The quadrifilar helix antenna

The characteristics of the quadrifilar helix antenna [1] and [2], a broad-band high-gain device, are described in detail. Experimental data on beam patterns, impedance, and axial ratio are given for both the circularly polarized quadrifilar helix antenna (QHA) and the linearly polarized counterwound quadrifilar helix antenna (CQHA). Bandwidths in excess of 5:1 are obtained. The low frequency behavior is discussed. Computation of the QHA characteristics by moment methods [3] is described and computed data on beam patterns and current distributions are given.     

Compact printed quadrifilar helical antenna

A method to reduce the axial length of a printed quadrifilar helix antenna (PQHA) is presented. Using meandering line techniques, the axial length of the conventional PQHA is reduced by 33%, making it practical to be implemented on a handheld terminal.     

Optimization of the quadrifilar helix antenna

Experimental data on the quadrifilar helix antenna have led to an optimum pitch angle and an optimum ground plane size. The ground plane size is an important parameter, and its optimum diameter is about three times the diameter of the helix. The optimum pitch angle is about35deg. Beam patterns and ellipticity data are given for the optimized model. Bandwidth is about 4:1.     

Printed half-wavelength quadrifilar helix antenna for GPS marineapplications

The authors present a new printed half-wavelength quadrifilar helix antenna using infinite microstrip feeding baluns. This new volute antenna allows low cost, ease of mass production, and substantially improved elevation pattern coverage and circular polarisation properties. Experimental results show that the printed volute antenna has a 3dB beamwidth of >145° and a front-back ratio of >20dB     

Printed quadrifilar resonant helix antenna with integrated feedingnetwork

A compact printed quadrifilar resonant helix antenna with integrated feeding system is presented. This antenna displays small size, low cost, hemispherical radiation coverage, large bandwidth, good efficiency and good axial ratio     

四臂螺旋天线设计与实现研究

文章介绍了四臂螺旋天线的结构特性和几何尺寸、螺旋模式;设计了一种小型四臂螺旋天线,采用巴伦平衡结构的自相移馈电方式馈电,将螺旋臂印刷在高介电常数陶瓷柱上,减小了天线的体积,通过仿真分析,该种天线具有良好的宽波束和圆极化特性。     

Effect of helix turn angle on the performance of a half wavelength quadrifilar antenna

The impedance and radiation pattern parameters of a /spl lambda//2 quadrifilar helix antenna (QHA) with turn angles in the range 0/spl deg/ to 235/spl deg/ are analyzed. It is shown that by selecting the helix turn angle to satisfy the minimum bandwidth and beamwidth requirements, an improved electrical performance and a reduction in the physical size of the antenna is obtained. This is demonstrated by comparing the performance of a conventional half turn QHA with structures having a smaller pitch length. The computed results are validated by experimental data at L-band.     

A study of the quadrifilar helix antenna for Global PositioningSystem (GPS) applications

An analytic model for computing the radiation properties of the quadrifilar helix volute antenna is discussed and various design considerations for GPS applications are presented. The effects of modifying the antenna length and diameter on the antenna amplitude and phase performance are presented, and using the antenna for dual-frequency operation is discussed. The effects of phase imbalances are presented and compared with measured pattern anomalies     

A band-switched resonant quadrifilar helix

A technique is presented that can be used to multiple tune a resonant quadrifilar helix. An example of a design is given with an antenna that covers two frequency ranges: 250-270 MHz and 290-310 MHz.     

陶瓷介质加载四臂螺旋天线

微波陶瓷介质加载的四臂螺旋天线,体积显著减小,而性能基本不变,是应用在小型化卫星导航定位设备中的理想天线。在介绍四臂螺旋天线结构组成、工作原理和发展过程的基础上,讨论了陶瓷介质加载四臂螺旋天线的特性和制作方法,并指出了存在问题和今后的研究方向。     

Synthesis of printed quadrifilar helical antenna

A method to reduce the axial length of a printed quadrifilar helical antenna by optimisation algorithm while maintaining the different features (radiation coverage, axial ratio, impedance) is investigated. The synthesis is performed on the antenna pitch angle     

Impedance matching arrangement for quadrifilar helix antennas

A ring arrangement of four wires near to the excitation point of a quadrifilar helix antenna can be used to achieve an impedance match. The matching technique is applicable to resonant, fractional turn antennas, and to shaped conical beam backfire mode antennas     

Broadband tapered printed quadrifilar helical antenna

A method to increase the bandwidth of a printed quadrifilar helical antenna is investigated. The wire width is modified all along the antenna without changing the other geometrical parameters. A new broadband tapered printed quadrifilar helical antenna is realised and measured     

Shaped-conical radiation pattern performance of the backfire quadrifilar helix

It is shown that shaped-conical radiation patterns can be realized by extending the resonant fractional-turn quadrifilar helix to an integral number of turns, i.e., the radiated energy can be concentrated into a cone with the gain decreasing from a maximum at the edge of the cone to a local minimum at the center. This pattern shape is near optimum for many spacecraft communications and navigation applications, providing approximately 3 dB improvement over cardioid shaped patterns.     

Broadband compact printed quadrifilar helical antenna for ballooncampaign applications

A new printed quadrifilar helical antenna design is investigated. The concept of this antenna combines a size reduction technique with a method to increase bandwidth. This new antenna is realised and measured     

The aperture-coupled helix antenna

Planar arrays with circular polarization are frequently used in a large variety of applications. The typical choices are quite limited when size, bandwidth, efficiency, and simplicity are important. The paper proposes a new type of radiating element that seems to cope with all these requirements. The well-known helix antenna is fed by a slot in the ground plane of a microstrip-feeding line. The measurements show a successful combination of the excellent characteristics of the helix antenna, with the simplicity of fabrication of the microstrip networks     

Miniaturised dielectrically-loaded quadrifilar antenna for globalpositioning system (GPS)

A new approach to designing a handset antenna for satellite applications is reported. It is based on precise control of the phasing between two bifilar helices, giving accurate resonant frequency position and radiation pattern volute. Results show an antenna with a gain of -2 dBi, 19 dB discrimination between the right and left hand circular polarisations and an axial ratio less than 1 dB. The front-to-back ratio is 24 dB. A return loss of 14.6 dB is also measured     

Compact band-notched ultra-wideband antenna

A novel band-notched ultra-wideband antenna having small dimensions (12.7 times 22 times 1.6 mm) is proposed. With the use of a modified ground plane, a microstrip feed with bevel, and parallel dual patches, the proposed antenna has very wide impedance bandwidth measured at 8.18 GHz (2.97 to 11.15 GHz, defined by 2:1 VSWR). By inserting slits in the ground plane, a band-notched frequency of 5.12 to 5.88 GHz is achieved. The transmission loss and group delay are measured and discussed.     

Compact broadband microstrip antenna

The development of a compact broadband microstrip antenna configuration is presented. The system uses a number of parasitic elements which are gas-coupled to a driven patch. The enhancement of bandwidth does not cause deterioration of the radiation pattern of the system.