3-D Helical THz Antennas Directly on Semiconductor Substrates
The fabrication of 3-D helical antennas, designed
for the low THz frequency range, will allow for the efficient
transmission and reception of circularly polarized radiation.
In this project a novel method of fabricating helical
antennas, singular and arrayed, for the low THz (0.1THz to
2.7THz) frequency range is studied. The
THz antenna structures are fabricated by using Laser Chemical
Vapor Deposition (LCVD) to form fibers that can be grown into
complex three-dimensional structures directly on semiconductor
substrates. By focusing the laser through a diffractive
optic, arrays of antennas can be fabricated at the same time.
THz radiation detection devices can be realized by combining
the LCVD antennas with MEMS micro-bolometers that convert
received THz radiation into a change in resistance.
Arrays of these antenna-bolometer pairs can be fabricated
on the same substrate to realize a THz imaging device. This
project was supported by SY Technologies.
Design of Smart Antennas Using Neural
Networks
The first problem addressed in this project
is the direction of arrival (DOA) estimation of mobile
users that are sending their messages to a phased array
antenna. A neural network was designed that was able to estimate
the directions of multiple sources that were accessing the
array antenna. In the second problem, another neural network
is used to find the optimal weights of an antenna
array that resulted in an array which successfully tracked
mobile users as they moved across the antenna view. The solutions
of these two problems using neural networks proved to be more
efficient than already existing approaches. This work has
been supported by AFOSR, Motorola, and STRICOM.
FDTD Analysis of Phased
Array Antennas
This work presents a new application of the
Finite Difference Time Domain (FDTD) method to the generalized
analysis of phased array antennas. The generality of
the FDTD method brings important advantages to the phased
array antenna analysis problem, allowing the modeling of complex
conductor and dielectric geometries with relative ease.
Additionally, a new broadband FDTD periodic boundary
condition was developed which allows the
array problem to be simplified to a periodic unit cell computational
domain. This hybrid frequency/time domain periodic boundary
condition enables solution of the periodic phased array problem
for arbitrary scan conditions in a broadband fashion.
The new method is also applied to stacked
phased array antennas built on photonic (Band-gap)
substrate materials to obtain more power and wider bandwidth.
This work is supported by Raytheon.
Design of a Low-Loss
Series-Fed Microstrip Array Antenna
This project involves the design and analysis
of a series-fed, low-loss, inverted microstrip array antenna,
operating at 1.413 GHz . . The array antenna is composed
of two sub arrays. Each sub array consists of an equal
number of microstrip patches all connected together through
a series microstrip line. The first element of each sub array
is coaxially fed but 180 degree out of phase. This approach
ensures a symmetric radiation pattern. The design approach,
is accomplished using the Method of Moments.
This work is supported by NASA.
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