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Smart antenna technologies have revolutionized communication systems, particularly in the context of the IoT (Internet of Things) applications. This research introduces an innovative approach to smart antenna technology by proposing a modified polygonal layout which utilizes dynamic beam direction adjustment based on user availability and the Direction of Arrival (DOA). CST Microwave Studio is used for the initial antenna design and the most efficient version is fabricated for experimental validation. Parasitic elements, slots and the defected ground structure technique are used to create a fully directional antenna capable of forming a beam that covers an acute angle. By appropriately arranging multiple identical patch antenna elements, a configuration is established that allows signals to be transmitted in all directions, ensuring full 360 degree coverage for desired users. Several polygonal antenna models are developed and tested experimentally to identify the most optimized configuration in the ISM band (Industrial, Scientific and Medical band) operating in 2.4 to 2.5 GHz range. An algorithm is also developed to steer beam through a control circuit consisting of radio transceiver modules and microcontrollers. This algorithm combines adaptive beamforming, feedback based beam steering and automatic retransmission control (ARQ) to optimize signal transmission to targeted users. User location is tracked by measuring parameter like the received signal strength indicator (RSSI) which allows the scheme to estimate the user's position relative to the antenna array.
The proposed smart antenna array design is then validated experimentally to demonstrate significant improvements in both performance and reliability. The antenna performance is evaluated based on radiation efficiency, power efficiency, signal quality, constant signal strength, Quality of Service (QoS) and its ability to increase communication capacity while eliminating dead zones. The optimized result of the proposed antenna design demonstrates a gain of 6.38 dBi, a return loss of -26.2 dB, VSWR of 1.01 with beamwidth of 49.3°. These results indicate a reshaped and strongly directional radiation pattern. In the proposed polygonal antenna array arrangement, the dead zone is minimized to only 3.33%, ensuring near-complete coverage and minimizing interference with radiation efficiency of 89.3% and electrical power efficiency of 74.6%. The proposed scheme offers significant improvements over traditional methods by enabling adaptive beamforming within a single sector and facilitating interference free sector-to-sector transitions, while efficiently radiating power toward the intended user without signal interruption. This thesis highlights the potentiality of the proposed smart antenna system to meet the growing demand for efficient, reliable and uninterruptible communication solutions particularly in the context next generation smart antenna technology. |
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