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This paper presents an axially displaced monopulse Cassegrain antenna with low profile at W band. The antenna configuration consists of a hyperboloid as the subreflector, a combination of series of paraboloids with different focal length as the main reflector to keep low profile, and is fed by five horns. Closed-form design equations are derived using the principles of geometrical optics. CST is implemented...
Two tracking antennas based on quasi-optical techniques for inter-satellite communications at sub-millimeter wavelengths are presented. One is scanning antenna and the other is monopulse antenna. The structures of the two antennas and their working principles are described in detail. The simulated and measured data are presented. Both antennas show good performances at THz frequencies.
In this paper, a low sidelobe slotted waveguide monopulse antenna array working at Ka-band is proposed. The design procedure of radiating element parameter extraction and the synthesis of planar array is introduced. A 28 × 28 circular slotted waveguide antenna array is presented. The simulated bandwidth (return loss less than −20 dB) of antenna array is 1.48% and the corresponding isolations between...
The coupling of aperture-coupled microstrip antenna with a backed substrate integrated cavity (SIC) is related to the SIC shape. To improve the coupling and try to reduce the size of the aperture, a method is presented in this paper by changing the shape of cavity. Due to the increase of the coupling, the bandwidth of the antenna will be enhanced with a relative smaller aperture, which is benefit...
In this paper, we generate the zero-order Bessel beam at W band using a diagonal horn, a convex lens, and an axicon. The generated Bessel beam has smaller beam spot size than the Gaussian beam. Some imaging experiments with the generated zero-order Bessel beam are done. The results show that the millimeter wave imaging with the zero-order Bessel beam can get an imaging resolution of about 1mm to 2mm.
A broadband proximity-coupled stacked patches antenna with backed cavity which has the low sensitivity of fabrication errors is presented. By adding two copper strips on the reverse side of the feed-line, the influence of the relative displacement between the feed layers and the cavity on the bandwidth performance of the antenna can be reduced. With this method, the antenna can bear the relatively...
In this paper, a kind of microstrip Yagi antenna whose central frequency is 5.2GHz is designed, because of its planar and end-fire characteristics, it is sticked on a cylindrical supporter to form a conformal monopulse antenna; the performance of antenna is simulated in electromagnetic simulation software HFSS.
In this paper, two compact antipodal Vivaldi antennas (AVA) with improved Radiation Characteristics are presented. U-typed tapered slot edge (U-TSE) AVA and comb-shaped AVA with U-TSE are simulated and optimized. The −10-dB reflection coefficient bandwidth of comb-shaped AVA spans from 2.3 GHz to 18 GHz (7.83∼1) and covers 15.7 GHz, while the bandwidth of conventional AVA which has the same dimensions...
In the present paper we propose a new way to generate Bessel-type beams in the terahertz rang. According to the technique of pattern synthesis of antenna array, a uniform circular antenna array (UCA) is designed optimally to produce quasi-Bessel or Bessel-Gauss pattern. These beams possess a long depth of field and therefore have many important applications in the quasi-optic and/or terahertz fields...
In this paper, a new structure of infrared imaging system consisted of a diffractive primary mirror, sub-mirror and emendation lenses are proposed. The focal plane field distribution of the imaging system is calculated to show the imaging performance, and the imaging performance is optimized by using ray tracing method and Stratton-Chu diffractive integral formula. The system has a better performance...
Two novel types of continuous Fresnel Diffraction Mirror (FDM) are designed and applied to a double-reflector monopulse antenna at Ka band. One FDM is a metal reflector, which the profile consists of a seris of hyperboloids, and the other is a metal reflector filled with dielectric, which will alter the eccentricity of the hyperboloids and has higher diffraction efficiency. These two monopulse antennas...
Bessel beams are diffraction-free beams and have many novel properties. In this paper, we designed the optical path to generate the Bessel beams in millimeter wave band using three elements. A dielectric hybrid-mode horn is designed to generate a Gaussian beam, a lens is used to transform the Gaussian beam, and an axicon is placed behind the transform lens to convert the Gaussian beam into a Bessel...
LTCC technology (Low temperature co-fired ceramic) provides an effective way to decrease the volume of the system and increase the reliability of the system. A kind of vertical transition, depicted in this paper, is used widely in the T/R module. The structure and operation principle of T/R module are discussed. The design results in a small size (40.9×15×5.7mm3) and low weight (10.1g). The measures...
A logarithmic axicon can extend the depth of field (DOF). A comparison of diffractive/refractive behaviors is made between the forward and backward logarithmic axicons when illuminated by a uniform plane wave at millimeter wavelengths. To determine accurately their diffractive/refractive fields, a rigorous electromagnetic analysis method is adopted in the present paper. The comparison results and...
This paper presents a design of suspended stripline dual-band filter, in which, inter-digitally coupled resonator pairs act as dual-mode resonators to realize the two passbands. Parallel coupling is adopted between adjacent dual-mode resonators and the input/output couplings are realized using tapped lines of certain height. A prototype dual-band filter with two bands located at 2.4 and 5.2GHz is...
In this paper, a five-layer sandwich radome wall, which can work at 14GHz and 94GHz simultaneously, is proposed. The transmittances of the radome wall with different frequencies and different incident angles are presented. The intersection losses of the dual-frequency radome with different scanning angles are simulated by the ray tracing method. The losses are less than 0.2dB at 14GHz and less than...
By matching the complex phase along the boundary, we analyze the reflection and refraction of Gaussian beams at the surface of an elliptical hyperboloid between media of different refractive indices. In our work, we extend the interface from a hyperboloid of revolution to an elliptical hyperboloid; and also expand the angle of incidence from the usual case of normal incidence to arbitrary angles of...
An ellipsoid of revolution is an important focusing element. By matching the complex phase, the formulas are deduced for reflection of Gaussian beams at the surface of an ellipsoid of revolution in this paper. The analysis is extended to an arbitrary angle of incidence, and the derived results are transformed into ABCD ray matrices. By making use of these matrices, we can handily design and estimate...
A novel wideband aperture-coupled patch antenna is presented in this paper. The antenna has a cavity of dielectric backed configuration, which can avoid the back radiation of the aperture and suppress the excitation and propagation of a parallel plate mode between the up and below ground plane. The antenna is fed by an inhomogeneous stripline, which is convenient for the vertical connection between...
A homogeneous dielectric spherical lens circular polarization multi-beam antenna working at millimeter-wave band is simulated. To achieve a compact, firm structure and ease of assemblage, the antenna lens and feeds are leaned against each other. The single-feed lens with different permittivity and radius is simulated. The material and radius of the lens is selected based on the foregoing simulating...
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