マルチモードSIRを用いたチップレスRFIDタグに関する研究

電気通信大学201

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

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

Passive Planar Microwave Devices

The aim of this book is to highlight some recent advances in microwave planar devices. The development of planar technologies still generates great interest because of their many applications in fields as diverse as wireless communications, medical instrumentation, remote sensing, etc. In this book, particular interest has been focused on an electronically controllable phase shifter, wireless sensing, a multiband textile antenna, a MIMO antenna in microstrip technology, a miniaturized spoof plasmonic antipodal Vivaldi antenna, a dual-band balanced bandpass filter, glide-symmetric structures, a transparent multiband antenna for vehicle communications, a multilayer bandpass filter with high selectivity, microwave planar cutoff probes, and a wideband transition from microstrip to ridge empty substrate integrated waveguide

Design and Synthesis of Dual Polarized Millimetre Wave Array Antennas for Advanced Wireless Communications

The millimetre-wave (mmWave) antenna arrays in traditional designs are usually very complicated, bulky and expensive. They suffer compromised radiation efficiency because of high insertion loss caused by the intricate feed networks. In addition, the cross polarization level is degraded, especially for the multibeam antenna arrays. To reduce the complexity and improve the electric characteristics, it is significant to develop mmWave antenna arrays with multi-functionality such as dual polarization, cross polarization suppression, beam switching and power splitting/combining, etc.In this thesis, four designs of sub-mmWave and mmWave dual polarized antenna arrays with low complexity, compact size and good electrical performance are proposed. Firstly, a dual slant polarized cavity-backed slot-coupled patch antenna arrays with modified feed networks is developed. This antenna array features high XPD, simple structure and low profile. Then, a dual polarized 2D multibeam shorted-patch antenna array with high XPD when beams scan to the maximum pointing angles is developed. Differential feed technique is used to design the multibeam antenna array for the first time. The third design is a dual polarized frequency-scanning cross slot antenna array realized on a single laminate. To enable high port isolation and excitation from orthogonal directions, a SIW crossover is proposed. This antenna array shows advantages in terms of low complexity, high XPD, high aperture efficiency and wide beam scanning range. A dual polarized slot-coupled patch antenna array differentially fed by an orthomode transducer is developed in the last design. The feed networks are taken into consideration of designing the subarray antenna. The via-loaded crossover is used to enable structure simplification and triple resonance is excited to improve operation bandwidth. This antenna array features low complexity, high XPD, high radiation efficiency, high gain and high integration.In this thesis, the design methods and synthesis procedures are detailed in order todeliver a comprehensive guide of designing the dual polarized antenna arrays. The design concept and outcomes of these antenna arrays are evaluated in the high frequency fullwave solver. All of the antenna arrays are prototyped and measured for validating the simulations. The measurements are in good agreement with the simulations, evidencing that the proposed antenna arrays have advantages in terms of high XPD, high aperture efficiency, high port isolation, low complexity and low profile. The design concepts depicted in this thesis and the developed antenna arrays could find potential applications in mobile communication systems and satellite communication systems