Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 116-123).

<p> The subject of this thesis is the design, fabrication and comparative testing of two prototype L-band ferrite digital latching phase shifters. One phaser is a variation of a design published by G.T. Roome and H.A. Hair, "Thin Ferrite Devices for Microwave Integrated Circuits", IEEE Trans. Microwave Theory Tech, vol. MTT-16 pp. 411-420, July 1968. The second design is original and is experimentally and theoretical compared to the first phaser. A comparative study was made because of technological difficulties in making these devices. Insertion losses of 2dB and an order of magnitude less than possible phase shift occurred because of inadequate production facilities. Thus, the comparative study gave a common mode error to the published device and the new device.</p> <p> Also, the theory of ferrite microwave phasers and a discussion of a particular system application which prompted this study are included in this thesis.</p> / Thesis / Master of Engineering (MEngr)

Wireless networks face ever-changing demands on their spectrum and infrastructure resources such as, increased communication bands, capacity-intensive data applications, and the steady growth of worldwide wireless subscribers. This rapid increase in the use of wireless communication and the dependence on a reliable connectivity leads manufacturers to seek systems which are ever smaller, low power, provide long range, and high bandwidth, whilst giving higher reliable technologies. In modern communication systems MEMS is now finding its way, replacing older more high power and non-linear systems. One of the important components of RF MEMS technology is the implementation of MEMS phase shifters for phased array applications that require better performance than arrays of conventional phase shifters. An important example is where RF MEMS devices can be applied to vary the characteristics of an antenna, such as beam steering or tuning in a multiband antenna. The core of this thesis is the development and fabrication of a novel Parylene based MEMS phase shifter. This is the first novel application of Parylene as the strength member of the MEMS bridge. The implementation provided MEMS devices with lower actuation voltage of < 25 V. The fabricated phases shifters provide higher RF performance such as < 1 dB insertion loss, linearity of > 65 dBm, and return loss of < -15 dB. The reliability of the fabricated devices were tested beyond 2 billion switching cycles. This is higher than competing MEMS capacitive devices with a maximum lifetime of 500 million cycles. The fabricated device provides a maximum phase shift of 16.82° at 2.5 GHz, whilst the nominal value of phase shift was 5.4° at 2.5 GHz within the stable region of operation. The fabricated device provides comparable results with respect to reference DMTL designs. The research carried out in this thesis has lead to a number of international publications and four granted patents. The generic nature of this technology can open new opportunities in the conception and application of new MEMS devices in communication and sensing applications. The ability to deliver miniature, low power and high efficiency MEMS capacitive devices, will revolutionise the next generation of tuneable RF components suitable for mobile and handheld devices of the future.

The objective of this research is to implement monolithic analog phase shifters based on barium strontium titanate (BST) coated sapphire substrates for IEEE 802.11b wireless local area network (WLAN) applications. It has been known that several BST thin film properties such as high relative permittivity, electric field dependence, fast polarization response, relatively low loss, and high breakdown field, allow for miniaturization and high performance of analog phase shifters. Before attempting to implement BST phase shifters, coplanar waveguides (CPWs) and interdigital capacitors (IDCs) based on various BST compositions and thicknesses have been developed and characterized to capitalize on the electrical properties of BST thin films. Based on the characteristics of BST thin films, two design topologies have been studied to implement phase shifters. The first topology is a reflection-type structure. The reflection-type phase shifter composed of a 3-dB coupler and two identical reflective terminations has provided a large phase shift with a relatively low insertion loss. The second topology is an all-pass network structure. The all-pass network phase shifter consists of only lumped elements so that one can shrink in size of devices. The total chip area of the all-pass network phase shifter is only 2.6 mm * 2.2 mm with a loss figure-of-merit (FOM) of more than 69 deg/dB at 2.4 GHz. This is the smallest size and the best performance obtained to date for BST phase shifters in the 2.4 GHz band and comparable or even better than the state of the GaAs MMIC phase shifters. The nonlinear response of the all-pass network phase shifter also was investigated with two-tone intermodulation distortion (IMD) measurement. Furthermore, the all-pass network phase shifter was studied to ascertain a design to ensure minimum performance variation over a range of temperature and to determine which BST composition performed best in the face of temperature variations. Compact beamforming networks (BFNs) for WLAN systems using client-based smart antennas have been demonstrated to validate the feasibility of BST technology for WLAN applications. The two-element BFNs have been shown to increase throughput and network capacity by rejecting interference.

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007. / Committee Chair: A. Rahman Zaghloul ; Committee Members: W. Russell Callen and Doug Yoder. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 203-216). Also available in electronic format on the Internet.

Please read the abstract in the section 00front of this document / Thesis (DPhil (Electronic Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / unrestricted

No description available.

Yes / A novel beam-forming module based on Wilkinson power divider technology, including attenuators and phase shifter chips is designed, fabricated and evaluated to be incorporated in a Relay Station connecting it with the Base Station under a 4G network. The proposed module is a 1:8 port circuit, utilizing two substrates, providing approximately 700 MHz bandwidth over 3.5 GHz frequency band and less than −20 dB transmission line coupling. Moreover an external control unit that feeds the beam-forming module with code-words that define the proper amplitude/phase of the excitation currents is established and described. The presented module is connected to a planar array and tested for two beam-forming scenarios, providing satisfactory radiation patterns.

This thesis presents the design of radio-frequency (RF) tunable active inductors (TAIs) with independent inductance (L) and quality factor (Q) tuning capability, and their application in the design of RF tunable phase shifters and directional couplers for wireless transceivers. The independent L and Q tuning is achieved using a modided gyrator-C architecture with an additional feedback element. A general framework is developed for this Q- enhancement technique making it applicable to any gyrator-C based TAI. The design of a 1.5V, grounded, 0.13um CMOS TAI is presented. The proposed circuit achieves a 0.8nH-11.7nH tuning range at 2GHz, with a peak-Q in excess of 100. Furthermore, printed and integrated versions of tunable positive/negative refractive index (PRI /NRI) phase shifters, are presented in this thesis. The printed phase shifters are comprised of a microstrip transmission-line (TL) loaded with varactors and TAIs, which, when tuned together, extends the phase tuning range and produces a low return loss. In contrast, the integrated phase shifters utilize lumped L-C sections in place of the TLs, which allows for a single MMIC implementation. Detailed experimental results are presented in the thesis. As an example, the printed design achieves a phase of -40 to +34 degrees at 2.5GHz. As another application for the TAI, a reconfigurable CMOS directional coupler is presented in this thesis. The proposed coupler allows electronic control over the coupling coefficient, and the operating frequency while insuring a low return loss and high isolation. Moreover, it allows switching between forward and backward operation. These features, combined together, would allow using the coupler as a duplexer to connect a transmitter and a receiver to a single antenna. Finally, a planar electronically steerable patch array is presented. The 4-element array uses the tunable PRI/NRI phase shifters to center its radiation about the broadside direction. This also minimizes the main beam squinting across the operating bandwidth. The feed network of the array uses impedance transformers, which allow identical interstage phase shifters. The proposed antenna array is capable of continuously steering its main beam from -27 to +22 degrees of the broadside direction with a gain of 8.4dBi at 2.4GHz.