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Toward Load Bearing Reconfigurable Radio Frequency Antenna Devices Using Ultrasonic Additive Manufacturing

Wolcott, Paul Joseph

Abstract Details

2012, Master of Science, Ohio State University, Mechanical Engineering.

Ultrasonic additive manufacturing (UAM) is a low temperature, solid-state manufacturing process that enables the creation of layered solid metal structures with designed anisotropies and embedded materials. As a low temperature process, UAM enables the creation of composites using smart materials or other components that would otherwise be destroyed in fusion-type processes. The process uses ultrasonic energy to bond metallic foils to one another under an applied load through a scrubbing action at the foil interface. This scrubbing action creates the nascent surfaces necessary for solid state bonding. To be able to take full advantage of the UAM process, the mechanical properties of composites made therein must be fully characterized. In this study, scanning electron microscopy is utilized to investigate the bonding behavior at the foil interface of samples tested in tension. Findings show a relationship between the amount of ductile fracture and the strength of UAM samples. In addition, fatigue testing was conducted on UAM Al samples to determine their lifetime under cyclic loading conditions. The results indicate a flat S-N behavior between the loading and number of cycles to failure. This indicates that lifetime prediction of UAM samples is difficult at this time due to the inconsistent bonding at the interface. It is theorized that the unbonded areas at the interfaces grow into one another and eventually lead to fast fracture.

Along with the developments made in understanding UAM mechanical properties, the design and manufacture of reconfigurable antennas was conducted with an eventual goal of developing a structural reconfigurable antenna using UAM. The reconfigurable antenna design concept uses shape memory alloy switches to electrically connect to an antenna structure to create discrete shifts in the antenna natural frequency. Using this design concept, three sets of shape memory alloy switches were made to connect with three different antenna structures. The first switch proved the concept of reconfiguration with a monopole antenna, yielding a frequency shift of 85 MHz. The second switch design used smaller dimensions to work in conjunction with a microstrip line, an antenna-like device. With this switch, the transmission of a radio frequency signal was tested to confirm the operation of the switches in both the on and off positions. This setup showed that the metallization of the antenna could effectively change the natural frequency while maintaining significant signal strength. A final set of switches was made for implementation into a planar antenna structure. The planar antenna was designed and constructed with free segments within the structure where switches are connected create reconfiguration. This antenna provides tunable frequency shifts from 2.43 GHz with no switches connected to 2.25 GHz when both switches are connected while maintaining a high gain and repeatable radiation pattern.

Marcelo Dapino, Ph.D. (Advisor)
S. Suresh Babu, Ph.D. (Committee Member)
105 p.

Recommended Citations

Citations

  • Wolcott, P. J. (2012). Toward Load Bearing Reconfigurable Radio Frequency Antenna Devices Using Ultrasonic Additive Manufacturing [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338385633

    APA Style (7th edition)

  • Wolcott, Paul. Toward Load Bearing Reconfigurable Radio Frequency Antenna Devices Using Ultrasonic Additive Manufacturing. 2012. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1338385633.

    MLA Style (8th edition)

  • Wolcott, Paul. "Toward Load Bearing Reconfigurable Radio Frequency Antenna Devices Using Ultrasonic Additive Manufacturing." Master's thesis, Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338385633

    Chicago Manual of Style (17th edition)