Rectangular Horn Research Articles

3-D Printed Monolithic GRIN Dielectric-Loaded Double-Ridged Horn Antennas

Monolithic integration of 3-D printed gradient index (GRIN) dielectric loading with a double-ridged rectangular horn standard gain horn (SGH) and its impact on antenna performance are demonstrated. Results show that the GRIN loaded horns improve sidelobe levels (SLLs) and beam symmetry, while maintaining good impedance match and relatively high radiation efficiency over more than an octave bandwidth from 7.5 to 18 GHz. Moreover, they have low weight and show good robustness to fabrication imperfections. This work paves the way for seamless integration of complex wideband antennas in 3-D printed systems such as unmanned aerial vehicles (UAVs).

Creating a Gain Improvement Technique for a Horn Antenna using a Metamaterial Structure Inserted with a Thin Dielectric Sheet

Objective: This paper proposed a new technique for the metamaterial on the structure of the curved-woodpile Electromagnetic Band Gap (EBG) inserted with a dielectric slab for gain improvement in a conventional rectangular horn antenna. Methods: We described a method to enhance gain by transferring the electromagnetic fields from the aperture of a horn through the EBG structure. Furthermore, we present the design procedures for inserting a dielectric slab into two layers of the EBG structure for the reduction of distance between the horn and proposed EBG structure. Results and Conclusions: Such a proposed technique not only has the advantage of decreasing the total length of the antenna system but also providing higher gain with a low profile structure. This idea has been verified by both simulation and experimental results. The fabricated antenna can achieve 23.9 dBi of gain or higher than the gain, which is obtained using a conventional rectangular horn antenna at around 7 dBi at an operating frequency of 10 GHz. It is apparent that a good qualitative agreement between the measurements and simulations was achieved.

Optimum design of double ridge horn antennas with general cross‐section

In this study, an analytical method is proposed for design of double-ridged horn (DRH) antenna, which is based on impedance matching of the structure by the method of least squares (MLSs). New basis functions are used for the MLS to obtain optimum impedance functions for the realisation of maximum matching. The resultant reflection coefficients are compared with available methods. The proposed optimum synthesis method is applicable to the arbitrarily tapered DRH antenna with a general cross-section. As two applications, the proposed method is used for the design of linear and non-linear flares of DRH antennas with rectangular and elliptical cross-sections for operation in the frequency band 2–18 GHz. For the proof of concept, a prototype model of the proposed rectangular horn antenna is fabricated and measured in the frequency domain.

Dual-Band Dual-Linear-to-Circular Polarization Converter in Transmission Mode Application to <inline-formula> <tex-math notation="LaTeX">$K/Ka$ </tex-math> </inline-formula>-Band Satellite Communications

Many wireless communication applications such as satellite communications use circularly polarized (CP) signals, with the requirement for easy switching of the polarization sense between uplink and downlink. Specifically, in satellite communications, the trend is also to move to higher frequencies and integrate the receiving and transmitting antennas in one dual-band terminal. However, these simultaneous demands make the design and fabrication of the composing parts very challenging. We propose, here, a dual-band dual-linear polarization (LP)-to-CP converter that works in the transmission mode. The working principle of this polarizer is explained through an example for Ka-band satellite communications at 19.7–20.2 and 29.5–30 GHz. The LP-to-CP converter is a single panel composed of identical unit cells with a thickness of only 1.05 mm and a size of 5.3 mm $\times5.3$ mm. Due to its operation in the transmission mode, the polarizer can be combined with a simple dual-band dual-LP antenna to obtain the desired dual-band dual-CP single antenna. However, the unique property of this polarizer is yet the fact that it converts a given LP wave, e.g., x-polarization, to orthogonal CP waves at the two nonadjacent frequency bands, e.g., left-handed CP at lower band and right-handed CP at higher band. The polarizer is tested both with 20 and 30 GHz LP rectangular horns to illuminate a dual-band transmit array (TA) to obtain wide-angle steering of CP beams. The performance of the polarizer and its association with the TA is evaluated through simulation and measurements. We also present design guidelines for this type of polarizer.

Dual-Polarized Antenna Fed by a Quasi-Planar Orthomode Transducer With Different Radiation Patterns

In this paper, a millimeter-wave (mmW) dual-polarized antenna with different radiation patterns is proposed. The antenna consists of a planar lens, a rectangular horn antenna, and a quasi-planar orthomode transducer (OMT) which provides two polarizations. The quasi-planar OMT with good isolation is based on the substrate-integrated waveguide technology, and it can be co-planar integrated with other mmW planar circuits seamlessly. A planar lens is designed on a quad-layered substrate and it has the priority of polarization selective that only takes effect on the horizontal polarization (H-pol). Consequently, high gain with the narrow beam in H-pol and low gain with wide beam in vertical polarization (V-pol) are achieved. To verify the idea, the proposed antenna is designed, fabricated, and measured, achieving a high gain of 26.4 dBi in H-pol, and a wide beamwidth in V-pol. This kind of antennas can be applied to make a balance between the range and coverage in communication and radar applications. In addition, the proposed quasi-planar OMT has potential applications in fifth-generation mmW wireless communications.

A terahertz spatial power combiner based on 2D periodic hole-shaped grating using nongradient optimization method

ABSTRACTThis paper describes a terahertz spatial power combiner based on a periodic hole-shaped hologram for a two-dimensional (2D) horn antenna array. The combiner consists of a 2D array of rectangular horns, a dielectric hole-shaped hologram, a focusing reflector, and a receiving horn antenna. The hologram is realized as 2D periodic holes, which transforms the beams of the antenna array into a pseudoplane wave. The transformed wave is coupled into a rectangular output horn antenna by a parabolic reflector with a shaped surface relief. The field distribution on the receiving plane can be obtained by using a nongradient optimization method to optimize the reflector surface. An example operating at 300 GHz is described. The theoretical power combining efficiency is about 63.1%. The computed field distribution agrees well with the result obtained using the commercial software FEKO Suite.

Improved finite‐range gain formula for open‐ended rectangular waveguides and pyramidal horns

A finite-range gain expression given in the literature for open-ended rectangular waveguide is improved by employing the gain correction factor approach of Polk by returning to the original aperture field integrals. In these, the phase factor is approximated to third order and the amplitude factor to second order with distance from the antenna from which series approximations have been obtained to simplify computation of gain. Comparison with measured and/or simulated results shows that the closed-form solution is as accurate as a previous expression beyond the far-field boundary, and is more accurate at shorter distances. The formulation is extended to pyramidal horns where results obtained compare well with experiment.

Microwave Applicator for Thermal Treatment of Bituminous Surfaces

A comprehensive study of a microwave applicator for thermal treatment of bituminous surface is presented in this paper. The applicator consists of a customized rectangular waveguide horn surrounded with a hexagonal lattice of cylindrical chokes preventing hazardous leakage of microwave radiation beyond an exposure area. Electromagnetic simulations based on a finite-difference time-domain method are applied in a design process and afterward, the prototype is manufactured with the aid of computerized numerical control machining. Eventually, the applicator is applied for experimental testing of microwave-assisted thermal treatment of the trial bituminous surface, which demonstrates that microwave energy may be a viable alternative to typical thermal bonding techniques used in road construction and maintenance processes if appropriate conditions are met.

Ultra-thin metasurface microwave flat lens for broadband applications.

We demonstrate a metasurface-based ultrathin flat lens operating at microwave frequencies. A series of subwavelength metallic split-ring resonators, which are sandwiched between two cross-polarized metallic gratings, are defined to obtain a radially symmetric parabolic phase distribution, covering relative phase differences ranging from 0 to 2.5π radians to create a lens. The tri-layer lens exhibits focusing/collimating of broadband microwaves from 7.0 to 10.0 GHz, with a gain enhancement of 17 dBi at a central wavelength 9.0 GHz while fed by a rectangular horn antenna. The measured focal length agrees reasonably well with design, achieving a 3 dB directionality <4.5° and confirming high-quality beam collimation along the propagation direction. The demonstrated metasurface flat lens enables light-weight, low-cost, and easily deployable flat transceivers for microwave communication, detection, and imaging applications.

Quasi-optical analysis of a far-infrared spatio-spectral space interferometer concept

FISICA (Far-Infrared Space Interferometer Critical Assessment) was a three year study of a far-infrared spatio-spectral double-Fourier interferometer concept. One of the aims of the FISICA study was to set-out a baseline optical design for such a system, and to use a model of the system to simulate realistic telescope beams for use with an end-to-end instrument simulator. This paper describes a two-telescope (and hub) baseline optical design that fulfils the requirements of the FISICA science case, while minimising the optical mass of the system. A number of different modelling techniques were required for the analysis: fast approximate simulation tools such as ray tracing and Gaussian beam methods were employed for initial analysis, with GRASP physical optics used for higher accuracy in the final analysis. Results are shown for the predicted far-field patterns of the telescope primary mirrors under illumination by smooth walled rectangular feed horns. Far-field patterns for both on-axis and off-axis detectors are presented and discussed.

Self-deformation in a direct current driven helium jet micro discharge

We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode.

Design and Calibration of a Compact Quasi-Optical System for Material Characterization in Millimeter/Submillimeter Wave Domain

A compact quasi-optical setup based on conventional rectangular horn antennas and two symmetrical parabolic mirrors is designed to provide a plane wave on the material under test. To measure the scattering parameters at millimeter/submillimeter wavelengths, a commercial vector network analyzer and waveguide frequency extension units are used. The calibration of the system is performed with a simple practical deembedding process to determine the S-parameters on the material surface without using high-cost micrometer positioners. A reliable extraction method is presented to derive the material permittivity and calculate the errors and uncertainties as direct functions of the sample and setup geometry and their physical characteristics. Several materials are measured and the complex permittivity is presented together with a detailed uncertainty budget.

DESIGN OF A PYRAMIDAL HORN ANTENNA WITH LOW E-PLANE SIDELOBES USING TRANSFORMATION OPTICS

Transformation optics is a convenient way to control the pattern of electromagnetic fields. In this paper, using a novel transformation, we propose the design procedure of a horn antenna having low backlobe and sidelobe levels in its E-plane. By applying conformal transformation, the rectangular horn proposed in this paper can be realized with isotropic materials. This proposed antenna can be easily implemented by both ordinary dielectric materials and isotropic graded refractive index (GRIN) materials. In the first proposed design, in addition to the isotropy, homogeneity is furthermore introduced into the horn, and only four kinds of isotropic materials are required throughout. In the second design, it is demonstrated that the designed structure can also be implemented by graded photonic crystals (GPCs) operating in metamaterial regime. They have low loss as well as broad frequency band and are easy to implement. Simulation results are presented to validate the design approach.

UTD-PO Radiation Pattern Analysis of Rectangular Horn Antennas With Cylindrical Corrugations

The calculation of the E-plane radiation pattern of corrugated E-plane rectangular horn antennas in which the corrugations have a cylindrical shape is hereby performed through a method based on a hybrid uniform theory of diffraction-physical optics (UTD-PO) formulation. The proposed method is successfully validated through comparison with the application of an electric field integral equation (EFIE) solved by the method of moments (MoM), with the UTD-PO analysis showing more computational efficiency than the EFIE and other numerical techniques based on the full discretization of the geometry. On the other hand, the use of cylindrical corrugations instead of the traditional rectangular-shaped corrugations is analyzed and, in view of the results, the former may offer a series of advantages in comparison to the latter, such as narrower main lobes as well as better fabrication-related aspects.

Efficiency Improvement for Conventional Rectangular Horn Antenna by Using EBG Technique

Efficiency Improvement for Conventional Rectangular Horn Antenna by Using EBG Technique

Radiation Characteristics of a Square Pyramidal Horn Antenna with Tapered DielectricE-Plane Boundary Walls Loaded With Periodic Conducting Strips

A rectangular pyramidal horn antenna fabricated with tapered dielectric E-plane boundary walls whose inner surface is periodically loaded with thin conducting strips is investigated. For better impedance matching, at the throat region of the horn antenna, 3 cm portion is metallised. The radiation characteristics of this horn antenna are compared with that of an identical conventional horn antenna with conducting E-plane boundary walls. Considerable improvement in the E-plane radiation characteristics is observed. As H-plane boundary walls are not modified, no change in the H-plane radiation characteristics is observed. However,the conventional horn antenna shows slightly better impedance matching than the test horn antenna.

0.34-THz Wireless Link Based on High-Order Modulation for Future Wireless Local Area Network Applications

This paper presents a 0.34-THz wireless link for future wireless local area networks (WLANs), which is based on high order 16-quadrature amplitude modulation (16QAM). The system adopts super heterodyne transceivers and parallel digital signal-processing techniques. The 0.34-THz transceiver consists of a 0.34-THz subharmonic mixer, a 0.34-THz waveguide H-ladder bandpass filter, and a 0.17-THz multiplier chain. Two 0.34-THz Cassegrain antennas with 48.4-dBi gain have been developed to extend the transmission distance. Based on a 32-way parallel signal processing, we have successfully realized the 3-Gb/s, 16QAM real-time modulator and demodulator. The measured data indicate that the lowest bit error rate of the 0.34-THz, 3-Gb/s data link is 1.784×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> over a 50.0-m line-of-sight channel. The maximum received energy per bit to noise power spectral density ratio ( Eb/N0) is 23.8 dB, while the output power of transmitter is -17.5 dBm and the noise temperature of receiver is 5227 K. In addition, this paper presents a 0.34-THz WLAN prototype based on IEEE 802.11b/g protocol. The WLAN prototype, which consists of an access point and two terminal nodes, achieves a transmission data rate of 6.536 Mb/s over 1.15 m by using rectangular horn antennas.

Design of a Circular Polarized Horn Antenna with an Anisotropic Metamaterial Slab

In this paper, a novel design of a circular polarized horn antenna is presented. An anisotropic metamaterial slab with metal periodic structures printed on a substrate is designed and its constitutive parameters and S parameters are analyzed. It shows that the metamaterial is anisotropic and can turn a linearly polarized wave to a circular polarized one. Then a novel horn antenna composed of a conventional rectangular horn antenna and the metamaterial slab is fabricated and measured. The results show that the novel horn antenna radiates a left handed circular polarized wave with an axis ratio below 3 dB at 16 GHz, and its gain and radiation pattern are the same as those of the conventional rectangular horn antenna.

Design and Simulation of High Gain X-Band Horn Antenna for Calibration

For calibrating the X-band equipment in the TT&amp;C ship based on wireless communication, we design a high gain rectangular horn antenna. Through analysing the theory of structure, the antenna’s preliminary size parameter is estimated and it is simulated based on HFSS. The antenna structure parameters are obtained after parameters optimization. The results of simulation indicate that the design of antenna indexes meet the needs completely. The structure of antenna is compact and it easy to process. The simulation method in the paper may also be referred to other related design.

E‐plane radiation pattern analysis of rectangular horn antennas with V‐shaped corrugations by UTD‐PO formulation

A new method for the calculation of the radiation pattern of corrugated E‐plane rectangular horn antennas based on a hybrid uniform theory of diffraction‐physical optics (UTD‐PO) formulation is presented. The method, which allows for the analysis of horns in which V‐shaped corrugations have been considered, has been validated with numerical data obtained through the application of both an electric field integral equation (EFIE) solved by the method of moments (MoM) and the finite element method (FEM)‐based full‐wave electromagnetic analysis software, HFSS. In this sense, the proposed solution is mathematically less complex and computationally more efficient than existing techniques.