Document Type



Doctor of Philosophy (PhD)


Electrical and Computer Engineering

First Advisor's Name

Dr Elias A Alwan

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Dr. Ahmed Ibrahim Mohamed

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Dr. Kemal Akkaya

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Dr Daniela Radu

Fourth Advisor's Committee Title

Committee Member


Dual-band antennas, antenna arrays, millimeter-wave antennas, RF front-end, higher order modes

Date of Defense



In recent years, vehicle crashes have taken nearly 38,000 lives per year in the U.S., according to the National Highway Traffic Safety Administration (NHTSA). To improve the safety of the drivers, the Federal Communications Commission (FCC) has allocated the Dedicated Short Range Communications (DSRC) frequency spectrum, viz. 5.850-5.925 GHz band for vehicular communication. However, the limited bandwidth at the DSRC band provided an impetus to explore the millimeter-wave (mm-wave) spectrum that promises much higher data rates. Nevertheless, operating in the mm-wave spectrum comes with the expense of high path loss and attenuation due to rain.

To overcome the abovementioned problems, a system that operates at both the microwave and mm-wave frequencies is of uttermost importance to support the next-generation transportation system. Notably, implementing a single platform for dual-band operation implies a reduction in the number of radios on a single-vehicle. In this dissertation, we present a communication system that consists of a novel dual-band antenna array, dual-band RF front-end, and a low-loss 3D antenna-in-package (AiP) integration. Notably, the receiver front-end has the capabilities to switch between the DSRC to the mm-wave bands based on the availability of the channel, especially during severe weather conditions.

This dissertation aims to design two dual-band antennas with high gain operating at 5.9 GHz DSRC and 28 GHz 5G mm-wave bands. At first, a shared aperture array with 28 GHz series fed array placed between the 5.9 GHz differentially fed patch array was fabricated. The lower band array acts as a parasitic element for the upper band array resulting in ~1.44 dBi gain improvement at 28 GHz. Next, we fabricated a low-profile single feed patch antenna operating at DSRC and 5G mm-wave. Specifically, the implemented antenna offers high gain at both the bands and rejects higher-order harmonics in between the bands. These antennas are designed on a single-layer substrate and fabricated using a low-cost printed circuit board (PCB) technique.

This dissertation also investigated the presence of mutual coupling between the antenna arrays and presented a coupling reduction technique using an open stub meandered bandstop filter. This technique offers high isolation, low envelope correlation coefficient (ECC), and high diversity gain. Further, a 60 GHz antenna array was designed with low-loss and high efficiency to interconnect heterogeneously stacked integrated circuits. The implemented array provides +450 scanning and low mutual coupling between the antenna elements.

This dissertation also presents the design and indoor experimental setup of the dual-band RF front end using Commercial-off-the-shelf (COTS) components. Specifically, noise analysis, linearity, and link budget of the dual-band front end were conducted with experimental verification.





Previously Published In

S. R. Govindarajulu, R. Hokayem, M. N. A. Tarek, M. R. Guerra and E. A. Alwan, "Low Profile Dual-Band Shared Aperture Array for Vehicle-to-Vehicle Communication," in IEEE Access, vol. 9, pp. 147082-147090, 2021, doi: 10.1109/ACCESS.2021.3124311.

S. R. Govindarajulu, R. Hokayem and E. A. Alwan, "A 60 GHz Millimeter-Wave Antenna Array for 3D Antenna-in-Package Applications," in IEEE Access, vol. 9, pp. 143307-143314, 2021, doi: 10.1109/ACCESS.2021.3121320.

S. Adamshick, S. R. Govindarajulu and E. A. Alwan, "A Novel Low Loss 3D System-in-Package Approach for 60GHz Antenna on Chip Applications," 2020 IEEE 63rd International Midwest Symposium on Circuits and Systems (MWSCAS), 2020, pp. 537-540, doi: 10.1109/MWSCAS48704.2020.9184617.

S. R. Govindarajulu, A. Jenkel, R. Hokayem and E. A. Alwan, "Mutual Coupling Suppression in Antenna Arrays Using Meandered Open Stub Filtering Technique," in IEEE Open Journal of Antennas and Propagation, vol. 1, pp. 379-386, 2020, doi: 10.1109/OJAP.2020.3010153.

S. R. Govindarajulu and E. A. Alwan, "Range Optimization for DSRC and 5G Millimeter-Wave Vehicle-to-Vehicle Communication Link," 2019 International Workshop on Antenna Technology (iWAT), 2019, pp. 228-230, doi: 10.1109/IWAT.2019.8730597.

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