Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 135-137). Also available via the Internet.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 161-164).

M.Ing. (Electrical & Electronic Engineering) / A new method is presented for significantly reducing the large number of complex computations associated with beamforming, -steering and adaption in large antenna arrays. The structure is based on linear interpolation over (L +1) array elements implying that the (L -1) antenna or sensor signals in-between are added with simple weights to the neighbouring antenna signals for beamforming and/or steering. If L is chosen to be a power of two, these simple weights become h t, i, etc. or multiples thereof. It is easily implemented on a microcomputer with shift operations and can be performed in reduced time compared to byte and word multiplications. The maximum value of L that can be used increases with decreasing mainlobe width. A problem that arises when performing beam steering on such an array is that the level of the sidelobes-more specifically the suppressed mainlobe images which are the result of the interpolation process-increase with increasing steering angle. The maximum.steering angle is determined by the constraints placed on the sidelobe level. To be able to steer wider than the maximum steering angle, it becomes necessary to apply complex interpolation to the array. Complex interpolation refers to the steering of the interpolator beam. The interpolation process reduces the number of weights. This results in a significant reduction of the number of computations associated with adaptive beamforming algorithms.

Internet of Things (IoT) is an emerging paradigm about building a massive internet to link billions of non-living things to make smart decisions for humans and improve their quality of life. For many of IoT devices, such as wireless sensor nodes dispersed in the environment, there is not much control over their placements or orientations. Thus, there is a need to develop orientation insensitive antennas that ensure reliable data transmission irrespective of devices’ positions or orientations. As billions of such IoT devices required in the future, a low-cost fabrication process suitable for mass manufacturing must be adapted. Antenna in package (AiP) concept is beneficial that the package is utilized to realize the antennas, not only saving space but also reducing the overall cost. For orientation insensitivity, antennas must be near isotropic and even have to maintain their radiation pattern for multi-bands or wide bandwidths in most applications. However, there is a dearth in the literature about design methodologies for near isotropic antennas, particularly for multi-bands near isotropic AiP designs. In addition, a near isotropic behavior is also important for polarization, particularly for CP antennas. To have simultaneous isotropy in radiation pattern and circular polarization is challenging. In the nut shell, this thesis presents theoretical models and derives conditions for wire AiP design for different specifications, single-band and dual-band near isotropic antennas, null free near isotropic antenna with wide CP coverage, and a full CP antenna with decent near isotropy (with very narrow null beam). The single-band AiP has only 5.05 dB gain variation at WiFi/BLE band and the dual-band AiP has a decent near isotropic radiation property and covers both GSM900 and GSM1800 bands. The theoretical model for null-free near isotropic antenna with wide CP coverage is presented with particle swarm optimization (PSO). The full CP antenna has a measured CP coverage of 70% with a small null in the radiation pattern. The results are promising and indicate that the conditions and methods proposed are useful for the future near isotropic AiP design. Also, this work provides designers flexibility to adjust the AiP design according to their own applications.

No description available.

Novel antennas attractive to fit in the internal space of a PDA (Personal Digital Assistant) for WLAN (Wireless Local Area Network) operations are presented in this dissertation. The proposed antennas have in common good impedance bandwidth (defined by 10 dB return loss), covering the dual-band WLAN operation in the 2.4/5.2 GHz bands. Two novel designs of foam-base surface-mount antennas are proposed in Chapters 2 and 3. Surface-mountable antennas, compared with ceramic antennas, are generally low cost in fabrication and rigid in nature. Low-profile and good dual-band operation of the proposed surface-mountable antennas can be observed in Chapters 2 and 3, and in addition, a few present-day WLAN bands at 5 GHz are covered in the operating bandwidths of the proposed foam-base surface-mountable shorted monopole antenna, shown in Chapter 3. Finally, in Chapter 4, a novel planar helical antenna printed on both surfaces of a dielectric substrate is demonstrated. This patent-pending helical antenna is very suitable to print and integrate on a circuit board of a PDA device for 2.4/5.2 GHz WLAN operation.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 109-118). Available also in a digital version from Dissertation Abstracts.

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No / This paper presents a physically compact, frequency tunable antenna design for use in mobile terminals. The full operating bandwidth is between 1750 MHz and 2400 MHz with good impedance match in the entire tuning range to meet the coverage requirements of the DCS, PCS, UMTS and WLAN bands . The antenna bandwidth is is realized by loading the embedded resonant slot of a PIFA, with a varactor diode, with an equivalent capacitance range of 0.5 pF to 2.5 pF.