Axial-mode elliptical helical antenna with variable pitch angle

F. Yang; P. Zhang; C.-J. Guo; J.-D. Xu

doi:10.1049/el:20081818

Modifications on the axial-mode helical antenna

Proceedings of the IEEE ◽

10.1109/proc.1967.5583 ◽

1967 ◽

Vol 55 (4) ◽

pp. 558-559 ◽

Cited By ~ 27

Author(s):

D.J. Angelakos ◽

D. Kajfez

Keyword(s):

Helical Antenna ◽

Axial Mode

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Improved Low-Profile Helical Antenna Design for INMARSAT Applications

International Journal of Antennas and Propagation ◽

10.1155/2012/829371 ◽

2012 ◽

Vol 2012 ◽

pp. 1-5 ◽

Cited By ~ 4

Author(s):

Shiqiang Fu ◽

Yuan Cao ◽

Yue Zhou ◽

Shaojun Fang

Keyword(s):

Pitch Angle ◽

Satellite Communication ◽

Design Method ◽

Impedance Matching ◽

Axial Ratio ◽

Antenna Element ◽

Helical Antenna ◽

Copper Strip ◽

Antenna Structure ◽

Low Profile

A new low-profile variable pitch angle cylindrical helical antenna employing a copper strip as impedance transformer is proposed in this paper. Under the circumstance of a limited antenna height, the circular polarization performance of the antenna has been enhanced by changing the pitch angle and the input impedance matching has been improved by adjusting the copper strip match stub. The design method of the proposed antenna is given. The optimal antenna structure for INMARSAT application has been fabricated and measured. The measured results show that in the whole maritime satellite communication work band the VSWR is less than 1.2, its antenna gain is higher than 9 dBi, and the axial ratio is lower than 2.5 dB. The experimental results have a good agreement with the simulations. The proposed antenna is compact and easy tuning. It provides a promising antenna element for maritime satellite communication applications.

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Modeling, Simulation and Analysis of the Characteristics of the Non-conventional Vertical Axis Wind Turbine with Variable Pitch Angle that Allows to Establish Different Control Strategies

Industrial and Robotic Systems - Mechanisms and Machine Science ◽

10.1007/978-3-030-45402-9_12 ◽

2020 ◽

pp. 109-118

Author(s):

Jesús García-Barrera ◽

Jorge Díaz-Salgado ◽

Oliver M. Huerta-Chávez ◽

Rafael Sánchez-López

Keyword(s):

Wind Turbine ◽

Pitch Angle ◽

Control Strategies ◽

Vertical Axis ◽

Vertical Axis Wind Turbine ◽

Variable Pitch ◽

Modeling Simulation

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Short helical antenna with extremely small pitch angle

Microwave and Optical Technology Letters ◽

10.1002/mop.22054 ◽

2006 ◽

Vol 49 (1) ◽

pp. 17-19

Author(s):

Ze-Hai Wu ◽

Edward K. N. Yung

Keyword(s):

Pitch Angle ◽

Helical Antenna ◽

Small Pitch

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A Review on Pitch Angle Control Strategy of Variable Pitch Wind Turbines

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.772.744 ◽

2013 ◽

Vol 772 ◽

pp. 744-748 ◽

Cited By ~ 1

Author(s):

Chao Tan ◽

Hong Hua Wang

Keyword(s):

Wind Turbines ◽

Pitch Angle ◽

Sliding Mode ◽

Integrated Control ◽

Variable Structure ◽

Network Control ◽

Neural Network Control ◽

Variable Pitch ◽

Structure Control ◽

Sliding Mode Variable Structure

This paper summarizes the development process of wind turbines control technology, reviews the application of traditional control, sliding mode variable structure control, H robust control, adaptive control, fuzzy control, artificial neural network control and integrated control in the pitch angle control system of variable pitch wind turbines, points out its present situation and development prospect.

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Recent Developments of the Mechanism of the Hydraulic Variable-pitch Aircraft Propeller

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1950_163_015_02 ◽

1950 ◽

Vol 163 (1) ◽

pp. 111-124

Author(s):

H. L. Milner

Keyword(s):

Power Plant ◽

Gas Turbine ◽

Pitch Angle ◽

Variable Pitch ◽

Jet Propulsion ◽

Recent Developments ◽

Gas Turbine Power Plant ◽

Centrifugal Action ◽

Engine Type ◽

Blade Element

After briefly outlining the main features of the variable-pitch propeller, this paper proceeds to describe the development of the piston-engined hydraulically operated propeller as a brake, both in the air and on the ground. Examples are given of the magnitude of the braking effort of a propeller when windmilling under controlled conditions and when in reverse pitch under power. The advent of the gas turbine, originally intended as a means of jet propulsion, opened up a new field of application for the variable-pitch propeller and this application with its attendant problems and their solution is discussed. Three types of gas-turbine power plant, together with the appropriate propeller arrangements are reviewed. These are: (1) the direct-connected turbine; (2) the compound-compressor turbine; and (3) the free-propeller turbine. Each engine requires a plurality of controllable pitch stops peculiar to the engine type, and these are described. The necessity for powerful controlling forces in maintaining the blades at any given pitch angle is made clear by consideration of the centrifugal action of a blade element, and an example of the magnitude of these forces is given for a specific case. Brief reference is made to developments in blade bearings, followed by an illustrated description of a contra-rotating propeller.

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