Jianqiong Zhang

A GW Level High-Power Radial Line Helical Array Antenna

High-power radial line helical array antenna is a novel antenna developed to realize directional radiation of high-power microwaves. This antenna directly accepts an azimuthally symmetric output of a high-power microwave source and radiates circularly polarized microwave with a boresight peak. It has a high efficiency, a compact structure, and a notable power-handling capacity. Starting from its fundamental design theory, an antenna prototype consisting of 48 elements is proposed. Numerical simulation and experimental measurement are accomplished for the prototype. In the range of 3.7-4.1 GHz, the experimental result shows an antenna VSWR of below 1.2, an antenna gain of over 23.2 dB, an aperture efficiency of more than 65%, and an antenna axial ratio of below 1.6 dB. In addition, the high-power experiment proves that this antenna has a power-handling capacity of more than 1 GW.

16-Element Single-Layer Rectangular Radial Line Helical Array Antenna for High-Power Applications

A 16-element single-layer rectangular radial line helical array antenna is proposed and investigated. In the single-layer radial line feed system, two new probes are used to satisfy the coupling requirement. The sequential rotation technique is introduced to improve the axial ratio of the antenna. An antenna prototype is designed, simulated, and measured. The results indicate its advantages of high aperture efficiency, low input VSWR, and favorable axial ratio. The field distributions of this antenna are analyzed through simulation, which prove its advantage of high power-handling capacity. This array is also used to form an 8 × 8 array antenna, which demonstrates its ability to be used as a subarray.

The high-power radial line helical circular array antenna: Theory and development

The High-power radial line helical circular array antenna is a novel antenna developed to realize directional radiation of high-power microwaves. This kind of antenna uses short helical antenna as its radiation element, and uses radial line as its feeding waveguide. New probes that can be fixed directly on the radial waveguide (without the need for medium support) are used to couple energy from the radial waveguide to the radiation elements. The design theory of this antenna is proposed, the pertinent designs are derived, and the performances of three principal antenna prototypes, including 3-circle 36-element double-layer array, 3-circle 36-element single-layer array and 3-circle 48-element double-layer array, are presented. The simulated and measured results prove that this kind of antenna has a high efficiency, a compact structure, and a notable power-handling capacity.

A HIGH-POWER LOW-LOSS MULTIPORT RADIAL WAVEGUIDE POWER DIVIDER

A 16-way radial waveguide power divider with the characteristics of low insertion loss and high power handling capacity is investigated. Its design theory and basic structure are proposed at flrst; a power divider with the center frequency of 4.0GHz is designed, fabricated, and measured. Good agreement between the simulated and measured results is found for the proposed power divider. The measured 15-dB return loss bandwidth is demonstrated to be 440MHz and the measured 0.5-dB insertion loss bandwidth is demonstrated to be 540MHz. The power handling capacity of the proposed power divider is analyzed through simulation, and the results prove its usability in high power applications.

High Power 12-Element Triangular-Grid Rectangular Radial Line Helical Array Antenna

A 12-element triangular-grid rectangular radial line helical array antenna is proposed and investigated. The major characteristic of this antenna is that its radiation elements are arranged in triangular-grid, which is helpful to reducing the number of elements demanded for a certain antenna aperture and grating lobe suppression capacity. The radiation element is optimized to facilitate the manufacture. The feed system with six different groups of output ports is designed to obtain equal- amplitude output using three kinds of probes. An antenna prototype with the center frequency of 2.856 GHz is simulated and measured. In the range of 2.75-2.95 GHz, the experimental result shows an antenna VSWR below 1.2, an antenna gain over 16.3 dB, and an aperture efficiency more than 80%. The field distributions of this antenna are analyzed through simulation, which prove its advantage of high power-handling capacity. Its ability to be used as a sub-array is also demonstrated by forming a 48-element array antenna.

Double - Layer Radial Line Helical Array Antenna with Rectangular Aperture

A double-layer radial line helical array antenna with rectangular aperture is proposed. With rectangular aperture, the antenna can be assembled to form high gain antennas. The use of double-layer feed system ensures an equal-amplitude in-phase feed for all elements in an expected frequency band, which can improve antenna gain and aperture e-ciency. This paper presents its design concept, derives pertinent design and performance, and a 16-element array antenna is simulated and measured. The experimental results show that in the range of 3.8GHz to 4.2GHz, the antenna gain is over 17.7dB, aperture e-ciency over 82%, antenna sidelobe level below i12:0dB, antenna axial ratio below 3.2dB, and antenna VSWR below 1.52.

Four-way radial waveguide power divider with high power-handling capacity

Abstract In this paper, a novel four-way radial waveguide power divider with low insertion loss and high power-handling capacity is proposed. This power divider consists of an input coaxial waveguide, a central probe, a radial waveguide, four equispaced identical coupling probes, four equispaced identical adjusting posts and four output coaxial waveguides. The novel coupling probes and the adjusting posts are used to realize favorable uniform power division. A power divider with the center frequency of 4.1 GHz is designed, fabricated and measured. Good agreement between simulation and experiment is noted. The measured 15 dB return-loss bandwidth of the power divider is about 600 MHz. The measured 0.5 dB insertion loss bandwidth is wider than 700 MHz. The differences and isolations between the output ports are also discussed. The power-handling capacity of the power divider is analyzed through simulation, and the result proves its usability in high power applications.

Design of the 4-element rectangle radial line helical array antenna

Radial line helical array antenna is a novel antenna which realizes the directional radiation of circularly polarized high power microwave. This paper put forward a rectangular radial line helical array antenna (subarray), which uses short helical antenna as its radiation element, each helix is excited by the energy coupled by a probe from a radial line waveguide, especially it can be simply assembled a number of subarray to a high gain array antenna. In this paper, a L-shaped coupling probe is advanced, which are suited to high power application. The 4-element helices and probes are arranged on the upper plate of the radial line waveguide to form a rectangular antenna array with uniform square lattice. The paper presents the fundamental conception of operation, derives pertinent design and performance, and gives the numerical simulation result on antenna prototype. In addition, numerical simulation result shows that: the subarray is easy to achieve uniform amplitude and phase distributions. At center frequency, the antenna gain is about 12.57dB with axial ratio 1.55. In the range of 3.6GHz to 4.0GHz, the antenna gain and aperture efficiency are over 11.6dB and 90%, antenna axial ratio and reflectance are below 1.55 and 0.2, respectively.

Mode matching analysis of metallic plates in radial waveguide

Mode matching method is a useful way to analyze the mode characteristics during the section change of the waveguide. By applying this method to the radial waveguide and solving specific problems due to the radial transmission of electromagnetic wave, a calculating method in radial waveguide based on mode matching is presented. The scattering characteristic of metallic plates in radial waveguide is calculated, and the calculated result is proved qualitatively by simulation, which indicates the validity of this method.

A compact TE11-TM01 mode converter for HPM application

ABSTRACT A mode converter using circular waveguide has been investigated. The conversion is based on the structure of two orthogonal circular waveguide and there is a tuning screw placed at the short-end used to increase conversion efficiency and bandwidth. The results show that the converter is not only compact but also wide-band, which realize a bandwidth of 11∼14 GHz for conversion efficiency over 90%. The simulated power capacity is 798 MW at 12.7 GHz under vacuum condition.