Abstract

The motivation for this work comes from the increased demand for short range high frequency data communication within and between integrated circuit (IC) chips. The use of wireless interconnects introduces flexibility to the circuit design, reduces power consumption and production costs, since the antennas can be integrated into a standard CMOS process. These findings have been well noted in literature. In addition, wireless interconnects operating in the mm-wave frequency range, at 60GHz, allow for a high data rate of over 1Gb/s for short range of transmissions. The drawback of wireless interconnects operating at high frequencies is the distortion in the radiation pattern caused by the silicon substrate inherent in a standard CMOS process. The high permittivity and a low resistivity of silicon in a CMOS process introduce radiation losses. These losses distort the radiating signal, reducing the directive gain and the antenna efficiency.

The objective of the work is to enhance antenna gain and improve the radiation efficiency with the use of a Jerusalem-Cross Artificial Magnetic Conductor (AMC). The Jerusalem Cross AMC can mitigate the effects of the silicon and improve data transmission for inter-Chip data communications. A Yagi antenna was optimized for end-fire radiation in the plane of the chip. It’s performance was studied when it was placed in the center and along the front edge of a standard 10mm by 10mm chip, with the AMC layer extending only below the feed system, Partial AMC, and then compared when it extends under the entire antenna, Full AMC. To examine the transmission characteristics two chips were placed facing one another, on an FR4 slab, with the antennas first placed at the front edges of both chips then in the center of their respective chips. For direct comparison a third configuration was made with one antenna in the center of a chip and the other at the edge of the second chip. The performance of this inter-chip transmission was examined with the three AMC layer configurations: No AMC, Partial AMC, and Full AMC. All simulations were performed using ANSYS HFSS.

The results show that the partial AMC improves the performance of the Yagi antenna when it was placed at the front edge of the chip facing out. The directive gain (Endfire direction) with the partial AMC was increased by 0.79 dB or 46% when compared to the antenna without an AMC. The radiation efficiency increased from 39% to 45%. When examining the antenna in the center of the larger substrate the full AMC layer improved performance. The directive gain increased by 0.93 dB or 5%. The full AMC layer improved the directional gain of the antenna in the center of the chip because it is more susceptible to the effects of the silicon substrate. Whereas when placed at the edge of the chip the antenna is mainly radiating in free space and not as influenced by the losses due to the silicon. Which is why the partial AMC improves radiation performance for the antenna placed at the edge of the chip. This is more clearly shown by the transmission results. When both antennas were placed at the front edges of their respective chips with full AMC layers the gain increased by 11% and the radiation efficiency increases by 12%; while when both antennas are placed in the center the directive gain increases by 26% and the radiation efficiency increases by only 2%. In the model with one antenna at the front edge of the first chip and the other antenna in the center of the second chip the full AMC improved the directive gain by 12% and 29% respectively. Both results show that the full AMC has a positive effect on the directive gain of the antenna, especially when placed in the center of the substrate.

Library of Congress Subject Headings

Interconnects (Integrated circuit technology); Networks on a chip--Design and construction; Antennas (Electronics--Design and construction; Metamaterials

Publication Date

2020

Document Type

Thesis

Student Type

Graduate

Degree Name

Electrical Engineering (MS)

Department, Program, or Center

Electrical Engineering (KGCOE)

Advisor

Jayanti Venkataraman

Advisor/Committee Member

Amlan Ganguly

Advisor/Committee Member

Panos Markopoulos

Campus

RIT – Main Campus

Plan Codes

EEEE-MS

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