Fan-beam Antenna Research Articles

A 3-D-printed Wideband Millimeter-Wave Fan-Beam Antenna With Flat-Top, Sharp Cutoff Patterns, and Beam-Scanning Capability

This article presents a wideband millimeter-wave (MMW) fan-beam antenna with a flat-top, rapid cutoff radiation pattern, and beam-scanning capability through the use of 3-D printer technology. The proposed antenna, consisting of several periodic structures that composed of dielectric and air slabs, is fed by the WR-28 waveguide. By tuning the ratio of dielectric slab thickness to that of unit cell, the effective permittivity is controlled flexibly. The phase distribution on the aperture is carefully modulated in this way to devote high-quality flat-top patterns. In addition, the beam can be continuously scanned within the angle range of 70° without scarifying the gain performance dramatically. For demonstration, a prototype with boresight fan-beam radiation is first fabricated and measured. The proposed antenna achieves an impedance bandwidth of 50% from 24 to 40 GHz. Measured results indicate that the wide beamwidth patterns show flat-top and sharp cutoff performance. Both E-plane and H-plane patterns draw low cross polarization (smaller than −22 dB). Another prototype, aiming to verify the beam-scanning capability, is investigated. Measured results demonstrate the performances of the proposed antennas. With such favorable electrical performance, simple structure, and low-cost fabrication, the proposed antenna is a promising candidate for 5G MMW and satellite applications.

Fan‐beam antenna design based on metasurface lenses

A fan-beam antenna system based on metasurface lenses is proposed for backhaul antenna applications at 10.4 GHz. The planar metasurface lens is composed of three pairs of subwavelength unit cells with high transmission and opposite phase. These phase shifters are arranged to transform the Gaussian distributed near field from a linear patch antenna array into the sin c-function distributed aperture field, which in turn brings a sector radiation pattern in the azimuth plane and a pencil beam in the elevation plane. The simulated and measured results demonstrate that the presented lens antenna offers a sharp roll-off fan beam with the azimuth beamwidth 60°, elevation beamwidth 10°, and the gain 18.2 dB with the flat-top ripple less than 2.0 dB.

Dual Radiator Based Low Profile Fan Beam Antenna for Millimeter Wave Fencing System

The paper describes the design, development, and characterization of a low profile, lightweight and linearly polarized fan beam radiating array antenna for millimeter wave fencing system. Dual antenna topology has been proposed for each transmit and receive tower to obtain maximum coverage area compared to a single antenna configuration. The radiator placement (height) has been optimized to minimize the dead zone region. Proposed RF fencing system utilizes an 8x32 probe-fed microstrip patch array antenna developed on 10 mils RT Duroid dielectric substrate material. ANSYS's High-Frequency Structure Simulator (HFSS) full-wave EM software has been utilized for simulation and analysis of designed radiating array. VSWR of the realized antenna is 1.75:1 over the frequency band of 34.5 GHz to 35.5 GHz. The E-plane and H-plane HPBW of the developed antenna at 35 GHz is 8.4 and 2.2 degrees respectively. The measured gain of the antenna is better than 25.4dBi over the frequency band 34.5 GHz to 35.5 GHz.

Towards the Sea Ice and Wind Measurement by a C-Band Scatterometer at Dual VV/HH Polarization: A Prospective Appraisal

Following the mission science plan of EPS/Metop-SG C-band scatterometer for 2023–2044, we consider the potential application of the sea ice/water discrimination method based on the minimum statistical distance of the measured normalized radar cross sections (NRCS) to the geophysical model functions (GMF) of the sea ice and water, respectively. The application of the method is considered for the classical spacecraft scatterometer geometry with three fixed fan-beam antennas and the hypothetical prospective scatterometer geometry with the five fixed fan-beam antennas. Joint vertical (VV) and horizontal (HH) transmit and receive polarization are considered for the spaceborne scatterometer geometries. We show explicitly that the hypothetical five fixed fan-beam antenna geometry combined with the dual VV and HH polarization for all antennas provides better estimates of the sea wind speed and direction as well as sea ice/water discrimination during single spacecraft pass. The sea ice/water discrimination algorithms developed for each scatterometer geometry and dual VV/HH polarization are presented. The obtained results can be used to optimize the design of new spaceborne scatterometers and will be beneficial to the forthcoming satellite missions.

A Planar Differential Wide Fan-Beam Antenna Array Architecture: Modular high-gain array for 79-GHz multiple-input, multiple-output radar applications

This article proposes a planar, wide fan-beam differential, corporate-fed patch antenna array architecture for automotive radar applications that mitigates the multipath and multiple reflections effects of its conventional series-fed counterpart. The proposed array architecture offers the merits of wide beamwidth in azimuth, high gain, yet, is applicable in multiple-input, multiple-output (MIMO) configurations. Two 8 × 1 arrays were developed, built, and measured at the 77-81-GHz band. In design 1, the width of driven 50-Ω patch is optimized for the widest beamwidth and the array feeding network employs impedance transformers for matching. The experimental verification showed an azimuthal half-power beamwidth (HPBW) of 70° with a 15-dBi gain. In design 2, the interelement spacing is increased for wider beamwidth and less mutual coupling, and the feeding network transformers were eliminated to mitigate scattering and radar cross section (RCS) in turn. A 130° azimuthal HPBW was measured. A 2 × 2 MIMO radar hardware was built, employing the proposed array architecture on a scalable radar platform to validate its applicability in MIMO radars. For the sake of comparison, another reference demonstrator with conventional series-fed arrays was built. Frequency-modulated continuous-wave (FMCW) radar range and angle measurements were performed where multiple reflections and multipath effects were mitigated.

Wide band ridge gap waveguide (RGW) fan beam antenna with low side lobes based on parabolic reflector principle

In this paper, a wide band ridge gap waveguide (RGW) fan beam antenna with low side lobe level (SLL) is presented making use of parabolic offset reflector concept in antenna geometry. In the proposed topology, in contrast to TEM based RGW horn, the amplitude distribution across the antenna aperture can be easily controlled. Furthermore, thanks to intrinsic feature of parabolic reflector in generating plane wave front, the phase distribution uniformity across the proposed antenna aperture is better than that of the RGW horn. These two facts allow the proposed topology to provide lower SLL compared to the RGW horn. A prototype of the proposed structure is designed and fabricated. Simulation and measurement results also show that wider operating bandwidth compared to the RGW horn can also be achieved using this topology. For the designed sample, the impedance bandwidth of 41% with -20 dB ≤ SLL ≤ - 15 dB and gain of 11.8-15.5 dBi is achieved. Results show that the proposed topology can be a good candidate for realization of high gain wide band RGW fan beam antennas with low SLL.

Multiple Fan-Beam Antenna Array for Massive MIMO Applications

In this paper, a multiple fan-beam antenna array is proposed for massive multiple-input multipleoutput (MIMO) applications. The proposed array is based on vertical spatial filtering to reduce radio frequency complexity in a massive MIMO system. A microstrip line feeding network is utilized to achieve a specific phase distribution for multiple fan beams. A 64-element antenna array is designed and fabricated to validate the design strategy. The proposed antenna array uses 16 ports to excite 64 antenna elements, which is more cost effective than traditional massive MIMO systems. The measured results demonstrate that the proposed antenna array can achieve two fan beams at 7 in the vertical dimension, and the measured gain of every port exceeds 10 dBi at 2.6 GHz.

PELICAN: Panoramic millimeter-wave radar for perception in mobile robotics applications, Part 1: Principles of FMCW radar and of 2D image construction

Robust environmental perception is a crucial parameter for the development of autonomous ground vehicle applications, especially in the field of agricultural robotics which is one of the priorities for the Horizon 2020 robotics funding (EU funding program for research and innovation). Because of uncontrolled and changing environmental conditions in outdoor and natural environments, data from optical sensors classically used in mobile robotics can be compromised and unusable. In such situations, millimeter-wave radar can provide an alternative and complementary solution for perception tasks. The aim of this paper is to present the PELICAN radar, a millimeter-wave radar specifically designed for mobile robotics applications, including obstacle detection, mapping and situational awareness in general. In this first of a two-part paper, the choice of a frequency-modulated continuous-wave radar is explained and the theoretical elements of this solution are detailed. PELICAN radar is using a rotating fan-beam antenna, and the construction of 2D representations of the surrounding environments with radar data is described through simulation results. The second part of the paper will be devoted for a detailed description of PELICAN radar, as well as experimental results.

Russian scatterometer: discussion of the concept and the numerical simulation of wind field retrieval

Orbital scatterometry is briefly overviewed and its trends are indicated. Two scatterometer concepts are currently considered for trade-offs: with fixed and rotating antenna systems. The concept with a rotating antenna system was selected and SeaWinds was chosen as the prototype for the first Russian scatterometer. The scatterometer concept was then further developed and instead of two pencil beams, a fan-beam antenna was proposed (about 1° × 6°). The fan-beam antenna allows successive measurements for horizontal and vertical polarization in each wind vector cell (WVC). This increases the number of observations of the WVC at different incidence and azimuth angles during flight. The scatterometer parameters required to implement the proposed measurement geometry for an orbit altitude of 650 km and a swath width of 1525 km are discussed. A numerical scatterometer model that accounts for both the specifications and the observation geometry is developed. The scatterometer performance, with subsequent formation of a swath and splitting into WVCs, is simulated. The procedure of wind vector retrieval includes two stages: 1) determining wind speed and wind direction in a single WVC; and 2) using the information from adjacent WVCs to correct wind direction. It is shown that the accuracy of wind direction retrieval by a WVC can be increased by simultaneous radar cross-section (RCS) measurements at vertical and horizontal polarization. The basic error in determining wind direction is due to a 180° wind direction ambiguity caused by the form of RCS azimuth dependence. Two-dimensional median filtering is commonly employed in scatterometry to increase the accuracy of wind direction retrieval. In this study, two-dimensional angular median filtering was employed and it is shown that the error in wind direction retrieval significantly decreased. The results of the research indicate that wind field can be retrieved by the new scatterometer with the level of precision required.

Easy installation CPW-fed technique for fan-beam array antenna using grounded reflector for wireless applications

A fan-beam linear array antenna employing a non-parasitic grounded reflector, a new Coplanar Waveguide (CPW)-fed network, and Grounded Coplanar Waveguide (GCPW) radiation elements is presented. This fan-beam antenna is achieved using a four-element conventional non-planar monopole integrated with CPW line, which is perpendicularly connected to CPW feed network. In addition, the grounded reflector is vertically connected to the ground part of CPW feed network. These three main parts together produce a fan-beam antenna that can satisfy beneficial input impedance, radiation patterns, and gain bandwidth requirements in the frequency range 3.2–3.66 GHz. This array covers applications of 3.3 and 3.5 GHz WiMAX (Worldwide Interoperability for Microwave Access) operating bands. Also, combining a non-planar GCPW monopole antenna as an array with a non-parasitic grounded reflector and CPW feed network provides designers with an advantageous fan-beam pattern to be generated. In addition, the reflector height is reduced to half by the concept of image theory. As a consequence, the spatial dimension of the antenna will be reduced. Therefore, this combination results in a cheap, lightweight, and easy installing non-planar printed array antenna at high frequency bands. Comparisons are made between results obtained with and without a reflector array antenna.

Wideband Fan-Beam Low-Sidelobe Array Antenna Using Grounded Reflector for DECT, 3G, and Ultra-Wideband Wireless Applications

A low-sidelobe fan-beam wideband linear array antenna employing a nonparasitic grounded reflector is presented. This fan-beam antenna is achieved using a six-element conventional planar monopole array antenna and feed network, which together produce sidelobes at - 26 dB. Dolph-Tschebyscheff distribution is employed, and a broadband array feed network is designed to satisfy beneficial input impedance bandwidth requirements in the frequency range 1.7-2.2 GHz. Therefore, this array covers applications of GSM-DCS2, DECT, and 3G. Combining planar monopole antenna as an array with nonparasitic grounded reflector allows an advantageous fan beam pattern to be generated. H-plane 3-dB beamwidths are controllable using grounded reflector height. In addition, the results are compared with and without reflector array antenna.

Design of a T-shaped terahertz imager

为了获得较高的帧速率以及降低成本，提出了一种带有波束扫描功能的T形太赫兹成像系统.系统包含两个共极化扇形波束扫描天线，它们以T字形正交摆放.收发天线具有基本相同的内部结构，由角锥喇叭馈源、产生扇形波束的椭圆主反射体以及用于实现波束扫描功能的旋转次反射体构成，而所有这些元件都镶嵌在两个平行金属板之间.给出了T形太赫兹成像系统的具体设计，提出了设计高性能扇形波束扫描天线的系统化方法，最后给出了一些实验的成像结果，以论证系统的功能.;To achieve relatively high frame rates with relatively low costs, a Tshaped terahertz imaging system with beamscanning function is presented. The system employs two orthogonally oriented copolarized scanning fanbeam antennas arranged in a Tshaped configuration. Both transmitting and receiving antennas consist of a pyramid horn feed, a fixed elliptical mainreflector to generate thin fan beam, and a rotating subreflector to realize beam scanning function, all of which are embedded between two parallel metal plates. In this paper, specific design details of such a system were discussed, especially for the systematic method proposed to design a fanbeam scanning antenna with high performance. In addition, some experimental imaging results were shown, which demonstrated the capability of the system.

Three-Shaped-Reflector Beam-Scanning Pillbox Antenna Suitable for mm Wavelengths

We describe the design and measured performance of an improved beam-scanning fan-beam antenna suitable for mm wavelengths. The fan beam is scanned in the direction orthogonal to the fan and can be polarized either in or orthogonal to this direction. The pillbox design is improved by the introduction of a third cylindrical reflector and optimum shaping of all reflector profiles using an iterative diffraction analysis that includes aberration and blockage effects. Good agreement between the calculated and measured results is obtained, confirming a beamwidth of 0.3° and a scan range of 13.5° (45 beamwidths) for both polarizations at 186 GHz.

A beam-scanning dual-polarized fan-beam antenna suitable for Millimeter wavelengths

The design and testing of a beam-scanning pillbox antenna for use in a 200 GHz imaging system is presented. The antenna features a rotating subreflector that scans the antenna's fan beam and a multimode structure that reduces ohmic loss and allows use of two orthogonal polarizations. The antenna has an aperture size of 450/spl times/5 mm, half-power beam widths of approximately 0.4/spl deg/ and 18/spl deg/ and a beam-scan range of 10/spl deg/. The gain of the antenna was measured to be greater than 33 dBi for both polarizations. The radiation patterns of the pillbox antenna have been measured in the radiating near field using an outdoor range. Good agreement between measured and calculated patterns has been obtained.

Optimum directivity coverage of fan-beam antennas

Cellular and point-to-multipoint wireless communication systems use fan-beam antennas for sector coverage from the central station. The ratio of the azimuth-to-elevation half-power beamwidth typically ranges from two for sites requiring low-gain antenna values to 25 or greater for sites covering large cells. This article presents an approximate formula for the antenna directivity of the fan-beam antenna using two parameters to describe the azimuth pattern shape, and two parameters for the elevation pattern. The directivity formula presented includes minor lobes. A variation of the fan-beam directivity formula is presented for the omnidirectional antenna. The directivity formula presented in this note is developed from separable-pattern functions, and uses a pattern-shape parameter in addition to the half-power-beamwidth value.

Application of fan-beam antennas for60 GHz indoor wireless communication

The application of fan-beam antennas in high-speed indoor wireless communication systems operating in the 60 GHz band is investigated. The effects of line-of-sight obstruction as well as antenna pointing deviation on the power link budget are experimentally studied in a typical laboratory environment. The results are contrasted with those obtained with alternative antenna configurations.

Recovery of a Spacecraft from Sun-Safe Mode Using a Fanbeam Antenna

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

An analysis of a rotating, range-gated, fanbeam spaceborne scatterometer concept

A new simple scatterometer concept combines the advantages of both the fixed, multiple beam, sidelooking radar such as AMI-Wind (ERS-1/2) and NSCAT (ADEOS), and the conically scanning pencil-beam radar such as SeaWinds. A wide, fanbeam antenna is rotated around a vertical axis with a slow rotation rate. For a satellite at an altitude of 725 km, the antenna footprint sweeps a circular donut of 1500 km diameter. Such a slow conical scan combined with the motion of the satellite at /spl ap/7 km/s ground speed results in highly overlapping successive sweeps such that an image pixel is revisited up to 10-11 times during an overpass. The pixels in the radial direction are resolved by range-gating the radar echo. Depending on the across-track position of the imaged pixel, the measurement acquisitions during an overpass consist of a set of /spl sigma//spl deg/ at different combinations of the azimuth and incident angles. A preliminary optimization of the system resulted in a C-band radar concept with a 15 km multiple-look spatial resolution and global coverage in two days. A sketch of the developed concept, preliminary system design, and predicted performance are described.

Proposal for a novel beam combination method for indoor high-speed wireless communication systems

A novel beam combination method for wide-band digital indoor communication systems such as wireless LANs and wireless ATMs is proposed. Crossed fan beams are used at the base station (BS) and personal stations (PSs). The beam combination method provides better transmission quality than the traditional pencil-beam combination and eliminates complex beam control in the BS. Maximum dispersion distributions in a transmission frequency bandwidth are calculated by a three-dimensional (3-D) indoor propagation delay simulation algorithm. A prototype fan-beam antenna for the PS is fabricated and measured at 20 GHz.

キネマティックGPSを用いた測高レーダの較正のための飛行実験

This paper deals with a flight experiment for calibrating the bias errors of the measurement system of a height finding radar. The radar, namely, the Navigation Accuracy Measurement System (NAMS), uses a vertically rotating fan beam antenna and estimates the height of an aircraft flying with a constant speed and altitude within the coverage of the beam. An aircraft (B99) equipped with GPS receivers was used for obtaining the GPS data on the aircraft position. A post processing for the GPS data obtained from the onboard receiver and those at a base station installed near the radar site was carried out using a kinematic positioning software called Flykin. The positions obtained from the radar and kinematic GPS processing (KGPS) were compared and the biases of the radar were estimated by the least square method. This paper proposes the method for estimating biases using KGPS data and examples of the results are shown briefly.