Behavioral Model and Predistortion Algorithm to Mitigate Interpulse Instabilities Induced by Gallium Nitride Power Amplifiers in Multifunction Radars

The incorporation of Gallium Nitride (GaN) Power Amplifiers (PAs) into future high power aperture radar systems is certain; however, the introduction of this technology into multifunction radar systems will present new challenges to radar engineers. This dissertation describes a broad investigation into amplitude and phase transients produced by GaN PAs when they are excited with multifunction radar waveforms. These transients are the result of self-heating electrothermal memory effects and are manifested as interpulse instabilities that can negatively impact the coherent processing of multiple pulses. A behavioral model based on a Foster network topology has been developed to replicate the measured amplitude and phase transients accurately. This model has been used to develop a digital predistortion technique that successfully mitigates the impact of the transients. The Moving Target Indicator (MTI) Improvement Factor and the Root Mean Square (RMS) Pulse-to-Pulse Stability are used as metrics to assess the impact of the transients on radar system performance and to test the effectiveness of a novel digital predistortion concept.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Electrical Engineering

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2017

Author dc:creator

• Tua-Martinez, Carlos Gustavo

Chairs dc:contributor.committeechair

• Pratt, Timothy J.
• Zaghloul, Amir I.

Committee members dc:contributor.committeemember

• Silva, Luiz A.
• Mullins, Donald E.
• Buehrer, R. Michael
• Foreman, Terry L.

• III-V semiconductors
• gallium compounds
• mean square error methods
• power amplifiers
• synthetic aperture radar
• Foster network topology
• GaN NMIC
• GaN power amplifiers
• amplitude transients
• behavioral modelling
• digital predistortion technique
• gallium nitride

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:9391

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/74445