Design of Reconfigurable Antennas for Multiband Radios

Ghaffar, Adnan
Li, Xue Jun
Seet, Boon-Chong
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Doctor of Philosophy
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Auckland University of Technology

In recent years, telecommunication technologies have witnessed exponential growth, especially in cellular communications and wireless sensor networks. To meet the demand of increasing transmission capacity, it is necessary to improve the signal-to-noise ratio of cellular communication channels and enable multiple frequency band operations. It is difficult to design a mobile device with multi-standard antennas.

Passive antennas have reached their limit, and the use of a frequency reconfigurable antenna to extend operational bandwidth is a promising solution. A reconfigurable antenna can be considered as one of the key elements in future wireless communication transceivers. By using reconfigurable antennas, the total antenna volume can be reused, thus leading to a compact system design.

Due to advancements in modern communication systems, mobile devices are becoming more compact. Motivated by this requirement, we propose a new design for compact reconfigurable antennas. These antennas operate in different bands and show good agreement results. A novel dual-band reconfigurable antenna with horizontal and vertical polarization was demonstrated. Its frequency and polarization reconfigurability have useful applications in tracking, sending and radar, etc. The current distribution and mathematical analysis of different modes justify the proposed concept.

Compact size along with the multi-band functionality is the great need of the current electronic and communication industry. For this purpose, different novel frequency reconfigurable monopole antennas are proposed. One antenna offers a wideband mode of 3-8GHz along with narrow bands at various frequencies of 2.1 GHz, 2.25 GHz, 2.45 GHz, 3.3 GHz, 3.5 GHz, and 8 GHz. Other antennas are proposed for 5G sub-6-GHz band, which make it a suitable candidate for the 2.1 GHz 4G-LTE band, 2.45 GHz ISM band, 5G-sub-6-GHz band and S-band satellite applications.

Flexible antennas have gained much attention in the wearable electronics industry. To cover this, a hybrid frequency and pattern reconfigurable antenna is presented. The frequency of the proposed antenna can be shifted from 2.1 GHz to 1.8 GHz by switching the state of both diodes in OFF and ON-state, respectively. For the ISM band applications, another capacitor-loaded DGS flexible antenna is explored. The strong agreement between simulated and measured results for both conformal and non-conformal conditions makes the proposed work a promising candidate for the applications operating in 3G, 4G, LTE, GSM, and ISM bands.

Reconfigurable antenna , PIN diode , Flexible antenna , Multiband application
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