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Felix A Miranda

Publications and source records attributed to Felix A Miranda.

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

RF Characterization of a Photocurable PEDOT:PSS:PEGDA Conductive Biomaterial for 3D-Printing Implantable Antennas

In this work, we demonstrate photocurable PEDOT:PSS:PEGDA biomaterial as a promising candidate for intracorporeal 3D printing. Intracorporeal 3D printing offers a less invasive method which offer flexibility to tailor the form factor of printed structures. Previous work has demonstrated the feasibility of a robotic probe to 3D-print biological tissues intracorporeally via a minor incision. This same probe could also 3D-print implantable antennas as long as a suitable conductive material is identified in terms of conductivity, biocompatibility, and ability to cure at room/body temperature for safety purposes. We assess the frequency-dependent conductivity of this biomaterial and explore the Radio-Frequency (RF) performance of resulting antennas operating in free-space and inside tissue-emulating phantoms. Results show that PEDOT:PSS biomaterial with 21% and 30% PEGDA content exhibit a conductivity of ~10 4 S/m up to 5 GHz, suitable for wireless implants. Comparing the two, 21% PEGDA content exhibits poorer curing abilities, while 30% PEGDA exhibits slightly lower conductivity. Measurements for 2.4 GHz free-space dipoles conducted in an anechoic chamber reveal only ~0.8 dB and ~1 dB lower gain for PEDOT:PSS:21%PEGDA and PEDOT:PSS:30%PEGDA biomaterial, respectively, as compared to their copper counterpart. For a 5 mm-deep implanted patch antenna, these two biomaterials exhibit 3.05 dB and 3.84 dB higher transmission loss than copper, respectively. If deemed necessary, this performance degradation can be overcome by increasing the overall antenna size since the printing process is now minimally invasive and miniaturization requirements can be relaxed.

3D-printing↗
NASA NTRS2020

Microwave Power Detection With Voltage-Gated Graphene

Commercially available, chemical vapor deposition grown, graphene has been used to realizevoltage-gate tunable, microwave power detectors. Corbino disc structures with chrome/gold contacts havebeen fabricated on top of graphene deposited on P-type silicon substrates with silicon dioxide gate oxides.Devices of varying sizes were used to detect a 433.92 MHz signal. These test structures exhibited a peak power detection sensitivity of 3.25 mV/mW at 292 K and 5.43 mV/mW at 80 K. The improved graphene detectors exceed the sensitivity of previously reported graphene detectors, 0.86 mV/mW, as well as previously explored carbon nanotube bolometers, 0.36 mV/mW

Michael R. Gasper↗
NASA NTRS2003

Radio Frequency Telemetry System for Sensors and Actuators

The present invention discloses and teaches apparatus for combining Radio Frequency (RF) technology with novel micro-inductor antennas and signal processing circuits for RF telemetry of real time, measured data, from microelectromechanical system (MEMS) sensors, through electromagnetic coupling with a remote poweringheceiving device. Such technology has many applications, but is especially useful in the biomedical area.

Rainee N Simons↗
NASA NTRSDate not supplied

Self-Healing RF/Microwave Communications Circuits/Systems for NASA Missions—A Review

The success of current and future NASA missions relies in great part on the performance reliability and robustness of the communication circuits and systems of said missions. Some of the manifestations of reliability and robustness are comprised by properties such as graceful degradation, which provide redundancy and potentially longer life to the mission, and the ability to perform efficiently in harsh environments destinations such as Venus and the Jovian and Saturnian moons Europa and Enceladus, respectively. While several approaches have been considered or are currently underway to develop communications circuitry capable of performing in harsh environments, they lack the flexibility to enable reconfigurability to preserve functionality under adverse or contingency scenarios. This paper discusses some examples of self-healing RF/Microwave communications circuits and systems that could provide advantageous options in support of NASA missions.

self-healing↗