Graduation Year

2015

Document Type

Thesis

Degree

M.S.E.E.

Degree Name

MS in Electrical Engineering (M.S.E.E.)

Degree Granting Department

Electrical Engineering

Major Professor

Thomas Weller, Ph.D.

Committee Member

Jing Wang, Ph.D.

Committee Member

Larry Dunleavy, Ph.D.

Keywords

3D Printing, high-pass low-pass phase shifter, switched line phase shifter, direct digital manufacturing, fused deposition modeling

Abstract

Digital RF phase shifters fabricated using additive manufacturing processes are presented and studied. The purpose is to explain the performance differences between phase shifters fabricated using additive manufacturing and those fabricated with conventional subtractive techniques. All phase shifters are designed to operate at a center frequency of 2.45 GHz with a 100 MHz bandwidth. The 1-bit 45° switched line phase shifters have an average insertion loss of 1.3 dB and a 220 mm2 footprint, while the 1-bit 180° high-pass low-pass phase shifters have an insertion loss 1.56 dB and a 180 mm2 footprint. The 4-bit high-pass low-pass, switched line hybrid phase shifters on the other hand show an average state insertion loss of 5.4 dB and have a 660 mm2 foot print. By carefully analyzing the performance of the various phase shifter designs it is shown that the limiting factors of additive manufacturing technology are the low conductivity of CB028 silver ink in comparison to copper, and the inability to print dielectrics with low surface roughness. Finally, parallel plate capacitors and a spiral inductor designed to be fabricated using additive manufacturing techniques are studied. This is done in order to better understand the advantages and disadvantages of such a design. By analyzing the component’s simulated performance it is shown that 3D printed capacitors and inductors are feasible as long as the capacitance or inductance values needed are low. Large value 3D printed components are impractical for RF applications due to their large size.

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