organic microlaser arrays, which act as sensing units, on the chip of photonic skins. With a bilayer electron-beam direct writing method, we fabricated flexible mechanical sensor networks composed of coupled-cavity single-mode laser sources on pliable polymer substrates. These microlaser-based mechanical sensor chips were subsequently used to recognize hand gestures, showing great potential for artificial skin applications. This work represents a substantial advance toward scalable construction of high-performance and low-cost flexible photonic chips, thus paving the way for the implementation of smart photonic skins into practical applications.


Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 347 ◽  
Author(s):  
Ying Wang ◽  
Xinyuan Zhou ◽  
Zaixing Yang ◽  
Fengyun Wang ◽  
Ning Han ◽  
...  

Photovoltaics (PVs) based on nanostructured III/V semiconductors can potentially reduce the material usage and increase the light-to-electricity conversion efficiency, which are anticipated to make a significant impact on the next-generation solar cells. In particular, GaAs nanowire (NW) is one of the most promising III/V nanomaterials for PVs due to its ideal bandgap and excellent light absorption efficiency. In order to achieve large-scale practical PV applications, further controllability in the NW growth and device fabrication is still needed for the efficiency improvement. This article reviews the recent development in GaAs NW-based PVs with an emphasis on cost-effectively synthesis of GaAs NWs, device design and corresponding performance measurement. We first discuss the available manipulated growth methods of GaAs NWs, such as the catalytic vapor-liquid-solid (VLS) and vapor-solid-solid (VSS) epitaxial growth, followed by the catalyst-controlled engineering process, and typical crystal structure and orientation of resulted NWs. The structure-property relationships are also discussed for achieving the optimal PV performance. At the same time, important device issues are as well summarized, including the light absorption, tunnel junctions and contact configuration. Towards the end, we survey the reported performance data and make some remarks on the challenges for current nanostructured PVs. These results not only lay the ground to considerably achieve the higher efficiencies in GaAs NW-based PVs but also open up great opportunities for the future low-cost smart solar energy harvesting devices.


Author(s):  
Amparo Herrera

One of the industry sectors with the largest revenue in the telecommunication field is the wireless communications field. Wireless operators compete for being the first to place their products in the market to obtain the highest revenues. Moreover, they try to offer products that fulfill the user demands in terms of price, battery life, and product quality. All these requirements must be also fulfilled by the designer of the MMIC (Microwave Monolithic Integrated Circuits) circuits that will be used in those wireless terminals, achieving a reliable design, with high performance, low cost, and if possible, in one or two foundry iterations so as to bring the product out to the market as soon as possible. Silicon based technologies are the lowest cost. The demand to use them is simply based on that fact, but their usage in these applications is limited by the ease of use for the designer, in particular, by the lack of adequate simulation models. These technologies don’t include some essential components for the design of RF circuits, which leads to measurement results quite different from those simulated. On the other hand, GaAs based technologies, more mature in the RF and microwave field, provide very accurate models, as well as additional tools to verify the design reliability (yield and sensitivity analysis), allowing good results often with only one foundry iteration. The deep study of the problems presented when designing Si-based RF circuits will convince the reader of the need to use special tools as electromagnetic simulation or coo simulation to prevent it. The chapter provides different simulation techniques that help the designer to obtain better designs with a lower cost, as foundry iterations are reduced.


Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-22 ◽  
Author(s):  
Airan Li ◽  
Chenguang Fu ◽  
Xinbing Zhao ◽  
Tiejun Zhu

Since the first successful implementation of n-type doping, low-cost Mg3Sb2-xBix alloys have been rapidly developed as excellent thermoelectric materials in recent years. An average figure of merit zT above unity over the temperature range 300–700 K makes this new system become a promising alternative to the commercially used n-type Bi2Te3-xSex alloys for either refrigeration or low-grade heat power generation near room temperature. In this review, with the structure-property-application relationship as the mainline, we first discuss how the crystallographic, electronic, and phononic structures lay the foundation of the high thermoelectric performance. Then, optimization strategies, including the physical aspects of band engineering with Sb/Bi alloying and carrier scattering mechanism with grain boundary modification and the chemical aspects of Mg defects and aliovalent doping, are extensively reviewed. Mainstream directions targeting the improvement of zT near room temperature are outlined. Finally, device applications and related engineering issues are discussed. We hope this review could help to promote the understanding and future developments of low-cost Mg3Sb2-xBix alloys for practical thermoelectric applications.


2008 ◽  
Vol 1116 ◽  
Author(s):  
Mohammod Aminuzzaman ◽  
Akira Watanabe ◽  
Tokuji Miyashita

AbstractRecent years have witnessed an explosion of interest in the application of polymers as the substrates for various electronic and display devices. The advantages of polymers are their mechanical flexibility, light weight, enhanced durability, roll-to-roll fabrication and low cost compared with rigid materials (such as silicon and glass). Hybrid polymers have drawn great attention because they offer the opportunity to prepare high-performance multifunctional advanced materials through the combination of properties of organic and inorganic segments. Recently, a new approach to construction of nanohybrid materials based on polyhedral oligomeric silsesquioxne (POSS) as an inorganic moiety has attracted a lot of interest. Double-decker-shaped silsesquioxane (DDSQ) is a new family of silsesquioxane consisting of nanometer-sized Si-O-Si cage structure functionalized with a wide variety of organic groups. DDSQ-based hybrid polymer (Double-decker-shaped polysilsesquioxane, DDPSQ) possesses many fascinating properties such as high thermal stability, good mechanical properties, low dielectric constant, excellent transparency, excellent flexibility and so on. Due to these fascinating properties, DDPSQ can be used as a potential candidate substrate for various flexible electronic devices. For such applications drawing of conductive metal (Au, Cu, Ag) patterns on a DDPSQ substrate is required. Herein, we have described fabrication of Ag microwiring with submicron resolution on a DDPSQ film by laser direct writing. The line width of the Ag-wiring fabricated by this laser direct-write maskless technique can be controlled flexibly by changing the objective lens magnification and the focusing point. With an objective lens magnification 100x, Ag microwiring with a line width of about 5 μm has been achieved. The Ag-wiring shows an excellent adhesion to DDPSQ surface as evaluated by Schotch tape test. The resistivity of the Ag-wiring is determined to be 4.3 × 10-6 Ω cm ,which is comparable that of bulk Ag (1.6 × 10-6 Ω cm).


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