About: Spiral antenna is a research topic. Over the lifetime, 1695 publications have been published within this topic receiving 17699 citations.
Papers published on a yearly basis
TL;DR: In this paper, a reconfigurable rectangular spiral antenna with a set of micro electro mechanical system (MEMS) switches, which are monolithically integrated and packaged onto the same substrate, is presented.
Abstract: A fully integrated solution providing scan-beam capability with a single antenna is presented in this paper for the first time. The proposed system includes a reconfigurable rectangular spiral antenna with a set of micro electro mechanical system (MEMS) switches, which are monolithically integrated and packaged onto the same substrate. The system is based on a single-arm rectangular spiral antenna, capable of changing its radiation pattern using radio frequency-MEMS (RF-MEMS) switches. The rectangular spiral and RF-MEMS switches are monolithically integrated on a conventional microwave substrate printed circuit board (/spl epsiv//sub r/=3.27 and tan/spl delta/=0.004) and quartz substrate (/spl epsiv//sub r/=3.78 and tan/spl delta/=0.0002). The spiral is made out of multiple lines, which are interconnected by RF-MEMS switches strategically located along the spiral. On activating these switches, the spiral overall arm length is changed and consequently its radiation beam direction is changed. The two proposed antennas radiate right hand circular polarization (RHCP) and left hand circular polarization (LHCP) for printed circuit board and quartz substrate respectively. The gain of the two antennas varies between 3/spl sim/6 dBi. They both satisfy the 3-dB axial ratio criterion at their operating frequency band, i.e., at 10 GHz and 6 GHz for the printed circuit board and the quartz substrate respectively. To the best of our knowledge, this is the first truly reconfigurable printed antenna design using MEMS devices as active elements integrated in the same low loss substrate. The excellent performance of the proposed system emphasizes the importance of being able to integrate MEMS switches into the same low loss substrate for antenna applications. This technology pioneers the design of arbitrarily shaped reconfigurable antennas including the design of reconfigurable antenna arrays.
TL;DR: In this article, a virtual doublet is achieved by placing a single spiral in a fight angle trough, where the direction of polarization and phase are controlled or varied independently of each other by rotation of the radiators.
Abstract: A pair of equally excited but oppositely sensed Archimedean two-wire spirals situated close to one another in the same plane-a doublet-is used to generate a linearly polarized field in which the direction of polarization and phase are controlled or varied independently of each other by rotation of the spiral radiators. An array of these doublets can be made to scan by rotation of the several spiral elements; an eight-doublet array which was made to scan over an 83\deg sector with small amplitude variation is discussed. A doublet fed from a ring network can be employed as a polarization diversity circuit. A virtual doublet is achieved by placing a single spiral in a fight angle trough. A preliminary scanning array comprising four spirals in a trough was made to scan \pm36\deg . The possibility of using a parasitic spiral in conjunction with a driven spiral for obtaining linear polarization of variable direction and phase is indicated. Also, a brief simplified analysis of the two-wire Archimedean spiral is presented, which leads to the concept of higher-order modes of radiation.
TL;DR: In this paper, an Archimedean planar spiral antenna is numerically analyzed in the presence of a conducting plane reflector, and it is shown that the spiral antenna has two distinct regions in the current distribution, which explain the radiation of a circularly polarized wave for the outer circumference C ranging over about 1.3 λ and C > 2.9 λ, where λ is a free-space wavelength.
Abstract: An Archimedean planar spiral antenna is numerically analyzed in the presence of a conducting plane reflector. The analysis shows that the spiral antenna backed by the plane reflector has two distinct regions in the current distribution, which explain the radiation of a circularly polarized wave for the outer circumference C ranging over about 1.3 \lambda and C > 2.9 \lambda , where \lambda is a free-space wavelength. Further consideration is given to a truncated spiral antenna whose outer circumference is on the order of 1.4 \lambda . The truncated spiral antenna maintains a decaying current distribution and radiates a circularly polarized wave over a 1:1.2 frequency bandwidth. It is also demonstrated that a power gain on the order of 8.5 dB is realized over the same frequency range.
11 Jan 2013
TL;DR: In this article, the authors present a comprehensive insight into the design techniques for different types of circularly polarized antenna elements and arrays, including the basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antenna, printed slots, spiral antennas, monopoles, dielectric resonator antennas, etc.
Abstract: This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arraysIn this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Advanced designs such as small-size CP antennas, broadband, wideband and ultra-wideband CP antennas are also discussed, as well as multi-band CP antennas and dual CP antennas. The design and analysis of different types of CP array antennas such as broadband CP patch arrays, dual-band CP arrays, CP printed slot arrays, single-band and multi-band CP reflectarrays, high-gain CP waveguide slot antennas, CP dielectric resonator antenna arrays, CP active arrays, millimetre-waveband CP arrays in LTCC, and CP arrays with electronically beam-switching or beam-steering capabilities are described in detail. Case studies are provided to illustrate the design and implementation of CP antennas in practical scenarios such as dual-band Global Navigation Satellite Systems (GNSS) receivers, satellite communication mobile terminals at the S-band, Radio Frequency Identification (RFID) readers at 2.4 GHz, and Ka-band high-speed satellite communication applications. It also includes the detailed designs for a wideband Logarithmic spiral antenna that can operate from 3.4-7.7 GHz. In addition, the book offers a detailed review of the recent developments of different types of CP antennas and arrays.Presents comprehensive discussions of design techniques for different types of CP antennas: small-size CP antennas, broadband CP antennas, multi-band CP antennas and CP arrays.Covers a wide range of antenna technologies such as microstrip antennas, helix, quadrifilar helix antenna, printed quadrifilar helix antenna, dielectric resonator antennas, printed slots, spiral antennas, monopoles, waveguide slot arrays, reflectarrays, active arrays, millimetre-wave arrays in LTCC, electronically beam-switching arrays and electronically beam-steerable arrays.Reviews recent developments in different types of CP antennas and arrays, reported by industries, researchers and academics worldwide.Includes numerous case studies to demonstrate how to design and implement different CP antennas in practical scenarios.Provides both an introduction for students in the field and an in-depth reference for antenna/RF engineers who work on the development of CP antennas.Circularly Polarized Antennas will be an invaluable guide for researchers in RD system engineers (antenna, telecom, space and satellite); postgraduates studying the subjects of antenna and propagation, electromagnetics, RF/microwave/millimetre-wave systems, satellite communications and so on; technical managers and professionals in the areas of antennas and propagation.
20 Aug 1996
TL;DR: A variety of improved antenna arrangements for ablation catheters and methods for constructing catheter with these antenna arrangements are described in this paper, where an elongated flexible tubular member adapted to be inserted into a vessel in the body of a patient is described.
Abstract: A variety of improved antenna arrangements for ablation catheters and methods for constructing catheter with these antenna arrangements are described. In various apparatus aspects of the invention, the catheter includes an elongated flexible tubular member adapted to be inserted into a vessel in the body of a patient. A transmission line suitable for transmitting electromagnetic energy is received within the tubular member. An antenna is coupled to the transmission line for generating an electric field sufficiently strong to cause tissue ablation. In one embodiment, the antenna takes the form of an antenna coil that is oriented such that its longitudinal axis extends substantially perpendicular to the longitudinal axis of the flexible tubular member. In another embodiment, a plurality of such laterally oriented antenna coils are provided at longitudinally spaced locations relative to the catheter axis. In other embodiments, the antenna coil is spirally wound. A variety of spiral antenna arrangements are contemplated. In some embodiments, the coil is wound in a substantially conical or frusto-conical manner expanding either distally or proximately. In still another embodiment, the antenna coil is wound in a substantially flat coil.
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