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    Item type:Publication,
    Switched Beam Multi-Element Circular Array Antenna Schemes for 2D Single-Anchor Indoor Positioning Applications
    (2021-01-01)
    Kawdungta, Rattiya
    ;
    Kawdungta, Supakit
    ;
    Torrungrueng, Danai
    ;
    Phongcharoenpanich, Chuwong
    This research investigates four switched-beam multi-element circular array antenna schemes operating at 2.4-2.5 GHz for two-dimensional (2D) single-anchor indoor positioning applications. The realization of the proposed antenna schemes involved two evolutionary stages: rectangular microstrip antenna with dielectric superstrate (i.e., element) and multi-element circular array antenna with radio frequency (RF) switch network. The number of elements of circular array antennas was varied between 4, 5, 6, and 8 elements. Multiple signal classification (MUSIC) algorithm was used to determine the direction of incoming signal and Friis transmission equation to estimate the transmission distance. Simulations were carried out, and results showed that the rectangular microstrip antenna with dielectric superstrate (one single element) achieved impedance matching (vert S-{11}vert < -10,,text {dB}) in the frequency range of 2.4-2.5 GHz, with unidirectional radiation pattern and 6.65 dBi antenna gain. In addition, four-, five-, six-, and eight-element circular array antenna prototypes were fabricated and experiments carried out in an indoor environment with two, three, and four incoming signals. The experimental results indicated that the eight-element circular array antenna could be deployed to reliably determine signal direction and distance, particularly for indoor localization with two incoming signals. The novelty of this work lies in the potential use of switched-beam multi-element circular array antenna schemes in place of conventional adaptive array antennas for 2D indoor localization. Compared with the conventional adaptive array antennas, the proposed multi-element circular array antenna schemes are relatively low-cost and easy to fabricate.
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    Item type:Publication,
    Realization of switched-beam metamaterial-inspired microstrip antenna
    (2017-04-19)
    Kawdungta, Supakit
    ;
    Phongcharoenpanich, Chuwong
    This research has proposed the enhancement technique of the antenna gain by using a superstrate of metamaterial (MTM). It is deployed with a switchable beam microstrip antenna with double parasitic patches, in which two PIN diodes. Simulations and experimental were carried out for the proposed switchable beam microstrip antenna and the proposed antenna with the superstrate of MTM. The simulation and experimental results are in good agreement and it is a good impedance matching (S<inf>11</inf><-10dB) along the operating frequency (2.4-2.5 GHz). The average measured gain is 7dBi with the unidirectional radiation pattern along the operating frequency. The proposed switchable antennas with and without the superstrate of MTM are operable in the 2.4-2.5GHz WLAN system and switchable in three directions of xy-plane.