Reconfigurable Reflectarrays and Array Lenses for Dynamic Antenna Beam Control: A Review

Advances in reflectarrays and array lenses with electronic beam-forming capabilities are enabling a host of new possibilities for these high-performance, low-cost antenna architectures. This paper reviews enabling technologies and topologies of reconfigurable reflectarray and array lens designs, and surveys a range of experimental implementations and achievements that have been made in this area in recent years. The paper describes the fundamental design approaches employed in realizing reconfigurable designs, and explores advanced capabilities of these nascent architectures, such as multi-band operation, polarization manipulation, frequency agility, and amplification. Finally, the paper concludes by discussing future challenges and possibilities for these antennas.Comment: 16 pages, 12 figure

MEMS-reconfigurable metamaterials and antenna applications

This paper reviews some of our contributions to reconfigurable metamaterials, where dynamic control is enabled by micro-electro-mechanical systems (MEMS) technology. First, we show reconfigurable composite right/left handed transmission lines (CRLH-TLs) having state of the art phase velocity variation and loss, thereby enabling efficient reconfigurable phase shifters and leaky-wave antennas (LWA). Second, we present very low loss metasurface designs with reconfigurable reflection properties, applicable in reflectarrays and partially reflective surface (PRS) antennas. All the presented devices have been fabricated and experimentally validated. They operate in X- and Ku-bands.Comment: 8 pages; 8 figures; International Journal of Antennas and Propagatio

Wireless actuation of bulk acoustic modes in micromechanical resonators

We report wireless actuation of a Lamb wave micromechanical resonator from a distance of over 1 m with an efficiency of over 15%. Wireless actuation of conventional micromechanical resonators can have broad impact in a number of applications from wireless communication and implantable biomedical devices to distributed sensor networks.Financial support from FemtoDx is acknowledged. (FemtoDx)http://nano.bu.edu/Papers_files/Wireless-APL-4961247.pdfPublished versio

Performance enhancement of G-band micromachined printed antennas for MMIC integration

The objective of the work of this thesis is to design, fabricate, and characterise high performance micromachined antennas with fixed and reconfigurable bandwidth. The developed integrated antennas are suitable for MMICs integration at millimetre wave frequencies (G-band) on MMICs technology substrates (i.e GaAs, Si, InP). This work is done through a review of the scientific literature on the subject, and the design, simulation, fabrication and experimental verification, of various suitable designs of antenna. The novel design of the antennas in this work is based on elevated antenna structures in which the radiator is physically micromachined above the substrate. The antenna design schemes offer a suitable method to integrate an antenna with other MMICs. Further, this method eliminates undesired substrate effects, which degrades the antenna performance drastically. Also in this work we have for the first time realized different micromachined antenna topologies with different novel feeding mechanisms - offering more degrees of freedom for antenna design and enhancing the antenna performance. Experimental and simulation results are provided to demonstrate the effectiveness of the proposed antenna designs and topologies in this work. A new approach for fabricating printed antennas is introduced in this work to fulfil the fabrication process requirements. It provides a new method for the fabrication of 3-D multilevel structures with variable heights, without etching the substrate. Further, the height of the elevated structures can be specified in the process and can vary by several microns, regardless of the substrate used. This can be used to further enhance the bandwidth and gain of the antenna - avoiding substrate thinning and via holes, and increasing the fabrication yield. Thus, the elevated antenna can meet different application requirements and can be utilized as a substrate independent solution. In this work we have introduced the concept of reconfigurable antennas at millimetre wave band. Also, we have investigated various aspects associated with lowering the pull-down voltage and overcoming the stiction problem of MEMS switches required for the proposed reconfigurable antennas. This was achieved by developing MEMS technology which can be integrated with MMICs fabrication process. Two novel reconfigurable elevated patch antenna topologies were designed to demonstrate the developed technology and their performances were discussed. The result we obtained from this work demonstrates the feasibility of MEMS reconfigurable printed antennas at G-band frequencies. This will open a new field in MMICs technology and increasing system integration capabilities and functionality. The devolved technology in this thesis could be utilized in many unique applications including short range high data rate communication systems and high-resolution passive and active millimetre-wave imaging

Polymer-Based Low-Cost Micromachining of Gap Waveguide Components

The millimeter-wave (mmWave) and sub-millimeter-wave (sub-mmWave) frequency bands have gained significant attention over the past few years due to the growth of commercial wireless applications. As the operating frequency approaches these higher frequencies, the dimensions of the waveguide-based components continue to decrease. The decreasing feature size of those waveguide components makes the traditional machine-based (computer numerical control, CNC) fabrication method increasingly challenging in terms of time and cost, especially above 100 GHz. Additionally, this method is a serial process and cost will not scale with volume production. Micromachining has the potential of addressing the manufacturing issues of mmWave components. However, the existing microfabrication techniques either suffer from technological immaturity, are time-consuming, or lack sufficient cost-efficiency. A straightforward, fast, and low-cost fabrication method that can offer batch fabrication of waveguide components operating at mmWave and sub-mmWave frequency range is desirable to address the needs for hardware on the growing market of mmWave and sub-mmWave wireless systems.Conventional metal waveguides have very strict fabrication requirements in terms of mechanical assembly and integration of RF electronics. In comparison, gap waveguide technology not only offers competitive loss performance but also provides several benefits in terms of assembly and integration of active components. A gap waveguide is a planar waveguide technology which does not suffer from the dielectric loss in planar waveguides and which does not require any electrical connections between the metal walls, in contrast to hollow waveguides. This thesis aims to realize gap waveguide components operating at mmWave and sub-mmWave frequency range, in a low-cost and time-efficient way by developing new polymer-based fabrication methods.A template-based injection molding process has been designed to realize a high gain antenna operating at D band (110 -170 GHz). We can confirm that injection molding of OSTEMER is a straightforward and fast device fabrication method. In the proposed method, the time-consuming and complicated parts need to be fabricated only once and can later be reused.A dry film photoresist-based method is also presented in this thesis to fabricate waveguide components operating between 220 - 320 GHz. Dry film photoresist offers rapid fabrication of waveguide components without using sophisticated tools. The measurement results presented in the thesis indicate that this dry film-based method is a promising method for fabricating waveguide components operating in mmWave and sub- mmWave frequency ranges

Millimetre-wave and Terahertz Electronics

Overview: The basic thesis for the advancement of millimetre-wave and terahertz electronics is represented in four sections: Signal Processing, Component Design and Realization, Modelling and Materials, and Paradigm Shift. The first section is at system and circuit levels and reports on complex signal process functions that have been performed directly on the millimetre-wave carrier signal, intended for realizing low-cost and adaptive communications and radar systems architectures. The second section is at circuit and component levels and reports on techniques for the design and realization of low-loss passives for use at millimetrewave frequencies. The third section is at component and material levels and reports on modelling techniques for passives for use at both millimetre-wave and terahertz frequencies. Finally, the fourth section introduces a revolutionary new technology that represents a paradigm shift in the way millimetre-wave and terahertz electronics (i.e. components, circuits and systems) can be implemented. As found with the new generation of mobile phone handsets, a fusion of two extreme technologies can take place; here, complex signal processing operations could be performed both directly on the carrier signal and with the use of a spatial light modulator. Based on a selection of 20 papers (co-)authored by the candidate †b, and published over a period of 15 years, it will be seen that a coherent theme runs throughout this body of work, for the advancement of knowledge in millimetre-wave and terahertz electronics