Conical Horn Research Articles

A novel method for cross‐polarization reduction of conical horns

AbstractIn this article, a new method for exciting the TM11 mode to symmetrize the radiation pattern and reduce the cross‐polarization level of the conical horn antennas is presented. The main idea of this paper is to excite TM11 mode with a frequency‐dependent phase difference relative to the TE11 mode in a manner that these modes appear in phase on the radiation aperture of the antenna in the desired frequency range of 8‐8.4 GHz. Finally, the performance of the TM11 exciter and horn antenna together were simulated and after reaching the predefined goals they were fabricated.

Uniform surface modification of polyethylene terephthalate (PET) by atmospheric pressure plasma jet with a horn-like nozzle

This work reports on surface modification of polyethylene terephthalate (PET) polymer by an atmospheric pressure plasma jet (APPJ) operated with argon. A distinguishable feature of this device is that it terminates with a conical horn-like nozzle. Three different nozzles diameters were employed with the purpose to obtain uniform surface modification over large area. Treatments in small 3D objects that fit inside the conical horn were also conducted. In this study, water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS) were performed to assess the samples wettability and the surface elemental composition, as well as, their radial distribution. Plasma-induced changes on the polymer surface morphology were evaluated by Atomic Force Microscopy (AFM). Electrical characterization of the plasma and investigation of the effect of the gas flow rate on the discharge power were carried out. After the plasma treatment PET surface became more hydrophilic over the entire area covered by the nozzle. This effect is caused by the incorporation of oxygen containing polar groups on the surface. It was also observed that depending on process parameters, the plasma treatment can extend even outside the area of the conical horn. The degree of surface modification depends on plasma dose while the treatment uniformity is determined mostly by the distance to the sample. Overall, a quite uniform surface modification was obtained over the entire area covered by the jet nozzle. Thus, the results suggest that by simply changing the jet geometry and choosing the right treatment parameters one can achieve a uniform treatment over an area whose size is determined by the horn diameter.

Design & Analysis of S-Band Right Hand Circularly Polarized Conical Horn Antenna for NavIC Receiver

In satellite communication systems the horn antennas are being used widely due to its robustness and capable to operate at frequencies which are very high. Here, the right hand circular polarized conical horn antenna is designed for S-band NavIC receiver. The waveguides and conical horn antenna dimensions are designed by using standard formulas and after that they are given to a simulation tool for the S band frequency. The performance parameters like return loss, radiation pattern, gain and directivity are considered for further analysis. In the circular waveguide from the TE11 mode conical horn antenna is to be designed into high gain and a good VSWR.

Gain and Bandwidth Enhancement of Tetracuspid-shaped DRA Mounted with Conical Horn

Abstract A novel Tetracuspid-shaped dielectric resonator antenna (DRA) mounted with conical horn is presented and investigated for broadband applications. The dielectric used for investigation is a ceramic composite material having a dielectric constant ( $\varepsilon_r$) of 12.9. Tetracuspid-shaped resonator geometry achieves a broadband impedance bandwidth of 70.9 % for |S11|<‒10 dB, ranging from 2 GHz to 4.2 GHz. Tetracuspid-shaped reduces the DRA volume by 78 % (without horn) as compared to conventional cylindrical DRA; with reduced volume of 14.4 cm3 which diminishes the cost and weight. Gain of proposed antenna is further enhanced up to 9.5 dBi in operating band by mounting a conical horn. Achieved average peak gain is ~7 dBi. Proposed antenna covers bands of different wireless communication systems like Wi-Max and WLAN (2.4 GHz, 2.5 GHz, 3.3 GHz and 3.5 GHz). The simulated results are validated by experimentally measured outcomes and these are well in agreement.

Loop Excitation of a Conical Horn

A Green’s function technique is developed for the full-wave analysis of a loop excited conical horn, considering all excited modes. The technique avoids the need for discretization of the horn antenna structure into several cascaded sections or the imposition of unknown currents over the entire horn surface, thus reducing the computational burden significantly. The aperture fields of the conical horn are investigated for varying horn lengths. Reflection effects at the aperture is found to be minimal for horn lengths over $5\lambda $ , corresponding to a horn aperture diameter of more than $2\lambda $ . Analytical expressions used to represent the aperture fields over the conical cap at the aperture are provided from which the radiation fields are derived to characterize the aperture radiation. It is observed that the loop excitation can be appropriately located relative to the horn apex to couple to appropriate modes to generate broadside or monopole-like pattern characteristics. Also, in addition to the simplicity of the feed configuration, the loop position can be properly selected to couple to multiple modes that has a significant impact on the pattern directivity and sidelobe levels. The developed technique is also used to rigorously evaluate and characterize the contribution of each mode at resonance.

Design of a dual-band radiation system for a complex magnetically insulated line oscillator

In this paper, a dual-band radiation system for a complex magnetically insulated line oscillator (MILO) is designed and investigated numerically. The radiation system comprises a coaxial plate-inserted mode converter, a power combiner and a conical horn antenna. The mode converter converts the coaxial TEM mode microwaves (1.775 GHz and 3.175 GHz) which are generated by the complex MILO into the coaxial TE11 mode microwaves, and then the coaxial TE11 mode microwaves are combined by the power combiner in a circular waveguide. Lastly, the microwaves are radiated by a conical horn antenna into the air. The gains of the dual-band radiation system are calculated to be 17.8 dB at 1.775 GHz and 18.9 dB at 3.175 GHz. The 3 dB beam widths are 20.5° in E-plane, 26.4° in H-plane at 1.775 GHz and 20.8° in E-plane, 15.1° in H-plane at 3.175 GHz. The power transmission efficiencies of the dual-band radiation system are 98.5% at 1.775 GHz and 95.7% at 3.175 GHz respectively. The power handling capacities of the dual-band radiation system are 4.2 GW at 1.775 GHz and 4.7 GW at 3.175 GHz, respectively.

Microwave conical horn antenna with dual circular polarization-Close-form design equations

In this article, we have proposed the closed form expressions for the optimized dimensions of different parts of the metallic stepped septum in a circular waveguide. Using these relations, a dual circularly polarized (CP) horn can be realized with good AR bandwidth, impedance bandwidth, and interport isolation. The relations are generalized for application at all frequency bands. Using these relations, horns have been designed and simulated at different frequency bands. Prototypes have been fabricated at some frequency bands and are experimentally validated. This design yields impedance bandwidth (S11 ≤ −10 dB) of about 18%, AR bandwidth more than 15%, and interport isolation about 24 dB at the band center. Experimental data for the Ka-band prototype are provided in detail. At the design frequency, the measured axial rations are <1 dB revealing cross-polar discrimination over 25 dB.

An assessment of a conical horn waveguide to represent the human eardrum

This study examined a model of the acoustic input impedance of the ear that includes a waveguide model of the eardrum. The eardrum was modeled as a lossless conical-horn with rigid walls. The ear canal was modeled as a one-dimensional lossy transmission line. The output impedance of the eardrum, the middle ear, and the cochlea, was modeled as a circuit analog. The model was fit to acoustic input impedance data from human ears using a nonlinear least-squares fit. The impact of a conical-horn shape for the eardrum was quantified by comparison with the eardrum modeled as a near-flat surface. The model provided a good match to the data over the frequency range examined. A conical-horn model of the human eardrum provided gain at high frequencies, most notably above 1–2 kHz, with a broader middle-ear frequency response. This finding may suggest that eardrum shape plays an important role in sound transmission to the cochlea.

The conceptual design of high temporal resolution HCN interferometry for atmospheric pressure air plasmas

A heterodyne interferometer operating at the frequency f = 890 GHz has been designed for measuring the electron density of atmospheric pressure air plasmas, it's density range is from 1015 to 3×1019 m−3 and the pressure range is from 1 Pa to 20 kPa. The system is configured as a Mach\ obreakdash-Zehnder type interferometer. The light source is hydrogen cyanide (HCN) laser with a wavelength of 337 μm, which is suitable for the high density area, 1018 to 3×1019 m−3, of atmospheric pressure air plasmas. The HCN laser power is up to 100 mW. The intermediate frequency, shifted by 500 kHz, is generated by the Doppler shift with a high speed rotating grating (HSRG), which is installed in a vacuum vessel with gas pressure less than 1 Pa. With the HSRG, the temporal resolution of the HCN interferometry can reach to 2 μs. Beam path analysis based on Gaussian optics is used in the design of the optical system. The VDI planar-diode Integrated Conical Horn Fundamental Mixers optimized for high sensitivity—typical RF responsivity is around 900 V/W —will be used in the HCN interferometry. The detailed optical design and opto-mechanical design for the HCN interferometry are presented.

Longitudinally Composite Ultrasonic Solid Conical Horns with Adjustable Vibrational Performance

Longitudinally Composite Ultrasonic Solid Conical Horns with Adjustable Vibrational Performance

A 24 GHz Dual-Polarized and Robust Dielectric Rod Antenna

This paper presents a robust and easy manufacturable dual linear-polarized dielectric waveguide antenna (DRA) for the 24 GHz industrial, scientific, and medical band. Dual-polarized operation is achieved by utilizing a square metal waveguide and a conical horn for exciting the surface wave on a tapered dielectric rod. In order to couple a signal into the square waveguide, an innovative dual-polarized, aperture-coupled microstrip-to-waveguide transition is shown. Additionally, two kinds of radomes, i.e., a foam radome and a half-wave wall monolithic radome are presented to protect the DRA. The antenna achieves a 10 dB bandwidth of 1.7 GHz and a gain of 11.5 dB including losses caused by the transitions and connectors. The sidelobe level and the cross-polarization level are lower than −25 and −26 dB, respectively. Designs and measurement results of all components are described in detail in this paper.

Step frequency continuous wave RADAR sensor for level measurement of molten solids

Step frequency continuous wave (SFCW) RAdio Detection And Ranging (RADAR) sensor is proposed for non-contact measurement of the absolute level of molten solids in industrial furnaces. A conical horn is optimized for operation over 10–16 GHz in mono-static configuration for level measurement. The absolute distance of a stationary target was measured with 3 mm accuracy using the SFCW RADAR sensor in mono-static mode. Stable measurements were recorded for 4.35 h in a furnace at 450 °C. Level measurements of molten glass and aluminum in 1100 °C furnace indicate the feasibility of industrial-level gauging.

A new Late Miocene ovibovine-like bovid (Bovidae, Mammalia) from the Kassandra Peninsula (Chalkidiki, Northern Greece) and implications to the phylogeography of the group

A new Late Miocene bovid, Urmiatherium kassandriensis sp. nov., from Northern Greece is described. The material comes from the Fourka locality in the Kassandra Peninsula (Chalkidiki), and the included fauna is estimated to be of Vallesian age. The two preserved crania represent a medium-sized taxon with short, conical horn cores, a flat cranial roof (consisting of the posterior part of the frontals, parietal and occipital), thick and porous frontals and pneumatized short parietals, an extremely thick basioccipital with voluminous posterior tuberosities and accessory articular facets for the atlas. The specialized atlanto-occipital joint recalls Pleistocene and extant ovibovines, but the braincase structure as a whole and the horn core features closely match Late Miocene ovibovine-like taxa, especially Plesiaddax and even more Urmiatherium. Nevertheless, the Kassandra bovid differs from representatives of both genera in the simpler horn core morphology and external brain anatomy. Urmiatherium is known to appear first in China and Iran at about 7.8 Ma, whereas its westernmost appearance on Samos Island (Greece) is dated much later. The presence of Urmiatherium kassandriensis sp. nov. in N. Greece suggests a farther west and earlier (Vallesian at least) first appearance of the genus. This would justify a basic geographic and phylogenetic split of Urmiatherium into two main Turolian lineages: a central-eastern Asian one leading to the sister species U. polaki and U. intermedium and a western one leading to U. rugosifrons.

Design of 77 GHz half‐shorted horn antenna with metamaterial lens

AbstractIn this article, we present new two‐layer and light‐weighted grid wire metamaterial lens implemented on the aperture of conical horn antenna to manufacture a small‐sized and high‐performance antenna applied in 77 GHz radar system. It could shorten half‐length of horn antenna without deteriorating its gain, broadband, and matching performance. The metamaterial lens is made by thin copper sheet whose thickness is only 0.1 mm. The measured results show that the metamaterial lens enhances the gain about 3.4 dB (@77 GHz) than short ordinary antenna with the same physical dimension, which equals to double its length. The high‐performance and small‐sized bulk make it suitable for 77 GHz radar system.

3D field-shaping lens using all-dielectric gradient refractive index materials

A novel three-dimensional (3D) optical lens structure for electromagnetic field shaping based on spatial light transformation method is proposed at microwave frequencies. The lens is capable of transforming cylindrical wavefronts into planar ones, and generating a directive emission. Such manipulation is simulated and analysed by solving Laplace’s equation, and the deformation of the medium during the transformation is theoretically described in detail. The two-dimensional (2D) design method producing quasi-isotropic parameters is further extended to a potential 3D realization with all-dielectric gradient refractive index metamaterials. Numerical full-wave simulations are performed on both 2D and 3D models to verify the functionality and broadband characteristics of the calculated lens. Far-field radiation patterns and near-field distributions demonstrate a highly radiated directive beam when the lens is applied to a conical horn antenna.

Rapid Design of Deployable Antennas for CubeSats: A tool to help designers compare and select antenna topologies

A novel methodology for the rapid preliminary design of deployable antennas for CubeSats is proposed in this article. It uses a graphical representation of antenna performance, consisting of a set of plots of different performance metrics against antenna geometry parameters. Coupled electromagnetic and structural design problems are addressed easily, enabling the rapid and direct comparison of different antenna concepts. This approach is demonstrated for a case study at ultrahigh frequency (UHF), comparing the performance of a dipole, a helix, a conical horn, and a conical log spiral (CLS), all based on dual-matrix composite deployable structures. The initial design space of antenna geometries is reduced by two orders of magnitude to a set of constraintsatisfying designs. A graphical user interface implementing the approach is presented, and the accuracy of the method is briefly addressed.

Электродинамическая модель оценки электромагнитной безопасности поля излучения конического рупора

Электродинамическая модель оценки электромагнитной безопасности поля излучения конического рупора

Ka-Band Lightweight High-Efficiency Wideband 3D Printed Reflector Antenna

This paper presents a lightweight, cost-efficient, wideband, and high-gain 3D printed parabolic reflector antenna in the Ka-band. A 10 λ reflector is printed with polylactic acid- (PLA-) based material that is a biodegradable type of plastic, preferred in 3D printing. The reflecting surface is made up of multiple stacked layers of copper tape, thick enough to function as a reflecting surface (which is found 4 mm). A conical horn is used for the incident field. A center-fed method has been used to converge the energy in the broadside direction. The proposed antenna results measured a gain of 27.8 dBi, a side lobe level (SLL) of −22 dB, and a maximum of 61.2% aperture efficiency (at 30 GHz). A near-field analysis in terms of amplitude and phase has also been presented which authenticates the accurate spherical to planar wavefront transformation in the scattered field.

Toroidal Plasma Lens Antenna

This letter proposes a novel toroidal plasma lens with circular polarization, as an alternative solution for electronic warfare antennas. The aim of the proposed solution is to reduce the antenna profile and the radar cross section, thus minimizing the probability of target detection. The results compare the performance of the proposed antenna to a conical horn and to a spherical/elliptical lens. The toroidal plasma lens achieved equivalent gain, with reduced antenna profile and reduced near-field backscattering from the plasma toroid, thus maximizing the true power delivered to the far-field region.

Design of a High-Isolation 35/94-GHz Dual-Frequency Orthogonal-Polarization Cassegrain Antenna

In this letter, a novel high-isolation 35/94-GHz dual-frequency orthogonal Cassegrain antenna is designed. The antenna consists of a D = 800 mm main reflector, a subreflector, and a dual-band orthogonal-polarization feed. In order to get similar feed horn's E – H radiation patterns and similar phase center positions at the dual frequencies separately, the dual-mode conical horn is designed in the feed. For obtaining a high isolation, a three-order low-pass filter is designed in the Ka-band waveguide feed port. The measured antenna gains are 43.6 and 51.3 dBi, and the sidelobe levels are −27.5 and −26.5 dB at 35 and 94 GHz, respectively. The isolation between the two ports is −61.0 dB in the Ka-band and −63.5 dB in the W-band. The proposed antenna is a suitable candidate for a dual-band radar system.