Date of Award
Master of Science (MS)
Adrian Del Maestro
The increased use of internet of things (IoT) devices will result in them being deployed
in a wide variety of environments and therefore warrant antenna systems that can be
adapted to improve link performance. Flexible communication technologies allow for
increased throughput, reliability, and improved efficiency in wireless channels. This
can be accomplished by implementing phased array antennas, among others. Phased
arrays create a beam that can be steered electronically, but are expensive to implement
given the many phase precise hardware components that need to be adjustable. A
software defined radio approach to beamforming can reduce this complexity for each
array adaptation, if made in software.
This thesis leverages software defined radio (SDR) for the purpose of phase measurements
and beamforming. A phase measurement system was created in GNU
Radio to determine phase differences between SDRs. This algorithm was tested on
a direction-finding system measuring the angle of arrival of a moving transmitter.
In addition, transmit beamforming was implemented via SDR on a tripolar array
and a four-element patch antenna array. Through simulation, the tripolar array has
an 3 dB improvement in gain over a single monopole antenna in azimuth. The
measured antenna patterns did not match the simulation, but the reconfigurability
of the SDR platform provided the ability to correct the nonidealities in the physical
antenna. The azimuth test results show that beamsteering can be accomplished with
a median power increase of 3 dB over the omnidirectional beamsteering case. The
patch antenna array was tested by simulating a Butler matrix, a beamforming network
typically implemented in hardware. The array pattern had a 3 dB beamwidth
of 22° in simulation and 20° through testing, with a maximum steering error of
3° across the four Butler cases. The presented validation of the phase measurement
and beamforming systems is promising for future work in the realm of beamforming
via software defined radio.
Number of Pages
Fennelly, Evan, "The Utilization of Software Defined Radios for Adaptive, Phased Array Antenna Systems" (2020). Graduate College Dissertations and Theses. 1299.