RF MEMS technology for millimeter-wave radar sensors

The dissertation discusses RF MEMS technology for millimeter-wave radar sensors. RF MEMS, which stands for radio frequency micro-electromechanical system, and radar sensor fundamentals are briefly introduced. Of particular interest are: Firstly, a self-aligned fabrication process for capacitive fixed-fixed beam RF MEMS components is disclosed. It enables scaling of the critical dimensions and reduces the number of processing steps by 40% as compared with a conventional RF MEMS fabrication process. Scaling of the critical dimensions of RF MEMS components offers the potential of submicrosecond T/R switching times. RF MEMS varactors with beam lengths of 30 μm are demonstrated using the self-aligned fabrication process, and the performance of a 4 by 4 RF MEMS varactor bank is discussed as well. At 20 GHz, the measured capacitance values range between 180.5 fF and 199.2 fF. The measured capacitance ratio is 1.15, when a driving voltage of 35 V is applied, and the measured loaded Q factor ranges between 14.5 and 10.8. The measured cold-switched power handling is 200 mW. The simulated switching time is 354.6 ns. Secondly, an analog RF MEMS slotline TTD phase shifter is disclosed, for use in conjunction with ultra wideband (UWB) tapered slot antennas, such as the Vivaldi aerial and the double exponentially tapered slot antenna. It is designed for transistor to transistor logic (TTL) bias voltage levels and exhibits a measured phase shift of 28.2°/dB (7.8 ps/dB) and 59.2°/cm at 10 GHz, maintaining a 75 Ω; differential impedance match (S11dd ≤ -15.8 dB). The input third-order intercept point (IIP3) is 5 dBm at 10 GHz for a Δf of 50 kHz, measured in a 100 Ω differential transmission line system.Ph.D.Electrical EngineeringUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/61348/1/vcaeken.pd

Design and development of dual-Polarised photovoltaic solar antennae for Ku-band SatComsp.

The aim of this thesis is to review the state-of-the-art of transparent patch antennae and to develop design techniques for the experimental development of dual-band, dual-polarised compact transparent patch antennae integrated with solar cells for Ku-band satellite applications. It can be specifically used for Fixed-Satellite-Services (FSS) operating over the frequency range from 11.7 GHz to 12.22 GHz (downlink) and 14.0 GHz to 14.5 GHz (uplink) bands. The research reported in this thesis demonstrated a suspended meshed patch antennae serves as a basic building-block element for a Ku-band dual-polarised transparent array antennae for long distance communications. The results are shown that the use of a suspended patch above a printed radiating patch and ground plane (all transparent) provides dual-band operation for the uplink and downlink. In this work, firstly, a compact low-profile linearly polarised meshed element has been designed, and simulated in CST Microwave Studio electromagnetic simulation software. The photovoltaic antennae element was then fabricated and measured. The comparison between the experimental results and simulation by CST demonstrates good agreement between predicted and practical measurements. The developed antennae element achieved the overall broad bandwidth of more than 1GHz (500 MHz in each of the uplink and downlink bands), and the nominal element gain is 6.055 dBi (downlink) and 7.61 dBi (uplink). A good compromise between the RF performance and the transparency is also obtained with optical transparency of 84% and negligible degradation of the RF performance. The design is then extended to develop a Ku-band photovoltaic antennae element for dualpolarised operation This element could be used for frequency re-use in Ku-band satellite downlink and uplink communicationsin order to double capacity. In addition, the simulation of a 2 x2 sub-array of dual polarised transparent antennae elements (using the experimentally measured performance of the single dual-polarised element) is presented. It has yielded a narrow beam with increased gain of 13 dBi and a cross-polar discrimination of greater than 30 dB is demonstrated, which is a requirement for frequency re-use operation. Hence, the dual-polarised 4-element sub-array described herein could be utilised as the primary building block for a 2D SatCom phased array antennae. In order to meet the full requirements of Kuband SatCom communications employing frequency re-use which essentially doubles the achievable capacity, i.e. two data channels can use the same frequency bands simultaneously using the two orthogonal polarisations with high cross-polar isolation. Using these new designs providing new knowledge in the field of photovoltaic communication antennae at high frequencies, and bridge the associated drawbacks with the current PV antennae

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

Dual-band beam scanning reflectarrays and novel wideband and polarization diversified planar antennas

The reflectarray antenna has been considered as a suitable candidate to replace the traditional parabolic reflectors because of its high-gain and low-profile features. Beam scanning capability and multi-band operation are the current trends of the reflectarray design. It is desired to implement these functionalities with simple and effective techniques. Narrow bandwidth is the main issue which restricts the applications of the microstrip antennas. New microstrip slot antennas and polarization diversified planar antennas are introduced as the solutions to the issue of narrow bandwidth in this dissertation. A dual-band beam scanning reflectarray has been developed. It is the first offset-fed reflectarray that has been ever practically developed to emulate a cylindrical/parabolic type of reflector. Unlike other beam scanning reflectarrays which integrate phase tuning devices into the reflectarray elements and control the reflection phase, the beam scanning capability of this reflectarray is provided by its feed array. This method significantly reduces the complexity of the design of the beam scanning reflectarray. A new dual-band reflectarray configuration is also developed to eliminate the possible top layer blocking effects in the dual-layer reflectarray configuration. Perforated patches loaded with slots on the ground plane and rectangular patches loaded with slots on the patches are adopted as the low and high frequency bands, respectively. It is guaranteed that no physical contact between any two elements will occur. The bandwidth of the conventional microstrip antenna is small. A new wideband circularly polarized microstrip slot antenna is introduced in this dissertation. Very wide 3-dB axial ratio bandwidth is observed for the proposed antenna. The antennas are assembled in triangularly arranged array with sequential rotation feed technique. Polarization polarity is an alternative solution to the narrow bandwidth. A reconfigurable circularly polarized microstrip antenna is proposed. The antenna has both right-hand and left-hand circular polarizations which are controlled by two piezoelectric transducers. In addition, a dual-band dual-linearly-polarized planar array is designed based on the concepts of polarization diversity and multi-band operation. The research presented in this dissertation suggests useful techniques for reflectarrays and novel antenna designs. The results should have many applications for the modern wireless communication and radar systems

Beam scanning by liquid-crystal biasing in a modified SIW structure

A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

Antenna Designs for 5G/IoT and Space Applications

This book is intended to shed some light on recent advances in antenna design for these new emerging applications and identify further research areas in this exciting field of communications technologies. Considering the specificity of the operational environment, e.g., huge distance, moving support (satellite), huge temperature drift, small dimension with respect to the distance, etc, antennas, are the fundamental device allowing to maintain a constant interoperability between ground station and satellite, or different satellites. High gain, stable (in temperature, and time) performances, long lifecycle are some of the requirements that necessitates special attention with respect to standard designs. The chapters of this book discuss various aspects of the above-mentioned list presenting the view of the authors. Some of the contributors are working strictly in the field (space), so they have a very targeted view on the subjects, while others with a more academic background, proposes futuristic solutions. We hope that interested reader, will find a fertile source of information, that combined with their interest/background will allow efficiently exploiting the combination of these two perspectives

Metamaterials and Metasurfaces

Ye

Personal Access Satellite System (PASS) study. Fiscal year 1989 results

The Jet Propulsion Laboratory is exploring the potential and feasibility of a personal access satellite system (PASS) that will offer the user greater freedom and mobility than existing or currently planned communications systems. Studies performed in prior years resulted in a strawman design and the identification of technologies that are critical to the successful implementation of PASS. The study efforts in FY-89 were directed towards alternative design options with the objective of either improving the system performance or alleviating the constraints on the user terminal. The various design options and system issues studied this year and the results of the study are presented

Design of Fully-Integrated High-Resolution Radars in CMOS and BiCMOS Technologies

The RADAR, acronym that stands for RAdio Detection And ranging, is a device that uses electromagnetic waves to detect the presence and the distance of an illuminated target. The idea of such a system was presented in the early 1900s to determine the presence of ships. Later on, with the approach of World War II, the radar gained the interest of the army who decided to use it for defense purposes, in order to detect the presence, the distance and the speed of ships, planes and even tanks. Nowadays, the use of similar systems is extended outside the military area. Common applications span from weather surveillance to Earth composition mapping and from flight control to vehicle speed monitoring. Moreover, the introduction of new ultrawideband (UWB) technologies makes it possible to perform radar imaging which can be successfully used in the automotive or medical field. The existence of a plenty of known applications is the reason behind the choice of the topic of this thesis, which is the design of fully-integrated high-resolution radars. The first part of this work gives a brief introduction on high resolution radars and describes its working principle in a mathematical way. Then it gives a comparison between the existing radar types and motivates the choice of an integrated solution instead of a discrete one. The second part concerns the analysis and design of two CMOS high-resolution radar prototypes tailored for the early detection of the breast cancer. This part begins with an explanation of the motivations behind this project. Then it gives a thorough system analysis which indicates the best radar architecture in presence of impairments and dictates all the electrical system specifications. Afterwards, it describes in depth each block of the transceivers with particular emphasis on the local oscillator (LO) generation system which is the most critical block of the designs. Finally, the last section of this part presents the measurement results. In particular, it shows that the designed radar operates over 3 octaves from 2 to 16GHz, has a conversion gain of 36dB, a flicker-noise-corner of 30Hz and a dynamic range of 107dB. These characteristics turn into a resolution of 3mm inside the body, more than enough to detect even the smallest tumor. The third and last part of this thesis focuses on the analysis and design of some important building blocks for phased-array radars, including phase shifter (PHS), true time delay (TTD) and power combiner. This part begins with an exhaustive introduction on phased array systems followed by a detailed description of each proposed lumped-element block. The main features of each block is the very low insertion loss, the wideband characteristic and the low area consumption. Finally, the major effects of circuit parasitics are described followed by simulation and measurement results

Satellite Communications

This study is motivated by the need to give the reader a broad view of the developments, key concepts, and technologies related to information society evolution, with a focus on the wireless communications and geoinformation technologies and their role in the environment. Giving perspective, it aims at assisting people active in the industry, the public sector, and Earth science fields as well, by providing a base for their continued work and thinking