Diffraction by an arbitrary subreflector: GTD solution

Lee, Shung-Wu; Cramer, P. W.; Woo, K.; Rahmat‐Samii, Y.

doi:10.1109/tap.1979.1142096

Cited by 38 publications

(3 citation statements)

References 15 publications

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“…To fulfill these required milestones, a Gaussian-profiled dielectric radome has been designed, which has the clear advantages of gain enhancement and beamwidth suppression in the E-plane without affecting the reflection coefficient and radiation characteristics. The dielectric enclosure is used for the sealing of the 10-slot SWA aperture to hold the vacuum or pressurized to enhance E-field breakdown strength [34][35][36]. The dielectric radome is based on the Gaussian function and can be defined as:…”

Section: Design Of Dielectric Gaussian Radomementioning

confidence: 99%

An Efficient Slotted Waveguide Antenna System Integrated with Inside-Grooves and Modified Gaussian Slot Distribution

et al. 2022

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In this work, an efficient slotted waveguide antenna (SWA) system is designed for S-band high power microwave (HPM) applications. The designed SWA comprises of 10-slot elements placed on the broad wall of SWA with a modified Gaussian distribution (MGD), integrated with two inside-grooves and a Gaussian dielectric radome of high-density polyethylene (HDPE) material. The inside-grooves are introduced to suppress the surface current on the waveguide, which results in high gain as well as sidelobe level (SLL) reduction in the E-plane. The MGD controls the SLLs, and the unique Gaussian profile shape radome offers constant radiation characteristics. The proposed antenna system, within existing size constraints, offers a high gain of 20.1 dBi in conjunction with a high-power handling capability of greater than 100 MW. The designed SWA system has compact dimensions of 8.46λ0× 1.38λ0× 1.50λ0, with SLLs of −20 dB and −22 dB in the H- and E-plane, respectively. The HPM antenna system, radiating at 3 GHz, is fabricated on aluminium material using the milling process. The simulated SWA system has good agreement with measured results. Moreover, the proposed SWA system offers clear advantages in terms of its robustness, design simplicity, high power handling capability, and high gain.

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Section: Design Of Dielectric Gaussian Radomementioning

confidence: 99%

An Efficient Slotted Waveguide Antenna System Integrated with Inside-Grooves and Modified Gaussian Slot Distribution

et al. 2022

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“…From the conclusion of differential geometry, principal curvatures of reflected wavefront 1 R1 , 1 R2 are eigenvalues of curvature matrix (Lee et al 1979)…”

Section: Phase Matchingmentioning

confidence: 99%

Deformation measurement by single spherical near-field intensity measurement for large reflector antenna

Wang

Yao

et al. 2021

Res. Astron. Astrophys.

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This paper presents a new method to obtain the deformation distribution on the main reflector of an antenna only by measuring the electric intensity on a spherical surface with the focal point as the center of the sphere, regardless of phase. Combining the differential geometry theory with geometric optics method, this paper has derived a deformation-intensity equation to relate the surface deformation to the intensity distribution of a spherical near-field directly. Based on the finite difference method (FDM) and Gauss-Seidel iteration, deformation has been calculated from intensity simulated by geometrical optics (GO) and physical optics (PO) methods, respectively, with relatively small errors, which prove the effectiveness of the equation proposed in this paper. By means of this method, it is possible to measure the deformation only by scanning the electric intensity of a single hemispherical near-field whose area is only about 1/15 of the aperture. The measurement only needs a plane wave at any frequency as the incident wave, which means that both the signals from the outer space satellite and the far-field artificial beacon could be used as the sources. The scanning can be realized no matter what attitude and elevation angle the antenna is in because the size and angle of the hemisphere are changeable.

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“…All of these losses are summarized in a diffraction loss term. They have been analyzed numerically and the loss terms are given in a tabulated form in Lee et al (1979) andMilligan (2005). For our antenna parameters the diffraction loss is about 0.22 dB.…”

Section: Antenna Efficiencymentioning

confidence: 99%

1.2 m Shielded Cassegrain Antenna for Close-Packed Radio Interferometer

Koch¹,

Raffin²,

Huang³

et al. 2011

Publications of the Astronomical Society of the Pacific

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Interferometric millimeter observations of the cosmic microwave background and clusters of galaxies with arcmin resolutions require antenna arrays with short spacings. Having all antennas co-mounted on a single steerable platform sets limits to the overall weight. A 25 kg lightweight novel carbon-fiber design for a 1.2 m diameter Cassegrain antenna is presented. The finite element analysis predicts excellent structural behavior under gravity, wind and thermal load. The primary and secondary mirror surfaces are aluminum coated with a thin TiO 2 top layer for protection. A low beam sidelobe level is achieved with a Gaussian feed illumination pattern with edge taper, designed based on feedhorn antenna simulations and verified in a far field beam pattern measurement. A shielding baffle reduces inter-antenna coupling to below ∼ -135 dB. The overall antenna efficiency, including a series of efficiency factors, is estimated to be around 60%, with major losses coming from the feed spillover and secondary blocking. With this new antenna, a detection rate of about 50 clusters per year is anticipated in a 13-element array operation.

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Diffraction by an arbitrary subreflector: GTD solution

Cited by 38 publications

References 15 publications

An Efficient Slotted Waveguide Antenna System Integrated with Inside-Grooves and Modified Gaussian Slot Distribution

An Efficient Slotted Waveguide Antenna System Integrated with Inside-Grooves and Modified Gaussian Slot Distribution

Deformation measurement by single spherical near-field intensity measurement for large reflector antenna

1.2 m Shielded Cassegrain Antenna for Close-Packed Radio Interferometer

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