Date Approved

8-17-2026

Graduate Degree Type

Thesis

Degree Name

Engineering (M.S.E.)

Degree Program

School of Engineering

First Advisor

Atilla Ozgur Cakmak

Academic Year

2025/2026

Abstract

Antennas are a critical component of unmanned aerial vehicle (UAV) communication systems where compact size, light weight, and reliable operation across multiple frequency bands are critical. While microstrip patch antennas are attractive for UAV applications due to their low profile, low cost, and ease of fabrication, they are often limited by narrow bandwidth and fixed-frequency operation. To address these limitations, this thesis investigates a mechanically and electrically reconfigurable dual-stacked patch antenna fabricated using additive manufacturing techniques.

The proposed antenna consists of a slotted driven patch operating near 2.5 GHz with a second resonant mode near 5 GHz. A parasitic patch is placed above the driven patch to couple with its 5 GHz resonant mode. Mechanical frequency tuning is achieved by varying the air-gap height between the stacked patches, while electrical frequency tuning is achieved by implementing a PIN diode across a slot in the driven patch separating the inner and outer regions. Through altering the electromagnetic coupling between the stacked resonators and modifying the surface current path of the driven resonator, the antenna is capable of real-time frequency reconfiguration. The effects of air-gap variation and PIN diode switching on coupling behavior and antenna performance are characterized through electromagnetic simulations combined with experimental measurements.

Electrical reconfiguration allows the final antenna to switch between discrete resonant frequencies near 1.95 GHz, 2.2 GHz, and 2.45 GHz in the lower band, and near 4.88 GHz, 5.00 GHz, and 5.30 GHz in the upper band. Mechanical air-gap variation continuously tunes the upper-band resonances, and when combined with PIN diode switching, the hybrid antenna achieves reconfigurable upper-band operation spanning approximately 4.47-5.43 GHz while maintaining peak realized gains above 9 dBi in both operating bands. These results show that combining adjustable air-gap variation with PIN diode switching provides an effective approach for real-time frequency reconfiguration while maintaining a lightweight, low-cost, and rapidly manufacturable antenna structure. The mechanical and electrical tuning mechanisms can be controlled independently or simultaneously, providing complementary frequency reconfiguration. These findings reveal the potential of additively manufactured reconfigurable antennas for UAV and other adaptive RF applications.

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