Citation

Md Jizat, Noorlindawaty (2023) Compact multi-layer Butler Matrix for 5G communications. PhD thesis, Multimedia University.

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Abstract

Due to an unprecedented demand for mobile data, the lower frequency spectrum has become congested, therefore high frequency in mmWave attracts research interest. In Malaysia, the Malaysian Communications and Multimedia Commission (MCMC) introduces Priority 1 bands for 5G, covering frequencies between 26 GHz and 28 GHz. In the industrial perspective, contemporary and spacelimited industrial wireless beamforming for Internet of Things (IoT) devices, mobile devices, sensor networks, base station, satellite communications, and automotive communications require a compact size structure. Beamforming is identified as a system which provide high capacity, improve network coverage, and reduce the interference by concentrates the signal, and at the same time eliminates the interference signals. One of the most preferred beamforming is the Butler Matrix because of its simplicity, ease of implementation, low cost, and low power. Although using the single layer Butler Matrix produce high gain, low profile structures and increases the signalto-noise ratio, the design structure has limitations including bulky size and high isolation due to the crossover structure. The crossover elements need to be carefully designed with high isolation to maintain the reflection and improve losses. Thus, a multi-layer technique has been introduced to simplify and circumvent the crossover elements. Nevertheless, the multi-layer made the Butler Matrix size larger due to the amplitude and phase compensation from the additional elements. The designs have complex fabrication and high cost. In the proposed research project, a reduced and compact Butler Matrix structure at 28 GHz is achieved using a via-hole technique. The NPC-F220A from Nippon Pillar Packing Co. Ltd., a substrate with low-loss tangent and low dielectric constant is used. The design features the via-hole structure where the signal is transitioned from one layer to another. The compact size of the Butler Matrix is obtained from an overlapping branch-line couplers which are arranged side by side on the different substrates and in the folded configuration. In this structure, no crossover and no phase shifter are used, where the functionalities are included in the via-hole and the design achieve up to 82.66 % size reduction in comparison with the conventional design at 28 GHz, using the same substrate material without having to compromise the performance. The proposed technique can be used in the beamforming system with a larger matrix to satisfy the 5G wireless communication at 28 GHz.

Item Type:	Thesis (PhD)
Additional Information:	Call No.: TK5102.9 .N66 2023
Uncontrolled Keywords:	Beamforming (Signal processing)
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK5101-6720 Telecommunication. Including telegraphy, telephone, radio, radar, television
Divisions:	Faculty of Engineering (FOE)
Depositing User:	Ms Nurul Iqtiani Ahmad
Date Deposited:	01 Oct 2025 07:08
Last Modified:	01 Oct 2025 07:08
URII:	http://shdl.mmu.edu.my/id/eprint/14648

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