A Miniaturized Metamaterial-Based Dual-Band 4×4 Butler Matrix With Enhanced Frequency Ratio for Sub-6 GHz 5G Applications


Shallah, Abdulkadir Bello and Zubir, Farid and Rahim, Mohamad Kamal A. and Md. Jizat, Noorlindawaty and Basit, Abdul and Assaad, Maher and Majid, Huda A. (2024) A Miniaturized Metamaterial-Based Dual-Band 4×4 Butler Matrix With Enhanced Frequency Ratio for Sub-6 GHz 5G Applications. IEEE Access, 12. pp. 32320-32333. ISSN 2169-3536

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This paper introduces an innovative 4×4 dual-band Butler matrix (BM) characterized by compactness and an enhanced frequency ratio (K). The design employs meandered lines and an interdigital capacitor (IDC) unit-cell-based composite right/left-handed transmission-line (CRLH-TL) metamaterial (MTM) structure. The BM integrates compact dual-band 3 dB branch-line couplers (BLC), a 0 dB crossover, and dual-band ±45° phase shifters on a single Rogers RT5880 substrate having relative permittivity εr of 2.2 and thickness h of 0.787 mm. Simulations and measurement results demonstrate reflection and isolation coefficients exceeding −20 dB at all ports, with obtained insertion loss of −6±3 dB over the 0.7 GHz and 3.5 GHz frequency bands. The achieved output phase differences of ±45°, ±135°, ±135°, and ±45° at the designed frequencies indicate a maximum average phase tolerance of ±4.5° concerning the ideal values. Importantly, the BM’s overall dimensions are 143 mm ×186 mm, resulting in an impressive 78% size reduction compared to traditional T-shaped BM designs. The proposed configuration is designed and simulated using CST Microwave Studio, with the agreement between simulated and measured parameters highlighting design reliability and effectiveness. Additionally, a performance evaluation comparing the proposed BM with existing circuits reveals its suitability for sub-6 GHz 5G dual-band antenna array beamforming networks (BFN) due to its compact size and improved band ratio.

Item Type: Article
Uncontrolled Keywords: Branch-line coupler, butler matrix, composite right/left-handed, crossover, frequency ratio, metamaterials, sub-6 GHz, 5G.
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: 02 Apr 2024 00:13
Last Modified: 02 Apr 2024 00:13
URII: http://shdl.mmu.edu.my/id/eprint/12268


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