J.C. Simons, J.C. Slater. / "May 31, 1951" / Bibliography: p. 3. / Army Signal Corps Contract No. W36-039-sc-32037 Project No. 102B. Dept. of the Army Project No. 3-99 10-022.

L.J. Chu. / "May 1, 1948." / Includes bibliographical references. / Army Signal Corps Contract No. W-36-039 sc-32037.

by L.J. Chu. / "June 3, 1947." / Army Signal Corps Contract No. W-36-039 sc-32037

Thesis (M.S.)--Ohio State University, 1984. / Includes bibliographical references (leaves 118-119). Available online via OhioLINK's ETD Center

As the wireless technology maturing, the wireless systems are evolving towards the development of new applications with broad band access and also the higher data rate. This necessity will give rise to the new WLAN standards as well as minimizing the cost, high QoS and security features of the wireless setup. It will also lift the trends towards the miniaturizination of hand-held devices, high data rates, higher bandwidth and robust performance on present and future WLAN standards, IEEE 802.11a/ 802.11b and 802.11g. A Coplanar waveguide (CPW) fed compact and optimized monopole antenna printed on a substrate of Rogers TMM 4 is studied in this paper. The proposed antenna is fabricated and measured to verify the response for Wireless applications. It is broadband antenna which has dual band characristics and can operate simultaneously both at 2.4 GHz and 5.2 GHz frequency bands for Wireless Local Area Network (WLAN) application. Furthermore it is studied in detail that how the antenna performance and operation is affected by changing the parameters of antenna. The antenna has satisfactory return loss characteristics in desired range of frequency. The antenna has acceptable gain and directivity. The proposed antenna has a return loss value S11 < -10 dB. The impedance bandwidth of antenna is high and the radiation pattern of antenna is omnidirectinal which fulfill the WLAN requirements.

Spectrum sensing plays a key role for radio resource awareness in cognitive radio. To enhance the capabilities of cognitive radio nodes, exploiting the spatial resource in addition to frequency and time re-sources seems reasonable. This thesis investigates the possibility of exploiting the spatial resources during sensing and transmission using sector antennas which is also termed as directional spectrum sensing and transmission. The measured radiation patterns from fabricated antenna and radiation patterns obtained from analytical expressions representing circular array of dipole are used for performance analysis. A ray tracer tool is used for modelling the urban environment as well as for wave propagation simulation. The power angular profiles obtained at different locations are further processed in MATLAB using measured and analytical radiation patterns to evaluate the performance in terms of spatial opportunity and detection of weak primary signals. The results show that exploiting the spatial dimension in spectrum sensing using sector antennas increase the opportunities for secondary communication and also improves the detection of primary signals as compared with an omni-directional antenna. Additionally, directional sensing and trans-mission are studied together using analytical radiation patterns. The results show that the service probability as well as range of communica-tion increases with an increase in number of sectors but saturation is achieved when nine sectors are used, indicating that six sectors antenna is the optimum choice for exploring the spatial resource in cognitive radio in a typical multipath urban environment.

Various compact and packaging-adaptive antennas have been designed for practical wireless communications systems such as global system of mobile communications (GSM), Bluetooth Industrial-Scientific-Medical (ISM) devices, IEEE802.11a WLAN, and Local Multipoint Distribution Systems (LMDS) applications. First, compact stacked patch antennas using LTCC multilayer technology have been presented. A set of design rules is established for the purpose of designing optimized bandwidth compact antennas on LTCC multilayer substrates. To verify its effectiveness, the proposed design rules are applied to three emerging wireless bands. The return loss and the impedance bandwidth are optimized for all three bands. A maximum bandwidth of 7% can be achieved for an antenna operating in the LMDS band. Furthermore, folded shorted patch antennas (SPAs) are designed to significantly reduce the resonant frequency of a standard patch antenna. The design methodology of this structure starts with a conventional half-wave and through a series of procedures, evolves into a smaller, lambda/8 wavelength resonant length structure. Upon varying the height of the lower patch, the resonant length can be reduced to lambda/16. A comparison between a folded SPA and a standard SPA validates the folding technique proposed in this document. The folded SPA is applied to the 2.4 GHz ISM band. The measured results are in good agreement with simulated results. This antenna can be implemented into 3D packages using multilayer laminates such as LTCC or LCP.

The objective of this dissertation is to design new architectures for multiple antenna wireless communication systems operating in a mobile-to-mobile environment and to develop a theoretical framework according to which these systems can be analyzed. Recent information theory has demonstrated that the wireless channel can support enormous capacity if the multipath is properly exploited by using multiple antennas. Future communication systems will likely evolve into a variety of combinations encompassing mobile-to-mobile and mobile-to-fixed-station communications. Therefore, we explore the use of multiple antennas for mobile-to-mobile communications. Based on the characteristics of mobile-to-mobile radio channels, we propose new architectures that deploy directional antennas for multiple antenna systems operating in a mobile-to-mobile environment. The first architecture consists of multiple input and multiple output (MIMO) systems with directional antennas, which have good spatial correlation properties, and provides higher capacities than conventional systems without requiring a rich scattering environment. The second one consists of single input and multiple output (SIMO) systems with directional antennas, which improve signal-to-interference-plus-noise ratio (SINR) over conventional systems. We also propose a new combining scheme to select the outputs of optimal combing (SOOC) in this architecture. Optimal combining (OC) is the key technique for multiple antenna systems to suppress interference and mitigate the fading effects. Based on the complex random matrix theory, we develop an analytical framework for the performance analysis of OC. We derive several important closed-form solutions such as the moment generating function (MGF) and the joint eigenvalue distributions of SINR with arbitrary-power interferers and thermal noise. We also analyze the effects of spatial correlations on MIMO OC systems with arbitrary-power interferers in an interference environment. Our novel multiple antenna architectures and the theoretical framework according to which they can be analyzed would provide other researchers with useful tools to analyze and develop future MIMO systems.

Radio Frequency IDentification (RFID) Tags have become quite widespread in many services in the industry such as access control, parcel and document tracking, distribution logistics, automotive systems, and livestock or pet tracking. In these applications, a wireless communication link is provided between a remote transponder (antenna and integrated circuit (IC)) and an interrogator or reader. A suitable antenna for these tags must have low cost, low profile and especially small size whereas the bandwidth requirement (few kilohertz to megahertz) is less critical. In this document, methods to reduce tag size, the performance optimization of the tag by using novel antenna matching techniques for increased operational bandwidth and gain/radiation pattern/radiation efficiency improvement are introduced for 13.56 MHz HF and 915 MHz UHF RFID tags.In addition, an evaluation of an active 915 MHz UHF RFID field study for container tracking at the port of Savannah, GA is also presented.

In this thesis, an internal mobile phone antenna with a distributed matching circuit for eight-band LTE/WWAN operation is presented. By selecting proper dimensions of the distributed matching circuit, the bandwidth of the proposed antenna can be greatly enhanced. Good radiation characteristics are also obtained, and the proposed antenna occupies only 60 ¡Ñ 10 ¡Ñ 3 mm^3 and is very suitable for slim mobile phone applications. Effects of the human body including user¡¦s head and hand are also studied, and the SAR and HAC issues are simulated and analyzed in this thesis.